UNIVERSITY OF CALIFORNIA LIBRARY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW -a)V i B 1^3^ 5to-10,'22 Digitized by the Internet Archive in 2007 with funding from IVIicrosoft Corporation http://www.archive.org/details/autonnotivetradetOOkunsrich AUTOMOTIVE TRADE TRAINING AUTOMOTIVE TRADE TRAINING RAY F. KUNS Principal Automotive Trade School Cincinnati, Ohio BRUCE- MILWAUKEE THE BRUCE PUBLISHING COMPANY MILWAUKEE. WISCONSiN Copyright 1922 THE BRUCE PUBLISHING COMPANY Printed in the United States of America INTRODUCTION As may be gathered from its title, this book has been worked out with one main idea in mind, namely, to present a clear-cut and concise explanation of the automotive-trades theory and practice, to all who are seeking information m this field. Another purpose hardly less important was to bring all this desirable information under one cover. Just as the mechanic must work with the tools at hand, he is very often required to do the job with the information at hand The various trades are so interrelated that it has not seemed wise to try to treat each one separately. The automotive trades vary widely in content. The automobile repair man makes the usual repairs and installs the new parts neces- sary to the machinery of the automobile. The automotive electrician handles the repairs and new installation of the electrical equipment. The storage battery man recharges and repairs the battery equip- ment. The vulcanizer installs new and repairs old tire equipment The radiator repair man cares for the radiator and other sheet metal repairs. Other phases of the automotive trades work are likewise special fields. However, it is frequently the case that one concern or even one man will be found doing all varieties or several combinations of automotive trades work. The owner is frequently desirous of doing the repair work on his car. With these facts in mind the author has attempted to organize the vast amount of information and to arrange the essential processes so as to give correct trade practice. Correct trade practice is very largely a fixed matter. Not all mechanics use the same methods, but the results arrived at must not vary. For this reason the theory of design and the construction of the parts or units under repair must be understood. Repairs must be carefully made in order to be right. The author is not particularly concerned as to whether the repairs are made by the owner of the car, or by the repair man to whom the owner has entrusted the work. His concern is rather in helping each to do the work in a manner which will result in a safe, satisfactory and permanent job. In other words, this volume is dedicated to the teaching of high standards of -workmanship. No attempt has been made to show methods of repair and over- haul on every make of automobile, but every type of equipment has been treated. The description of design and operation is given in the first part of each chapter and the usual line of repair work for that type of equipment appears in the latter part of the chapter. To learn what information is available on any type of equipment, the index should be consulted with reference to both job sheets and general information. The author is desirous of acknowledging the splendid help re- ceived from his associates on the faculty of the Cincinnati Automotive Trade School. Each one deserves commendation for his help in his own particular line: Mr. E. O. Bathgate on chassis; Messrs. Frank Buerkle and William Schatz on engines ; Mr. Frank Bechtold on service ; Mr. Fred Schuster on battery work ; Mr. Chas. Shields on vulcanizing; Messrs. Floyd E. Hauss, Roy E. Cahall, Fred Schaeper- klaus and Walter von Schlichten on starting, lighting and ignition. Acknowledgment is also due to the following manufacturers of automotive apparatus and equipment for their splendid co-operation: Akron-Williams Co., Akron, O. The Allen Motor Car Company, Columbus, Ohio. American Bosch Magneto Corp., Detroit, Mich. Apperson Bros. Automobile Co., Kokomo, Ind. Atwater Kent Manufacturing Co., Philadel- phia, Pa. The Borg & Beck Co., Chicago, 111. The Buda Co., Harvey, 111. Buffalo Forge Co., Buffalo, N. Y. Buick Motor Co., Flint, Mich. Byrne, Kingston & Co., Kokomo, Ind. Cadillac Motor Car Co., Detroit, Mich. Chandler Motor Car Co., Cleveland, Ohio Cincinnati Storage Battery Co., Cincinnati, Ohio. Cole Motor Car Co., Indianapolis, Ind. Connecticut Telephone & Electric Co., Meri- den, Conn. Continental Motors Corp., Detroit, Mich. Dodge Bros., Detroit, Mich. Eisemann Magneto Corp., Brooklyn, N. Y. Dyneto Electric Corp., Syracuse, N. Y. The Electric Storage Battery Co., Philadel- phia, Pa. Essex Motors, Detroit, Mich. Ford Motor Co., Detroit, Mich. Franklin Automobile Co., Syracuse, N. Y. Gemmer Manufacturing Co., Detroit, Mich. General Electric Co., Schenectady, N. Y. The Goodyear Tire & Rubber Co., Akron, Ohio. Gray & Davis, Inc., Boston, Mass. Greenfield Tap & Die Corp., Greenfield, Mass. The Haynes Automobile Co., Kokomo, Ind. Hudson Motor Car Co., Detroit, Mich. The K-V/ Ignition Co., Cleveland, Ohio. The Kelly-Springfield Motor Truck Co., Springfield. Ohio. King Motor Car Co., Detroit, Mich. The Leece-Neville Co., Cleveland, Ohio. The Lavine Gear Co., Milwaukee, Wis. Maxwell Motor Sales Corp., Detroit, Mich. The Nash Motors Co., Kenosha, Wis. National Lamp Works, Cleveland, Ohio. National Motor Car & Vehicle Corp., In- dianapolis, Ind. Nordyke & Marmon Co., Indianapolis, Ind. North East Electric Co., Rochester. N. Y. Oakland Motor Car Co., Pontiac, Mich. Oxweld-Acetylene Co., Chicago, 111. Packard Motor Car Co., Detroit, Mich. The Park Drop Forge Co., Cleveland, Ohio. The Peerless Motor Car Co., Cleveland, Ohio. The Pierce-Arrow Motor Car Co., Buffalo, N. Y. The Pierce Governor Co., Anderson, Ind. Remy Electric Div., General Motors Co., Anderson, Ind. Reo Motor Car Co., Lansing, Mich. Republic Motor Truck Co., Alma, Mich. Rochester Motors Co., Inc., Rochester, N. Y. Ross Gear & Tool Co., Lafayette, Ind. The Simms Magneto Co., East Orange, N. J. Splitdorf Electrical Co., Newark, N. J. Standard Steel Car Co., Pittsburgh, Pa. Stearns-Knight Motor Car Co., Cleveland, Ohio. Stromberg Motor Devices Co., Chicago, 111. The Studebaker Corp., South Bend, Ind. Stutz Motor Car Co., Indianapolis, Ind. The Tillotson Manufacturing Co., Toledo, Ohio. Thermoid Rubber Co., Trenton, N. J. The Timken-Detroit Axle Co., Detroit, Mich. Torbensen Axle Co., Cleveland, Ohio. The Timken Roller Bearing Co., Canton, Ohio. Wagner Electric Mfg. Co., St. Louis, Mo. Weaver Mfg. Co., Springfield, 111. Westinghouse Electric & Mfg. Co., Spring- field, Mass. Weston Electrical Instrument Co., Newark, N. J. The Wheeler-Schebler Carburetor Co., In- dianapolis, Ind. Willard Storage Battery Co., Cleveland, Ohio. Willys-Overland, Inc., Toledo, Ohio. The Zenith Carburetor Co., Detroit, Mich. TABLE OF CONTENTS CHAPTER 1 PAGE FRAMES AND SPRINGS— Frames— Springs— Radius Rods— Hotch- kiss Drive— Springs; Quarter Elliptic. Semi-Elliptic, Three-quarter Elliptic, Full Elliptic. Cantilever " 9-19 JOBS— 1— Tightening Spring Clips. 2— Adjusting Shackle Bolt. 3— Lubricating Spring Shackles. 4— Graphiting Spring Leaves. 5— Spring Overhaul. 6 — Straightening Car Frame 14-9 CHAPTER 2 STEERING GEARS AND FRONT AXLES— Planetary Steering Gear— Worm and Gear— Worm and Sector— Screw and Nut- Pinion and Sector — Front Axle Types — Axle Repair Work — Front Axle Design — Camber — Toe-In — Castering Effect — Steering Knuckle Arm Design 20-39 JOBS — 7 — Testing and Re-Aligning Front Wheels. 8 — Overhaul Ford Front Radius Rod. 9 — Overhaul Ford Front Wheels and Bearings. 10 — Tightening Up Ford Steering Gear. 11 — Overhauling and Re- bushing Ford Front Axle. 12 — Ford Steering Wheel Inspection and Lubrication. 13 — Adjusting and Lubricating Timken Front Wheel Bearings. 14 — Replacing Front Wheel Spindle Cones or Races. 15 — Replacing Wheel Bearing Cups. 16 — Straightening Damaged Front Axles. 17 — Replacing Steering Knuckle Body. 18 — Steering Gear Lubrication. 19 — Adjusting Steering Gears. 20 — Overhauling Drag Link 30-9 CHAPTER 3 REAR AXLES AND BRAKES— Live Axles— Plain Live— Floating: Semi, Three-quarter, Full — Live Axle Types of Drive — Bevel Gear and Pinion — Worm and Gear — Single Chain Drive — Dead Axle Drive — Internal Gear Drive — Double Reduction Gears — Differen- tial Construction — Rear Axle Trouble — Brakes: Braking Surface, Types of — Double Width Drum — Transmission — Brake Shoes — Brake Names — Brake Equalizers 40-72 JOBS — 21 — Adjusting External Brake Bands. 22— Adjusting Internal Expanding Brakes. 23 — Removing Grease and Oil from Brakes. 24— Relining Brakes. 25— Squeaking Brakes. 26— Adjusting Packard Twin Six Foot Brakes. 27— Adjusting Packard Twin Six Hand Brakes. 28— Split Housing Type Rear Axle Over- haul. 29— Overhauling Rear Axles of Single Piece Housing Construction. 30— Pulling Rear Wheels. 31— Adjusting Rear Axle Bevel and Pinion Gears. 32 — Remove Ford Rear Axle from Car. 33— Removing Universal from Axle. 34— Disassembling Ford Rear Axle. 34-a— Disassembling Ford Axle Differential Inspection and Reassembly ^^''^^ CHAPTER 4 CLUTCHES TRANSMISSIONS AND UNIVERSALS— Transmis- sion Units— Progressive— Friction Disk— Progressive Selective— Selective— Gear Ratio— Reverse Gear— Special Transmission Types —Transmission Troubles— Planetary Type Transmission— High Speed— Slow Speed— Reverse— Planetary Principle Explained— Speed: Slow— Reverse— High— Clutches: Types of. Cone, Plate, Disk. Grease and Oil Soaked— Neatsfoot Oil— Clutches: Grabbing Slipping, Wet— Universal Joints: Mechanical Principle— Angle of Drive— Type of Universals— Slip Joint— Fabric Unversals— Slip ^^^^^^ Joint Unnecessary Table of Contents — Continued PAGE JOBS — 35 — Removing Transmission Bands. 36 — Relining Ford Trans- mission Bands. 37— Adjusting Clutch on the Ford Car. 38— Over- hauling Ford Transmission. 39 — Standard Selective Type ot Trans- mission Overhaul. 40 — Standard Selective Type Transmission Care. 41 — Cleaning and Oiling an Exposed Cone Clutch. 42 — Applying a New Lining to a Cone Type Clutch. 43 — Relining a Disk or Plate Clutch. 44 — Adjusting a Borg and Beck Type Clutch. 45 — Clutch Collar Care. 46 — Universal Joint Lubrication. 47 — Universal Joint Overhaul 31-101 CHAPTER 5 POWER GENERATION AND POWER PLANTS, ENGINES— Power Generation — Names and Location of Engine Parts — Opera- tion: — Four Stroke Cycle — Cycles Completed per Minute 102-113 CHAPTER 6 FUNCTIONS OF ENGINE PARTS, TROUBLES AND REPAIRS — Crank Case — Cylinder Blocks and Cylinders — Engine Types — Cylinder Heads — Cylinder Care and Repair — Scored Cylinders — Frozen or Bursted Cylinders and Cylinder Heads — Crank Shafts: V Type Engines, Right and Left Hand, Six Cylinder Firing Order — Crank Shaft Troubles — Main Engine Bearings: Burned, Taking Up Main, Scraping in Main — Pistons — Material and Construction: Piston — Piston Clearance Allowance — Piston Rings — Leak Proof Rings — Pistons: Pins, Pin Fit — Securing the Piston Pin — Connect- ing Rods — Piston Pin Bearing — Rod Bearings — Cam Shaft — Two Valves Per Cylinder — Cam Shaft Drive — Valve Lifters — Valves — Valve Grinding — Rocker Arms — Knight Type Engines — Valve Timing — Valve Lap — Degrees Converted to Inches 114-174 JOBS — 48 — Fitting or Taking Up Connecting Rod Bearings. 49 — Scraping Connecting Rod Bearings. 50 — Fitting or Taking Up Main Engine Bearings. 51 — Scraping Main Engine Bearings. 52 — Polishing a Crank Shaft. 53 — Removing a Piston Pin of the Clamp Type. 53-a — Removing a Piston Pin Where the Bushing is in the Rod. 54 — Removing Piston Pin Bushing from Piston. 55 — Fitting Main Engine or Crank Shaft Bearings on Ford En- gine. 56 — Removing Engine from Ford Car. 57 — Adjusting Con- necting Rod Bearings on Ford Engine. 58 — Adjusting Valve Tap- pets. 59 — Methods of Removing Valves. 60 — Cleaning Valves. 61 — Grinding Valves. 62 — Reseating Valves. 63 — Timing Engines. 64 — Silent Chain Care. 65 — Removing a Cylinder Head. 66 — Replacing a Cylinder Head. 67 — Shellacing a Cylinder Head to Prevent Compression Leaks. 68 — Fitting New Piston Rings. 69 — Fitting New Pistons. 70 — Scraping Out Carbon 147-174 CHAPTER 7 OILING SYSTEMS — Full Splash — The Splash and Circulating- Forced Feed — Oil Pumps — Centrifugal or Rotating Vane Pump — Gear Pump — Plunger Type Pump — Indicating Devices — Sight Feed — Pressure Gauge — Caring for Oiling Systems — Oil Wears Out — Draining Oil — Troubles Due to Loss of Lubricating Qualities 175-192 JOBS — 71 — Cleaning Valve Stems and Guides and Piston Rings. 72 — General Instructions for Draining, Flushing and Refilling the En- gine Crank Case. 73 — Draining Oil From Packard Engine. 74 — Draining Oil from Hudson Engine. 75 — Cleaning an Oil Pan 189-192 CHAPTER 8 COOLING SYSTEMS— Air: Direct, Indirect— Water Cooling— Ther- mosiphon — Forced or Pump Circulation — Cooling System Care — Table of Contents — Continued PAGE Radiator Hose — Rubber Hose Troubles — Steaming Radiator — Radiator Mountings — Radiator Types — Tubular Type — Honeycomb or Cellular Type — Radiator Troubles — Types of Pumps — Pump Drive — Pump Troubles — Impeller Troubles — Cooling Fans — Fans: Care, Belt, Belt Adjusting — Changes of Temperature — Hood and Radiator Covers — Thermostat Control — Cooling Solutions — Non- Freezing Solutions Recommended — Overheated Motors — Boyce Motometer — Recognizing an Overheated Motor — Causes of Over- heating — Cooling the Overheated Engine — Filling an Overheated Engine — Non-Leak Solutions — Use of Cereal Preparations — Use of Liquid Preparations — Cleaning the Radiators 193-212 JOBS — 76 — Radiator Hose Care. 77 — Radiator Care. 78 — Removing a Radiator. 79 — Testing a Radiator for Leaks. 80 — Repairing a Radiator Leak with a Liquid Compound. 81 — Repairing a Radiator. 82 — Overhauling a Water Pump. 83 — Packing a Pump 208-213 CHAPTER 9 FUEL SYSTEMS— GASOLINE SYSTEMS— Gravity System— Pres- sure Feed — Vacuum Systems — Vacuum Tank — Stewart Vacuum Tank Parts — Principles of Carburetion: Liquids: Evaporating, Vola- tile — Heat — Vacuum — Spraying — Vaporization and Carburetion — Carburetor Design — Mixture: Explosive, Rich, Lean, Correct — Power — Venturi Tube — Nozzles — Gasoline Level — Float and Needle Valve — Float Troubles — Hot Air Stove — Hot Spot Mani- fold — Hot Water Heat — Exhaust Gas Jackets — Valves: Choke, Air, Adjusting Air — Adjusting Gasoline Nozzle — Throttle — Meter- ing Pins — Dash Pot — Fuel Systems: Plain Tube or Compound Nozzle Type, Air-Bled Jets 213-261 JOBS — 84 — Maxwell Carburetor. 85 — Packard Twin Six Carburetor. 86 — Tillotson Carburetor. 87 — Buick Carburetor. 88 — Kingston Carburetors — Models E and L. 89 — Rayfield Carburetor — Model L L 3 P. 90— Zenith Model L Plain Tube Compound Nozzle. 91— U. S. A. Standard Carburetor. 92— Cadillac Carburetor. 93— Stromberg Type M. Plain Tube Carburetors. 94 — The Stromberg Economizer. 95 — Dodge Carburetor. 96 — Ball and Ball Carburetor on King Cars. 97 — Hudson Supersix Carburetor. 98 — Pierce Arrow Carburetors. 99 — Schebler Dash Pot Air Valve Type Car- buretor. 100 — Carburetor Jobs 231-261 CHAPTER 10 FUNDAMENTAL ELECTRICAL DATA— Fundamental Principles — Source of Supply — Primary Battery — Secondary Battery — Mag- netic Lines of Force — Volts — Ampere — Ohm — Abbreviations or Symbols — Rating Electrical Power — Conductors — Non-Conductors or Insulators — Positive and Negative — Magnetism: Producing, Residual — Electro Magnets — Magnetic Poles — Magnetic Needle — Permanent Magnets — Magnetizing Steel for Permanency — The Molecular Theory — Saturation — Flux — Current Generation — Inter- nal Circuits — Induction — Armatures — Alternating Current — Direct Current — Commutator — Field — Current Control — Resistance Units — Fuses — Ground — Terminals and Poles — Direction of Induced Cur- rent — Solenoid — Condenser 262-285 CHAPTER 11 BATTERIES AND BATTERY CARE— Battery: Rating, Wear- Battery Construction: Battery Box — Cell Jars — Element— Plates: Table of Contents — Continued PAGE Positive, Negative — Active Material — Forming Plates — Separators — Cell Covers — Sealing Compound — Terminals and Straps — Bat- tery Care: Distilled Water — Battery Freezing — Testing Battery — Hydrometer Reading — Battery Charging While in Service — How To Recognize Battery Faults and Good and Damaged Battery Parts: Tests Which Indicate the Need of Opening the Battery — Sulphation — Overheated Plates — Damaged Separators — Frozen Plates — Judging the Value of Positive Plates — of Negative Plates — of Battery Case — of Jars and Jar Covers 286-324 JOBS — 101 — Opening Batteries for Inspection and Repair, 102 — Open- ing Willard Type "Sjwn" and "Sjrn" Battery. 103 — Reassem- bling the Battery. 104 — Element Repair and Inspection. 105 — Battery Shop Repair Methods. 106 — Making and Using a Test Outfit for Reading Voltage of Individual Cells with Closed Circuit. 107 — Cadmium Test. 108 — Grounded Battery. 109 — Removing and Resealing Exide Single Cover Type Covers. 110 — Opening Cin- cinnati Batteries. Ill — Making and Using Electrolyte. 112 — Charging a Repaired Battery. 113 — Caring for Batteries on Charge. 114 — Discharging a Battery. 115 — Caring for Batteries in Stor- age 300-324 CHAPTER 12 BATTERY IGNITION— Battery Ignition— Ignition Coil— Principle of Inducton Coil — Air Gap — Timer-Distributor — Spark Control — Switches — Condensers — Spark Timing — Vibration Coil Ignition: Principle of Vibrator — Timer — Timing the Spark 325-363 JOBS— 116— Atwater Kent Ignition System, Type CC. 117— Atwater Kent Ignition System K-2. 118 — North East Ignition System for Dodge Cars. Model O. 119 — Hudson Delco Ignition. 120 — Buick Delco Ignition. 121 — Pierce Arrow Double Distributor. 122 — Remy Ignition. 123 — Connecticut Ignition System. 124 — Wagner Ignition. 125 — Open Circuit in the Primary of the Ignition Coil. 126 — Open Circuit in the Secondary of the Ignition Coil. 127 — Open Circuit in Ignition Coils with Connected Windings. 128 — Short Circuit in the Primary of the Ignition Coil. 129 — Short Circuit in the Secondary Winding of the Ignition Coil. 130 — Ground Between Primary and Secondary Windings. 131 — Grounded Condenser. 132 — Short Circuited Condenser 337-363 CHAPTER 13 MAGNETO IGNITION— Magneto: Low Tension, H or Shuttle Type Low Tension — Inductor or Stationary Coil Type — Magnets — Pole Shoes — Non-Magnetic Metals — Armature — Slip Rings — Breaker Points — Transformer or Step-Up Coils — Contact Points in Series — Shunt Current Interruption Induction — Distributing High Tension Current from a Low Tension Magneto — Timing Spark on Low Tension Magnetos — Dual Ignition — Dual Ignition Switch — Push Button Starting — Low Frequency Inductor Type Magnetos — No Brushes — High Frequency Inductor Type Magnetos — Method of Generating — External Circuit on Ford Ignition — High Tension Magnetos: Types: High Tension Armature — Low Tension Circuit in Armature — High Tension Inductor 364-428 JOBS — 133 — K-W Low Tension Magneto Generator. 134 — K-W High Tension Magneto. 135 — Simms High Tension Magnetos. 136 — Bosch Magnetos, Du Types. 137 — Bosch High Tension Magneto B-4 and B-6 Types. 138 — Bosch High Tension Magnetos, Types Table of Contents — Continued PAGE ZR-4 and ZR-6. 139— Bosch NU-4 High Tension Magneto. 140— Bosch Dual Ignition Systems. 141 — Bosch . Duplex Ignition Sys- tem. 142 — Bosch Vibrating Duplex Ignition. 143 — Bosch Adjust- able Impulse Starter Coupling. 144— Eisemann High Tension Mag- neto G-4. 145 — Eisemann Magneto GA-4. 146 — Eisemann Dual Ignition. 147 — Dixie Magneto. Aero Models 448-449 and 648- 649. 148 — Dixie Magneto. Models 46, 462 and 246. 149 — The Splitdorf Impulse Starter. 149A — Splitdorf Adjustable Magneto Coupling 379-428 CHAPTER 14 STARTING MOTORS AND GENERATORS— Division of Duties- Regulating Generator Output — Inserted Resistance or Vibrating Relay Controller — Differential Compound Wound or Bucking Series Field — Third Brush Control — Cut-Out Relay 429-409 JOBS— 150— Wagner Starting Motor. 151— Buick Delco Motor Gen- erator. 152 — Dodge Northeast Motor Generator. 153 — Dyneto System as Used on the Franklin Car. 154 — Gray and Davis Gen- erator and Cut-Out. 155 — Gray and Davis Starting Motor Two Unit System. 156 — Hudson Delco Motor Generator Single Unit. 157 — Maxwell Simms System. 158 — Remy Oldsmobile. 159 — Wagner Generator. 160 — Instructions for the Use of Weston Model 441 Fault Finder. 161 — When the Starting Motor Does Not Operate. 162 — Open Circuit or High Resistance in Starting Switch. 163 — Open Circuit or High Resistance in Motor Field. 164 — Open Circuit or High Resistance in Motor Armature. 165 — High Resistance in Ground Connection. 166 — High Resistance in Battery Terminal. 167 — Short Circuit in Motor. 168 — Short Circuited Wiring to Starting Motor. 169 — Open Circuit in Wir- ing to Motor. 170 — Ground in the Motor Armature. 171 — Ground in the Motor Field. 172 — Grounded Brush Holders. 173 — Grounded Wiring to Motor. 174 — To Determine if Generator is Generating. 175 — Defective External Field Regulator. 176 — Mercury Tube Regulator. 177 — Series Field Regulator. 178 — Vibrating Regulator. 179 — Third Brush Regulation. 180 — Open Circuit in the Shunt Field of Generator. 181 — Open Circuit in the Armature of Generator. 182 — Shunt Field of Generator is Short Circuited. 183 — Short Circuit in the Armature of Generator. 184 — Grounded Armature or Field or Brush Holders on Generator. 185 — Short Circuit on Lines Between Generator and Battery. 186 — General Test for Relay Trouble. 187 — Open Circuit in the Voltage Coil of the Relay. 188 — Open Circuit in the Series Coil of the Relay. 189 — Fitting Brushes and Sanding Commutator. 190 — Undercutting Mica 441-489 CHAPTER 15 WIRING AND LIGHTING— Single Wire or Grounded System- Double Wire or Insulated Return — Wiring — Lighting Switches — Head Lights — Dash and Tail Lamps — Spot and Search Lights — Ammeters — Voltmeter — Junction and Fuse Boxes — Bulbs and Sockets — The Proper Lamp for the Service — Design of Lamps for Use with Storage Batteries— Design of Lamps for Use with Dry Cells — Design of Lamps for Use with Battery Generator Systems- Design of Lamps for Magneto Lighting Systems— Some Funda- mentals of Light Projection 490-517 Table of Contents — Concluded PAGE JOBS — 191 — Splicing Lighting Cables. 192 — Sweating or Burning on a Terminal. 193 — Attaching Wires to Lamp Sockets. 194 — In- stalling and Wiring an Ammeter. 195 — Polishing Lamp Reflectors. 196 — None of the Lights Operate. 197 — Head Lights or Side Lights Not Operating. 198 — Short Circuit in Branch of Lighting Circuit. 199 — One Headlight or One Side Light Not Operating. 200 — Tail Light or Cowl Light Not Operating. 201 — To Measure the Current Taken by the Lights 509-517 CHAPTER 16 TIRE CARE AND VULCANIZING— THE PRINCIPLES OF TIRE CONSTRUCTION— Tires: Fabric, Cord— Tire Care— Trueing Up Wheels — Tread Cuts — Inflation — Fabric Breaks — Tire Repair Materials: Tread Gums — Camel Back — Cushion and Tube Repair Gum — Repair Fabrics — Cord Patch — Vulcanizing Cement — Reliners — Valve Patches — Semi-Cured Retread Bands — Soapstone — Sectional Air Bags — Why Repairs Fail — Suggestions for Hand- ling Repair Materials — Practical Vulcanizing Hints — Vulcaniza- tion : Cures — Tube Repairs 518-568 JOBS — 202 — Repairing Pin Holes and Small Punctures. 203 — Repair- ing Large Injuries and Blow Outs in Tubes. 204 — Splicing Inner Tubes. 205— Vulcanizing Tube Splice. 206— Cold Patching. 207 — Applying Valve Patches or Pads. 208 — Replacing Valve Stems. 209 — Outer Casing Repairs, 210 — Tearing Down Quarter Section. 211 — Building Up the Quarter Section. 212 — Tearing Down for Half Section. 213— Building Up the Half Section. 214— Tearing Down for Full Section. 215— Building Up the Full Section. 216— Inside Section. 217 — Repairing of Cord Tires. 218 — Full Section Cord Tire. 219— Cord Tire Full Section. 220— Width of Breaker. 221— Repairing Tread Cuts. 222— Preserving the Tread. 223— Re- pairing Scraped Side Walls. 224 — Retreading. 225 — Building Up the Retread. 226— Curing the Retread. 227— Third Circle Re- treading. 228— Retreading Cord Tires 538-568 CHAPTER 17 GARAGE SHOP REPAIR METHODS— Taps and Dies— Forging— Soldering — Lead Burning — Oxy-Acetylene Welding — Connecting and Starting Welding Unit — Properties of Metals — Preheating — Preparation of Welds — Character of Flame — Manipulation of Blow- pipe — Sources of Trouble — Steel — Cast Iron — Malleable Iron — Aluminum — Cutting of Steel — Oxy-Acetylene Cutting 569-614 JOBS— 229 — Lifting an Engine From a Car. 230 — Using a Garage Press. 231— Using Taps. 232— Using Dies. 233— Building a Forge Fire. 234 — Forging Hand Tools. 235 — Hardening and " Tempering. 236 — Tinning a Soldering Iron. 237 — Soldering a Leaky Carburetor Float. 238 — Remove Carbon by Burning. 239 — Burning Connector Straps On Batteries. 240 — Practical Oxweld- ing Problems. 241 — Adding Filling Rod to Weld. 242 — Welding Heavy Steel Plate. 243— To Fill Up a Section of a Gear or Pinion that has had a Tooth or Teeth Stripped. 244— Building Up Lugs and Bosses. 245 — Welding Cast Iron. 246 — Welding Automobile Cylinders. 247 — Building Up of Teeth on Cast Iron Gears or Pinions. 248 — Welding Cast Aluminum. 249 — Welding an Alumi- num Crank Case. 250— Brazing Malleable Iron. 251— Brazing a Heavy Steel Part to a Light Steel Part. 252— Practical Cutting Problems 569-616 8 AUTOMOTIVE TRADE TRAINING CHAPTER 1 FRAMES AND SPRINGS Chassis, as the term is applied to their product by the manu- facturers, has come to mean all details of the motor car, excepting only the body. Standard manufacturing practice is the building of one type of chassis, but fitting many types of bodies onto it. The line of flow of power, or power transmission, should be learned early by the student, in order that he may understand the value and duties of the various units of construction. When a part is mentioned in his hearing he should have in mind instantly the location of that part or unit, or at least its relative position in general design. He should have in mind as well its purpose. For instance, practically all modern motor cars are equipped with gasoline engines. Power is transmitted to the crankshaft and flywheel of the engine, thence to the clutch, to the transmission, to the universals and pro- pellor shaft, to the differential, to the rear axle shafts, to the wheels, and to the road. It must be understood that these units are always in the line of flow of power. Design may vary in minor details but that need occasion no confusion. It is useless to study about any unit used in the transmission of power if its position and interrelation with other units are not known. With these points in mind any unit may be studied in detail and its functions observed. Frames. — The frame is so well designed and constructed in most cases that it rarely needs repairs more than heating and straightening parts of it thrown out of position due to wrecks or other mishaps. Occasional- ly brackets need to be re- placed and at times even side or cross members. In cases of cracks in the frame, they are often welded without removing either the body or the engine, or other units from the frame. Springs. — The correct method of springing a car is ^'^- ^- Cadillac Frame and Springs, one over which manufacturers and designers have puzzled and labored for years. On the springs depends in large measure the roadability of the car. The springs dare not be neglected if we would secure long life from them or from the more vital parts of the car. They must 10 Automotive Trade Training .b^^.' xllvMr 111 a^hhL. I i /^ B ■ H ■p \2) 1 1 lU ti ! 1 s 1 Oi- ■» f^ .-0 a^'^l ts Di rS" V li ^ ©— ^^BfflH^^ 'i^B^^flB'isl^' ^^y ^H^^^Oj^ ) M;:*|^-. <.g| «»*, 8 f- 1 ^•■' ■•" ] ) sJ/-/ Mi w^ 'i^^ o o 03 ;3 J2 « "o'S «2 o o o a KM J^rt 03 ft !2~ OJ CS O ^ 5 r=; ^ w ii -s >=i ci a ?= !M S i^ .« .'-' — '" o fl PhShh fa 0^.5 g I I I I I I -u C3 tc ^ rt a 5 ^ a- rC3 3 P W jj 2 « S^ C K ^ I. I I I I I ;|i (-1 +-> Fig. 2. Plan View Studebaker Chassis with Names of Parts. Frames and Springs 11 take all manner of twists, strains, jars and jolts, besides carrying the weight of the car and load. Through the front springs must be transmitted the steering effort. That is, when the wheels are turned there is a tendency for the car to continue in its course while the wheels and axle tend to leave their rightful position under the car. The springs while relieving the car of the road shock, must also exert a side strain or pressure to carry the car out of its forward course to the side and around the corner. These things it must do and not permit the steering gear links to become disarranged so that faulty steering or accidents result. The front springs also keep the front axle in alignment. If one is broken, the axle may drop back and cause an accident or at least a hard steering car. Fig. 1-A. Cadillac Motor Car Frame. To prevent breakage the following points must be observed: Keep the shackles lubricated and snug. Keep the spring clips tight. Keep the center bolt tight. Keep the leaves well graphited. What has been said of the front spring applies to the rear spring as well. Here we have in many cases additional strains and stresses due to a greater load and the fact that the driving effort is transmitted from the axle to the frame of the car through the springs. Radius Rods. — Radius rods are not found on all chassis. They may be used on the front or on the rear to hold the axle in line with the frame and the other units of the car while permitting the proper spring action. Hotchkiss Drive. — This is the name applied to the type of spring suspension and rear axle drive where the rear axle is carried by semi- elliptic springs. No radius rods, torque tubes or torque rods are supplied. Instead the axle is clipped to the springs in rigid posi- tion, no turning at the spring seat being permitted. This throws the torque as well as the driving effort and car load all upon the springs. In cases where the rear axle Is supplied with a torque tube or rod to keep the axle from turning, under driving strains, the spring seats are arranged with a bearing permitting a certain amount of oscillating movement. 12 Automotive Trade Training Quarter Elliptic Springs. — This type of spring is in use on some of the Hghter cars for both front and rear axle work. The spring is used inverted and the heavy end is chpped rigidly to the frame of the car. This type is also called the cantilever. Semi-Elliptic. — More of this type are used than any one other. It is used almost altogether on the front, and in a very large number of cases on the rear. Its peculiar advantage seems to be in the fact that it permits lively spring action v^ithin a reasonable range. This results in safer steer- ing and less rear axle trouble. Three - Quarter - Elliptic. — Formerly quite popular, this spring has been largely super- ceded by the semi-elliptic and cantilever for rear end work. Where used, the drive is in most cases through the lower semi- elliptic and the added quarter is attached to the frame of the car and projects rearward to meet the lower half. Full Elliptic. — Used in a few cars this spring is noted for its ease of riding. In the case of the Franklin car the drive as well as the steering effort is regulated and controlled by or through the springs. This necessitates very careful and rigid mounting of the upper half since no radius rods are used. In cases other than the Franklin, radius rods are in use thus permitting of different types of spring mountings. Cantilever. — For use on the rear end of motor cars the can- tilever spring is favored by a number of manufacturers. The spring is shackled at the front end, the center is pivoted, and the Fig. 3. Essex Chassis. Frames and Springs 13 Fig. 4. Rear of Packard Truck Chassis, showing frame and spring suspension. Note also Radius Rod. Fig. 5. Marmon Springs. Fig. 6. Buick Hydraulic Pressed Steel Frame. 14 Automotive Trade Training Fig. 6A. Buick Cantilever Spring. rear end attached to the axle housing. The spring affords a large measure of riding comfort, due to its ability to absorb road shock without transmitting the same to the car body and passengers. JOB 1. TIGHTENING SPRING CLIPS. Fig. 7 shows the proper method of tightening the spring clips. It is not advisable to draw up on one of the nuts to the neglect of the others, but draw on each in turn, so that the same tension is put on each. Owing to the fact that the clips and nuts and threaded portion of the clips are exposed to all manner of dirt, and are very frequently wet and mud coated, it is to be expected that they will rust. They should be tightened each month or every 2,000 miles. Keeping these clips tight is the only known spring insurance. Proceed as follows to tighten: Fig. 7. Tightening Spring Clips. Frames and Springs 15 1. Select an end or socket wrench which is a snug fit on the clip nuts. Use a creeper to roll under the car. Take an oil can with you. 3. Test the nuts to see if they are rusted. If they show signs of sticking turn them off rather than on. Use oil to help loosen them and to prevent further rust. When all four nuts of any one set of clips are working freely they should be drawn up snug and tight. 3. If the car is new there is little likelihood of rust, and the clips may be drawn tight at once. 4. Where a rusted clip nut is tightened before it is freed on the clip end, it is very misleading, as the workman thinks he has the job snug when the clip is still quite loose. 5. Where the small center bolt shows, this should always be tested to see that the nut sets snug. JOB 2. ADJUSTING SHACKLE BOLTS. One of the most annoying rattles about a car is caused by the side play in the spring ends in the shackles. In some cases this can be overcome by drawing up on the shackles and in other cases it is necessary to add shims. TIGHTENING BY USE OF SHIMS. FIG. 8. 1. First crowd the spring to one side of the shackle using a heavy screw driver to pry with. 2. Measure the thickness of the shim required. This may be sheet brass or sheet steel. 3. Remove the shackle bolt and clean it of all grease and dirt. Make certain that the oil or grease grooves are clean. SHIMS , SHIMS Fig. 8. Adjusting Shackle Bolts by the Use of Shims. 4. With a rag and kerosene, clean the eye in the end of the main spn'ng leaf. 5. Cut the shims to the shape of a washer, having drilled or punched the hole first. If this is not done the shim is very hard to hold. 6. Put some engine oil in the eye and on the bolt and reassemble with the shim in place. The shim may be tight enough to require some crowding to get it in place. 7. Draw up on the nut until it is just fairly snug. Insert a cotter key. 8. After the car has been in service a short while the shackles should be inspected and tightened again. 16 Automotive Trade Training TIGHTENING BY DRAWING ON NUTS. FIG. 9. 1. Proceed to remove and clean as above. 2. Replace, turning the bolt into the threaded shackle until no play is evident. If too tight, a very bad condition is present. The shackle holds the spring eye as in a vise and the result may be a broken spring at a short dis- tance from the spring eye. It is likely also to give forth a harsh grating noise as the parts work together. 3. Replace the nut and cotter key. 4. In some cases the shackle side is not threaded. In adjusting this type it is only necessary to draw up on the nut and replace the cotter key. JOB 3. LUBRICATING SPRING SHACKLES. Due to the constant action and the weight carried as welUas the liability of foreign matter to work into them the spring shackles are in constant need of attention. The usual plan of lubrication is to drill a hole through the center of the bolt and then another one in to meet this midway between the two ends. A flat portion is also provided at this point to permit the grease or oil to work out into the spring eye. 1. Where grease cups are used they should have one turn daily when the car is In service. Use a medium cup grease. 2. Where oilers are used they should be kept full, or receive an applica- tion daily. . Fig. 9. Adjusting Shackle Bolts. Saifonet ^ocHet Fig 10. Aloinito Method of Shackle Lubrication on Ilea Car. Frames and Springs 17 3. The trouble with all shackle lubrication is the liability of the oil or grease ducts stopping up. 4. To open up the oil holes or ducts remove the bolt and clean as sug- gested in Job 3. 5. Fig. 10 shows a special oiler and grease gun used to lubricate the Reo car shackles. The bayonet socket is slipped over the bayonet end of the oiler. Grease may then be forced from the grease gun into the shackle. 6. At least once each season, preferably in the spring after the weather conditions are settled and less mud will be encountered, the shackles should be taken apart and cleaned thoroughly. Fig. 11. Shackle Bolts Worn for Lack of Lubrication. JOB 4. GRAPHITING SPRING LEAVES. When the leaf springs are assembled in the factory they are properly lubricated by giving each leaf a coat of oil or grease over its entire surface. This grease is worked out in service and requires frequent replacement. Several preparations are on the market which will penetrate through between the spring leaves if they are applied to the side of the spring. If the spring is not too dry a good grade of oil will do the same. The standard practice in spring lubrication as followed in the garages is as follows: 1. Set the jack under the frame of the car and remove the weight from the spring. 2. Use some device to spread the leaves, having first removed the small spring clip bolt, if that is possible. An old screw driver or spring leaf end may be driven between the leaves to spread them, or a special spring spreader such as is shown in the illustration, Fig. 12, may be used. 3. The best grease to use for spring lubrication is powdered or flake graphite mixed with engine oil, or some of the finer grades of graphite grease. 4. Use an old hack saw blade or thin strip of sheet metal to insert the lubricant between the leaves. 5. Continue the work until all parts, which it is possible to separate, have 18 Automotive Trade Training been lubricated. The grease will work from these points to those points which it was impossible to separate far enough to insert the saw blade. JOB 5. SPRING OVER- HAUL. Where the springs are badly rusted or where there is a broken leaf to be replaced it is necessary to remove the spring from the car. 1. Jack up the car, hav- ing the jack placed under the frame. 2. Block the car frame in this position. 3. Remove the shackle bolts, as well as the axle spring clips, 4. Take the spring to the bench where the first step is to remove the center bolt. Fig. 12. Spreading Spring Leaves. 5. Remove the shorter leaves, laying them aside. To remove or separate the longer leaves, it is necessary to open the small spring clips. This is simple in the case of the type shown in Fig. 12, but where the one piece type is used a chisel must be driven under the end to raise them sufficiently to allow the leaves to be separated. 6. Use a coarse grade of sandpaper to remove all rust, dirt and scale. 7. Refit any new leaves needed. 8. Apply an even coat of graphite lubricant to the spring surfaces. 9. Reassemble the spring, being certain to have all the long ends together. Springs are very frequently made with the bolt hole closer to one end than the other. In cases where this is considerable it is easily detected, but in slight cases it is often the source of much trouble. 10. When all the leaves are laid together use a "C" clamp, or a vise to hold them until the center bolt is in place. 11. Next see that all clamps are properly tightened: To tighten the single piece type a few blows from a hammer are sufficient. 12. Replace under the car making certain that the spring is not inserted backward. Where the center bolt is offset the short end, if a front spring, goes to the front, if a rear spring, the short end goes to the rear in most cases. This is done to give a longer wheel base. 13. All shackles should be cleaned and properly adjusted. JOB 6. STRAIGHTENING A WRECKED OR BENT CAR FRAME. It very frequently happens that in a wreck certain parts of the frame are sprung, bent, or broken. If the trouble is merely a bent portion the repairman may proceed with confidence to put it back in proper condition. 1. Remove those portions of the car mounted close to the damaged part. This may mean that only the fender and skirts close to the damaged sec- tion need be removed, or it may mean every unit mounted on the frame must be removed. If the frame is sprung out of line either vertically or horizontally, it will be necessary to strip the frame to permit of lining it with a center wire. 2. With the damaged part exposed and accessible, the next step is to secure the proper equipment to handle the work. It is far better to use a bending bar, or jacks, to exert the pressure than to use a sledge to drive with. Frames and Springs 19 3. Apply heat from a welding flame, gasoline torch, or kerosene pre-heat- ing torch to the portion of the frame which it is desired to straighten. By- localizing the heat to the damaged spot it is quite possible to bring the portion back to the original position with the least effort, and without putting some other part out of line. 4. Keep a fire extinguisher at hand in case of need. 5. In case the entire frame is out of line it is possible to chain the ends to a heavy timber, set a screw jack at the sprung portion and thus exert pres- sure at the correct point to spring it back into position. 5. When the frame has been brought into approximate position, the smaller bends, kinks and irregularities may be removed by heating and ham- mering. A heavy sledge to back up the blows is indispensable for this work. CHAPTER 2 STEERING GEARS AND FRONT AXLES The five most common types of steering gears are the screw and nut, the worm and sector, the worm and gear, the planetary gear, and the pinion and sector. Any type may be said to be irreversible which has sufficient gear reduction, so arranged that there is little or no chance of the road shock being transmitted to the wheel. That is, power or effort can be transmitted only from the hand wheel to the road wheel and not in the reverse direction. This insures greater safety and comfort to the driver. Fig. 13. Packard Twin Six Steering Gear, Linkage and Front Axle. Planetary Steering Gear. — The planetary type, as arranged on the Ford steering gear, is shown in Fig. 29. The brass internal gear is held rigid by the steering gear post. The pinion gear on the steel shaft attached to the hand wheel is rotated with it. The planetary gears are thus given two motions. First they are caused to rotate on their central pivots, but they cannot rotate on their pivots without causing the spider on which they are mounted to rotate. While rotating each planetary gear moves forward or backward in a circle around the central gear within the outer gear. From the spider shaft the steering effort is transmitted to the steering arm and then through the drag link to the steering knuckles and wheels. This is somewhat the same principle as used in the Ford transmission for gear reduc- tion. The gear reduction is approximately 4 to 1. 20 Steering Gears and Front Axles 31 Inject /a trie ant for t>ear/n(^^ I^emoi^e p/uq to repfen/st?--.^^^ ca^e tvith lutncant Pinion and <^ear adju^stment .^Steennc^ spindle Gear nousincf Front i^heel t?eann<^'S hteerwf arm <5teerin<^ connectinc^ rod '-^teerin^f react7 rod ^/3dju/e tfoke on ncftif hand end Throttle fetter ySparM Jeirer Fig. 14. Reo Steering Gear and Linkage. Fig. 15. Dodge Steering Gear. 22 Automotive Trade Training Worm and Gear. — The worm and gear secures its name from its type of construction. A worm is fastened onto the lower end of the shaft having the hand wheel attached to the upper end. Turning the worm causes the gear shaft in mesh with it to be rotated or ^^*w^J^B ■Hi^'^^^ ■* \ * 1 w,' I ft ( 1 , ^ ■ ,jo r ^^^r^ "^ MMM^Ehh 1 ^^^BiMt ^^^^^.^Mi Fig. 16. Gemmer Worm and Gear Steering Gear. oscillated. This gear shaft in turn carries the steering gear arm. An attempt to turn the worm and hand wheel by turning the steering gear arm will show exactly how irreversible the transmission of power may be. Turning the hand wheel gives an idea of the power developed. Steering Gears and Front Axles 23 Fig. 17. Lavine Screw and Nut Gear, Details and Assembly. The gear ratio varies from about 7 to 1 in touring- cars to about 11 to 1 in the case of heavier cars and trucks, according to the duty imposed on it. Worm and Sector. — This is approximately the same as the worm and gear with the exception that since only a sector of gear is used it cannot be adjusted for wear as can the worm and full gear, where a new quarter may be turned to come in contact with the worm, thus compensating for the gear teeth which may have been worn thin. The Screw and Nut. — The screw and nut type is compact and efficient. Instead of the worm a screw thread is used. The thr 24 Automotive Trade Training on the screw is cut both right and left hand. One side, or half of the head or nut, is cut with left-hand threads, and the other side of the nut or head is cut with right-hand threads as shown in Fig. 17. Consequently, as one-half of the nut is going up on the thread, the other side is going down, and vice versa. The half nuts or heads are so arranged as to actuate rollers or trunnion blocks, which in turn actuate the shaft and steering gear arm. This type is termed the semi-irreversible as it will permit the front wheels to follow the sand or mud ruts without any care from the driver. On the other hand Fig. 18. Ross Fore aud Aft Steering Gear for Trucks. Steering Gears and Front Axles 25 not enough road shock is transmitted to the wheel to cause undue tiring of the driver. Pinion and Sector. — Here the worm and screw thread is replaced by a pinion. The pinion actuates a section of gear similar to a ring or bevel gear. The pinion and sector are exposed, not being encased in the housing as in all other types. The action is very direct and road shock is transmitted rather forcefully to the hand wheel. This type is obsolete. FRONT AXLES Front Axle Types. — The types of front axles most popular today are the Elliot, Reversed Elliot, and Lemoin. In a few cases tubular Fig. 19. Ross Cross Steering Gear for Trucks. 26 Automotive Trade Training axles are still used though this is comparatively seldom. The usual type or style of section of the axle resembles the "I" beam. Light- ness and strength, together with great ability to resist crystalliza- tion and consequent cracking and breaking, are prime essentials. A n ht m 'JS! ItI: II ^1 i ^ i H ^1 r H 'm ^ m^ lr?i HI S .r^i ^^^^^H f !i m « i !_ \ g ;'^i 1 ^l\ ^^^^ y <-j H ^ \ .^^^^^1 / -E o. / "^ s •§ •"£ \ ^^^^^^^^v / 'Sj d II '\ \ ■H^^B ^^141^; \i ^^BB ^illE ill" Kl ^^m ^ 1 ^!* Is good piece of axle steel will stand considerable bending and straight- ening while cold without breaking. Axle Repair Work. — The usual types of repair jobs on the front Steering Gears and Front Axles 27 axle include, rebushing of yokes, replacing of "King Bolts" or steering knuckle pivots, aligning front wheels, adjusting front wheel bearings, straightening sprung axles, replacing or straightening front radius rods, and work of like nature. Front Axle Design. — In the case of the front axle as elsewhere the student must understand the principles incorporated in the design Fig. 22. Axle End showing Spindle and Steering Arm. of the axle if he is to make repairs on it, otherwise he may do that which would leave the car unsafe to be operated on the highways in some cases, and in other cases be the source of continuous expense to the owner. In designing the front axle three important items are cared for. These are camber, toe-in, and castering effect. The repair- man must be able to retain these in making repairs in the same proportion in which they were originally provided. Oi>)n Dollar ittmi Storint Ki«U<- Fig. 23. Overland Four Front Axle. Note Camber provided. 28 Automotive Trade Training Camber. — The camber of the front axle is provided for several reasons. First to allow the car to hold the road better, especially when the road is crowned. A second reason is to have the weight of the car and load transmitted in a direct line through the center of the spokes of the front wheel, (which is usually dished) from the hub to the rim, to the tire, to the road. If no camber were provided the wheel would tend to exercise an undue strain on the steering knuckle and spindle. A third reason is that the closer under the steering knuckle pivot the center of the tire is brought as it comes in contact with the road, the less the effort required to steer the car. A correspondingly less degree of road shock is transmitted to the steer- ing wheel. The amount of camber varies from a slight amount to as much as three inches. That is, the center of the tires at the top of the wheels will stand as much as three inches farther apart than the center of the tires at the bottom of the front wheels. The method of providing the camber is indicated in Fig. 23. Toe-in. — Toe-in, as it is called, is provided by bringing the front of the front wheels closer together than the rear of them. This is done to make the car easier to steer, and to compensate for the tendency of the wheels to flare out at the front when being operated at speed over the road. The amount of the toe-in provided falls within rather definite limits, 3/16" to 5/16" being the standard amount allowed. Refer to Fig. 24. riEWEDTFiOM TOP --— — cr x C '/3* SHOULD 3E 1/4'GaEaTER TIfaifX Fig. 24. Illustrating Toe-in. Steering Gears and Front Axles 29 Castering Effect. — This also is provided that steering may be easier and safer. Instead of allowing the steering knuckle pivot to stand straight up and down, or perpendicular, the lower end is brought forward and the upper end is thrown backward. This is much the same as the pivot is arranged in a bicycle. Fig. 25 shows how the steering axis is thus brought ahead of the point of actual contact with the ground. This construction is the feature that permits the rider of the bicycle to ride and steer the wheel without touching the handle bars. The same principle is in use in the casters on which a piece of furniture rolls over the floor. The casters always align themselves with the direc- tion in which the piece is being moved. The castering feature as applied to automobiles will cause the front wheels to align themselves with the direction of travel of the car. After rounding a curve, the wheels automatically attempt to straighten out and keep straight with the car and road. Steering Knuckle Arm Design. — Still another feature of front axle design is the shape and position of the steering knuckle arms. Generally speaking, if lines were drawn through the centers of steer- ing knuckle pivots and tie rod bolts they would meet close to the center of the rear axle. This may be noted in Fig. 2. This provides the proper mechanical movement and length of the lever arm to cause the front wheels to be held in a perpendicular position with Fig. 25. The steering axis meets the ground in advance of the point of contact of the wheel. Fig. 26. Application of Timlien Roller Bearings to the Spindle and to the Knuckle Head. reference to whatever radius they may be traveling on in rounding a corner. Since the front axle of the car is fixed, the front wheel on the side toward which the turn is made will always be ahead of the other one with reference to the center of the curve being rounded. As a con- sequence of this the same radius would not strike the center of each 30 Automotive Trade Training wheel, and since the wheels must be maintained perpendicular to the radius the car is traveling on the wheels, they would not be parallel on a curve as they would be on a straightaway. A test made on cars in the shop will prove this. In attempting to verify the above, first turn the wheels of the car to the side sharply. If lines are next stretched along the sides of the front wheels it will be found that they will meet at a distance ahead of the car depending on the amount the wheels are turned aside and on the length of the wheel- base of the car. These matters are not presented with the idea of confusing the student, but rather that he may have such an understanding of the principles of design that an axle to be repaired in any detail may be so cared for as to insure safety and service without undue wear and strain being placed on tires, knuckles, spindles, bearings, bushings, steering gears, and other details affected. JOB 7. TESTING AND RE-ALIGNING FRONT WHEELS. Service and safety are absolutely dependent on proper alignment of the front wheels. 1. Jack up both front wheels. 2. Turn them, noting whether they run true. 3. Resting a soft pencil on a block or box mark the center of each tire as the wheel turns. 4. Set the wheels in true with the car. (Straight ahead.) 5. Measure from center to center, or from mark to mark on the exact front of the wheels. Use a strip of wood, marking the distance with a pencil. A better device is the adjustable measuring device illustrated in Fig. 27. This insures the same distance from the floor being used at the front and rear of the wheel. 6. Test the marks on the rear of the tires. Is there any difference in the measurement? 7. How much difference should there be, and why is this allowed? 8. What is camber? How much is allowed? 9. What is toe-in? How much should be allowed? 10. If the amount of toe-in is not correct, the clamping screw in the ad- justable tie rod yoke should be loosened. Remove the yoke pin and turn the yoke on or off as desired. 11. After the adjustment is again tested and found to be correct, the yoke pin and the locking or clamping screw are replaced and tightened. Make certain that the cotter keys are in place. JOB 8. OVERHAUL FORD FRONT RADIUS ROD. A common fault of the Ford car is to have the front radius rod sprung by striking a rut or curb. 1. Remove the lower half of the ball joint bearing which is the ball joint cap. Place parts where they will be kept safely. 2. Remove cotter keys from front ends of radius rods. 3. Loosen nuts until just even with ends of radius rod. 4. With a lead or bronze mallet jar the ends loose from the axle. If no soft metal hammer is at hand use a wood mallet, or a piece of hard wood under a hammer. Steering Gears and Front Axles 81 »-iIv Fig. 27. Testing the Alignment of Front Wheels. Remove nuts. Place away. Remove radius rod and clean. Test rod for alignment and any bends. If out of true, get instruction for straightening on arbor press. 9. In straightening Ford parts of this nature no heat is applied, they are straightened cold. 10. Have work inspected and if approved reassemble in the car. Do not reverse in axle or it will throw the front axle out of plumb. 11. Inspect to see if all is tight and all cotters in. 32 Automotive Trade Training JOB 9. OVERHAUL FORD FRONT WHEELS AND BEARINGS. 1. Jack up car. 2. Remove hubs. 3. Remove cotter keys. 4. Remove castellated nut and washer. 6. Remove adjustable bearing cone. One spindle has right and other left-hand threads. Why? 6. Remove wheel. 7. Remove felt washers. 8. Clean all parts. 9. To remove and inspect balls first compress and remove ball retainer. 10. Inspect all steel balls for cracks and pits. Remove defective ones and replace with good. If very bad, all should be replaced. 11. The inner bearing cups may be pressed or drifted out if their removal is found necessary. They are a press fit and should be replaced when worn. 12. All parts being cleaned they may be reassembled. Pack with cup grease. 13. After wheel is in place, test for side play due to too loose an adjust- ment. Test for tightness as too tight will cause undue wear. One good way to get proper adjustment is to tighten until the wheel shows signs of binding, then back off the adjustable cone until the wheel runs freely. 14. Put on washer and nut, and have inspected. 15'. If approved, place in cotter key; a new key. Why? ^ JOB 10. TIGHTENING UP FORD STEERING GEAR. Should the steering gear become loose, that is, so that a slight movement of the wheel does not produce immediate results it may be tightened in the following manner: 1. Disconnect the two halves of the ball sockets which surround the ball arm at the lower end of the steering post and file off the surface until they fit snugly around the ball. 2. If the ball is badly worn it is best to replace it with a new one. Also tighten the ball caps at the other end of the steering gear connecting rod in the same manner. 3. If the bolts in the steering spindle arms appear to be loose, the brass bushings should be replaced with new ones. Refer to Fig. 28. 4. Excessive play in the front axle parts may be detected by grasping one of the front wheels by the spokes and working it in such manner as to show up any excessive wear. 5. After the car has been in service two or three years excessive play in the steering gear may make necessary the renewal of the little pinions, as well as the brass internal gear just underneath the steering wheel spider. 6. It is also advisable to inspect the front hangers occasionally to over- come any excess vibration. If found, remove old hangers and replace with new ones. JOB 11. OVERHAULING AND REBUSHING FORD FRONT AXLE. Refer to Fig. 28. 1. Remove wheels. 2. Remove radius rod. 3. Remove steering knuckle spindles by removing nut and spindle or king bolt. 4. Press out spindle body bushing. Steering Gears and Front Axles 33 5. Press in new ones. 6. Press out spindle connecting rod bushing. 7. Press in new ones. 8. Reassemble, using care to see that all parts fit properly. In this work it may be necessary to ream the bushings to fit them to the bolts. Any burrs Spindle Oiler Spindle Bolt Spindle Body Bushing Spindle Con Rod Boll Spindle Con Rod Yok^ Spindle Arm Clamp Boll Spindle Arm Nut Spindle Body Bushing Spindle Bolt Nut Spoke Felt Washer Hub Bolt Large Ball Race Hub Flange Hub Spindle rease Chamber! Ball Bearings djusting Cone. ock Nut ub Cap Washer Ball Retainer Small Ball Racei Stationary Cone Ball Retainer ust Ring Fig. 28. Ford Front Axle Details. may be removed from bushings with a scraper, knife or fine file. 9. Put on wheels. 10. Test wheels for alignment, 11. Test job for any unfinished work. Pig. 29. Ford Steering Gear. ]M»K»01I Aim 4L 1^ i»4 ^inM BM^ IM^ QM^ «K!«9it OS MQKw Hie mft «ii %t^ •! tilt xmo xmfiimeoiiT wasBL Steering Gears and Front Axles 35 JOB 14. REPLACING FRONT WHEEL SPINDLE CONES OR RACES. It sometimes is necessary to remove the cone or bearing race which fits over the spindle. This is shown in Fig. 30. These races are worn in normal service but at times a cracked ball or bearing will hasten the wear. When worn or pitted they must be removed and new ones installed. 1. Remove the wheel. 2. With a hammer and drift, work the stationary cone or bearing race off, by driving on the back of it. 3. When replacing use a piece of pipe for a drift as shown in Fig. 31. 4. Do not permit the pipe to rest on the shell which is the roller retainer, or it will be broken. In the case of the inner stationary cone as used on the Ford and other ball-bearing types, the same device is useful as it insures an even pressure and a workmanlike job. 5. Considerable force is at times necessary to drive a cone or race off or on. One a bit undersize will force some of the softer metal of the spindle off as it is forced on, thus cutting it down to a slightly smaller size. 6. The workman must remember that the cones and races are hardened, and striking them with a hardened hammer will very likely chip them and result in future damage. JOB 15. REPLACING WHEEL BEARING CUPS. The hardened steel races mounted in the front wheels for the ball bearings are called outer and inner ball cups. These are press fits. To renew proceed as follows: 1. Remove the wheel and clean it of all grease. A stream of hot water is beneficial in this work, or kerosene and a stiff paint brush may be used. 2. Insert a block of wood or a pipe through the rear of the hub as the wheel lies on a block on the bench. 3. Making certain that the drift, which is the pipe or the stick of hard wood, rests on the ball cup in the outer end of the wheel hub, it may be driven downward. This will force the cup out. 4. Having the outer ball cup out, there is more room available to drive the inner cup outward having the drift inserted from the outer hub end. 5. When the new cups are being inserted care must be used not to strike them with a steel hammer. Use a lead mallet, or a block of wood may be used as a drift. 6. Repack with grease and reassemble the wheel. Discard any broken, chipped, or undersize balls. Fig. 31. Mounting Wheel Bearing. JOB 16. STRAIGHTENING DAMAGED FRONT AXLES. It is quite possible to straighten front axles and use them with safety and assurance of proper service if the mechanic has proper facilities for doing the work and making the proper tests when the work is in progress. For those desiring to attempt work of this nature the following suggestions are given: 36 Automotive Trade Training 1. Remove the axle from the car, blocking the car so that there is no danger of it falling on the workmen. 2. From such portion of the axle as appears to be left in its original shape, make an estimate of the work needed to bring the sprung portions back to shape. 3. If it is a Ford axle or only sprung a slight amount, it is not advisable to heat it, instead straighten it while cold. This means, it must be placed in the garage press in such manner that the correct force may be brought to bear. 4. If the axle is one of the heavier type and rather badly damaged it may be heated at the point showing most damage. When heated to a red heat it may be caught in a heavy vise and straightened by means of pulling on the pro- jecting end. A bending bar is of assistance in this case. 5. Avoid the use of a hammer as far as possible as the appearance as well as the actual value of the job is marred by any appreciable amount of hammer- ing. In some cases the use of the hammer is necessary. 6. When the axle appears to be in proper shape, test by setting two fram- ing squares on the spring perches and sighting over the blades to see if they are in alignment. If so, the central part of the axle has no twists. 7. Insert a piece of cold rolled steel in each of the yokes. Sight them to see if they are parallel. If only one end of the axle was damaged, this end should be brought to the undamaged one by applying heat between the spring seat and yoke, and after gripping the axle in the vise again, use a bending bar to twist it into alignment with the good end. 8. I'f both ends are thought to be out, castering must be provided to a slight extent. To test for this, sight a cold rolled steel bar fitted into the yoke with a square blade set on the spring seat. If they align there is no caster. If the top end of the cold rolled bar or pin shows at an angle with the square, the top is back of the blade and the bottom would be ahead of the blade, the axle has caster. A slight amount is all that is needed. If the reverse of the above is true the fault must be remedied or steering will be made difficult and actually unsafe. 9. In straightening and in replacing the axle the repairman must keep in mind at all times which is the front and which is the rear of the axle. 10. Unless especially equipped for such work no attempt should be made to heat, treat or temper the axle. Allow it to cool and it will be in condition to put into service. Do not cool in water. JOB 17. REPLACING STEERING KNUCKLE BODY. When, because of natural wear or accident, it is necessary to replace the steering knuckle spindle body, proceed as follows: 1. Jack up car, remove wheel and put aside. 2. Remove pivot bolt sometimes called "king pin" or "bolt." 3. This permits the spindle body to be lifted out of the axle yoke. 4. Remove bearing or stationary cone. 5. Fit pivot bolt into the new spindle body bushings. 6. Replace and reassemble wheel in position. JOB 18. STEERING GEAR LUBRICATION. One of the most important points to keep well lubricated is the steering gear mechanism. The bearing just under the steering wheel is lubricated with engine oil. The working parts in the gear case are lubricated usually by a heavy oil, or a light grease, or a mixture of engine oil and cup grease. The Steering Gears and Front Axles 37 type of lubricant is dependent to a certain extent on the nature of the construc- tion. 1. Oil the top bearing. (Fig. 32.) Ott PlUC Fig. 32. Steering Gear Adjustment and Lubrication. U. S. Model. 2. Oil controls (spark and throttle)) several drops to each point ol bearing or wear. 3. Inspect gear for any other points requiring oil lubrication. 4. Fill the case with grease, or heavy oil, using the kind specified by the manufacturer. 5. Locate and fill any grease cups. 6. To lubricate the drag link it is necessary to remove the boot covering the ends. (Used in most cases.) Remove all dirt and hard grease. If in bad condition, it is well to take apart and clean before repacking. Finally replace boot after packing all parts in cup grease to insure lubrication, and exclude mud and dirt. 38 Automotive Trade Training JOB 19. ADJUSTING STEERING GEARS. Since the safety of the car and the occupants is dependent on the proper adjustment of the steering gear and its proper functioning, too much care cannot be given to it. The worm and gear type is provided v^ith several adjustments, in most cases. The most common adjustment is to remove the up and down or endwise play of the worm within the housing. 1. Inspect the gear case for the locking screw nut or bolt. 2. Release the locking device. 3. With a large wrench turn the adjusting nut down on the thrust bearing until all the end play is taken out. Note Figs. 33 and 34, If no other play is Fig. 33. Allen Steering Gear Adjustment. evident it may be necessary to release the adjusting nut a bit to allow the required play in the steering wheel. This should be from %" to 1^". 4. Some gears, as for instance the Dodge and Allen, are provided with eccentric bushings for the gear shaft to work in. By turning these bushings which are originally assembled with the thin side next to the worm, the play between the worm and the gear may be removed and the wear compensated for. This adjustment is shown in Fig. 33. 5. Another adjustment is shown in the same figure. This is the thrust washer and screw arrangement holding the gear in position. Sometimes when this is not provided in this way it is necessary to remove the case cover and remove a thin shim thus taking the play out at that point. To prevent undue wear, none of the adjustments mentioned should be made too tight. JOB 20. OVERHAULING DRAG LINK. In the ends of the drag link are mounted several cups, a spring, and an adjusting screw locked by a long cotter key. This is the standard type of drag link construction. To clean and adjust proceed as follows: 1. Fig. 13 shows the steering connecting rod or drag link. Remove the cotter key from the end. Steering Gears and Front Axles 39 2. With a heavy screw driver remove the adjusting nut through the slot of which the cotter key is ordinarily placed. 3. Remove the hardened ball cups and the compression spring, and pull the drag link from the steering arm ball. 4. Clean all parts, inspecting same for wear. 5. Replace parts in proper order having first packed them in medium cup grease. 6. Do not draw the adjustment too tight or undue wear will result. If too loose, the steering gear is not safe and is likely to be noisy. 7. Each end is similarly constructed although not exactly alike in every case. When removing parts, note very carefully their proper relation to each other. Replace in their former order. As a rule the new adjustment will be a bit closer than the old to account for the wear. 8. Inspect and make very certain that both cotter keys are in position. Fig. 34. Thrust Bearing Worm Adjustment. CHAPTER 3 REAR AXLES AND BRAKES Rear axles may be divided into two general classes, live axles and dead axles. The live axle is used universally in passenger vehicles. The dead axle is still used to some extent in trucks. Live Axles. — As to the relative merits of live axles of various types, designers have contended for some years. Each has its peculiar advantages as well as disadvantages. These will be men- tioned as the types are considered. In considering any axle to deter- mine what type it is, one main point only need be remembered and that is whether or not the axle shaft actually carries any load or strain other than that of transmitting the turning or driving effort to Pig. 35. Dead Axle Load Carrying Member as used on Torbensen Internal Gear Rear Axles. the rear wheel. If it takes a load or weight directly on either end, then that end is not floated. If either end is relieved of all strain other than driving torque, then that end is floated. Plain Live. — A plain live axle is one in which each end of the shaft is resting directly in bearings. The driving weight as trans- mitted from the pinion gear and differential must be born by the inner end of the shaft, while the outer end of the shaft carries directly the weight of the entire chassis body and load. The advantage of this type is lighter construction and less play in parts since all parts Fig. 37. Live Axle Shafts. 40 Rear Axles and Brakes 41 ;. i If ke Adjust. he car p-keepa gre driving dogs 11 ft '! If 2 - o. ^r -WM rm £i i^-^*^!™™ If 4 -ill . »: 1 ». i: ;*.■ ill I ML 1- 1 j Jl :H^jK*'^^! w^ ^i Iff 1 ^^^^^^^^^EfllHi^^^^^^. J i t! Hj^^^^^^^^^^^^^ ' ^. e J 4- ''^» ^1 n^k Ti^ H 1 h 1 si 1.S V •Off 1 , '1 1:1 •51 mi ^ r«. .1 ir Isl 5| ■-— ^^i_i ^A2J1 kiL-^ ^-s _JL^ .•swsrrwBiillY , ;,J',- ■ . , "1 s^H ^11 38 ' ■. ^^ ■ ""■ ''if i i ^;s- J^ ^>^ s^m^^^^^^^^^ 1 -.id Br. presse strong forgin 1 Brake Banc drum, no dti r Bearing- of all axle ^"^LJ i^ 11. Si ii ,^a ^ c f '^' Jfi .23 - tefc- External Brake /|^ Adjusting Screw /Hi B ^ HK^ internal Brake U^E^Fulcrutn Lever ^^^Httvrnal Brake Intrrnal Brake m| nil H Huntl l.ininft \^ ^^^^^^^1 Mjj||B i. Kxternal Brake x*^ ^^BSA ^1^ Adjustment L>. .._. . -s. "S Bearing {".a^f Clamp Bolt Internal BruKe Band Lining '**'!.J?i«% . Fig. Gl. Typical Passenger Car Brakes. Rear Axles and Brakes 55 Fig 62. Brake Drum Mounted on Rear Wheel. Double Width Drum. — In this case the brake bands are assembled side by side. Both are external contracting or internal expanding, usually the latter as this per- mits of them being kept clean and dry. Grease and oil working out from the axle housing is likely to cause the internal type to lose its braking efficiency. When this happens, the wheel should be removed, the grease and oil washed or burned out, the drum cleaned, and then reassem- bled. Transmission Brakes. — In the Ford car a brake drum is placed on the driving plate which is always turn- ing when the rear wheels are in motion. Applying the brake band to this drum by depressing the brake lever checks the speed of the car. Since the gear ratio through the rear axle is approximately 4 to 1, the braking effect is four times as powerful at this point as it would be if applied to the same size drum and band on the rear wheel. One bad feature of the transmission brake is the lack of understanding of this feature. A sudden forceful application of the brake throws a tremendous strain on the ring and pinion gears as well as other axle parts. At times this results in breakage and complete loss of control of the car. Another undesirable feature of the transmission brake is the danger of skidding if one wheel has a good dry road grip and the other is on ice or a wet portion of the roadway. In this case the sudden application of the brake which locks the propeller shaft will cause a rapid spinning backward of the wheel on the slippery portion while the car skids sidewise or continues to move forward. This action of the differential is the same as occurs when pulling through bad places in the road and only one wheel has traction and the other spins. The transmission brake is used on other chassis besides the Ford. It is used on a number of passenger vehicles and has met with a degree of favor on commercial cars. The drum is mounted on the outside to the rear of the transmission case and may be used either in connection with the foot or hand brake. Fig. 63. Brake Shoes. — In certain cases a metal shoe without any lining 56 Automotive Trade Training is used as an internal expanding brake. This type is almost obsolete having been, superseded by the internal expanding band type on which a fabricated lining is riveted. Fig. 63. Packard Truck Transmission Brake and Drum. Brake Names. — The usual practice is to connect the hand brake (not emergency brake) to the internal expanding bands, and the foot brake (not service brake) to the external contracting bands. Brake Equalizers. — Equalizers are used by some car manufac- turers and discredited by others. The idea of the equalizer is to automatically apportion the same braking effort to each of the rear wheels much as the two horse evener permits of each horse drawing half the load. It has the disadvantage of putting both brakes of any set out of commission if there is a break on either side. On the other hand there is far less danger of the brakes gripping or wearing unevenly in continued service, and far less skill is needed to secure a fair adjustment. The fixed type of adjustment, where each side is actuated in a fixed relation to the brake levers, permits of one side being used after the other may have become broken or damaged in such manner as to make it useless. This type requires expert skill and judgment in adjusting for wear. If one side is set to act more quickly than the other the car will skid to the side whenever the brakes are applied suddenly. JOB 21. ADJUSTING EXTERNAL BRAKE BANDS. In all brake adjustment and service two prime points must be remembered. The brake must be so set and connected to the hand or foot lever that action Rear Axles and Brakes 57 Fig. 04. Timken Cam Brake. certain and sure when it is desired to stop the car. It is not so essential that the bands grip the wheels until they will slide, as it is that they will exert a firm even pressure all the way about the drum and give that ideal braking effect which is just under the point needed to start the wheels sliding on a dry road- way. Once a wheel starts to slide the brakes should be instantly re- leased as this is a dangerous con- dition and the momentum of the car will carry it much farther with the wheels sliding than when they are rolling over the roadway with the proper gripping effect on it. The second point to be remem- bered is that the brakes must be so set that they will not drag and consume a needless amount of power which may result in burned brakes and an overheated motor. Practically all brakes operating on the rear wheel drums are of the same general construction. The adjustments are to be made along the following lines: 1. Jack up the rear wheels so that each is free of the floor. It is essential to have both wheels free at the same time. Since two jacks leave the job a little unsteady it is well to block up one side with wood blocks, a trestle, or like arrangement. This permits of shaking and pulling on the brake parts without danger of the car dropping from the jacks. 2. Inspect the entire braking mechanism to learn its general condition and see where the lack of proper braking effect lies. 3. Note if the brake pedal has the proper travel. 4. Note if the brake band is worn badly. 5. Note if the brake drum has any grease on it. 6. Note whether the brake band fits evenly around the drum. 7. Have a helper press the foot pedal forward, noting whether the upper and lower halves are gripping equally, or whether, due to poor adjustment, the upper or lower half of the band only is opera- tive. 8. Have the helper set the pedal at a certain point, while each wheel is tested to see if the braking effect is properly equal- ized. 9. Inspect all springs to see that they are operating properly. 10. Having made the above inspection the brakes may be adjusted where needed. If the entire job must be gone over proceed as follows: 11. Set the adjusting screw Fig Timken Toggle Brake. 58 Automotive Trade Training at the rear of the brake band until the clearance between the drum and band is from 1/64" to 1/32". This will insure the brake being free at that point. 12. Adjust the center top adjustment, if one is provided, to have the same clearance. 33. Adjust the center bottom adjustment, if there is such, until the clearance there is the same again. 14. At the front end of the lower half is usually found a pair of lock or jam nuts. These should now be adjusted until the proper clearance of 1/^64" to 1/32" is shown on all of the lower half of the band. 15. The upper end of the brake band is now drawn down by means of the thumb nut until the proper clearance shows all the way along the top half of the band. 16. With the band properly fitted to the drum the next adjustment to make is that of the pull rods and clevises. It is very essential in making adjustments on the pull rods not to bring the levers on the equalizing bar at the center of the car past centers. Rather leave them back of center so that the application of the brake fully will leave them in a vertical position. For this reason it is best to take up the rear rod rather than the forward one. Fig. 66 shows the right and wrong method. RIGHT WAY Fig. G6. Methods of Adjusting Pull Rods (Hudson). JOB 22. ADJUSTING INTERNAL EXPANDING BRAKES. Two types of internal expanding brakes are in common use. The first and most common is the type expanded by means of a cam, and the second is the toggle type. Either type may or may not be adjustable within the drum. Where no adjustment is provided within the drum all adjustment to take up wear must be made on the clevises under the floor boards or on the pull rods. In doing this work it is necessary to proceed as follows: 1. Jack and block both sides of the axle to hold the wheels free of the floor. 2. 3. 4. 5. come Remove the wheels. (Refer to Jobs 21 and 29.) Inspect the lining and free it of all grease or oil. Note whether an inner adjustment is provided as that shown in Fig. 65. Where an inner adjustment is provided it should be set so as to over- any unnecessary clearance. The wheel will have to be placed on a Rear Axles and Brakes 59 number of times possibly, to secure just the proper adjustment. It is well to have the pull-rod clevis dropped for this work. 6. Next adjust the pull-rod clevis until all the slack is out of it, and with the lever in "off" position the clevis pin may be replaced. 7. Test the wheel for drag. 8. Test the wheel for braking effect. 9. In case there is no inner adjustment the pull rods alone must be Fig. 67. Dodge Rear Axle and Brake Adjustments. depended on. When they no longer hold, and permit of no further adjustment, it is usually necessary to reline the bands or shoes. 10. It sometimes happens that the adjustment is entirely up and that the lining is still good. To provide more take-up the brake pull rods are removed and additional threads cut on them. 11. Test wheels for braking effect. Make certain that the brakes are sufficiently firm to hold the car on any grade. Note also any tendency to drag or to grab. JOB 23. REMOVING GREASE AND OIL FROM BRAKES. 1. Jack up the rear axle. Block car to niake secure. 2. Pull wheels. (Job 29.) 3. Remove both inner and outer brake bands if such are used. 4. Take the bands to the bench or cleaning trough where they may be cleaned with gasoline or kerosene. 5. Learn the cause of the grease working out from the axle housing into the brake drum. 6. If the housing has oil above the specified level which is even with the filling plug, or about one-third full in most cases, it must be allowed to drain off. . . , 7. If the trouble is with the felt washers in the bearmg mountmg they must be replaced. 60 Automotive Trade Training 8. Sometimes grease will work under or through bearing races. A soft rag wrapped properly under the bearing cup will sometimes correct the trouble. 9. Where the brake lining is of a porous nature the oil is likely to saturate the lining to such an extent that it is impossible to wash it out. In this case the gasoline torch or the welding flame may be used to heat the lining and thus dry it out. As the grease or oil is forced out by the heat it will burn with a yellowish flame. 10. With a very hot flame of this nature it is quite possible to burn the lining. In no case should it be heated until it starts to glow. In fact, heating at all is to be discouraged except in the case of linings so saturated that nothing else will correct the trouble. If this work is done with the bands in place the operator should have a fire extinguisher at hand. JOB 24. RELINING BRAKES. The job of lining brakes is readily done if a few vital points are remem- bered. Selection of brake lining is a matter for the car owner to settle but he should be encouraged to put on a good standard product. Experienced drivers know so well the value of good lining and good brakes that they are willing to pay the price for them. 1. Jack up the car and block securely. 2. Pull the rear wheels. Place parts where they will be safe and kept free from dirt, especially the bearings. 3. Remove the brake bands or shoes. 4. Measure the width of the old lining and estimate the probable thickness Fig. 68. :Brake Lining Surfaces of it in its original form. Consult the manufacturers specifications if in doubt. 5. Measure the length and order the exact amount needed. 6. Remove all old lining from all the bands. Remove all old rivets, rust, dirt and grease. 7. Fit in and cut all pieces for the bands. 8. In lining the internal bands or shoes the lining is first placed on the Rear Axles and Brakes 61 band, drawn tight and clamped at each end. If no clamps are at hand several stove bolts may be used to hold the lining in position. Next take a punch to mark the lining, marking from the inside out, unless it is possible to use the hand drill to drill immediately. 9. Remove the marked band and drill each point marked with a 5/32" or 3/16" drill depending on the size rivet used. 10. Countersink for rivet heads, if necessary, and replace the lining in position. 11. In riveting where solid rivets are used, as they are in most cases, the head should be rested on the end of a blunt punch or bolt while the end is being riveted over, 12. Do not attempt to hammer the end over flat, but give it a few sharp blows to upset it in the band and form a burr too large to prevent it being pulled out. 13. In selecting rivets for any particular piece of work they should extend through the band a distance equal to the thickness of the rivet. 14. Under no circumstances should any but a soft copper rivet be used. These may be secured from the supply houses. 15. In lining the external bands care must be used to make the lining lay close to the bahd. In no case must it be permitted to buckle, nor must it be too short else the lining will not conform to the curve of the band and drum, with the result that it is impossible to prevent the brakes from dragging. 16. Some mechanics make the practice of riveting each end to the lining in place as the first step, allowing a slight buckle of the lining inward. After the ends are secured this small buckle is hammered out thus insuring an even laying lining. This buckle must not be left until all but a few rivets are in, or difficulty will be experienced in getting it out. 17. The careful mechanic will make certain the rivet heads are all below the surface of the lining. JOB 25. SQUEAKING BRAKES. Most cases of brake squeaks can be removed by properly aligning the band on the drum and readjusting. In some cases the trouble can not thus be Fiff 62 AUTOMOriNK TkADI*: 'rKAlMNC, remedied. Hudson engineers recommend the method illustrated in Fig. 69 for correcting this fault. In fact, the practice of leaving out a piece of lining at the rear of the band when relining brakes is meeting with much favor. To remove the objectionable piece proceed as follows. 1. Set the brakes. 2. Select a drill just slightly smaller than the thickness of the lining. 3. Drill between the band and the drum at the two points indicated. 4. Remove the piece of lining thus cut loose. JOB 26. ADJUSTING PACKARD TWIN SIX FOOT BRAKES. Refer to Figs. 70 and 77. The foot pedal is connected with the external brake bands. The clearance allowed between the bands and the drum is 1/32" all the way around. 1. Adjust the nut on the rear support until the clearance is proper at that point. 2. Adjust the two nuts on the shank of the clevis just below the eyebolt at the front of the brake until the distance between the lower half of the brake band and the drum is also 3^2". 3. Adjust the "T" handle which operates the adjusting screw until there is a clearance of 3^2" between the upper half of the band and the drum. 4. To check for equalization make sure that, with brakes released, the brake pedal connecting rod is so adjusted that the stops on the equalizer levers just clear the rear of the rear cross channel when the pedal is against the floor board. The connection from the brake cross shaft to the rear axle should be so adjusted that the clevis pins at the upper end of the brake toggle levers clear the band by %" on each wheel. This insures proper equalization. The equalizer bar should ordinarily be set in the upper holes of the equalizer levers. For city and for moderate speed driving they may be set in the lower holes thus reducing the effort required to obtain a given braking result. Fig. 70. Packard Twin Six, Rear Axle and Brakes. Rear Axles and Brakes 63 JOB 27. ADJUSTING PACKARD TWIN SIX HAND BRAKES. The hand brake lever controls the internal expanding brake shoes. These must be so adjusted that when applied there is the same resistance on each rear wheel. Make the following adjustments: 1. Make all adjustments for wear on the side pull rods connected to the cam shaft levers. 2. By removing the rear wheel the hand brake band can be set concentric Avith the brake drum by means of the set screw at the rear. The band should just clear the drum at this point. 3. The hand lever should be in the sixth notch from the front when the brakes are applied. JOB 28. SPLIT HOUSING TYPE REAR AXLE OVERHAUL. Certain- of the lighter cars use a rear axle having the housing bolted together in the center rather than the one-piece construction. This construc- tion is also found in a few of the heavier cars and some of the trucks. 1. Jack up the car and block up under the frame to hold all the weight free of the axle. If a hoist or crane is available, it should be used for this work. 2. Drop all brake rods, radius rods, spring clips, etc., which will in any manner prevent the axle being removed as a unit. 3. If the car cannot be raised high enough to permit the axle being pulled out to the rear, without the wheels striking the fenders, the wheels must be pulled and the housing dropped to the floor. (Refer to Job 30.) 4. Place the axle housing on the horses, or rack, and remove the propeller tube and shaft. 5. Remove the bolts holding the two half housings together. 6. Pull these away from the axle shaft assembly. 7. The next step is to open up and inspect the differential, noting carefully the method of assembly. 8. Very frequently the differential side gears are pressed onto the inner end of the axle shafts. To remove them it is necessary to press or drift the side gear downward a bit to remove the split retainer ring. This is usually at a point close to the inner end of the axle shaft. When the split ring is removed the side gear may be pressed or drifted oflf the axle shaft. 9. The parts should all receive careful inspection and those showing signs of wear should be replaced. 10. In reassembling the utmost care must be used to have all parts properly assembled. In some cases the gear adjustment is a fixed nature. That is, no provision is made for taking up wear. If the parts are otherwise in 540od condition, but an unwarranted amount of backlash is evident, it may be removed by the judicious use of shims. The most common method is to place a metal shim back of the thrust bearing which holds the bevel gear in contact Avith the pinion gear. A number of careful tests are necessary to insure the proper clearance of .005" to .008" between these gears. 11. Pack all parts with a medium cup grease or apply heavy oil to them so that lubrication is immediate when the car goes into service. 12. Reassemble under the car, being careful to have each and every part in proper position and properly secured with cotter keys and lock washers. 13. When reassembling the wheels on the axle care must be used to have the bearings properly adjusted and the brakes properly fitted. 14. It is a good plan to go over each part of the work as a matter of final inspection, and then again after a few days of service testing all nuts with the wrench to make certain they are snug. This refers to externally located parts. 64 Automotive Trade Training Fig. 71. Overland Four Rear Axle and Brake Adjustments. Brake Linings Axle Shaft Inner Brake Cam Rear Axles and Brakes 65 JOB 29. OVERHAULING REAR AXLES OF SINGLE PIECE HOUSING CONSTRUCTION. In most cases of full floating, and in some cases of other axles, the housing is a pressed steel construction,' so arranged that the differential assembly may be put in from the front or rear of the housing and the axle shafts from the ends. In this construction it is seldom necessary to remove the axle from the car. The usual plan of overhaul in this case is to run the car, or lift it, onto blocks which will give sufficient room for the workman to get under it and at the inspection plate to the re^r of the axle housing. After the car is in position, properly secured to prevent moven-'-.nt, proceed as follows: 1. Remove axle drive shafts. (Job 30.) 2. Remove inspection plate at center rear of housing. (Fig. 72.) Fig. 72. Method of opening up axle for inspection and adjustment of the bevel gear. 3. If the differential is to be removed next release the four holding studs or nuts. 4. This permits of the caps being removed and the entire assembly being lifted out. Fig. 73 shows the assembly out but the caps and nuts in position. The same figure shows the notched adjusting rings by means of which the differ- ential assembly is brought into proper relation to the pinion gear. 5. The differential and bearings may now be taken apart and inspection and replacements made. 6. The pinion gear assembly should next be inspected and all worn parts replaced. 7. Replace the pinion gear assembly in position. 8. Replace the differ- ential assembly in posi- tion. Fig. 73. Differential assembly and mounting. 9. Adjust these as suggested in Job 31. 10. Replace axle shafts. 11. Replace the inspection cover and fill with lubricant to the proper level. 12. Test. Make final inspection and adjustments. 66 Automotive Trade Training Dll SpJlift ; R ■ Hi-vei Qtiii DiL Beaiusg Fig. 74. Marmon Rear Axle Parts opened up for inspection. JOB 30. PULLING REAR WHEELS. The student should first study the external construction to note the type of axle being worked on and thus decide what is necessary to remove the wheel. Note the following points: 1. If the hub cap is a comparatively small one and the hub bolts have the rounded heads exposed the hub is of the socalled fixed type. The wheel is keyed to the shaft on a taper joint. To remove proceed as follows: a. Jack up the axle to free the wheel. b. With a hub wrench remove the hub cap. c. Remove the cotter key and the castellated nut. d. Attempt to pull the wheel by hand. Failing in this, put on a wheel puller which may be of the hub type which is scr6wed onto the threaded end of the hub and locked in position with a set screw, or it may be of the heavier type which is adjustable to fit over the center of the wheel back of the spokes or hub. When properly fitted, in either case the wheel is pulled by drawing on the center screw of the puller. e. If the wheel proves stubborn it may be necessary to jar the set screw of the puller or the hub of the wheel to break its grip. f. If no wheel puller is at hand, several scantlings or two-by-fours may be used to pry outward on the wheel, at the same time giving the end of the axle shaft a sharp blow with a bronze, lead or wood mallet. g. Under no circumstances should the end of the shaft be driven on without proper pressure being applied at the rear of the wheel, nor should a steel faced hammer be used on the end of the shaft. 2. If the hub cap is small and the hub flange is held on by means of a number of hexagon nuts visible from the outside, proceed as follows: a. Remove the hexagonal nuts, six or eight in number. b. Gripping the hub cap and flange firmly, work it loose and pull ofif the flange when the shaft will be drawn with it. c. Remove the locking device and then the nuts and bearing, after which the wheel may be removed by hand. Rear Axles and Brakes 67 d. Be very careful to note the proper assembly of parts and preserve the sarings free of all dirt and grit. e. When replacing the bearings they should be cleaned and packed with ean cup grease. 3. When the hub cap is large the first step is to remove it, after which le axle drive shaft may be pulled by hand and the wheel removed as suggested nder 2. Fig. 75. Reo Rear Axle Adjustment. JOB 31. ADJUSTING REAR AXLE BEVEL AND PINION GEARS. For the most efficient operation as well as for quietness, it is very essential lat the pinion and bevel be properly meshed. If they are set too close igether the axle will be noisy and growl or hum. Straight bevel gears are ore prone to be noisy than the spiral bevel. The clearance recommended for •operly adjusted gears is from .005" to .008". Fig. 76 shows the results of proper and improper methods of adjusting ese gears. A careful study of the chart is well worth the student's while. 68 Automotive Trade Training There are three main reasons for rear axle adjustments. They, with the proper method of correcting same, are given below. To Take Up Wear In Bearings: 1. Loosen the lock on the holding bolts. This is usually a wire, or cotter keys. Rear Axles and Brakes 69 2. Turn the adjusting rings until all perceptible looseness is removed, but the differential or pinion shaft is running free. 3. Set and lock. To Take Out Excessive Backlash: 1. Release the locking devices on each side of the differential. 2. Turn both adjusting rings at the same time so as to allow the entire differential to be moved toward the pinion. 3. Allow the clearance recommended above. 4. Lock and secure parts. Fig. 77. Packard Rear Axle. Note method of adjusting pinion gear and bevel gear. To Remove Noise and insure Proper Meshing of Teeth: 1. If the gears are new they should be set so that the rear edges of the teeth are even. This is effected through the adjustment of the pinion gear shaft forth and back. 2. Take up any play in the bearings. 70 Automotive Trade Training 3. Move the gear in, test for noise by running the engine. 4. Move gear outward, tes*^^ again for noise. 5. Allow it to remain at the quietest point and secure by tightening and locking the holding screws. 6. Any excessive backlash must be removed by adjusting the differential. 7. When .005" backlash is allowed a barely perceptible amount of motion is detected between the gears. 8. If it is desired to test the actual line of contact of the pinion on the bevel, which is the most certain method, the pinion must be coated with bearing blue and the marks left on the bevel gear noted. Or, the blue may be applied to the bevel and the results of driving it with the pinion noted by the marks left in the blue. 9. Ordinarily gears should be inspected each 5,000 to 10,000 miles, and adjusted if necessary. 10. An axle which grows suddenly noisy should be inspected and adjusted immediately. This will frequently effect a marked saving of expense for new- parts. JOB 32. REMOVE FORD REAR AXLE FROM CAR. 1. Jack up the car. 2. Remove hub caps. 3. Remove cotter keys and nuts. 4. Secure a wheel puller from the tool room, turn on the hub and lock with the screw. Turn the set screw onto the spindle and thus draw the wheel off the tapered spindle. 5. Remove 4 bolts at the universal ball cap. 6. Disconnect the brake rods. 7. Remove nuts from the spring perches. 8. Raise the frame of the car. 9. Remove the rear axle. JOB 33. REMOVING UNIVERSAL FROM AXLE. 1. Remove two plugs from the top and bottom of the ball casting. 2. Turn the shaft until the pin comes opposite the hole. 3. Drive out the pin. 4. Pull or force the joint from the hous- ing. Fig. 7S. Timkeji Bevel Gear Mounting in tlie Rear Axle. JOB 34. DISASSEMBLING FORD REAR AXLE. Fig. 79. 1. Remove the radius rod nuts on the front end. 2. Remove the nuts from the studs holding the rear of the torque tube to the differential housing. 3. Remove differential housing bolts. 4. Working over the pan to catch the grease pull the parts apart. 5. Be very certain to place all nuts, bolts, etc., where they will be safely held for reassembly. 6. Clean the parts of grease. Rear Axles and Brakes 71 JOB 34-A. DISASSEMBLING FORD AXLE DIFFERENTIAL. INSPECTION AND REASSEMBLY. Fig. 79. 1. Remove all studs holding parts together. 2. Note as parts come apart how they are assembled. 3. Clean grease from them. 4. Study these differential gears to see how they function. 5. Which are the spider gears? 6. Which are compensating gears? 7. How are spider gears held on the spider? What work does the spider do, if any? t2 Automotive Trade Training 8. Remove one compensating gear by forcing or pressing down on the shaft far enough to permit the small split ring to be removed, and then press gear off shaft. 9. What prevents the shaft and gear from turning separately? 10. Reassemble differential, replacing any worn or defective parts. 11. Have them inspected. 12. Reassemble the rear axle housing. Great care must be used to see that the thrust bearings are properly assembled, otherwise the housing will be broken. Cup grease will hold them in place. 13. Have them inspected. 14. Remove the pinion gear from the propeller shaft by removing the cotter and nut, after which the pinion may be driven off, using a soft metal hammer or a block of wood. 15. Reassemble the propeller shaft in the torque tube and bolt it to the rear axle housing. 16. Have it inspected. 17. Place it under the car and fasten it in place. 18. Place on the wheels. Set up the nut quite snug. Inspect after 30 days to see if it is still tight. Tighten if necessary. CHAPTER 4 CLUTCHES, TRANSMISSIONS AND UNIVERSALS. Transmission Units.— Along with all other units of chassis design, the transmission has become standardized in the use of the sliding gear selective type. The most popular form is the four speed selec- tive where three speeds forward and one reverse are provided. The selective progressive is in use to a slight extent, as are also the five speed selective and the planetary and friction disk drive. Of the progressive and friction disk little need be said as they are considered obsolete. Progressive. — In the use of this type of gear box for the operator to obtain certain speeds, it is necessary that the gears must be meshed with and passed through other gears than those giving the desired speed. For instance, it is necessary to pass through second speed to reach high from a neutral position, and from high to intermediate, to neutral position, to low, and through it to reach reverse. This system is noisy and troublesome. Friction Disk. — A large disk is mounted on the rear of the trans- mission shaft. Against its polished sides or steel surface a friction wheel is forced. The closer the friction wheel is brought to the cen- ter of the disk, the slower the speed. The farther from the center toward the edge, the faster or higher the speed. If the friction wheel is brought to center position it is in neutral and if past center reverse is obtained. Progressive Selective. — In this case all gears or speeds may be selected at will, excepting only reverse, to reach which it is necessary to pass through low again. This provision is necessary as four speeds forward are provided. Selective. — The selective is the nearest approach to the ideal. Any gear or speed may be selected at will by the driyer, whether it be low, intermediate, reverse, or high. Reverse may be reached directly from high as is the need when stopping to turn. Inter- mediate, or high, may be entered immediately as is desirable in start- ing down a grade. The need of change gears in the motor car, either passenger or truck, is a matter of fact. Even the multiple cylinder engine as lepresented by the twin types does not develop sufficient power at slow speeds to warrant attempting to do without them. The inherent nature of the gasoline engine is such that it does not develop its best power at speeds commensurate with starting on high gear. This is brought out in the chapter on engines. Gear Ratio. — In figuring gear ratios it is best to remember that 73 u Automotive Trade Training in practically every case what is known as high gear is a direct drive through the gear box or transmission case. Although the gears are turning, the counter shaft is not carrying any load as it must at all other speeds. The countershaft is so designed as to be kept turning in order to facilitate speed changes and provide proper lubrication of gears and bearings. In high gear the transmission shaft is locked together and turns Fig. 80. Reo Transmission and Universals. as one solid shaft. This arrangement allows the power to flow from the engine to the propellor shaft turn for turn or a 1 to 1 ratio. The entire gear reduction in high gear, between the engine and the rear road wheels, takes place in the ring and pinion gear ratio in the Clutches, Transmissions, Universals • 75 rear axle. This varies somewhat, but about 4 to 1 may be considered an average. When the control lever or gear shift lever is put into intermediate, neutral, low, or reverse, the transmission shaft is broken or divided into two independent parts. One end may turn at speeds different from the speed of the other end. This is possible since the shaft is made with a joint and bearing at a certain point which permits of the Pig. 81. Packard Passenger Car Clutch and Transmission. shaft ends turning at diflferent speeds except when on high gear. When in the second speed position the line of flow of power is inter- rupted and shunted out of a straight line through the idler gear, to the counter shaft, thence back to the transmission shaft, through the intermediate or second speed gear, and thence on to the propeller shaft and rear axle. This allow^s the power to be transmitted to the propeller shaft at a somewhat reduced speed, the exact reduction vary- ing but being approximately 5 to 3. In this case then the engine to rear wheel reduction would be about 1 to 7. Shifting the control lever to low or first speed position gives a further reduction through the same shunt excepting that power now flows from the engine to 76 Automotive Trade Training the transmission shaft, to the counter shaft, to the low speed gear, to the transmission shaft and the propeller shaft. This gives a gear reduction from the engine to the propeller shaft of approximately 3 to 1, with a consequent gear reduction from the engine to the road wheel of approximately 12 to 1. No set figures even for passenger cars can be given, as reverse or low may be as low as 20 to 1. Speed ratios from that figure up to 3 to 1 on high gear may be found. Fig. S2. Packard 'Truck Transaiission. Reverse Gear. — When the corL|rol lever is shifted into reverse position the sliding gear on the transmission shaft is meshed not with a gear on the counter shaft, but!* -with an idler gear driven by the countershaft. The introduction of the additional gear gives the reverse direction of drive. The line of flow of power is from the engine to the transmission shaft, to the counter shaft, to the idler gear, to the reverse gear, to the transmission shaft, to the propeller shaft, rear axle and wheels. Special Transmission Types. — Transmission gears and cases are built to carry varying loads. Trucks and tractors require heavier gears and cases. To obviate the danger of stripping gears in shifting, some trucks are Equipped with transmissions in which the teeth of the gears are always in mesh. Speed changes are effected by means of sliding dogs which engage in dog clutches. The dogs having heavy jaws are less likely to be chipped, bent, or broken. Clutches, Transmissions, Universals 77 Transmission Troubles. — Transmission troubles most apt to occur are worn or broken teeth, worn or broken bearings and worn, bent, or broken shafts. A common fault which causes much inconvenience is to have the gear teeth worn a little tapering or sprung out of line due to having the load put on the teeth before they are fully meshed. This condition will cause the gears to pop out of mesh on a long hard pull. If taken when the trouble is first noticed it may be remedied by putting more pressure on the shift rod pawl spring. Fig. S3. Pierce Arrow Progressive Selective Transmission. Note the improved feature as shown in the over-running clutch which permits of shifting from high into second at high car speeds. It is seldom, however, that a permanent repair is effected in this manner. For a permanent repair it is necessary to replace the worn gears and parts with new ones. Planetary Type Transmission. — Here is used a mechanical prin- ciple rather difficult to grasp. Instead of a chain of gears as used in the selective type transmission where speeds are secured by shifting sHding gears, the planetary type uses a set of gears mounted on the flywheel which are always in mesh. In the case of the Ford car three stub shafts, studs or pinions, are mounted on the flywheel. The triple gears are mounted on these. A transmission shaft is mounted on the center of the flywheel. On this shaft is mounted a set of drums and three spur gears of varying sizes suitable to just mesh with the three sizes of the triple gears and the spaces between their inner edges around the transmission shaft. 78 AuTOMOTU'E Trade Tr \1N1NG High Speed. — Just as in other types the drive is straight through the transmission on high gear to the universal and propeller shaft. All drums and triple gears turn as one mass and part of the flywheel. On high gear the triple gears are stationary on their pinions, merely taking a free ride on the fly-wheel as it turns. Slow Speed. — Pressing on the slow speed pedal stops the slow speed drum from turning. When it is stationary and the flywheel is turning, the triple gears are caused to turn on their pivots. This is because the slow speed drum shaft has a gear on the end of it which is in mesh with the triple gears on their center or largest part. As these triple gears revolve they in turn drive the driven gear which is mounted on the hollow shaft attached to the brake drum and driving plate. Their driving action is such that they cause the driven gear and parts to be driven backward Avhile the flywheel turns for- ward. While the flywheel turns forward three revolutions, the driven gear and driving plate are backing up two revolutions. The driven gear being mounted on the flywheel has turned for- ward, however, one full turn over its original position. (These figures are only approximate.) Reverse. — The same princi- Fifr. 84. Packard Truck showing position of P^^ applies here, as it must be Transmission Units. Understood there can be no change of direction of drive from the triple gears since they are riveted together and turn as one at all times, and always in the same Clutches, Transmissions, Univ^ersals 'J'^ direction. These gears turn in the same direction on their pivots as the flywheel and crankshaft turn on the engine bearings. In both cases the direction of rotation as viewed from the rear is counter clock-wise. Pressing on the reverse pedal causes the reverse drum to be held while the triple gears travel around it. Since this gear doing the holding is larger than that part of the triple gear engaging it, each turn of the flywheel will give more than one turn of the triple gear. Four revolutions of the flywheel will give five turns of the triple gear which drives the driven gear backward at the same rate since these gears are of one size. In the case of reverse gear, while the flywheel travels forward four revolutions, the driven gear, driving plate and brake drum are driven backward five revolutions. This is one more backward for the propeller shaft then the flywheel gave forward. This gives a reverse gear ratio of approximately 4 to 1. This reduc- tion is in the transmission. When considered in relation to the rear axle ratio of about 4 to 1 the gear ratio between engine and rear road wheel is about 16 to 1 on reverse. On low speed the ratio is about II to I, on high speed about 4 to 1. (All figures given approxi- mate.) Planetary Principle Explained. — The term itself is derived from a fancied or real resemblance to the action of the planets as they travel around the sun. They have two motions, one as they travel in their orbits around the sun, the other a revolving motion as the earth turning on its axis. Since the principle is one of the most puzzling mechanical principles the student comes in contact with, several statements of problems are given. Suppose you are aboard a railroad train one mile long. We will say you are at the front end which is at the depot. There are 90 cars in the train. While the train moves ahead one mile you walk toward the rear. At the end of the mile you have come to the sixty- first car from the engine or head of the train. The rear end of the train or the caboose is where the engine started. How far have you actually traveled with reference to the point at which you boarded the train or how far are you from the depot? Now suppose the train is on a circular track, and that the caboose is in front of the engine, an endless train on an endless track. Repeat the problem. Again at the end of a mile travel for the train or engine you are 60 cars from the engine and 30 cars from the rear of the train, but now you can continue walking back while the train goes forward. Each mile run by the train finds you one-third of a mile farther from the depot. When the engine has traveled three miles you have traveled one mile from your starting point or once around the track. Next suppose you start walking back as the engine starts for- 80 Automotive Trade Training ward, and that you walk back 120 car lengths while the train and engine travel forward one mile which, as stated, is equal to 90 car lengths. How far from the depot, or your starting point, would you be and in which direction? Continuing this problem, while the train Flywheel Reverse Drum Bushing Slow Speed Drum Bushing Clutch Discs Clutch Disc Drum Clutch Finger Pin Clutch Push Ring Driving Plate Clutch Finger Adj. Screv\r Clutch Finger Clutch Spring Clutch Spring Support Slow Speed Gear^ W^^^^^I^^^^H^l^^^\ \ \ Vlutch Shift Clutch Disc Drum Key Reverse Gear^ ^^^^Sl^^^^^^^^^K X W \ \ Driven Gear Sleeve Bushing Transmission Shaft Brake Drum Driving Plate Screw Slow Speed Drum Fig. 85. Ford Planetary Transmission showing drums, gears, clutcli and other parts. goes forward three turns or miles you will have walked back four turns or miles, having actually traveled one mile from the depot, and that in a reverse direction to the direction the train is being run. The Ford flywheel may be said to be the train of cars. The driven gear with its hollow shaft, brake drum and driving plate may be said to be the person. Slow Speed. — On slow speed the triple gears are made to drive the driven gear and plate backward two turns to three forward of the flywheel. Actually it travels one turn ahead to three ahead of the flywheel. Reverse. — On reverse speed the triple gears are made to drive the driven gear backward five turns to four turns ahead for the flywheel. Actually it now gains one turn backward to four ahead for the fly- wheel. High Speed. — The clutch is not used at any time except when coming from neutral into high. On low and reverse the transmission Clutches, Transmissions, Universals 81 bands serve as friction clutches to apply the power evenly. The clutch on neutral is held out by the hand lever. When left in, which should be done with care, it locks the transmission shaft to the driv- ing plate, by means of the friction plates, the action being identical to that of any other disk clutch. The main difference is that it is not used for low or reverse speeds. JOB 35. REMOVING TRANSMISSION BANDS. 1. Take off the door on top of the transmission cover. 2. Turn the reverse adjustment nut to the end of the pedal shafts (same for the brake adjustment nut), then remove the slow speed adjusting screw. 3. Remove the bolts holding the transmission cover to the crank case and' lift off the cover assembly. 4. Slip the band nearest the flywheel over the first of the triple gears, then turn the band around so that the opening is downward.^ 5. The band can now be removed by lifting it upward, 6. The operation is more easily accomplished if the three sets of triple gears are so placed that one is about ten degrees to the right of the center at the top. 7.. Each band is removed by the same operation. 8. By reversing this operation the bands may be installed. 9. After being placed in their upright position on the drums, pass a cor<£ around the ears of the three bands, holding them in the center so that when putting the transmission cover in place no trouble will be experienced in getting the pedal shafts to rest in the notches in the band ears. 10. The clutch release ring must be placed in the rear groove of the clutch shaft. 11. With the cover in place remove the cord which held the bands in place while the cover was being installed. Caution. Be sure no small parts as a switch key, etc., are left where they' may fall or be knocked into the transmission case; also tie a cord to all smalt tools being used to prevent loss. JOB 36. RELINING FORD TRANSMISSION BANDS. 1. Carefully remove the old lining. 2. True up the metal band. 3. Place on the new lining and clamp it fast. 4. Place a block of wood in the vise, end grain up, shaped to conform tot' inside of band. 5. Hook the band over this. 6. Drive rivets through the lining into the wood. Use long and short rivets as required. It will be necessary to use a punch on some of the rivets to drive to the seat. 7. Spread rivets having the rivet head resting securely on metal. With a ball pein hammer drive the ends of the rivets a little below the surface of the lining. Unless extrerhe care is used the band will be driven out of true and, require more time to straighten than the entire job should require. JOB 37. ADJUSTING CLUTCH ON THE FORD CAR. 1. Remove the plate on the transmission cover under the boards at the driver's feet. 2. Take out the cotter key on the first clutch finger and give the set screw one-half to one complete turn to the right with a screw driver. 82 AuTOMoTivi-: Tradi-: Training «5 w fe Z 1 Oto-c2 O o£. ea on *^.ta 3. Do the same to the other finger set screws. 4. Be sure to give each the same number of turns and don't forget to replace the cotter key. 5. After a considerable period of service the wear in the clutch may be Clutches, Transmissions, Universals 83 taken up by installing another pair of clutch discs rather than by turning the adjusting screws in too far. Caution: Let us warn you against placing any small tools or objects over or in the transmission case without a good wire or cord attached to them. It is almost impossible to recover them without taking off the transmission cover. JOB 38. OVERHAULING FORD TRANSMISSION. 1. Remove the engine. Job 56, Chapter 7. 2. Remove the transmission cover. 3. Remove the engine block with the transmission assembly. 4. Remove the bands. 5. Release the clutch finger adjusting pins. 6. Remove the driving plate studs. 7. Remove the clutch discs. Keep in order. Replace in exact former position. 8. Remove the disc drum stud. 9. Remove the disc drum with a special drum puller. 10. Pull the transmission. n. Remove the driven gear from the back end of the brake drum using a press or special puller. Be careful not to break the drum. 12. Drums may now be taken apart after making certain that woodruff Ivcys are removed from the brake drum shaft. 13. To renew clutch spring and collar: (a) Press the clutch spring support into the driving plate until the pin is exposed or in line with holes; (b) drive out the pin; (c) release the tension and the parts may be disassembled. 14. Examine triple gear rivets. Replace or tighten. 15. Inspect all bushings for wear and replace where needed. 16. Any necessary magneto work may be done at this time. 17. Clean all parts, especially clutch discs. Do not confuse these. Scrape with knife and scrub with kerosene. 18. Repairs having been made, parts may be reassembled, reversing operations. JOB 39. STANDARD SELECTIVE TYPE TRANSMISSION OVERHAUL It is not unusual for the transmission gears to be so worn as to make their replacement necessary. The main cause of this is the failure of the driver to understand the proper method of handling' his car with reference to speed •changes and clutch manipulation. Clashing and scraping of gears in shifting and allowing the load to come onto them when only partly in mesh will quickly •damage the gears. The transmission shaft also is subject to unusual wear for the same reasons. In overhauling the transmission proceed as follows: 1. Inspect the job to see what is necessary to remove the transmission case as a unit. In many cases it is necessary to remove the rear axle. In others this is not necessary. 2. Take the case to the bench where the exterior is first cleaned. 3. Inspect the case to learn what is necessary to remove the bearings, shafts, and gear assemblies. Drain the oil. 4. Remove the gears and shafts. 5. Clean all parts free from grease and oil. 6. Inspect parts to see which must be replaced. Where gears are chipped, cracked, or worn beveled, it is necessary to replace them. Where the bearings and bushings are worn it is necessary to replace them. Inspect the bushings 84 Automotive Trade Training in the end of the clutch shaft or in the forward end of the transmission shafts This is particularly subject to wear, 7. Where gears are riveted together or onto the shaft, it will be necessary to cut out the old rivets and replace them with new when the new gears are in position. 8. Note particularly the assembly so as to avoid any mistakes in reassem- bling the parts. Clutches. Transmissions, Univeksals 85 9. When the gears are all reassembled in the case, they should be shifted to see that the full width of the teeth is engaged when they are in mesh. This is very important. 10. It is sometimes possible to change the position of the gears by adjustments on the shifting forks. 11. See that the pawls and springs which lock the shifting fork rods in position are in good condition. 12. Where the clutch is a unit with the transmission go over it carefully. If the lining is dirty and greasy it should be cleaned with gasoline or kerosene. If badly worn it is economical to replace it at this time. 13. Replace the overhauled case in the car, making certain that all of the bolts and nuts are properly secured. 14. Fill to the level of the center of the counter shaft with the proper lubricant. (Job 40.) 15. Test. JOB 40. STANDARD SELECTIVE TYPE TRANSMISSION CARE. 1. In the case of a new car it is well to drain away all old oil and flush out the transmission case after several hundreds of miles of service. The reason for this is the fact that at times in process of manufacture foreign substances are left in the transmission case and may work considerable damage. Also, the first few weeks of service will occasion more wear as the parts wear in. than the succeeding thousands of miles will produce. All filings, chips and fragments of metal are carried by the oil to the bearings, unless the trans- mission is flushed and drained as suggested. 2. Refill the case with the oil recommended by the manufacturer. This is usually a heavy black molasses-like oil known variously as transmission oil, steam cylinder oil, and 600 W. In some instances a light graphite grease is used, and in other cases cup grease and gas engine cylinder oil are mixed to form a "dope" which is used for transmissions and rear axles. 3. Never fill ^ transmission case with a cup grease alone. It will all work out of the gears and bearings, clinging to the sides of the case where it does no good whatever. 4. After the first proper cleaning the case should be drained, flushed and properly refilled each 5,000 miles. 5. If the shift lever tends to pop out or jump out of second, or any other speed on a long, hard pull, it is likely that the gears are a bit worn or l)eveled. This trouble is sometimes due to the fact that the shift lever pawl spring needs strengthening. To do this, remove the old and replace with a new spring. A washer under the old spring will at times remedy the trouble. CLUTCHES The use of the clutch might be said to be similar to the hitching up and unhitching of a horse from a wagon. When the clutch is in, the power may be applied to move the load. When the clutch is out, power is no longer being transmitted through to the rear axle. Even and smooth application of power is possible when the clutch is in good condition and is eased in by the driver. A sudden leaving in of the clutch is like a horse starting too suddenly. Disaster is likely to be the result. In the case of the horse and wagon sudden starting results in broken harness and singletrees. The same equipment will move equal and larger loads for many years if the horse can be 86 A U TO M OT 1 V E 1' K ADE T R A 1 N 1 N G taught to take hold on the load slowly and steadily. The horse will also last longer. With the motor car sudden dropping in of the clutch will spin the wheels, cut tires, stall motors, break transmission Fig. 88. Heavy Duty Clutch of the Multiple Disc Typa. shafts and gears, break rear axle gears and shafts, and generally bring rack and ruin to all power transmission parts. An even steady application of power through easing in of the clutch will result in a saving of all parts used in the transmission of power as well as tires. Careful handling of the clutch will do more than any one other thing the driver is tble to do to prolong the life Fiyvviu-el Fig. 89. Marmon Cone Clutcb and Fly Wheel. Clutches, Transmissions, UxNixeksals 87 of the car. Careless handling of the clutch in the shifting of gears and general use of it will take many years from the normal life of the chassis. Types of Clutches. — Plate, multiple disk and cone clutches are those in general use. These may be designed to operate with or without oil. If without, they are said to be dry clutches, if running in a bath of oil they are said to be wet clutches. The dry clutch Fig. 90. Allen Transmission and Plate Clutch holds a larger degree of favor. In every clutch the principle of opera- tion is to bring some material possessing great friction qualities into contact with a polished steel surface. Pressure of the clutch springs holds it against the steel surface and pressure on the clutch pedal leleases this first pressure by compressing the clutch springs. The great pressure induced in the clutch spring when it is compressed by the clutch pedal and related parts will immediately throw the clutch back in when the foot pedal is released. Because of the strength of the clutch spring it is sometimes impossible to leave the clutch in S8 Automotive Trade Training without having it grab. It also makes it very hard to teach the Device how to handle the clutch as he is apt to think that all he needs to do is to release all pressure from the pedal to have it engage properly. Releasing or throwing out the clutch stores in the clutch spring the power used in throwing the clutch in. This power must -be released very gradually in order to insure proper starting of the car. Cone Clutches. — The cone clutch is usually fitted into the rim of the flywheel. The flywheel has the rim turned or bored out on a slight angle as may be noted in the illustrations. This insures a wedg- ^^^^^^^^|RS^^__^ 1 L -Sj ^■■^^ ^^2>^ ■irr- •^*^'^^ ^ ^ ^ ill ■n ■H ^ i^B^^^^^^ fci Fijr. 01. Pan) Pnssenyer Car Multiple Disk Chitch. ing action as the clutch comes in, and a clearing action as the clutch is thrown out. The clutch is controlled by means of the left foot pedal as are all other types. The spring action here may be of several types. Either one large spring is mounted over the clutch i)haft, or the clutch shaft is provided with a collar and web through Avhich bolts are run allowing three or more springs to be used on the back of the flywheel to give the proper tension for holding the clutch in or properly engaged. Either style may or may not be ad- justable for spring tension. Plate Clutch. — The plate clutch, of which the Borg and Beck is the most popular type, is one in which a single plate or heavy disk Clutches, Transmissions, Universals 89 is gripped between two rings of friction material. One of these rings is fastened to the face of the flywheel, and the other to a thrust ring mounted on and driven by the flywheel. When the clutch is out, the single driving plate is left free to stand still beween these two friction lined surfaces. The load is taken by this plate as the clutch is left in, and the speed of the plate is gradually picked up or brought up to a speed corresponding to that of the engine fly- 90 Automotive Trade Training wheel. At this point it is gripped and held. Through it the power then flows or is transmitted to the transmission propellor shaft and rear axle. Disk Clutches. — The main point of difference in the wet and dry disk clutch may be said to be one of operation. With the dry clutch the driver must be depended on to leave the clutch in gradual- ly and easily. With the wet clutch the oil may be said to make the operation semi-automatic, as oil left between the plates is forced out gradually, until when the oil is practically all forced from between the plates or disks the clutch is holding fully. The manner of transmitting the power is identical in each case. In most designs a set of pins is mounted on the flywheel and on these pins is mounted one set of disks. When the flywheel is turning the plates mounted on it turn with it, although they are free to move back and forth on the pins as the clutch is thrown or left in. These- disks do not touch the clutch shaft but have an opening at the center large enough to clear it readily. When disks are mounted on the clutch shaft, which is usually the front half of the transmission shaft, they are made and mounted in such manner that they are free to slide forth and back on the shaft, but must always turn with it. These disks are made small enough to permit their turning inside the set of pins mounted on the flywheel and carrying the other set of disks. Of the two sets every other disk is mounted on the flywheel pins,, and every other one is mounted on the clutch shaft. For the sake of clearness, suppose that there are nine disks tO' the clutch. Five of these would be mounted on the flywheel pins, and it is likely that these five would carry the rings of fric- tion material. Four of the disks without lining would be mounted on the clutch shaft, turning only with it. Pushing the clutch pedal down releases the pressure holding the plates or disks together, thus permit- ting them to separate. With the pressure off, the disks on the clutch shaft gradually come to a stop. To hasten this action most designs incorporate a clutch brake which comes in- to action as the clutch pedal reaches its limit of travel. With the foot pedal down and the plates separated, the clutch is said to be out Fijr. 93. Kelly Springfield Cone Clutch. Releasing the Clutches, Transmissions, Universals 91 clutch pedal permits the clutch spring to throw the plates back to- gether at which position the clutch is said to be in. As stated above, the set of plates carried by the flywheel are the usual ones to receive the clutch lining, as weight is not detrimental in this case as it is in the case of the set on the clutch shaft which must be stopped quickly. Fig. 94. Borg and Beck Dry Plate Clutch. Grease and Oil Soaked Clutches. — Occasionally, especially the exposed cone type become soaked with oil and grease, and slipping of the clutch results. This surplus oil should be removed and the clutch lining treated with neatsfoot oil. Neatsfoot Oil. — This is the standard remedy for clutch leathers and linings. Properly used, it makes the leather soft and pliable 92 Automotive Trade Training bringing out its natural friction qualities, thus giving the clutch a chance to hold onto the polished steel. Automotive accessory supply houses carry a line of neatsfoot oil especially prepared for clutch Hnings. It may also be secured from drug stores. Castor oil is sometimes used as a substitute. Grabbing Clutch. — This condition is due to a dry hard lining. Either leather or fabricated linings are subject. An application of neatsfoot oil vv^ill make the lining soft and pliable, after which it will respond to careful handling by the driver without grabbing. Slipping Clutch. — Just the opposite of grabbing is the case here. The remedy is the same. The lining should be restored to its original state by the application of neatsfoot oil. At times the wear on the lining has decreased the normal spring tension or the springs them- selves may have become weak. In this case it is advisable to increase the spring tension, or to replace the old springs with new ones. Sometimes a spring will become broken. This fact cannot always be detected as the springs are frequently entirely enclosed. To in- spect the spring it may be necessary to dismantle the clutch. Wet Clutches. — A clutch made to run or to operate; in oil may need to have the oil drained, the parts flushed with kerosene and the case refilled with the grade of oil recommended by the manufacturer of the car in question. The wet clutches may be of any type, but the wet disk is most popular. The wet cone clutch is also in use. If the oil is not of the proper consistency, slipping may result. JOB 41. CLEANING AND OILING AN EXPOSED CONE CLUTCH. In cases where the clutch is of the cone type, the dirt and grease accumulating on it will result in clutch trouble. To remove it the floor boards are removed and a stiff paint brush and kerosene are used to wash the oil and dirt away from the parts. When the exterior parts are clean the brush is next cleaned and a fresh supply of kerosene secured. Prop the clutch lever with a short stick to hold it in "out position". Wash out the grease from the clutch lining and the face or seat on the flywheel. Apply a coat of neatsfoot oil. JOB 42. APPLYING A NEW LINING TO A CONE TYPE CLUTCH. When the clutch facing, which is usually leather, is worn or burned to a point where it will no longer hold, it is necessary to reline or recover the cone. Certain fabrics similar to brake lining are also used for clutch facings. The methods of replacing old with new are similar no matter which material is used. It is a very excellent plan to use the type of facing recommended by the car manufacturer since he has doubtless experimented with a number of styles and knows what is best for his product. 1. In most cases it is necessary to drop the transmission unless the trans- mission happens to be built as a unit with the rear axle, in which case the rear axle may have to be pulled. 2. Make such further arrangements and adjustments as are necessary to get at the cone. 3. Remove the old lining being careful not to harm the cone surface. Clutches, Transmissions, Univeksals 93 Clutch Pedal should be ad- justed so there is % inch be- tween pe^al and bottom of Toe Plate. This Stop is provided for the purpose of limit- ing the amount of throw, so that pedal does not hit toe-plate. Adjust here in conjunction with Clutch Pedal Stop. I f sufficient /^throw-out cannot be obtained through the ad- justments, a n earlier separa- tion of Clutch Discs can be obtained by placing a #2 inch washer on each driving stud at this point. Wear of Clutch during first 500 miles moves Clutch Collar away from Clutch necessi- tating freedom of Clutch Pedal so it can move farther up through Toe Plate. Showing Clutch fully di sen- gaged. Fig. 95. Hudson Clutch Pedal Throw Out Adjustment. 94 Automotive Trade Train i Nc; 4. Fit on the new lining stretching it evenly. If a leather cone lining, it is well to soak the leather in water or neatsfoot oil before applying. 5. Countersink for the rivet heads and see that they are sunk well under the surface of the lining. 6. In cases where flywheel disks with spring arrangement are used, they must be in proper position when the facing is applied. 7. Reassemble the clutch, being very careful to have all parts cleaned. :greased and in their proper position. The clutch spring may be compressed in the vise and wired together to make its assembly somewhat easier. JOB 43. RELINING A DISK OR PLATE CLUTCH. When the take-up on this type of clutch is all used so that the clutch can no longer be adjusted to prevent slipping, it is necessary to remove the transmission and clutch in order to dismantle it and reline the disks or plates with new facings. Use the style recommended by the manufacturer. 1. Remove the transmission and clutch assembly, or such parts as may be necessary. 2. Dismantle the clutch parts, preserving them in order. 3. Remove the old lining. 4. Replace the old with the new lining»or facings. These are usually applied two to one disk with the rivets through both. In selecting rivets for this work make certain that they are just the proper length to properly head up when the other, or head end of the rivet, is properly countersunk in the opposite Iming. 5. Set the countersunk head on a punch held in the vise while riveting the end over with a small ball pein hammer and rivet set or punch. 6. Reassemble clutch using extreme care to have all parts put back in order. See that parts are clean and bearings properly adjusted and lubricated. 7. After the new facings are in service a short time, they are very likely to need some adjustment for the first wear which is more rapid than later when they have been worn in. JOB 44. ADJUSTING A BORG AND BECK TYPE CLUTCH. In Figure 96 is shown the Allen car with indicated clutcli adjustment. In some cases it is necessary to remove the inspection plate of the clutch and flywheel housing. 1. Remove the inspection plate if such is used. 2. Turn over the engine until the two adjusting screws are located. 3. Holding the clutch in the "out" position these are both loosened. 4. Gently tap or move these screws in a clock-wise direction from Y^" to 3/2". Tighten the adjusting screws. A very little movement is sufficient. 5. Replace the inspection cover and floor boards. Test. If further adjustments seem necessary make them in accordance with the above instructions. JOB 45. CLUTCH COLLAR CARE. The clutch is always thrown to the "out" position by pressure on the foot pedal. This pressure is transmitted to the clutch collar and through to the springs. The collar is standing still while the clutch and springs are revolving. A tremenduous pressure is thrown onto the clutch collar bearing, and unless this bearing receives proper lubrication the collar will become worn and make trouble when gears are to be shifted. 1. Keep the collar lubricated by giving the grease cup a turn each day when the car is in service. 2. Make certain the grease reaches the collar or bearing. Clutches, Transmissions, Universals 95 3. The bearings are either bronze or ball thrust. 4. Do not allow the weight of the foot to rest on the clutch pedal while the car is in service except when the clutch is actually in service. To do so Qutch Pedal Location Adjustment Fig 9G. Adjusting Borg and Beck Type Clutch, is likely to start the clutch slipping, or by placing a constant strain on the collar •cause it to be burned out. Either of the above conditions is serious. 5. A burned clutch collar acts just as a clutch brake, and in bad cases •causes the clutch to stop so quickly that it is impossible to shift gears properly. UNIVERSAL JOINTS Mechanical Principle.— The mechanical principle of the universal joint is simple, although in its application some very complicated problems are met. A universal joint may be said to be the coupling of two shafts endwise so that the one may give a rotary motion to the other when forming an angle to it, and at the same time may be moved freely in all directions. Many elaborate and complicated forms have been worked out and designed to fit some particular need, but all forms reduce in principle to the plain gimbal joint shown in Fig. 100. To a casual observer the need for universal joints in the propeller shaft of an automobile is not always present. At first glance it would seem that the propeller shaft might be run in a straight line from the transmission case to the rear axle wnthout the use of any uni- versal joints, but a moment's thought will show how impossible this is. The absolute necessity for a universal arises from the fact that the engine is mounted on a rigid frame and therefore moves up and 96 Automotive Trade Training iTEtRlNCr VVUKEl, l-RONT UNIVEKSAL JOINT W./TOM'.1i.!( Fig. 97. Front end of Allen Chassis. down with the springs while the rear axle follows the contour of the road. Or, the result may be said to be the same as if the frame were still and the rear axle moving up and down'. Aside from the move- ments described above there is always present a slight weaving of the frame which adds to the necessity of the universal. FRHMT PDripirt I f.fi SHAFT AND UNIVERSAL JOINTS SUPJOW 0!L TIGHT WASHER REAR PROPELLER SHAFT AND UNIVERSAL JOINTS Fig. 98. Propeller Shafts and Universal .Joints for Trucli Use. (Standardized Military Model Class B.) Clutches, Transmissions, Universals 97 In some machines the transmission is placed at a distance from the clutch and is not attached to the crank case. This is known as mounting the transmission admidship. With this construction it is necessary to provide universals between the engine and transmission to care for the weaving of the frame and the likelihood of the two- units not being mounted in absolute alignment. Fig. 99. Illustrating need of universals and contrasting straight line and angular drive. Angle of Drive. — In Fig. 99 is shown what is meant by straight line and angular drive as applied to the automobile chassis. The problems which must be solved in designing a universal are evident when considering the lower chassis. In the ordinary form of the metal universal the ends of the shaft are forked and fitted over a central or connecting piece in the shape of a cross, which construction allows each shaft to be moved freely in any direction. The amount of movement is held within certain limits. A rotary motion of one is readily transmitted to the other without much loss of power unless the angle of drive becomes too great. It is evident that the nearer to a straight drive the less the friction in the universals and the greater efficiency obtained. The nearest approach to the ideal is to have the motor car so designed that the line of drive is approximately straight when the car is loaded. Action then is about equal above and below center when the car is driven over the road. Cars having a considerable angle of drive when under full load have that angle greatly increased as the car is driven over rough roads and spring: action takes place. This induces faster wear. Type of Universals. — All universals formerly used for motor cars were made from metal. These were either the ball and socket, block and trunion, or the split ring types. These features are cared 98 AuTOMOTixi; Trade Tratninc, Fig. 100. Simple Metal Type of Universal. for in every case ; that is, arrangement is made within certain limits for the transmission of power from one shaft to the other no matter what angle the shafts may .be in with relation to each other. One other provision is also made. That is the slip joint. Fig. 101. Thermoid Hard.v Fabric T^niversal in Detail and Assembly. Fig. 102. Result of Thermoid Hardy Strength Test. Slip Joint. — When the rear springs are in action the distance between the transmission and the rear axle is constantly changing. When the springs are compressed and when they rebound the distance is first shortened and then lengthened. Provision for tak- Clutches, Transmissions, Universals 99 ing care of this difference is made within the universal joint in what is known as the slip joint. Referring to Fig. 98 it will be seen how the spliced shaft moves back and forth within its counterpart. Fabric Universals. — The Thermoid-Hardy universal is perhaps the foremost one of this type. It consists of a coupling in which the ends of the shafts are permanently bolted to disks of flexible fabric in such manner that there are no metal to metal bearing surfaces. Friction is thus entirely eliminated and no lubrication whatever is needed. The result is a pliable joint of enormous strength and great durability, which requires no protection and no attention. The fabric is so treated that it is impervious to oil and water and no amount of sand and dirt from the roadbed can injure it. The elastic disks act as cushions in the driving shaft, absorbing all the damaging shocks •and jolts which are intensified by metal to metal contact. This' tends to increase service and protects the other parts of the car used in transmission of power. Another great advantage is the absolute silence of the joints in operation. The shock absorbing properties of the fabric universal are espe- cially noticeable in starting a car. The engine is called on to move Fig. 103. Thermoid Hardy Universal applied to the rear end of propeller shaft for a truck. a ton or more of dead weight each time the clutch is left in. The flexible fabric is so elastic that the engine is permitted to take up the load without a sudden clash of metal parts, as the forward end of the 100 Automotive Trade Training propeller shaft is permitted to turn a bit before causing the axle shafts to start turning. The result is a more even flow of power from the engine to the drive wheels with less severe strain on the running gear. The elasticity also insures an even turning speed as an}) fluctuations in the velocity of the propeller shaft are taken up and equalized in the joint. Slip Joint Unnecessary. — One advantage of the flexible fabric construction for a universal is that it allows considerable longitudina or end play. The need of this for the all metal joint has beer explained. The fabric type will care for as much as one inch play This is as much as is ever found in any well designed car and mon than in most cases. TRANSMISSION Fill with Tranvfniuioft frca** monthly throggh gcw ■hiti • cpenin« UNIVERSAL JOINX. Fill w.th leatpoonh ol f rraM naenthly UNIVERSAL JOINT y^ Pill with icatpoonful of grc«s«. monthly Fig. 104. Universal Joint Lubrication. Note Leather Boots. Clutches, Transmissions, Universals 101 A test of this type of universal was made to learn the compara- tive strength. A picture of the result is shown in Fig. 102. As can be seen the tubular shaft was twisted before the joint proper was damaged at all. JOB 46. UNIVERSAL JOINT LUBRICATION. Because of the fact that it will operate without lubrication, the universal joint is perhaps the most neglected unit on the car. Lack of lubrication is certain to cause the metallic joint to deteriorate very rapidly and become very noisy. 1. Raise the floor boards. 2. Locate and remove the filler plug. This is usually a one-eighth or one- quarter inch pipe plug. 3. With a grease gun force into the plug hole a quantity of medium cup grease sufhcient to fill the joint about one-half full. 4. In cases where the joint is dry due to neglect of proper filling, or due to replacement of parts or overhaul, it is well to apply a quantity of medium oil to start lubrication and then fill with the cup grease. 5. Never fill the joint entirely. JOB 47. UNIVERSAL JOINT OVERHAUL. In all cases where the universal has worn to such a degree that there is an unwarranted amount of backlash, it is necessary to replace the parts subject to wear. In removing the universal joint it is frequently necessary to pull the rear axle. In some cases where two universals are used this is unnecessary. In every case where a torque tube is used it is necessary to pull the axle. 1. Inspect the job to learn what work is necessary. 2. Do this preliminary work and pull the universal. 3. Take the universal to the bench and clean free of all grease and oil. 4. Dismantle completely. Inspect and order the parts needed. 5. Reassemble and replace in the car. ^ 6. Lubricate as suggested in Job 46. CHAPTER 5 POWER GENERATION AND POWER PLANTS ENGINES, POWER GENERATION Power Generation. — In order that the student may properly understand engine care and operation, and more especially all phases of engine repair work, he must have a thorough working and speak- ing knowledge of the theory of the internal combustion engine. He must know exactly the relation of moving parts to each other, also Fig. 105. Packard Liberty Airplane Engine. the closeness and types of fits between them. He must know the proper functioning or working of each and every part of the engine, be it bolt or shaft, gear or valve, block or gasket, port or piston. Knowing this, he will be in a position to grasp the purpose and meaning of the various systems as the oiling system, the fuel system, 102 Power Generation and Power Plants 103 the cooling system, the ignition system, the starting and lighting system, all of which are built in as an integral part of the modern motor car engine or power plant. To these units is added the trans- mission to make what is termed the unit power plant. Pig. 106. Continental Engine 7R. Fig. 107. Sectional View, Continental 7R. 104 Automotive Trade Training The commercial power plant is a plant where under one or more roofs is housed the means of developing or generating power to be transmitted elsewhere in the community, there to light lamps, to turn machines and to do work. The automobile power plant is that part housed under the hood and used to generate power which trans- mitted to the rear axle will propel the car. Incidentally it also gener- ates its own electrical energy which is used to ignite the charge with- in the cylinders, light the lamps, charge the storage battery, and per- form other minor operations. Limitations of space and need of great power have resulted in Fig. 108. Dodge Power Plant, Left Side. the engineers perfecting the design of the various units in a remark- able manner, until nowhere else is to be found such compactness and flexibility of power as in the automotive equipment power plants. The basis of their start was, of course, the cylinder in which a charge- of fuel was exploded and made to do work. It is common knowledge that when certain fuels are set afire they burn so fast that the result is termed an explosion. Natural gas, acetylene gas, alcohol, gasoline, kerosene, benzine, nitro-glycerine, and certain other fuels are regarded by all as being dangerous to handle due to their Hability, tinder certain favorable conditions, to explode. Except for the tre- mendous force or power developed by these when exploded no one would fear them. Coal is handled, usually without a thought of danger or harm from an explosion. Yet, it is quite possible to pul- -verize this fuel, mix it with the proper amount of air or oxygen and explode it with disastrous or beneficial results, depending altogether Power Generation and Power Plants 105 on whether or not the force or power generated from the explosion is directed into the proper channels by means of some mechanical device. In the case of the internal combustion engine, and more partic- ularly the gasoline engine as used in the motor car, the engineers have designed and built a machine which takes a raw fuel, breaks it into small particles, mixes the vaporized particles with air, puts a quantity of the mixture in a cylinder, forces that quantity into a small space, Fig. 109. Dodge Power Plant. Right Side. • sets it on lire thus exploding it, uses the power developed, throws off the burned or useless smoke and gases, and is ready and able to do this complete operation hundreds of times a minute. As this chain of events takes place in first one cylinder and then in another, and in regular intervals of time in each and every cylinder, the engine develops that regular flow of power which is so desirable. All systems saving only the lighting serve one major purpose only, that of generating power and delivering it to the transmission system. Each bit of fuel burned in each cylinder means a bit of power developed and controlled to do the work we want performed. A certain per cent of the power developed within the engine is neces- sarily used to overcome internal losses as friction, etc., and keep the engine itself in motion. Only the surplus, over and above this amount, is available for driving the car. Names and Location of Engine Parts. — Whether the engine is a four, six, eight, or twelve cylinder, the general design is quite sim'lar. 106 Automotive Trade Training Parts used in the construction bear the same names and general rela- tion to each other. Referring to the two cuts of the Dodge Unit Power Plant and the cut of the Dodge Engine Section (Figs. 108, 109, 110), the proper names of most engine details may be learned. Other cuts appearing elsewhere will also prove of help to the student in becoming familiar with general design and names of engine parts. Operation. — Since the gasoline engine is not capable of generat- ing power until first set in motion from an outside source of energy, an electric starting motor has been incorporated in most cases. Press- Power Generation and Power Plants 107 ing the starting switch draws current from the storage battery, which drives the starting motor, which in turn drives the crankshaft, or turns it over with all the parts directly related to it, in fact all the moving parts of the engine, until a fuel charge has been drawn in, compressed and fired. When this first chaige is fired the engine becomes active, having now power within itself to keep the parts turning. However, it is so arranged that in another half revolution, in the case of a four, another charge is fired in another cylinder, in another half revolution another charge is fired in the third cylinder, in still another half revolution the fourth and last cylinder is fired, and after still another half revolution of the crank shaft the cylinder first to fire is fired for the second time. Each of the other follows Fig. 111. Packard Twin Six Unit Power Plant. in its regular turn, thus keeping the engine operating and developing the desired power. The operation of the engine with reference to handling fuel is called the four cycle principle, more properly called the four stroke cycle. The Four Stroke Cycle. — A cycle is a completed chain of events which leaves the operation finished so that the next event due is the one with which the start was made. To illustrate, consider the cycle of seasons. The year which is one cycle of seasons is completed every 365 days. These 365 days are divided into twelve months while the twelve months are divided into four seasons, winter, spring, summer, and fall. Since the birth of Christ, 1921 of the cycles of seasons have been completed and the 1922nd is well under way. The 108 Automotive Trade Training seasons occur in order always. The Creator has arranged the mechanical features of the Universe so that no other order is possible. The earth revolves on its axis, follows on its way on its orbit, the sun retains its position and as a result we regularly have winter, spring, summer, fall, etc., etc., cycle of seasons after cycle of seasons. In designing the gas engine, engineers have found that there are four events or operations which must always follow each other with unvarying regularity. If they occur in any other manner for any reason, the engine fails. Practice is absolutely dependent on prin- ciple. To obtain power from any cylinder of any engine the events for that cylinder must be in the following order : Intake of air and fuel, compression of charge, explosion of charge and development of power, exhausting of burned gases thus completing for that cyHnder the first cycle of operations. However, the engine does not stop with the completion of the cycle but goes immediately into another cycle until each cylinder has a continuous chain of events occurring in it, as intake, compression, power, exhaust; intake, compression, power, exhaust; and on and on. ^ The 'student will remember that while one cylinder is running its cycles the others are falling in line with theirs, so that the events occurring in each cylinder might be compared as given in "Fig. 112, representing the order in the Dodge engine. Also remember that a cycle requires four strokes of the piston, and two revolutions of the crankshaft and flywheel to complete it." "sA stroke of piston and piston rod is either from top to bottom or from the bottom of the cylinder to the top of it. One stroke equals cycle. Two strokes equal 1 revolution or J4 cycle. Three strokes equal 1^ revolutions or % cycle. Four strokes equal 2 revolutions or 1 cycle. In the diagram the width represents the length of a cycle. Two revolutions make one cycle. Four strokes make one cycle. The firing order of the cylinders is 1-3-4-2. Supposing cylinder 1 is on power, cylinder 3 must be on compression since in this case it fires next. Cylinder 4 must be on intake 1 1 0/i/e Cf/cM 0/T& /kro/ut/en One. Ifero/uiiof due One Stroh One StmJte StmHe / < B / c 3 c- < £ 1 4- / C^ ^, £ 2 £ / C^ < 1 < £ / ^ 3 C^ < £ 1 4- 1 t- < £ Z e / ^ < / < £ 1 C^ 3 ^ < £ / A revolution or ^ Power Gexeration and Power Plants 109 < O eo -S— •*> 3 while 3 is compressing, and on comoression while 3 is firing. Two, which is the fourth cylinder to fire, must be on exhaust while 1 is firing, because it will be on intake when 3 is fired, and on compres- 110 Automotive Trade Training sion when 4 is fired. In the case of the four cyhnder engine, at no time is the same event occurring in two or more cylinders at the same time. For each half revolution of crank shaft and flywheel one is fired, one exhausts burned gases, one draws in a new charge, and the other compresses a fuel charge. There are always as many EXHAUST VALVE EXHAUST Ot/TLCT PASSAGE GAS INTAKE PASSAGE EXHAUST VALVe xmaust outlet / PASSAGE ^XHAUST VALVE EXHAUST OUTLET / PASSAGE GAS INTAKE PASSAGE EXHAUST VALVE EXHAUST OUTLET PASSAGE Fig 114. Four Stroke Cvcle illustrated. cycles in operation in an engine as that engine has cylinders. In c. four cylinder engine four cycles are in operation ; in a six, six cycles ; in an eight, eight cycles ; and in a twelve, twelve cycles. Each cycle will be completed in two revolutions of the crankshaft. Since in the case of the four cylinder engine, four cycles are in Power Generation and Power Plants 111 112 ' Automotive Trade Training operation four will be completed in two revolutions of the crank- shaft ; in the six, six will be completed in two revolutions ; in the eight, eight will be completed, and in the twelve, twelve will be completed in the two revolutions. One-half the number of cylinders represents the number of cycles completed each revolution of the crankshaft, and since there is one power impulse for each cycle com- pleted, one-half the number of cylinders represents the number of power impulses per turn of the flywheel and crankshaft. This gives two power impulses per revolution of engine flywheel for a four cylinder engine, three for a six cylinder, four for an eight, and six for it twelve cylinder engine. From this is easily learned the reason for the more even flow of power as the number of cylinders is increased. Cycles Completed per Minute. — Since the above figures repre- Fig. 116. Peerless Eight Power Plant. sent actual conditions v^ithin the four cycle engines, and 1,000 revolu- tions per minute may be taken as an average engine speed in driving, it would be well for the student to gain an idea of the rapidity with which the events in a cycle take place, and what it has meant to design an engine which would insure their occurring in right order and in the fraction of a second. In a four cylinder engine there are two power impulses, meaning two completed cycles per revolution, therefore there would be 2,000 completed cycles within the engine per minute. Since each cycle means four events there will be 8,000 events within the engine per minute. Two thousand of these are Power Generation and Power Plants 113 intakes, 2,000 are compressions, 2,000 are power impulses, and 2,000 are exhaust operations. In a twelve cylinder there would be 6,000 cycles completed per minute which means 24,000 events or operations, which include 6,000 power strokes, 6,000 exhaust strokes, 6,000 intake strokes, and 6,000 compression strokes. The student would find interest in estimating the number of events or operations within the six and eight cyHnder engines, and then the number occurring in a twelve cylinder when driven at its highest rated speed. While one year of 365 days is. needed to complete a cycle of seasons, as many as 1,700 cycles may be completed within a single cylinder of a modern engine in a minute. Multiplying this by the number of cylinders gives a rather accurate figure for the modern high speed engine at its best or greatest speed. Each one of these cycles requires four strokes of a piston to com- plete it. How it has been possible to have this number of operations occur in such short spaces of time will be learned in studying the function- ing of engine parts, particularly valves, cams, timing gears, pistons, camshafts, and crankshafts. CHAPTER 6 FUNCTIONS OF ENGINE PARTS TROUBLES AND REPAIRS Crank Case. — The crank case is used as a rule to carry all other parts of the engine and is in turn carried by brackets cast integral with it or bolted to it. The outer ends of these brackets are attached to the frame. If there are three of these brackets supporting the weight of the engine, the engine is said to have three point suspen- sion; if four, four point suspension. The three point suspension is most in favor as it permits of greater movement within the car frame without throwing strains onto the engine itself. The crank case is Fig. 117. standard Eight with Pan or lower half of crank case dropped. Note position of Pistons. Rods, etc. •usually divided into upper and lower halves. The engine brackets may be attached to either part but are found more often on the upper half. This part is usually the one carrying the main engine bearings. "When this arrangement is used, the upper part is called the crank case while the lower part is called the oil pan. This arrangement frees the oil pan of all weighty parts and permits of the pan being dropped for bearing inspection, either rod or main bearings, also for cleaning, without removing the engine from the frame of the car- Fig. 119, showing the Marmon crankshaft mounted in the crank case with oil pan removed, illustrates this. While the above is the most approved design, engines may be 114 Functions of Engine Parts 115 Fijr. lis. Sectional View of Cadillac Crank Case. found with the l:)rackets on the lower half, and even in rare instances crankshaft bearings may be found in the lower half of the crank case. In still other instances the crank case is cast in one piece with inspec- tion plates on the sides to be removed for minor repairs. This is m * • Au B m t =^ 18$ fc,r*i» !,5 m I 'ik ^ --x^l.> Fig-. 119. Marmon Upper Half Crank Case. called the barrel type case. For major repairs the engine must be lifted from the frame of the car. Then all cylinder blocks must be pulled from the case as well as all rods and pistons removed from the crankshaft, after which the shaft with the main bearings loosened and 116 Automotive Trade Training ST RAIN en sc/fcf^ Fig. 120. Cole Eight, Oil Pan and Tray. removed may be pulled from the end of the case through the opening left when the main bearings were removed. It is also well to remove the flywheel before attempting to remove the shaft as there is less danger of harming bearings or shaft without its added weight. In the case of some eights the crank case is split vertically and the shaft bearings attached to one-half of it. Fig. 121. Marmon Cylinder Blocks with Head Removed. Owing to the size of the crank case, aluminum has been used very extensively in casting them since it materially reduces the weight. However, as this metal is always costly, an increasingly large number of the oil pans are made from pressed steel. In some instances the upper half is made from cast iron and is supported with pressed steel brackets. Functions of Engine Par rs 117 In a number of instances the upper half of the case is cast inte- gral with the cylinder casting, and in some instances the barrel type case is cast integral with the cylinder blocks. Either method makes for fewer parts. Each has its own peculiar advantages and dis- advantages as will be noted in study and shop practice. Distributor intake Clamp Crank Shaft Cam Gear Bearing Stud Crank Shaft Cr;mk Shaft Ct-ar Bearing Cap Fig. 122. Front View Apperson Eight, L Head Motor. In all cases the lower half or oil pan is provided with suitable oil levels depending on the type of oiling system in use. Cylinder Blocks and Cylinders. — The function or purpose of the cylinder is to provide a place for the piston to move up and down in. In it is placed and fired the charge of fuel which develops the power All ports, gaskets, valves, etc., must be made to fit correctly and be kept in good condition, else when the charge is fired the gases will escape from the cylinder without doing their duty which is to drive the piston down in the cylinder. The piston and piston rings must be well fitted to the cylinder wall which must be perfectly smooth and true, else the gases will escape down past the piston into the crank case, again failing to fulfil their duty. Cylinders are cast singly, in pairs, in sets of three, or in blocks of four or six. The water-cooled single cylinder is no longer used on automobile engines to any extent, although it is perhaps the 118 Automotive Trade Training Lett Side with Concealed Valve Mechanism. Fig. 123. National Six, I Head. best in airplane design where a thin steel cylinder has a still thinner steel shell welded over it to provide space for the cooling water. In the case of the automobile engine these spaces for the water are cored out in the engine casting. The result is a neat efficient cylinder block casting. Functions of Engine 1 ARTS 119 Engine Types. — Engines are spoken of as being either T, L, I, or F heads due to a general resemblance to the form of the letters -when the engine head and cylinder casting is viewed in cross section or from the end. The L is considered as inverted, and in point of number of manufacturers using it is considered most popular. Four Fig. 124. Kelly T Head Truck Engine. 120 AuTOMOTUE Trade Training cylinder L head engines are mentioned as well as four cylinder T head, four cylinder I head, or six cylinder T head, etc. Cylinder Heads. — The L head motor is perhaps the simplest of all designs. It is very popular in fours, eights and twelves where the heads are usually made removable. The I head, or as termed by some manufacturers the "valve in head", is popular in sixes and in some twelves. The term "valve in head" is somewhat misleading as it might imply that no other construction would permit of valve in the head construction. As a matter of fact motors are in use in which the valves are in removable L heads. The term 'T head" is preferable. The T head has usually been cast with a solid head t^lthough this method is not imperative. It is more popular in sixes perhaps than elsewhere. Since two cam shafts are required to operate the valves, the T head motor is more expensive to build than an L head of the same type. Valve size, however, is not limited. The valves of all other types of motors are operated from the single cam shaft. The F head has one valve overhead and one in an L pro- jection operated from the valve tapped direct. In considering cylinder block design and construction, it is well to remember that any engine having any of the standard numbers of cylinders might use any of the standard forms of heads cast in- tegral or removable, and that it might be built in either the vertical or V type. It is also well to remem- ber that price, purpose, accessibility and manufacturing practice have held and will continue to hold de- sign within certain pretty well de- fined limits. For instance, we check off the items removable T head V type motor. Such a motor could be built, but for obvious reasons is not being built. Cylinder Care and Repair. — Proper lubrication of cylinders is the best safeguard for them and will do much to prolong their life. All the features tending to cause over- heating of the engine contribute to rapid wear of the cylinders. Proper care of the engine will maintain them in condition for much service, but wear is bound to occur to some *"'*■ 'contSwf mS l!'"""- extent due to the side pressure of FcNCTioNS OF Engine Parts 121 the piston when it is under the stresses of compression or power development. Another feature contributing to cyHnder trouble is the constant heating and cooling of the cylinder metal. This will induce strains in the cylinder block and a new engine is almost cer- tain to come out of true to some extent due to this cause. This trouble may be corrected rather automatically by the new piston and rings wearing to their seat as the car is operated over the first Inlet f'alre--^ 1 ^^,..,.-— Water o jtlet W-^^Cuhnder head 1 ySparH pluf hole W^ Exhaust ya//e 1 / Ignition catplea ^^Hh '''j^'Distriifcitor \ jMIJ, ^ i prater inlet "^^^H Cam "/ i £j 1 ?F^*^\ 1 % 1 ^iFm Water pump-^ J rrom radiator Generator-^ . -k Fig-. 120. Reo Removable Head. 500 or 1,000 miles. To correct the few thousandths of an inch which normal service will leave a cylinder out of round, it is frequently necessary only to lap in a new piston, or if the trouble is of a more serious nature, it may be necessary to rebore the cylinders and fit over-size pistons.- Scored Cylinders.— The causes which result in scored cylinders are lack of lubrication, foreign substances in cylinder as carbon, grit, spark plug porcelains, broken rings, loose piston pins, etc. The latter type of score is the hardest to remedy. A score is a cut or a scratch formed in the cvlinder wall as the piston moves up and down in the 122 Automotive Trade Training F/nncf order l-d-4-S 1 Fig. 127. Three bearing 4 throw crank shaft with .pistons and rods assembled (Reo). cylinder. To remove these score marks it may be sufficient to lap or grind them out using an old piston or block of wood for a dummy. If severely scored, reboring up to 1/32" oversize will usually serve to remove it. If the score is a deep one, it will be necessary to have \ ' i ir 1 -■ LlL.1 i 1 1 1 L4l t-« Ik ~ns y m^t , 1 |||W||e|"i -^ '""f^jjp* ^.yw*^ J Fig. 128. Four bearing five throw crank shaft with pistons and rods assembled (Reo). the score filled in by welding, after which the inside of the cylinder will have to be machined and new piston and rings fitted. The most usual practice is to replace the badly scored cylinder block with a new block as it is the one certain method of effecting a permanent Functions of Engine Parts 123 repair. This may mean all new pistons and rings, but the mechanic must be guided by circumstances in determining this. Frozen or Bursted Cylinders and Cylinder Heads.— Some cylinder blocks are protected in a measure from freezing by means of small lead or steel plugs fitted into the water jacket. When expansion due to freezing occurs within the water jacket, these plugs may be forced Fig. 129. Cadillac Eight Crank Shaft Assembly. out, thus relievin_g the internal pressure, as they are designed to give before the jacket cracks. In a bad case of freezing they may not save the casting. In the majority of cases these plugs are not provided. A badly cracked block or head is usually replaced with a new one. Repairs are made on minor breaks by several methods. A small crack or break may be repaired by using X-Liquid, Neverleak, or similar radiator repair compound to seal it from the inside. These preparations are so compounded that they solidify only when steamed out through the crack. No harm will result from leaving them in the radiator a time after the leak has stopped. Crank Shafts. — ^The function of the crank shaft is to receive the power delivered to it by the piston and piston rod, from the cylinder, and transmit this power to the transmission. While doing this it must be so arranged as to care for all cylinders at correct intervals of time. As the number of cylinders have been increased the design and 124 Automotive Trade Training construction of the crank shaft has necessarily become more and more compUcated. High speed motors, too, have exerted a decided pressure toward their refinement. The strains and stresses coming on a shaft are numerous and varied. If a shaft is permanently sprung =m^ Fig. 130. Two Bearing, Three Throw, Counterbalanced Crank Shaft. Fig. 131. Five Bearing, Four Throw, Counterbalanced Crank Shaft. Fig. 134. Three Bearing, Six Throw, Counterbalanced Crank Shaft. Fig. 136. Nine Bearing, Eight Throw. Counterbalanced Crank Shaft. a few thousandths of an inch out of true, it will make trouble by binding in the main bearings. While it must be heavy enough to resist springing, it must be kept as light as possible to prevent undue Functions of Engine Parts 125 vibration and weight. To decrease weight and insure strength addi- tional bearings are used. More main crank shaft bearings or engine bearings mean a longer engine as well as additional trouble in lining up the bearings. 126 Automotive Trade Training Type of Crank Shafts. — Crank shafts are plain or counter- balanced. They are made for motor car engines of the four, six, eight, and twelve cylinder types. Usually drop forged steel is used. Sometimes the counterbalancing weights are bolted on but one-piece constriftction is considered standard practice and the best. The counterbalance shafts shown in Figs. 130 to 136 are forgings not machined. In speaking of crank shafts they are distinguished first by the number of bearings, second by the number of throws, third counterbalanced or plain, and fourth by the number of cylinders cared for. In the case of the Ford engine the crankshaft, Fig, 161, is a three bearing, four throw plain shaft for a four cylinder engine. In the case of the Overland, Fig. 192, the crank shaft is a two bearing, three throw plain crank shaft for a four cylinder engine. In the case of the center throw, two rod bearings are accommodated on the one throw. Some of the older cars used a five bearing, four throw plain shaft for four cylinder motors, and seven bearing, six throw shafts for the six cylinder motors. This was usual practice where the cylinders were cast separate. In fact, the method of casting cylinders has had a very definite bearing on the style of shaft to be used. If main engine bearings are to be used between each pair of throws, or any pair of throws, the distance between cylinders must be increased a distance equal to the length of the bearing. This has a very decided effect on the length of the finished motor. With the pairing and tripling of cylinders in block casting the number of bearings to the shaft were decreased. Where a center bearing is used on a four cylinder engine the two cylinders in the center of the block are farther apart than the two on either end. In the case of the six having four main bear- ings on the shaft the cylinders are again paired even though all are cast in block, while if three cylinders are grouped closely together at either end of an engine group cast in block, the shaft used will have but three main bearings. These statements apply particularly to passenger car motors. In the heavy duty motors a larger number of main bearings is the usual practice. In the case of airplane motors where single or separate cylinder castings or units are used the shaft is usually provided with one more main bearing than there are throws to the shaft. Crank Shafts for V Type Engines. — These are the same as those for the four or six cylinder motors. That is, a shaft similar to that used in a four is used in an eight, and a shaft similar to that used in a six is used in the twelve cylinder motors. Usually the shaft is heavier and main bearings larger. Two methods are used in attach- ing the rods. In one case, as the Standard 8 shown in Fig. 117, the Functions of Engine Parts 137 Fig. 137. Chandler Crank Shaft Assembly. Hand. Firing Order l-5-3-(»-2-4. Right rods are fitted side by side while in other cases, as that of the Cadillac 8 shown in Fig. 129, the rods are yoked together. Technically speaking there are no such crank shafts as four cylinder and six cylinder, but rather four or six throw shafts for the four or six cylinder motors. To determine the type of shaft, count the number of main bearings, and the number of throws, note whether plain or coun- terbalanced, and the num- ber of cylinders provided for as indicated by the number of rod bearings or crank pins. Right and Left-Hand Shafts. — In the shafts for the fours and eights there are no right or left-hand shafts, but in those of the sixes and twelves a shaft may be either right-hand or %^ fe^C^BBE^^'^^M Jk left-hand depending on the ^•^ ^rar^UHMK I ■^'■W relative position of the cen- ter throws with reference to the end throws. Place the end throws, that is number one and six, on top dead center. When facing the engine from the front the student can determine whether the shaft is right •or left-hand. If the center throws are to the right side, 120 degrees advanced over the end ones, 1 and 6, the shaft is right-hand. If the center throws, 3 and 4, are 120 degrees to the left, the shaft is left- hand. A right-hand shaft would be a left-hand shaft if it were turned end for end in the engine. Right and left-hand has no reference to the direction of rotation of the shaft as all American engines are made to turn to the right. The point of interest here is the bearing the Fig. 138. Chandler Engine. l^y AuTOMuTixE Trade Training shaft construction has on the hring order of the engine and its in- fluence on cam shaft design. Six Cylinder Firing Order. — The most popular lirhig order for the right-hand shaft is 1, 5, 3, 6, 2, 4, while for the left-hand the most popular and usual order is 1, 3, 5, 6, 4, 2. There are several other firing orders for each shaft, but the best distribution of power im- pulses is secured with the above orders. Attempts to memorize liring orders lead only to confusion except in cases where only one or two makes of engines are handled. The student should become so familiar with the engine principle that a study of piston and valve action would give him the proper firing order for any engine in question, in first hand investigations. Crank Shaft Troubles. — Serious crank shaft troubles are rather rare as a rule. Occasionally a shaft may be broken in which case a new one is usually installed. This of course means that the bearings must be fitted to it, either burned in or scraped in. In many cases it is best to install all new bearings with the new shaft. Crankshafts may be welded, but the practice is not to be recommended for ordi- nary repairs. In a case where no new shaft is available it is standard practice. Foreign substances such as dirt, grit, steel chips, etc., sometimes work their way into the bearings and may score the shaft very badly. Failure of the oiling system is also responsible for scored and Avorn bearings. Upon the degree of injury depends the method of repair. In badly scored shafts the best repair is to have the work done on a grinding machine in a recognized machine shop. There are on the market certain tools for hand use which are reliable when used by an experienced mechanic. If the damage to the shaft is of a minor nature the repair may be effected by means of a simple lapping or grinding tool made from two blocks of wood arranged to be clamped over the crank pin or journal in such manner as to secure even tension. That is, it would have to have provision for adjustment and some form of shim must be used to prevent it closing down on the low spots. A steel or cast iron lapping jig may be made up using the same precautions, or an old rod with its babbitt bearings, shim bolts and all complete may be used to do the work. In normal service, a shaft wears gradually due to the fact that more pressure is exerted at certain points in its travel than at other points, as when receiving the power impulse, it is certain to wear out of round. This trouble will only develop after a great deal of normal service, and can be corrected as suggested above and in the job sheets. Main Engine Bearings. — The function of the main engine bear- ings, or main bearings as the mechanic terms them, is to carry the Functions of Engine Parts 129 crank shaft in proper position and alignment at all times while per- mitting it to turn within them with the least possible amount of fric- tion and loss of power, which is being transmitted through it to the transmission from the cylinders. These bearings are what is known as plain bearings in most cases. In certain types of engines ball or antifriction bearings are used, but they have never become popular for general use. I'he cause of this is likely difficult assembly, noise and lack of adjustment. The main bearings are almost always of the spHt bushing type. They are composed of a white metal or babbitt bearing surface mounted in a bronze back or cast iron back, or in some cases directly in the engine frame and bearing caps. The bearing made up of the thin layer of metal sweated onto the harder metal has several advan- tages. It provides a greater amount of metal in direct contact with the shaft which serves to conduct the heat generated in the bearing away more readily. It is a well known fact that heat will not travel from one piece of metal to another as readily as it will travel and be dissipated within its own mass of metal. Witness this in heating a piece of metal in a fire. If there is a crack present it is shown up immediately due to the fact that on one side of the crack the metal may show a red, while on the other side the metal will still remain black. The metals may even lay so close that the eye cannot detect the crack until the change in color gives evidence of it. The larger the bearing, the more frictional heat will be dissipated by it and the less danger of that bearing being burned out. Burned Bearings. — Bearings are burned for one reason only and that is lack of dissipation of heat generated within the bearing, or improper cooling -of the bearing. Heat within a bearing is due to the friction of the rapidly moving or turning shaft sliding over the surface of the bearing metal. As an experiment the student should try rubbing his hands briskly together. The faster they are rubbed the warmer they become until they even become rather unpleasantly warm. Addition of pressure causes still more heat to be generated. This heat is due to friction. If soap and water are used between the palms while continuing the rubbing, the heat generated is barely noticeable. This is due to the fact that the soap and water form a good lubricant. Water only will relieve some of the friction, but not nearly so much of it as the application of soap and water. The water might be said to be' a poor grade of lubricant. These liquids serve as lubricants because they prevent the hands from coming in contact with one another. The soap particularly serves to maintain a thin film of lubricant between the palms, thus preventing contact. The same condition exists in a well lubricated plain bearing. The shaft does not actually come in contact with the bearing metal, but rides on the oil film. Should it for any reason actually come in contact 130 Automotive Trade Training with the bearing metal in a dry state disaster will follow in a few seconds. In this case the bearing is said to burn. The internal fric- tion generated causes the metal to become heated, and if continued it will start to seize on the shaft in small particles and drag around with it. As the heat continues to develop it will become softer and softer and string out more and more, and even in extreme cases of burning will become so hot that it will melt and run out of the bearing and drop down into the crank case. Long before this happens there is usually evidence of trouble, although it may happen so quickly in the case of sudden failure of the oiling system, or exhaustion of the oil supply, that little warning or time is given. Fig, 139. Marmon Main Engine Bear'ng. CranM ^shaft ^fiaft Fig. 140. Keo Crank Shaft and liod Bearing. While internal heat is the cause of bearings burning out, the cause of the heat may be due to several conditions. Failure of the lubricating system, poor quality of oil, excessive speed, hot weather, failure of the engine cooling system, foreign matter in the oil, and overload are the most common causes. There are varying degrees of burns from that in which the bearing metal is turned a blue black up to the point where the bearings seize, and the final point when the metal flows from the bearing. Babbitt melts at about 800 degrees. Depending on its alloys it may vary either way from this point. Taking Up Main Bearings. — This is a necessity at intervals vary- ing from a few thousand miles up to thirty, forty, or even fifty thousand miles of service, depending very largely and directly on the skill and care of the driver. Much depends also on the quality of Functions of Engine Parts lai oil used. When this work is found necessary great care and good judgment must be used. Refer to Job 50. Scraping in Main Bearings. — This is needed as a rule less often than taking them up. It is usually necessary only after years of normal service or when a bearing has been burned or otherwise abused. It is a tedious job and one requiring judgment, skill and patience. Naturally it is also. expensive, as it is almost always neces- sary to remove the engine from the frame and rather completely dismantle it. Refer to Job. 51 for further directions. Pistons. — The function of the piston is to draw in the gasoline and air on its downward stroke, compress this fuel charge on its upward stroke, receive the power as developed from the firing of the charge, transmit this power to the piston rod and crank shaft, and on its second up stroke free the cylinder from burned gases. MATERIAL AND CONSTRUCTION Piston. — Pistons are usually made from cast grey iron although many made of aluminum or aluminum alloy are used. One of the Pig. 141. Fig. 142. Marmon 2-Piece Piston. At left, Piston Assembled. At Center, Aluminum Head and Body. At right, Iron Skirt. developments of piston design is that of the Marmon where an iron sleeve is used over an aluminum body. This obviates all dan- ger of piston pin scores. The two parts are assembled from the inside, using cap screws to hold the parts together. While alumi- num pistons have a desirable quality of lightness, the expansion to which they are subject when heated is about twice that of the iron pistons. This feature contri- butes toward a noisy motor when cold, and loss of compression in cold winter months. Accordingly, cast iron pistons hold rather steadily in favor and are so designed, cast, and machined that the weight is not exces- sive and can be cared for in balancing up the crank shaft and fittings. Marmon Piston Rod Assembly. 133 Automotive Trade Training Piston Clearance Allowance. — Ordinarily the mechanic does not turn down or machine pistons. However, he will need to understand allowances in fitting them and be able to judge clearance rather accurately. Special allowances are made in special cases, but a rule safe to follow in the regular routine of w^ork is, for cast iron allow .00075" at the skirt and .002" at the lands of the piston for each inch in diameter of the piston. Double these amounts for aluminum. Piston Rings. — The function of the piston ring is to seal the joint between the piston side and the cylinder walls at all times, so as to prevent loss of power by gases escaping down past the piston. At the same time they are required to prevent the oil from working up into the combustion chamber in excess quantities, or unburned gaso- line working down. The individually cast and machined ring made from grey iron is standard. There are two styles of plain ring with two types of joint. The step or bevel cut eccentric or concen- tric rings are what is known as plain type piston rings and are used in a large percentage of engines. The advantage of the eccentric ring lies in the fact that a more even tension is maintained over the entire circumference of the ring. It might be com- pared to the Indian's bow which had the thickest part where the greatest strain came in use and per- mitted of an even bending. In this case the groove in the piston for the ring must be deep enough at all points to accommodate the thickest section of the ring. This groove need not be so deep in the case of the concentric, but the pressure will not be so even in this case and breaks are very likely to occur at the point opposite the joint when applying it to or removing it from the piston. Designers are agreed that the greatest single trouble with a piston ring is the liability to loss of power through loss of gases past the piston ring joint or lap. To over- come this many types of so-called leak proof rings have been designed. '''^ .l?f andl'.T/'" _ . . _^ , . Assembly. Leak Proof Rings. — Kmgs purportmg to pre- vent leakage of gas past the piston, and particularly past the joint, are numerous. . Many excellent designs and excellent rings may be found. Because the trade name of one of the oldest and best of this type of ring was "Leak Proof", mechanics have come to class all specially designed rings of more than one-piece construction leak- proof rings. The main point desired is to prevent gas escaping past the ends or through the joint. Functions of Engine Parts 133 Two methods are used in attempting to obtain the desired result. Either some special form of lap is used, or the ring is made in two or three pieces, with the laps so arranged that there is little chance for leakage of gas through them. Generally speaking, that ring is best which is best fitted to the cylinder wall and the piston ring grooves irrespective of the type of lap. Certain types of rings do give better results in certain motors granting workmanship is equal in each case. Refer to job sheets for data on fitting rings. Piston Pins. — The function of the piston pin is to hold the piston and the piston rod together and in proper relation. It forms a flexible joint with an oscillating movement which permits the proper move- ment of parts to transmit power from the cylinder to the crank shaft. Piston pins are made from a high grade of steel machined and hard- ened, after which they are ground to size. They are made to size within very close dimensions and can usually be obtained in over- sizes which range from .001", .002", .003", .005", .0075", .010" oversize. The pins are usually made hollow because they must be made light, and at the same time have sufficient bearing surface to withstand tremendous hammering and pounding while carrying heavy loads. Piston Pin Fit. — The piston is cast with bosses to carry the pin. Sometimes provision is made for bushing these. The pin fits into these bosses in a close manner, .001" being sufficient clearance, unles.^ the lubrication is force feed when .002" to .003" is allowed. This :lose fit is needed to prevent a piston pin knock as the piston, when it reaches upper or lower dead center, must be stopped and the direction Df drive reversed. If there should be any perceptible play, the con- tinual action of the piston on the pin would quickly result in sufficient wear to cause a knock to be heard. After this point is reached the fcvear is more rapid because the more the play the greater the force Df the knock and consequently the more rapid the wear. Instead of 1 rotary movement the pin has an oscillating movement which results n uneven wear. This appears on the top and bottom of the pin and n the same points with reference to the piston pin bushings. Securing the Piston Pin. — More badly scored cylinders result :rom loose piston pins than from any one other cause. A piston pin score is very difficult to repair, although it can be done by welding Dr filling in with certain metals. The block is usually replaced with I new one. To prevent scoring means that the pin must be so secured in the piston that it is impossible for it to work endways IS it is the end of the pin projecting past the piston into the cylinder ,vall which causes piston pin scoring. Numerous methods of secur- ng the pins in place are in use as the setscrew method, the dowel 3in method, the bolt method, etc. Whichever method is used is also :)rovided with some lock to prevent it working loose, and out. 134 Automotive Trade Training Greatest care should be used to see that the fastening device, be it wire, washer, cotter key, or what not, is in first class condition. It is not a good plan to use many of these devices the second time as bending has weakened them. Connecting Rods. — The usual style of the ^ connecting rod is H section drop forgings, although in the full force feed round hollow rods are used at times to facilitate oiling. In this case the oil is forced up through the centei* or hollow of the rod from the crank shaft to the piston pin. In case of full force feed oiling systems where the H section rod is used, a copper tube is run up on the outside of the rod to carry the oil. The drop forged type gains slightly in weight and strength from the piston toward the crank shaft. The function of the piston rod, or rod, as the mechanic calls it, is to convert the reciprocating motion of the piston into the revolving motion of the crank shaft, at the same time transmitting power from the pis- ton to the shaft as on the power stroke, or from the shaft to the piston as on the compression stroke. It must be strong to resist end thrust, and light to prevent undue vibration. Piston Pin Bearing, — The piston pin is carried in the upper end of the rod. At times the rod is designed to carry the piston pin bush- ing or bearing in the upper end. A close run- ning fit is provided for the pin in the bushing, while a press fit is provided in the piston bosses Pig. 144. Rochester for the piston pin ends. It is good practice ^^^Assembiy. ^"^ where this type of construcion is used to secure one end of the pin only, leaving the other end free to expand when heated without distorting the piston. More often, however, the pin is secured in the iipper end of the rod and the bearings are in the piston bosses. Reference is made to this method in Job. 53. Rod Bearings. — The lower end of the piston rod carries' the rod bearings. This is of the split bushing type, also known as a "plain bearing". It is very similar to the main bearings. Adjusting and scraping of rod bearings is somewhat easier than that of the main bearings since they are more accessible and may be handled in- dividually, and the fitting of one has no influence on any other as is the case in the main engine bearings. Rod bearings will be badly Functions of Engine Parts 135 worn or burned if run dry or even partially dry. A very disagreeable knock will develop in this case. The bearing should be adjusted immediately any evidence of wear is noticed. Fig. 145. Rochester Valve Mechanism. " Cam Shafts. — The function of the cam shaft is to open the valves at correct intervals of time, hold them open the correct length of Fig. 146. Reo Cam Shaft and Related Parts. 136 Automotive Tkaue Training time, and permit them to close at the correct moment. The design of the crank shaft must be taken into consideration in determining the firing order of the engine. The design of the crank shaft and the desired firing order of the engine are the determining factors in designing the cam shaft. What the repairman needs to remember is that the firing order of any engine is fixed when the design of the cam and crank shaft Fig. 147. Rochester Deusenberg Cam Shaft. is determined on by the designer and manufacturer, and that there- after there is only one firing order for that engine. If it is found necessary to determine the firing order of any engine, the action of the valve lifters as they raise and ride on the cams of the cam shaft will be the readiest source of information. Fig. 148. Cadillac 8 Valves and Cam Shaft Arrangement. Two Valves Per Cylinder. — Always, in the poppet type engine valve design, one valve is provided for intake and one for exhaust for each cylinder of the engine. In some cases four valves per cylinder are provided, two for intake and two for exhaust. Engines using four valves per cylinder are known as "dual valve" engines. The intake valve opens on a down stroke of the piston in its respective cylinder, while the exhaust valve was open on the previous up stroke. For two strokes, or one revolution, or one-half cycle Functions of Engine Parts 137 4H^ f ' Fiji-. 14i). MiiniKi Valve Mechanism. neither valve is opened. This is during the com- pression stroke and the power stroke as they follow in succession after the intake stroke. The valves are actuated by the cams on the cam shaft which the engine timing gears hold in fixed relation to the crank shaft while driving it at one-half crank shaft speed. In the operation of the valves, the valve lifter riding on the cam is caused to raise on the cam nose, thus raising the valve from its seat by push- ing up on the bottom of the valve stem (in the case of an L or T head motor). The distance the valve raises off the seat is about 5/16" to }i". The length of time it is held open depends on the design of the cams. Cam Shaft Drive. — Two methods, both posi- tive, are in use for driving the cam shaft from the crank shaft. One is by the use of timing gears and the other by the use of the silent chain. In order that the correct speed relation or ratio be maintained at all times, it is necessary that the tim- ing gear on the crank shaft have just one-half as many teeth as the timing gear on the cam shaft. i ^^^^^K** *'^^Hflp*'«i^B' '' t J 1; ly i' i L. ; «y^ i^EK^mJ^K]:! iii^ H' z\ S t !5k!^ iSl-l,!yi!^i^^'^^^1H '"^' '^^^^^R^ Fig. 150. Phantom photo of typical Stearns Knight motor, showing sleeve-valves and their operating mechanism. 138 Automotive Trade Training thus giving a gear ratio of 2 to 1. The student will need to famil- iarize himself with the statement of the travel of the two shafts in degrees as, while the gear ratio is 2 to 1, the one travels through •'Exhaust Stroke — Intake Stroke —Explosion or Power Stroke —Compression Stroke Fig. 151. Willys-Knight 8 Sleeve Valve Engine Section. Note position of parts in each stroke of the cycle. only one half of a circle, or 180 degrees, while the other travels through a full circle, or 360 degrees. This is true of all four cycle engines and must be understood thoroughly by the student to grasp the actual theory and process of valve timing. Functions of Engine Parts 139 Fig. 152. Reo Valve Mechanism. Fig. 153. Buick Self Lubricating Valve Mechanism. 140 Automotive Trade Training Fig. 154. Reo Cam Shaft. Valve Lifters. — Most valve lifters are made with a large seat or base to rest on the cam. This base is hardened to resist v^ear. The upper end of the lifter w^hich rests immediately under the valve stem is provided with a screw for adjustment. This permits of setting the lifter to compensate for wear either within the lifter on the cam or the valve, as well as for expansion of the valve stem due to heat from the engine. Valve lifters seldom give any trouble except for a loose or bad adjustment. Valves. — The poppet type valve is in use in a very large percentage of the automotive equipment en- gines. Other styles of construction have at times proven successful, but in no instance have they been found to possess enough good fea- tures to offset the cheapness and desirable points of design of the poppet valve. Valves are made from steel in one piece, and with a steel stem and cast iron, or other special head. Certain special steels as tungs- ten or nickel steel are used because of the fact that experience has shown that these metals will resist the high temperatures best. In some cases the inlet valves and the exhaust valves are made from different materials, each selected with a view to the conditions under which they do their work. Valve Grinding. — Under service conditions a variety of causes result in valve wear which makes necessary the reseating of the valve on the valve seat. This is done either by grinding, or in cases of extreme wear, by the use of the reseating tools followed by grinding. Conditions contributing to valve trouble are the excessive heat which very often causes warping of the valve head. Constant action as it is dropped or forced onto the valve seat will cause uneven wear of the head. The constant rise and fall of the valve in the valve stem guides under strong spring pressure will cause uneven wear and ultimately result in improper seating of the head, as well as leaking Fig-. 1")"). Studebaker Bevel Timing Gears. Functions of Engine Parts 141 past the intake valve stems causing uneven operation of the motor. Carbon and heat will pit the valve seat. Carbon under the valve head will allow the flow of gases. All of these troubles contribute to a loss of power as the compression is imperfect and the power impulse loses force due to lack of compression and a loss of the exploded gases past the leaky valves. Invariably, or almost so, the intake valves require less attention than the exhaust. Several causes, contribute to this. The intake valve deals with a clean cool mixture.. The exhaust valve handles a flaming, hot, dirty, smoking, carbon depositing gas. When the engine has been in operation a length of time sufficient to produce the results and conditions noted above, the valves are ground, valve lifters or tappets adjusted, and carbon removed, thus restoring to the motor its usual power. As to the actual need of valve grinding as opposed to the imaginary need of valve grinding much might be said. Because of the fact that valve grinding is com- paratively simple it is one of the first things the amateur turns to.. Some believe it a panacea for all engine ills. While it is true that leaky valves do cause much trouble, it is also true that carbon causes the leaking valves and a multitude of other ills which will be relieved and corrected by its removal. Valves may require reseating after 50 miles of service or after 50,000 miles of service. When they need the reseating they should have it. Frequent grinding wears away the head and the valve seat in the combustion chamber, making the actual point of contact wide and hard to maintain. As the valve head is made thinner and thinner it warps and burns more and more easily. Most valves are machined with the face of the seat at an angle of 45 degrees with the stem, although some are 60 degrees. Rocker Arms. — In the case of the I head motor the valves are located over the cylinders in the head in an inverted position with reference to the valves in the L or T heads. This necessitates the introduction of a rocker arm mounted on the top of the head to receive the lift from the push rods resting on the valve Hfters. The rocker arm receives this lift on its outer end, and as it rocks on its rocker pin it forces the inner end down on the upturned end of the valve stem, thus opening the valve. Valve timing is identical with the L head motor. This arrangement of valves is conceded by engineers to make a motor having in it a bit more power than any other construction. It is not as simple nor as sturdy a type of con- struction, as the number of small moving parts is greatly increased. The greatest difficulty is to keep these parts properly lubricated. Complete enclosure of parts has done much to correct lubricating faults. Knight Type Engines. — One form of valve construction which has proven itself the equal of the poppet valve type, and even in 142 Automotive Trade Training point of valve care a bit superior, is the Knight Sleeve Valve motor. The Stearns Knight, shown in Fig. 150, is typical of all Knight motors as all are made under the same Letters Patent. Instead of the piston being fitted into the cylinder, the cylinder is fitted with an outer and inner sleeve. The piston is fitted into the inner sleeve. The two sleeves are made a free sliding fit and in their upper ends ports are pro- vided for the intake and exhaust mechanism. As will be noted in the cut, the sleeves are operated for short up and down strokes by means of eccentric rods worked from the eccentric shaft. This shaft takes the place of the usual cam shaft. At certain points in sleeve valve travel the intake ports are opened permitting a charge to enter. The ports are then closed and remain closed until after the compres- sion and power strokes, when the movement of the valves or sleeves is so timed as to bring the exhaust ports or slots in line and permit the exhaust of the burned gases. Valve timing is identical with all four stroke cycle motors in that the eccentric shaft travels at one-half crank shaft speed, and the intake must be set to open at five to ten degrees past the top dead center. Valve Timing. — The student has previously considered the four cycle principle. He has learned the various strokes. For theoreti- cal purposes the stroke and operation were considered as identical. That is, the intake consumes exactly one stroke, or one -half revolu- tion, and the compression, power, and exhaust each just one stroke or one-half revolution, or 180 degrees crank shaft or flywheel travel. Actually these operations vary considerably from 180 degrees, one- half revolution, or one stroke. For instance, good practice does not open the intake valve <>ii T. D. C, (Top Dead Center), but about ten degrees past T. D. C. in flywheel travel. This valve does not close at B. D. C, (Bottom Dead Center), but at about 35 degrees past B. D. C. This gives on an average about 205 degrees for in- taking the fuel charge. From the time the intake valve closes to T. D. C, the cylinder is on the compression stroke or operation. This represents a distance of about 145 degrees of flywheel travel. At the end of the compression stroke the charge is fired, the piston being forced downward. When the flywheel has traveled from T. D. C. to about 45 degrees from B. D. C, or through 135 degrees, the exhaust Pig. 156. Studebaker Valve Mechanism Valves inclined at 20 degree angle. Bell Crank Lift. Functions of Engine Parts 143 valve is opened and remains open until B. D. C. has been reached and passed on up through the full 180 degrees to T. D. C, and to about five degrees past when it closes. In a few more degrees travel the cam shaft opens the inlet valve again. The power stroke is about 135 degrees long as measured in crank shaft or flywheel travel, the exhaust about 230 degrees, while the intake is 145 degrees, and the Fig. 157. Maxwell Timing Gears. compression about 205 degrees. With a minus valve lap of five degrees added the sum of 720 degrees is obtained, which is equal to and represents two revolutions of crank shaft and flywheel, four strokes or operations, and one complete cycle. During this time the cam shaft has traveled through one complete revolution or 180 degrees. Each valve has been opened just once. The time the valves remain open is determined by the design of the nose of the cam, the exhaust cam having a broader nose than the intake cam. The time at which the valves open is determined by the setting of the cam shaft in relation to .the crank shaft. Sumjnarizing the above figures gives the following table which is representative of the average in valve timing and not of any specific engine : 1 revolution equals ^ cycle, equals 360 degrees travel. 2 revolutions equal 1 cycle, equals 720 degrees travel: Intake, first quarter cycle or stroke equals 205 degrees travel Compression, second quarter cycle or stroke equals 145 degrees travel Power, third quarter cycle or stroke equals 135 degrees travel Exhaust, last quarter cycle or stroke equals 230 degrees travel Minus valve lap, equals 5 degrees travel One completed cycle totals 720 degrees travel 144 AuTOMOTiNE Trade Training Fig. 158. Right and Left Side Views of Rochester Model G Deusenberfr Type Engiiu'. JJure 414", Stroke 6". Note Horizontal Valve Aftion. Valve Lap. — ^This is the term applied to the condition of valve action with reference to the closing of the exhaust valve and openincT of the intake valve. Either a plus or minus lap is possible. With a plus lap both are held open for a few degrees of flywheel travel at the same time. In rare cases this will be as much as from ten to twenty degrees. The minus lap rarely exceeds ten degrees and is more often less than five. As stated previously, these figures are fairly representative of Functions of Engine Parts 145 the general average. In actual valve timing where no mark is on gears, or old gears are being re- placed with new ones, it need not be expected that every type of motor will correspond exactly to the figures given. In timing up some engines, especial- ly those with coarse gear teeth, it would likely be impossible to more than approximate these figures^ Since valve timing Avith respect to setting of the timing gears together is usually done with the ex- haust valve just closing- and the intake just open- ing, one tooth out of time either way would be so obvious that there would be little room for doubt as to when the exact teeth were in mesh to have the exhaust closing at about five degrees after T. D. C, and the intake opening about five degrees later. When timing any engine care must be used to have the piston in the cylinder Mechanism with the cover being worked from, us- ually No. 1 on top dead center. Another method of timing valves, quite as reliable as the one given above, is that given with reference to the timing of the Hudson Super-Six in Job 63. Here distance is measured by inches of piston travel as well as inches of flywheel travel. Degrees Converted to Inches. — While it may be difficult to figure the number of degrees within a certain space on the flywheel by the use of a protractor, it is comparatively easy to find the number of degrees included in one inch of the flywheel circumference. With a tape line measure the distance around the flywheel and divide this into 360 degrees. Fig. 150. National Yalv plates removed. Lnbrii-ation 'is effected through the hollow rocker arm shaft. 146 Automotive Trade Training ROCKER ARM OIL WICK ROCKER ARM COVER. ADJUSTING BALL LOCK NUT WATER JACK SPARK PLUG COVER COMBUSTION SPACE PUSH ROD VALVE PUSH ROD COVER CYLINDER. VALVE LIFTER CAP VALVE LIFTER GUIDE CLAMP- VALVE UFTER SPRING VALVE UFTER GUIDE VALVE UFTER CAM ROLLER PIN CAM ROLLER CAM SHAFT EXHAUST MANIFOLD INTAKE MANIFOLD HOT AIR CHAMBER CONNECTING ROD CRANK CASE CRANK SHAFT Fig. 160. Buick Valve Mechanism ami related parts. Functions of Engixe Parts 147 JOB 48. FITTING OR TAKING UP CONNECTING ROD BEARINGS 1. The following directions apply equally to the work whether it is done for practice or in actual service work. 2. Remove the rod from the crank shaft. 3. Note how assembled so as to insure proper reassembly. 4. Learn also and note: a. Front end of crank shaft. b. How flywheel would be fastened, c. Cam shaft side, 148 Automotive Trade Training d. Number of main bearings, e. Number of throws on shaft, f. Number of cylinders shaft would care for. Adjusting a bearing. a. On removing the rod cap you note a number of shims are found. b. These should always be retained in order that on reassembly they go back in original position. c. Remove several thin shims and try reassembling the rod. Is it too tight? d. Keep adjusting shims until you have learned what too tight is. Have it inspected. e. Replace shims until you learn what too loose is. Have it inspected. f. Now adjust for proper fit as though it were to go into the car and you were the sole judge of correctness. Have it inspected and rated, g. Always be sure to place a coat of oil on the bearing on final assembly. To neglect this may burn out a bearing before the oil reaches it. Fig. 162. Packard Engine. Note method of assembling- rod bearings. Als:) size of main bearings. JOB 49. SCRAPING CONNECTING ROD BEARINGS. 1. The following methods should be used whether the work is done with the shaft out of the engine or with the shaft in position in the engine. In the first case the piston must be maintained at right angles to the shaft. 2. Remove the rod cap and shims. 3. Treat the crank pin of the shaft with a thin coat of bearing blue. 4. Clamp the rod to the shaft having in the proper amount of shims. 5. Rotate the rod on the shaft for three or four turns. 6. Remove the rod. 7. Note bright spots on the bearing and take it to the instructor for explanation. Functions of Engine Parts 149 S. Secure a bearing scraper and with this remove the bright spots which are the high points. 9. Continue this operation until you have at least a 75 per cent bearing which will be indicated by the frequency or closeness of the spots. In a well fitted bearing the blue will appear evenly distributed over the bearing after fitting. 10. It may be necessary to remove or add shims in work of this nature from time to time. 11. When finally fitted, the weight of the piston on the rod should be sufficient to carry the rod slowly downward when started from the top, but not loose enough to oscillate back and forth. In fitting rods in an engine where this test cannot be made, a fair idea of their correctness may be secured by tapping the rod side to side with a hammer. A medium blow should cause it to move endwise on the crank pin. If it does not move, it is too tight. If it can be shoved with the hands it is too loose. Caution: Enough shims must be used to hold the cap in the correct position when the nuts are drawn up tight. Never release nuts to get the right clearance. Always add shims and draw tight. Bearing scrapers. Bearing scrapers must be kept sharp. A good India oil stone is best for this. Get your instructor to show you how to sharpen them. -Ring Grooves CONNECTING POO (BlAOS) Fig-. 163. Cole S Connecting rods are of the Yoked Type. The inner bearing ia non- adjustable. When the play is too great these are replaced with new ones. The Blade rod is adjustable. Its beatings are fitted over the back of the inner bearing which is fastened to the yoked rod. JOB 50. FITTING OR TAKING UP MAIN ENGINE BEARINGS. 1. Except in rare cases it is not advisable to attempt to scrape in bearings with the engine in the car frame. In the case of bearing adjustment where the bearings are worn loose, but are otherwise in good condition, the work is ordinarily done with the engine in the frame. In either case proceed as follows. 2. Remove bearing caps and shaft. 3. Clean, oil and reassemble. 4. Fit rear bearing first, by the adjustment of shims. a. Remove a thin one. b. Assemble and test. 150 Automotive Trade Training C. Continue to adjust until proper tension or fit is obtained. 5. Remove or loosen cap on rear bearing. 6. Adjust center bearing. 7. Release center bearing cap. 8. Adjust front bearing. 9. Reassemble all caps using a coat of oil on the bearings. 10. Have each bearing when finished, inspected and final assembly inspected and rated. Semoi'e caps to adju^sT crank Oeari/ii^s and connect/na rods. I JRemot'e o// ^p/a^h p/afes Defore J I anempT/ncf to rake out p/otons,. ^^k Ma/n o/ 1 pipe Connect/nf rod^' '| O/i pump p/t^nt^er ^3e ~5ure to /ocH nut's w/t/? i^/re after maH/ni^ adjuatment^. Fig. 164. Adjusting Rod and Main Bearings (Reo). JOB 51. SCRAPING MAIN ENGINE BEARINGS. 1. It is the usual practice, in case bearings are in such condition that they need scraping, to remove the engine and place it in such a position that the work of scraping in the bearings is made accessible. Where a minimum amount of work is required the engine is sometimes left in the car frame. The Fig. 165. Laminated Shims. Peel off a layer at a time in adjusting bearings. engine should be removed from the car and placed in an advantageous position, after which the crank case should be removed so as to get at the bearings and shaft. The rods should also be removed. 2. Remove the bearing caps and clean free of all oil. 3. Apply a thin even coat of bearing blue to each crank shaft bearing, but not to the crank shaft bearing bushing. 4. Place the shaft in position in the case. 5. Rotate or turn the shaft three or four times. 6. Remove and scrape off the high points on bearing bushings. Functions of Engine Parts 151 7. Repeat the operation until all bearings are properly spotted in. At least a 75 per cent bearing surface should be obtained, otherwise the life of the bearing will be greatly shortened. 8. Extreme care and considerable time are required on this job. 9. Metal should be removed by very careful scraping. Do you know what .001" is? This paper is .003" thick. It might be written 3/1000. In scraping, inetal should not be removed by thousandths of inches but rather by one-eighth of thousandths, or one-fourth of thousandths. That is, to remove an amount OSITION or WRENCH WHEN L OCKING SEARING, j L POSITION OE WRENCH WHEN ADJUSTING SEAGING. Fife'. 106. Adjusting Main Engine Bearings. Earlier Models (Reu). of metal, the thickness of this paper would require from 25 to 50 cuts of the scraper. 10. Be patient and observant on your first bearing work. All speed that is possible on work of this nature will come to you later. 11. What may happen if too much metal is removed from the front bearing? 12. What may happen if all new bearings of greater than original thickness are fitted? 13. Having the shaft properly fitted or aligned in the crank case, the bearing caps may be fitted. 152 Automotive Trade Training 14. a. Draw the end ones to hold the shaft in place. b. Work the center bearing to a fit. c. Slack the nuts on the center bearing a trifle. d. Fit the rear main bearing. e. Fit the front main bearing. f. Have each step inspected as you work. g. See that all oil grooves are cared for. 15. Have final assembly carefully oiled and keyed with cotter keys. 16. Have it inspected and rated. JOB 52. POLISHING A CRANK SHAFT. In use a crank shaft will frequently be worn so that grooves and ridges show, or are noticeable to the finger tips as they are run over the shaft bearing. In other words, it is scored. The score marks must be removed by one method or other before a bearing can be properly fitted. 'Having them removed and the shaft trued up it may be polished by one of several methods. As good a method as any is the following: 1. Wrap a piece of emery cloth a little narrower than the bearing around the shaft bearing. Pwten Rings Oil Hole* Space for Oiling Oil Return Holes Piston Pin Oil Return Holes Connecting Rod Connecting Rod Bearing Dip Pin Fig. 167. Overland Piston and Rod with names of parts. 2. cloth. 3. 4. Take a light rope or heavy cord and give a number of turns around the Draw this back and forth having one end in either hand. Continue this until the shaft has a good bright polish. 5. Care must be used to see that emery cloth moves from side to side as well as round and round. 6. Oil may be used on the cloth if desired, but this is likely to loosen some of the grains of emery from the cloth. If this happens the shaft may be scratched. In any event, great care must be used to insure a good polish. Functions of Engine Parts 153 JOB 53. REMOVING A PISTON PIN OF THE CLAMP TYPE. 1. Where the clamp type of piston pin is used, the pin is clamped in the rod and the bushings which constitute the bearings are in the piston pin bosses. 2. Learn how the piston pin is secured, 3. Free the pin by loosening the clamp fastener. 4. Remove the pin by driving on the end of it with a hammer and a soft punch. Either hold the piston on the knees while the operator is seated on the bench, or set the piston on its head on the bench and drift out the pin while holding the piston in the crook of the arm. To press out a piston pin without a special form of press is very dangerous as the piston is very often pressed out of round, and in some cases is injured beyond repair. 5. Note the position of the bearing. Is this arrangement always used? What other arrangement might be used? JOB 53A. REMOVING A PISTON PIN WHERE THE BUSHING IS IN THE ROD. 1. Make an inspection to learn the method of securing the pin. 2. Loosen the pin fastener which will be found in the piston pin boss. 3. Remove the pin by driving with a punch having the piston resting on the knees of the operator while he is seated on a bench, or set the piston on the head on the bench and hold with the arm while driving against the pin. To press out is very dangerous as the piston is very often pressed out of round. 4. Note where the bearing is. Is this arrangement always used? Could it be elsewhere? JOB 54. REMOVING PISTON PIN BUSHING FROM PISTON. 1. This is work which requires good judgment on the part of the operator, or mechanic. Unless extreme care is used the piston may be ruined. 2. Secure a drift of a slightly smaller diameter than the outside of the bushing. 3. Hold between the knees while seated on a bench and drive the bushing into the piston. 4. In replacing a bushing, or putting in a new one, first file the burr from the ends on a taper not over 1/16" long. Start true and drive in, using a wood block. 5. In removing a bushing from a rod set the new bushing on the old and press the old one out and the new one in. Be careful of burrs. JOB 55. FITTING MAIN ENGINE OR CRANK SHAFT BEARINGS ON FORD ENGINE. 1. After the engine has been taken out of the car, remove the crank case. transmission cover, cylinder head, pistons, connecting rods, and transmission and magneto coils. Take off the three babbitted caps and clean the bearing surfaces with gasoline. Apply bearing blue to the crank shaft bearing surfaces which will enable you, in fitting the caps, to determine whether a perfect bearing surface is obtained. 2. Place the rear cap in position and tighten it up as much as possible without stripping the bolt threads. When the bearing has been properly fitted, the crank shaft will permit moving with one hand. If the crank shaft cannot be turned with one hand, the contact between the bearing surfaces is evidently too close and the cap requires shimming up. one or two brass liners usually being sufficient. In case the crank shaft moves too easily with one hand, the 154 Automotive Trade Training shims should be removed or the steel surface of the cap filed ofif, permitting it to set closer. 3. After removing the cap, observe whether the blue "spottings" indicate a full bearing the length of the cap. If "spottings" do not show a true bearing, the babbitt should be scraped and the cap refitted until the proper results are obtained. 4. Lay the rear cap aside and proceed to adjust the center bearing in the same manner. Repeat the operation with the front bearing, with the other twc> bearings set aside. 5. When the proper adjustment of each bearing has been obtained, clean the babbitt surface carefully and place a little lubricating oil on the bearings, also on the crank shaft; then draw the caps up as closely as possible, the necessary shims, of course, being in place. Do not be afraid of getting the cap bolts too tight, as the shim under the cap and the oil between the bearing surfaces will prevent the metal being drawn into too close contact. If oil is not put on the bearing surfaces, the babbitt is likely to cut out when the motor is started up before the oil in the crank case can get into the bearing. In replacing the crank case and transmission cover on the motor, it is advisable to use a new set of felt gaskets to prevent oil leaks, JOB 56. REMOVING ENGINE FROM FORD CAR. . 1. Drain the water out of the radiator and disconnect the radiator hose. 2. Disconnect the radiator stay rod which holds it to the dash. 3. Take out the two bolts which fasten the radiator to the frame and take the radiator ofif. 4. Disconnect the dash at the two supporting brackets which rest on the frame. 5. Loosen the steering post bracket fastened to the frame, when the dash and steering gear may be removed as one assembly, the wires first having been disconnected. 6. Take out the bolts holding the front radius rods in the socket under- neath the crank case. 7. Remove the four bolts at the universal joint. 8. Remove the pans on either side of the cylinder casting, turn ofif the gasoline, and disconnect the feed pipe from the carburetor. 9. Disconnect the exhaust manifold from the exhaust pipe by unscrewing the large brass pack nut. 10. Take out the two cap screws which hold the crank case to the front frame. 11. Remove the bolts which hold the crank case arms to the frame at the side. Then pass a rope through the opening between the two middle cylinders and tie it in a loose knot. Through the rope pass a "2x4", or a stout iron pipe about ten feet long, and let a man hold each end. Let a third man take hold of the starting crank handle, when the whole power plant can be lifted from the car to the work bench for adjustment. » JOB 57. ADJUSTING CONNECTING ROD BEARINGS ON FORD ENGINE. 1. Drain of? the oil. 2. Remove the plate on the bottom of the crank case, exposing the connecting rods. 3. Take off the first connecting rod cap and draw-file the ends a very little at a time. Functions of Engine Parts 15^ 4. Replace the cap, being careful to see that punch marks correspond, and tighten the bolts until it fits the shaft snugly. 5. Test the tightness of the bearing by turning the engine over by the starting handle. Experienced mechanics usually determine when the bearing is properly fitted by lightly tapping each side of the cap with a hammer. 6. Loosen the bearing and proceed to fit the other bearings in the same manner. 7. After each bearing has been properly fitted and tested, tighten the cap bolts and the work is finished. Remember there is a possibility ot getting the bearings too tight, and under such conditions the babbitt is likely to cut out quickly, unless precaution is taken to run the motor slowly at the start. A good plan after adjusting the bearings is to jack up the rear wheels and let the motor run slowly for about two hours, keeping it well supplied with water and oil, before taking it out on the road. JOB 58. ADJUSTING VALVE TAPPETS. It is possible to set the tappets on the modern engine up so close as to make them noiseless in practically every case. This, however, is not good practice. While it may please the operator and owner temporarily, in the end it is certain to be the poorest sort of economy. It is generally conceded and known that the heat of the engine is sufficient to cause the valve stems to expand quite a bit over their length when cold. The result is that when they are hot the cam and cam shaft will have to bear the weight of the explosion on the top of the valve since it will not quite close onto its seat. This load, which is Considerable, may also result in the springing of the valve stem. It also contributes to cut and worn tappet faces and cams. Because of the fact that the valve does not quite seat there is always a loss of compression past it which causes the face of it to be burned very quickly. Valves were designed To adjust the clearance, loosen 'these two nuts, and screw the bal] stud in or out of the rocker arm, using a screw driver through the hole in the upper nut Pry up on this end of the rocker arm before measuring clearance Fig. 168. Adjusting Valve Clearance on Overhead Valves (National Sextet). 156 Automotive Trade Training UJ§UI WZ-I a/t .004''Md^/mu/r7i c/earance Inlet ya/ye <3pr/nc^ Inlet yd/ye Inter /at re otem <:^u/de' Va//e pu^t? rod ^^"^E^ttdust ra/ye ^fem efu/diS .OO^^'^Majr/mum c/edrddce Hdjust inlet yat/epu<5h rod here /IdjUssrment toc/c nut In let mtre //fter- Ka/Ke t/ffer efuide ta/re t/fter rotter p/n Fat ye t/fter rotter Fig. 170. Reo F Head Valve Operating Mechanism. 1. To adjust tappets the engine should be put in the same position as for grinding valves, that is, on compression stroke for the cylinder to which the tappets belong. 158 Automotive Trade Training 2. With a thickness or feeler gauge test the clearance between the top of the tappet adjusting screw and the bottom of the valve stem. 3. The amount of clearance should be adjusted to .004" for intake and .006" for exhaust or that recommended by the riianufacturer of the particular engine being repaired. 4. Why is this amount of clearance not the same in all cases? 5. In the case of tappets not adjustable the valve stem will need to be filed if it is too close. JOB 59. METHODS OF REMOVING VALVES. As the student is already aware, the position of the valves in the engine is not always the same. Neither is the method of securing them in position just the same in every case. The usual method of holding the spring in place is to put a cupped washer under the spring, and under the washer either a horse shoe retainer or a pin. In rare cases the valve adjustment is on the lower end of the valve stem and the spring and washer are thus retained. 1. Learn the best method of getting at the valves. a. Remove valve covers. b. Remove port plugs. c. Remove head. 2. Having valves accessible, next proceed to remove them. a. Fit on a valve lifter. b. Release tension on pin or retainer by compressing spring. c. Release spring. d. Remove valve lifter. e. Remove valve. f. Inspect for marking. If not marked be certain to do so at once, otherwise the valves will become mixed and much trouble will result. 3. In this manner remove all valves. JOB 60. CLEANING VALVES. After the valves have been removed from the engine, the next step is to clean them free of all carbon accumulations. At times, too. there will be rust on the stem, particularly where the oiling system has failed. Several methods are in use for cleaning them. 1. Scrape the carbon off with a knife. 2. Polish the head and stem with fine emery cloth. This may be done. a. Bore a hole in a board that will be a snug fit for the valve stem. Hold the board in a vise and polish by running a strip of emery around the valve and the stem. b. Hold the valve in a portable drill or breast drill chuck. Polish while turning by holding the emery cloth against the valve. c. Hold the valve in the drill press or lathe chuck and polish. d. Polish by hand. 3. Kerosene is often of aid in removing carbon deposits and gummed oil. JOB 61. GRINDING VALVES. The following directions apply equally well to all types of cars, except- ing to those of the removable valve cage construction. In that case the cages are removed and the end of the valve stem is gripped in the vise, after which the cage is rotated on the valve in much the same manner as the following process where the valve is rotated. 1. Secure a valve grinding tool and some compound. Functions of Engine Parts 159 2. Place a little valve grinding compound on the valve face, using the finger to distribute it. 3. Place the valve in the engine until it rests on the valve seat. 4. Have the piston for cylinder No. 1 on T. D. C. compression stroke. This may be obtained by turning the engine by hand until both the exhaust and intake valves are seen to work one foUow^ing the other closely and then one-half turn farther. Fig. 171. Grinding Valves Using a Screw Driver as a valve grinding tool (Overland). 5. With the grinding tool turn the valve about three-fourths turn around and then reverse, at the same time applying a light even pressure. 6. Start with a coarse or medium compound depending on the condition of the valves. 7. Continue until all pits are removed, then finish and polish with fine compound. 8. Considerable patience is required in this work. A light coil spring placed under the valve head will facilitate its removal. Also help to speed up the grinding as it can be depended on to raise the valve and let it be reseated quickly at another point. 9. Have the job inspected as you 'progress and when the first valve is finished. Valve Lifting Tod Valve Spring Valve Spring Seal Valve Seal P« Valve Stem Fig. 172. Lifting Valve Springs (Ford, 160 Automotive Trade Training 10. When all are finished the work should be rated. 11. When reassembled it will be found necessary to test all valve tappets and have them adjusted when necessary. JOB 62. RESEATING VALVES. In cases where the valves have been ground a number of times and show a considerable shoulder it will be necessary to reseat them to secure a good job, otherwise the seating face grows too wide and the valve is also liable to hang on the shoulder in its face. A number of good sets of tools are on the market which may be used for this work. The sets consist of a tool used for refacing the valve itself and a separate tool which is used to ream out the valve Fig. 173. Lifting Valve Springs (Overland). Fig. 174. Grinding Valves. seat. In some cases the valve port wall is reamed out to permit of a so-called hair line contact of the valve on its seat. 1. Re-face the valve first by carefully setting it up in the tool, taking just a light cut from its face. 2. Reseat the valve by using the reaming cutter properly fitted to the cylinder casting in the valve port. 3. In either case use a firm even pressure, and do not remove any more metal than is necessary to secure a true seat or face. 4. Grind as in Job 61 to finish. JOB TIMING ENGINES. The student having studied the previous instruction given in this chapter on valve timing will be in a position to understand the actual operation as explained below. These instructions will apply in a general way to any job of valve timing. A number of charts representative of general practice are given. 1. Ordinarily timing gears, whether chain driven or gear driven, are marked, but this is not always the case. After the timing gears have been exposed, which means removing the plate covering them, the next step is to inspect the gears for timing marks. Functions of Engine Parts 161 2. If no marks are present, the mechanic will do well to place some after first setting the engine in timing position. I S •4 A 3. The parts may now be disassembled to allow for any replacement and repairs. 4. When replacing the timing gears the cam shaft must be replaced in proper position as well as the crank shaft and pistons, after which the gears may be replaced. 162 Automotive Trade Training 5. Where new gears are to be placed in the engine it is possible to transfer the marks from the old. However, in such case the engine should be timed with complete exactness to check up the setting of the gears as there is a4ways a possibility of making a mistake in transferring marks. rLyyyHC£L t/at/ns mafks. ALL -^ CrUA/D£/f CONT/NCNTAL MOTO/fS HA^^B: the rOLLOkV/A/G r/RJNG OffDE/f AND ROTATE CLOC^I/V/SC, y^El^£D FROM FRONT. Fig^ 176. Continental 4 Engine Timing, 6. In all cases of engine timing the real proof of exactness is not the marks on the gears, but the position of the crank shaft and piston assembly in relation to the cam shaft, valve tappets and valves. This proper relation has been explained at an earlier point in the chapter. 7, Never attempt to check up the engine timing until the valve tappets have been properly set. Too great a clearance in the tappet adjustment will Functions of Engine Parts. Marks on Gear Te«(h 163 Can SIwHGma Crank SImH C«w Fig. 177. Showing Method of Marking Timing Gears. 5Cr0ffC RCtlOVitIG Any 6CA^5, TURtiCRAriK^iMArT TO PO^lTlOn 5H0Wn,(nilCK FuncnnAKK5'As,'5'0PP05iTc)ifi WHICH posmon thc 't inur v^lvc /3 JU6r f^cAor TO 0PCti(BAO4" at the point shown in Fig. 180. This is standard practice. A chain either too tight or too loose is prone to be noisy. The one too tight is also subject to breakage and causes undue wear on the bearings. The one too loose is likely to jump from the gears and thus do great damage, Functions of Engine Parts 165 There are several methods of tightening chains. In many cases where the generator is chain-driven, the chain is tightened or loosened by manipulating the eccentric block through which the end of the generator shaft enters the chain case. In other cases an idler gear is utilized. Where great wear and stretch are apparent it may be necessary to remove one or two links. In cases where two links may be removed at one time the chain may be connected without any trouble. Where only one link may be removed the two ends of the chain will not fit together and permit alignment. To correct this fault WASHER ROCKER PIN SEAT PIN When the chain is properly adjusted there should be about Yi" shake back and forth Fig. 180. Silent Chain Adjustment and Assembly (National Sextet). two links are removed and a hunting link is substituted. This link will align the ends of the chain properly. OPENING CHAIN. Two methods are in use in this work. Some chains are provided with a special link which is fastened in place with cotter keys, or wire, or other special fastener. In some cases no special link is provided and the ends of the seat pin, Fig. 180, are riveted over the washer thus inclosing and retaining the rocker pin which is made shorter than the seat pin. When the chain is riveted together at each pin it will be necessary to file off the riveted end of the seat pin to remove it. When replacing seat pins, new pins should be used to permit of making a workmanlike and safe job. It is also well for the student to learn the direction of rotation of the silent chain. Arrow heads are sometimes stamped on the chain links to indicate this. As shown in Fig. 180, the seat pin should travel ahead. LUBRICATION. In practically every case the chain is housed in the timing gear case and lubricated by the engine oiling system. This is splash 166 Automotive Trade Training in some cases, in others the chain dips into a well of oil, and in others a stream of oil is fed onto the chain as it runs. JOB 65. REMOVING A CYLINDER HEAD. A large percentage of cars use engines fitted with removable heads. This in itself is a most splendid feature when it comes to carbon removal, valve Fig. 181. ritjmoviiiy a Cylinder head (Allen). care, etc. On the other hand, a cylinder head carelessly handled may be the source of much trouble. The act of removing the head is one requiring good judgment on the part of the mechanic. The following outline of steps for this work will help the student: 1. Drain the radiator. 2. Remove all hose connections which will prevent the head being lifted free. 3. Loosen all other parts such as vacuum tank and horn which may be attached in any way to the head. 4. Remove all the nuts or studs holding the head in position. 5. Test head with the hands to see if it is loose. 6. Failing to be able to loosen the head with the hands the engine. may be cranked over. The compression will break the head loose. When using this method to loosen the head it is well to have a nut or stud in place at each end to prevent the head being forced all the way off. 7. When the head is loose, the next step is to get it raised far enough to permit the workman lifting it by placing his fingers between the cylinder head Functions of Engine Parts 167 and the block. This may be accomplished by the judicious use of a screw- driver. The gasket will be harmed by the screw driver if the point is jabbed into it. 8. With the head blocked up to permit the workman to grasp it, the usual practice is to stand astride of the engine while raising the head up and off the studs. 9. Next raise the gasket from the block, using extreme care that it is not twisted, kinked, or otherwise harmed. Put it in a place where it will be safe from any abuse. JOB 66. REPLACING A CYLINDER HEAD. The work of replacing a cylinder head in such a manner that no parts will be damaged, and yet that all joints may be perfectly sealed, is a difficult one for the inexperienced. The following suggestions will be of help: COUNTEP BORED Pig. 182. Method of counterboring to relieve tight point on cylinder head assembly. 1. Clean all carbon deposits, rust, grease, or dirt from the machined surfaces of the head and block. 2. Test with a straight edge such as a steel rule or square to see that the two surfaces are true. 3. Remove any and all burrs around the edges and around the studs such Fig. 183, Cadillac, right hand cylinder head removed. 168 Automotive Trade Training as those shown in Fig. 182, Where the burr is around the stud, the stud should be removed and the hole countersunk. Burrs raised around the edges should be removed with a flat file. If the gasket has been s-hellaced on, the old shellac will have to be scraped off. Make certain that there is nothing at any point which will prevent the head from coming down evenly. 4. If the old gasket is badly worn and in poor condition the best and safest plan is to replace it. A gasket well cared for should last for five or six head removals. 5. Coat the gasket both sides with cup grease; also place a light coat of cop grease on the machined surfaces of the head and block. 6. Place the head in position making certain that there are no tools, studs, nuts or other objects in the cylinders. 7. Place in all studs, or if they are already in the block, place on all nuts, running them down until all are ready to seat on the head. With a socket wrench which fits the heads or nuts properly, draw each stud in turn until all are exerting a slight pressure on the head. Continue this operation until by the most careful work all studs have been drawn tight. To draw on one stud to the neglect and exclusion of others will most certainly cause trouble. 8. A stud is tight when, a decided pressure is brought to bear on the head. By using a large wrench, or long handled one, it may be drawn tighter than is actually needed. This may result in the cylinder block being distorted in some cases and this distortion may be so bad as to cause leaky valves. In other cases the stud may be pulled up in such a manner that the metal immediately around the stud is raised and instead of the leak being stopped it is made worse. 9. In cases where undue pressure or force is used the studs are frequently broken off in the block. This means the head must be removed and the broken stud taken out. 10. After the engine has been run long enough to warm it up thoroughly the next step is to go over all studs once more to give each one a final turn. This is usually possible due to the fact that the heat has expanded the stud a bit, and also to the fact that the heat will run out some of the cup grease. JOB 67. SHELLACING A CYLINDER HEAD TO PREVENT COMPRESSION LEAKS. It frequently happens that due to an old gasket, or head, which is in bad condition, it is difficult to make the cylinder head gasket joint leak-p'-oof. In making a test to learn if the gasket is permitting leaks, proceed as follows: 1. Remove head and gasket. 2. Clean free of all grease. 3. Coat the gasket each side with white lead. 4. Replace the gasket and head. 5. Run the engine, under load if possible. 6. Remove the head again. Any points where the white lead shows black streaks are points at which the compressed gasses have been leaking from the cylinders. 7. Clean the gasket of all the lead, grease and oil. 8. Coat the gasket and machined surfaces of the head and block with a thin coat of rim and gasket shellac. 9. Allow the shellac to dry until it is tacky to the touch. Apply the head in the usual manner. 10. In cases where cylinder head gaskets develop serious leaks between the cylinders, it is sometimes advisable to shellac in a strip of paper on the part of the gasket indicated by the arrow in Fig. 184. This will prevent the com- pression starting a leak which will later develop into serious trouble. Functions of Engine Parts 169 FOULED CONDITION OF CASKET AT THIS POINT INDICATES LEAKAGE BETWEEN CYLINDERS r Fig. 1S4. Hudson block with liead removed. JOB 68. FITTING NEW PISTON RINGS. To properly seal the walls between the piston and cylinder the piston ring must be most carefully fitted. Three forms of clearances must be figured by the mechanic. The side and back clearances are illustrated in Fig. 186. The end clearance is illustrated in Fig. 187. These clearances are figured always in thousandths of an inch. A feeler gauge is absolutely necessary to a good piece of work. The workman who attempts jobs of this nature without the proper measuring devices, depending on his eyesight alone, will never earn the title ot mechanic. The person with a trained eye may tell the difference between .002" and .004", but the average workman can not say with any degree of accuracy whether a certain space is .010" or .030". In fitting new rings proceed as follows: 1. Drain the radiator, remove the cylinder head, and do such other preliminary work as may be necessary to remove the piston. Make certain that the piston rod and cap are properly marked so as to insure their proper return to the orig- inal cylinder. Do not lose any shims from the bearing. 2. Remove the rings. If difBcult to remove, use three old hack saw blades or strips of sheet metal to slip under the rings and hold them expanded while slipped over the ring grooves. Fig. 185. 3. If the old rings are to be used again they should be main- tained in order that the top one may be returned to the top Fig. 185. Using skids to remove piston rings. groove, and so on. 4. To learn if the old rings are fit to be used again, first roll them in the grooves of the piston to note side clearance. This should be just enough to 170 Automotive Trade Training SIDE CLEARANCE Fig-. 186. Piston King Clearance. allow them to slide without gripping the sides of the groove. In other words, there should be no appreciable play up and down in the groove. Fig. 190. 5. Test the old ring in the cylinder to learn if there is an excessive amount of end clearance. If this is .003" or more for each inch of diameter of the cylinder, the ring should be replaced with a new one. For instance, if the thickness gauge shows this end clearance to be more than .009" for a 3" piston the clearance is too great and the ring needs to be replaced. Fig. 187. Piston Kiny Clearance. 6. In fitting new rings the first step is to secure the proper size of ring from the supply house or dealer. Usually these are a bit large and to fit them the ends must be filed to permit of the proper clearance. 7. Place the new ring in the cylinder. File ofT the end until it will just lay even with no clearance. 8. Note whether the ring lies in close contact with the cylinder walls at all points, or whether, with a light beneath it, it shows away from the walls at certain points. If it does stand away a considerable amount at any one point, it may be necessary to pien it at that point to make it conform more nearly to the cylinder! This is a job requiring patience or the ring will be broken. Rings are cast grey iron. Fig. 188. 9. With the ring conforming pretty well to the cylinder, it may 1)e placed on an old piston or on a dummy piston and lapped to a still better fit. To do this, place a bit of fine valve grinding compound on the ring's outer surface. Moving the dummy piston and ring up and down in the cylinder while giving it a circular motion will quickly fit the ring to the cylinder wall. Do not use the coarse grinding compound in this lapping operation. Clean the ring and Functions of Engine Parts Openfn^ 171 Fig. ISS. Piston Ring in need of piening to make it fit up to the cylinder wall. the cylinder most carefully after the operation is completed. 10. Put the ring in position in the cylinder and make a test with the thickness gauge for end clearance. The top ring should have a clearance of .0015" to .003" per inch diameter of the cylinder. The lower rings, not being subjected to quite as much heat as the top one, may be a bit closer. File until proper clearance is obtained, remembering that in the case of the bevel cut lap when the clearance shows on the gauge as .004", it is in fact .006", or one and Fig. isn. losing a thickness gauge in fitting a piston ring. Measuring end clearance. one-half times as great as the thickness gauge shows. This fact is due to the angularity of the lap. A step cut ring will show the actual clearance when measured. 11. The next point is to test the side clearance and fit the ring into the piston groove. In this work the ring is rolled around the groove as indicated in Fig. 190. Starting at diflFerent positions make at least three tests to see if the ring appears to be the same width at each point. If too wide, the width is 173 Automotive Trade Training reduced by placing a sheet of medium or fine emery cloth on a plate glass surface or on a surface plate. A perfectly true bench top or board may be used in case nothing better is at hand. Grasping the ring under the finger tips the mechanic gives it a rotating motion on the emery cloth, testing each little while to see how it is being reduced. As quickly as one point shows signs of fitting, that point must be protected from further cutting as the work proceeds. When all points are just entering the groove, extreme care must be used so as to finish up the work in such a manner that the ring will just slide around the groove in the piston when it is put in position on the piston. It should have just a little tacky or sticky resistance to sliding. The piston expands more than the ring when heated and will clear it nicely. 12. The final test for the ring is to learn if the ring is a bit thinner than the groove is deep. This is the back clearance and should be .002" per inch diameter of the piston. Too great a clearance allows the carbon to collect back of the ring and this in turn may cause rings to stick. 13. Carefully fitted rings will do more to repay for the expense of making the job right than perhaps any one other thing. They mean more power, more mileage, less oil consumption, less fuel consumption, less carbon accumulation, less bearing trouble and fewer repair bills. Fig. 190. Pitting Piston King to Groove. JOB 69. FITTING NEW PISTONS. There are a number of causes which contribute to such wear, normal, or abnormal, which make necessary the fitting of new pistons. If no abnormal conditions are present the engine will give many miles of service without the pistons or cylinders wearing to such a degree that the old pistons must be discarded and new ones installed. However, even in normal service there is some wear on the piston and the cylinder tends always to wear out of round and egg shaped. Under abnormal conditions as when the engine overheats or is run without oil, or when the cylinders and pistons score for any reason, it is almost certain to produce enough damage that the pistons at least will have to be replaced. In cases where the cylinders are scored badly as would be the case in piston pin scores, the cylinder block would have to be repaired or replaced. In the minor cases of scoring, and to correct the cylinder worn oval due to long- service, the following method may be used to fit new pistons. If the cylinder is worn from .010" to .015" out of round the job is one requiring reboring and the following method would not give a mechanically correct job: 1. Tear down the engine and get the cylinder block in such condition Functions of Engine Parts 173 cither in the frame of the car, or on the bench, or stand, that the work may proceed without hindrance. 2. Measure up the cylinders to learn the size of the new pistons to be ordered. In some cases it is advisable to put the cylinders in good condition before ordering the new pistons. 3. To put the cylinder in good condition use an old piston for a lapping tool. Mount a handle on the wrist pin to use in working the piston up and down and round and round as the work is in progress. This handle may be made from wood, or from pipe fittings, or several old connecting rods may be bolted together at the yoke end and the piston fitted onto one of the piston pin ends with a round stick in the other piston pin end. 4. For a lapping or grinding compound it is best to use a valve grinding compound, selecting a grade which the work would seem to require. If a coarse compound is used to start the work, the finer grades must be used to finish it and to remove all the scratches. Avoid emery compounds for this operation. .'j. The ideal motion for the work of lapping or grinding is a revolving one. supplemented by a vertical or in and out motion. To simply work the piston up and down in the cylinder without turning it will not grind it true. The revolving motion is essential in grinding the cylinder round. 6. The work is difficult and requires patience and skill. After grinding for a considerable time the piston will become so small that the work is hindered. A larger piston must be substituted, or the one in use must be split with a hacksaw in such a manner that the two sides may be wedged apart a bit to compensate for the wear. 7. When the cylinder has been brought to a fair degree of accuracy which can be determined with a pair of inside calipers or micrometers, the new piston may be fitted. To do this use fine valve grinding compound and lap or grind in as suggested for the use of the old piston. 8. The clearance of the new piston should be figured according to the manufacturer's specifications, or failing knowledge of that, the allowance may be figured as follows: For cast iron pistons allow .001" to .0015" clearance for each inch cylinder diameter at the top of the piston. The skirt, which is not subject to as great degree of heat, may be made a closer fit, .00075" per inch of diameter being recommended. For aluminum pistons aflow .003" to .004" for each inch of cylinder diameter at the top of the piston. Allow somewhat less clearance at the bottom. 9. Pistons should be fitted from the bottom of the cylinders and in their natural position. 10. In running in new pistons and new rings care must be exercised to have plenty of oil and not to operate the engine at excessive speeds. JOB 70. SCRAPING OUT CARBON. This is a piece of work readily learned by the student. The actual work of removmg the carbon by scraping where the head of the engine may be removed is slight. 1. Remove the head. Job 65. 2. Scrape all the carbon from the tops of the pistons, the valves, and the cylinder block. Use a putty knife and screw driver to scrape with. 3. Scrape all the carbon from the cylinder head. Use any round nose tool to work into the corners. 4. If plugs need it clean them of carbon. Never take a spark plug apart or attempt to help its condition as long as the porcelain is burned a clean brown or tan. 174 Automotive Trade Training 5. Wipe all parts free of carbon and carbon dust. 6. Replace head. Jobs 66 and 67. 7. Where the head is cast integral and it is desired to remove the carbon by scraping, the first step is to remove all of the port plugs. 8. Bring the piston in cylinder No. 1 to top dead center on compression stroke. This leaves both valves closed. 9. While in that position proceed to scrape the carbon loose. Use compressed air to blow it from the cylinder. 10. This work requires patience and some thought. The mechanic must be able to visualize the inside of the combustion chamber and the work of his scraper. He can not see how the work is coming. He will in time learn the feel of the scraper and know when the work is completed. 11. Scrapers for this work come in sets of three and are made from cold rolled steel. In special cases where none of the scrapers seem to fit they may be bent to such shape as may be best, or other special scrapers may be made up. 12. When each of the cylinders in turn has been finished the port plugs are cleaned. These plugs will frequently give as much trouble with compression leaks as would a removable cylinder head. This is due in practically every case to abuse in handling them. Proper tools to turn them are not at hand and the mechanic uses a punch and hammer to turn them. This results in distortion of the machined seat with the result that no gasket will make them tight. 13. To prevent trouble at this point it is good practice to use flake or powdered graphite mixed to a paste with machine oil to coat the threads with when replacing them. 14. Turn the port plugs in snug. Heat the engine by running and give the plugs another turn. CHAPTER 7 OILING SYSTEMS To facilitate a study of engine lubrication, the main types of systems only will be mentioned. These are : 1. Splash. 2. Splash and circulating. 3. Force feed. Of the latter two there are a number of variations. The student \ 1 j Fig. 191. Cadillac Oiling System. must not lose sight of the purpose of the oiling system while learning the details of design. Full Splash. — The full splash is not used in automobile engines today. It is still used to a certain extent in marine and stationary engines, where the engine remains largely in a level position and is not tilted on an angle for considerable length of time as in hill climb- ing. Here an outside supply is arranged to drop a certain amount of oil into the single oil reservoir into which the rods are dipped. Tilting the engine runs all the oil to one end of the oil pan and while over oiling some parts it is under lubricating others. The Splash and Circulating. — This is perhaps the most popular 175 176 Automotive Trade Training for fours and sixes as it is not so likely to cause trouble. Here oil is carried or pumped from a reservoir to a second level in the oil pan and allowed to fill up oil wells or grooves into which the rod dippers may dip at all times. To accomplish this result satisfactorily each rod has its own well, and coming onto a hill does not materially disturb the lubrication as the circulating system keeps the oil sup- plied to these wells from which it is splashed up into the cylinder walls, piston walls, valve ports, and onto piston rods, piston pins, valve tappets, cams, cam shaft bearings, and timing gears. Besides, Fig. 1^- Overland Splash and Circulating Oiling System. • a vapor is even supplied to valve stems, and springs inside the in- spection plates, or under the valve cage covers. Usually the oil pan is made with two levels, the lower level acts as an oil reservoir, while the upper is the one which contains the oil grooves. As long as there is oil in the lower level sufficient to fill the pump well, or sump, the pump keeps the oil flowing to the upper level from which it is splashed and used to lubricate moving parts as indicated in Fip". 192. All surplus oil finds its way back to the lower oil level ready to be recirculated. Forced Feed. — There are several varieties of force feed. This is particularly adaptable to the V type motor, as all attempts to use the splash system here have resulted in failure, due to more oil being splashed into the left-hand block (from driver's position) over- lubricating it, and under-lubricating the right-hand block. Oiling Systems 177 Fig. 193. Buda Engine. An example of the Pull Forced Feed oiling system. Note the drilled crank shaft and the direction of travel of the oil through it. In the force feed system the oil is circulated from the oil sump in the oil pan through a screen into the circulating tubes, into the main bearing caps, from where it finds its way through oil grooves and holes, into the crank shaft which has either holes or tubes provided for carrying the supply to the crank pins within the rod bearings. From this point the oil is sprayed onto the cylinder walls and piston pins, cams, tappets, etc. ; or in what is termed full force feed the oil is forced still farther and carried up through the connecting rod, or along it, through a tube to the piston pin, from which it is forced to the piston bushings and cylinder walls and rings. The cam shaft bearings are also fed by oil under pressure, while the cams, valve lifters, gears and chains are very largely dependent on splash, even in the full force feed. While the splash of oil often plays a very distinct part in the force feed the student must remember that there are no dippers on the rods, nor is there any provision for the rods to dip into the oil and splash to the other parts. Rather the unused portions or surplus of oil forced to the engine bearings are sprayed or splashed or thrown ofT as the shaft turns. Fig. 195. Oil Pumps. — In automobile engine oiling systems, the oil is cir- 178 Automotive Trade Training culated by means of pumps, except in the case of the Ford, where the oil is carried up to the top of the flywheel hous- ing by the flywheel, where a certain amount is caught in the funnel shaped opening of the oil circulating tube and then flows by gravity to the front end of the engine. Other sys- tems utilize the gear pump, the rotary vane or centrifugal pump, and the plunger type pump. Centrifugal or Rotating Vane Pump. — This type of pump as used in the Dodge consists of a vane or impeller so driven that oil is draw^n from the oil sump coming into the oil pump case, then thrown off and out at another opening, thus finding its way to the bearings, oil wells and grooves. Fig Buda Kiifiiiie. Timing Gear end view of tlie Full Force Feed oiling system. Note the operation of the Geared oil pump and the saber type of oil gauge. Note parts lubricated by splash. — Jf * XS M_ll^^ ^^1 m g r Fig. 195. Continental Red Seal 7R. Full Pressure Lubricating System. Oiling Systems 179 Fig. 190. Haynes Gear Type Oil Pump. Gear Pump. — In this case oil is taken into the oil pump case and thrown off by two small gears having teeth of coarse pitch. These gears are driven from the engine and oil coming in goes ai;^und the gears and not be- tween them. A small quantity is carried between each tooth and the pump case, much as the old chain pump carried successive cups of water to the top of the well and dumped it in a flowing stream from the spout of the pump. Oil coming from one side meets that coming around the gear from the other side and more and more is brought around ; cir- culation is started and continues as long as oil remains or the engine continues to operate. Plunger Type Pump. — In the plunger type pump commonly used on the force feed system, oil is drawn into the pump body after which a valve closes ; as the plunger descends the oil must be forced out. An opening with another one-way valve is provided for this. After the oil has been forced out the plunger starts upward again, when the second valve closes to prevent oil being drawn from the lubrica- tion line rather than the oil sump or well. However, the first valve has again opened and permits oil to enter. The operation continues regularly, the check valves controlling the direction of flow. The amount of flow is controlled by adjusting the length of stroke on the plunger which is usually operated by cam action. Indicating Devices. — There are two general methods of indicat- ing the working of the oiling systems, the sight feed and the* pressure gauge. Sight Feed. — In the case of the sight feed a small metallic case with a glass dial is placed on the dash or instrument board. As the oil is circulated by the pump it is carried to the sight feed into which it may be seen flowing. A small vane is mounted in the instrument at times in order that the action or flow of oil may be more readily detected. From the sight feed the oil returns to the engine where it is used to lubricate the moving parts. > Pressure Gauge. — In the case of the pressure indicator the opera- tion ;is similar to that of the air or steam gauges. Pressure in oiling systems varies from two- or three pounds to as much as fiftyjn some 180 Automotive Trade Training Oiling Systems 181 Oii Li^-ft feedtng flecker Armt Each R^ct-er Afm Ped tndividuBlly Small Stand Ftps to Give Constant Oil Pressof* Feed to Bc-j^fif Arrr.a \ Line FeBOino Ganeratof Gear eat Bejflna Overflow from cut Preeaure Reflulator Oiro«te^VVV\KK\S^ i^ PUMP OUTLET CONNECTION DAiH CAUOE . Pipe CONNECTION OIL P^JHP I0W6R GEAft (AH SHAFT 0»L PUt^P DRIVING — • 0EAR5 .OIL PUMP SHAFT erARiNC J>iL PUMP 5HAFT UPPER CffANK CASE .OIL PUMP SCRUN ,OlLPUMP ORive GEAR OIL PUMP COV&R OIL PUMP SCREEN COVER Fig. 200. Buick Oil a'uinp. 184 Automotive Trade Training Fig. 201. Continental 7R showing Gear Type Oil Pump. with compressed air. The screen in the oil sump at times is clogged with dirt and must be cleaned. Failure of the pressure to register may be due to a broken line, thinned oil, a clogged tube, etc. In the case of full force feed, if the pressure gauge shows a sudden jump above normal pressure, it may be due to dirt in the line or stoppage of some of the passages. Failure of any of the oil lines is pretty certain to result in badly scored or burned parts; usually some in- dications of approaching trouble may be detected on the gauges, either sight feed or pressure. Since cold always tends to make oil Fig. 202. Packard Truck Gear Type Oil Pump. Oiling Systems 185 heavier or thicker, the pressure on the gauge will show more in start- ing the engine than after the engine warms up. Caring for Oiling Systems. — A properly functioning oiling system, properly cared for, will do more to lengthen the amount of service to be obtained from an engine than any other one thing. No system is flawless. No engine is flawless. Careless operation of the engine increases the likelihood of trouble. The exercise of proper care may do much to eliminate the development of trouble. ^, ««« « , , „, , ^., «. . Oil Wears Out. — The grade of Fig. 203. Packard Truck Oil Strainer ., , . . ,, ^ and Relief Valve. Oil to be uscd IS usually recom- mended by the manufacturer of the motor car. Generally speaking, the older the car the looser the parts have become, due to natural wear, and the heavier the oil permissible and desired. No matter what the grade or quality of oil, it will wear out. The purpose it serves is to provide a film between two metals to prevent them touch- Fig. 204. Continental 7R showing Oil Strainer, Oil Lines, Floats, and Gauge. 186 Automotive Trade Training Fig. 205. King Oiling System. ing each other. This is necessary to prevent wear as they perform their vv^ork, as for instance in the crank within its bearing, the shaft actually rides on the oil. The oil might be said to act similarly to the balls between the outer and inner race in a ball bearing. To provide for a heavier load, in the latter case, larger balls are used or a greater number of smaller ones. In the engine bearing, the greater the load the greater the bearing, consequently the larger the film of oil carrying the load. As the engine runs the oil is worn round and round in the bearings. It is hammered by the impact of the piston l)lows, and ground between the piston and cylinder wall. In this way small Cork npaf- ~-0/l finer ^screen Touch mm r/rj<^er. - u//7e/7 fill/ncf, to injure ~3e/7£f Wis ca/re // neceO'Sari^ to make /nd/cafor read correcf/i/. Fig. 20(j. Keo Oil Gauge and Filling Tube. UlLlNG ^VSTE-\ 187 particles of metal are picked up. Carbon and gasoline also are carried down by it from the combustion chamber and it gradually accumulates such a quantity of foreign materials that it is no longer fit for lubrication. Draining Oil.- — When this condition is present it is necessary to draw the oil from the crank case, flush and refill with new oil. This should be done each thousand miles the car is run, during the summer. m ' ! .-.,.. :;.■ I mmm^-—^^. M '^^TW- iSHi^tt^ l^tlM' #%i ■; 1 r ^ ^ ^rm-^ .¥T i r^ ^4---iM" Fig. 207. Buick Motor. In winter it may be necessary to drain the oil more often as the heavy grades of gasoline are hard to vaporize and more will be drawn into the cylinder than is burned. This works down into the oil and thins it out. New cars, or cars just overhauled, should have the oil drawn from the engines after not more than 500 miles' service. Troubles Due to Loss of Lubricating Qualities. — Destroying the lubricating qualities of the oil brings about many unsatisfactory con- ditions, for which there is no apparent cause. These conditions are usually difficult for the inexperienced driver to comprehend. Some of the troubles which are a direct result of the impaired qualities of the lubricating oil, are as follows: 1. Hard starting. 2. Premature piston wear. 3. Premature cylinder wear. 4. Premature piston ring wear. 188 Automotive Trade Training ■ e 9 1 pi ^ 1? f' )f#jj J ^ ■ 1 V ^ I / 7 ^ r r 1 I c ■^, ^ o ~ A ^ i 5 s tD o r r, ~ ^ . u 1 c^ - 3 ■ i- ^ Oiling Systems 189 5. Connectingf rod bearings burning out. 6. Crank shaft bearings burning out. 7. Excessive gasoline consumption. 8. Smoking due to the abnormal increase in the height of oil level in the crank case on account of gasoline working into the base of the motor. 9. Excessive carbon in cylinder. 10. Tendency to overheat, due to lack of lubrication. 11. Very poor or no compression. All of the above result in lack of power and poor performance. This diluted mixture tends to soften the carbon and practically makes a carbon-gasoline lapping compound which has a tendency to aggra- vate the wear already caused by parts running without adequate lubrication. To eliminate so far as possible the above conditions: 1. Keep motor free from carbon. 2. Replenish regularly the oil supply in the engine base. For trucks in constant service this should be done every week in cold weather, decreasing to once a month in the heat of summer. 3. Use choke sparingly. 4. Do not adjust carburetor to give a rich mixture. This helps in starting, but the excess fuel eventually finds its way to the oil reservoir. Always make carburetor adjustments after the motor has run for some time and is thoroughly warmed up. , 5. Use best grade of gasoUne obtainable, especially in cold weather. JOB 71. CLEANING VALVB STEMS; AND GUIDES, AND PISTON RINGS. Dtte to the oily, gumnny carbon-like deposits around the piston rings and about the valve stems and guides, it is a good plan to treat these points with kerosene each thousand miles pf service. To do this will insure better power, compression, and lubrication, fewer repair bills, and smaller gasoline and oil bills. This operation may be carried out as follows: 1. Do this work just before draining the oil as indicated in Job 72. This is in order to prevent an undue waste oi engine oil since it is necessary to drain the oil after the process indiicated here is finished. 2. Open up the auxiliary air valve, or carburetor, in such manner that the end of a rubber tube or of the oil gun may be inserted. With the engine operating under its own power the oil gun is used to feed kerosene into the carburetor just as fast as the engine will take it without choking and stopping. If the engine tends to stop, the throttle should be opened and closed rapidly, which operation will likely keep it running until the kerosene has been worked through the engine. Run from one quart to two quarts through the engine in this manner, depending on the number and size of the cylinders. 3. Remove the inspection plates. Spray or squirt the kerosene onto and 190 Automotive Trade Training into the valve guides, valve springs, tappets and tappet guides, working down and out the old grease and loosening the gummy accumulations about the valves and guides. 4. Clean all surplus oil from the tappet compartments, and clean up the engine where the kerosene and oil have run over. 5. Replace the inspection plates, after they have been cleaned and freed of dirt and grease. 6. Proceed to drain, oil and flush the crank case as directed in the next job sheet. JOB 72. GENERAL INSTRUCTIONS FOR DRAINING, FLUSHING AND REFILLING THE ENGINE CRANK CASE. It is impossible to sufficiently emphasize the need of proper care of the engine oiling system. New cars and even used cars find their way into the repair garage much more frequently than would be necessary if the oiling systems were cared for according to the directions of the car manufacturer. Not all engines may be drained, flushed and refilled in the same manner. Two examples are given in Jobs 73 and 74. These directions are according to the specifications of the manufacturer in each case. In the one the engine is to be cranked with the kerosene in the engine, in the other the motor is not to be cranked with the kerosene in the crank case. Wherever possible to obtain the car manual it should be followed most carefully. In every case, it is absolutely essential that the old oil be drained and thu crank case flushed and washed out with kerosene once for each thousand miles of service. Where the car manual is not at hand the following directions may be safely followed: 1. Warm up the engine a bit to get the old oil flowing. 2. Remove drain plug and drain ofif oil into a bucket. 3. By shaking the car it is frequently possible to run out additional oil, after it would otherwise have stopped flowing. 4. Replace plug in drain. 5. Pour in from two to four quarts of kerosene. 6. Either run the engine under its own power, for 30 seconds at a slow speed, or operate it with the starter for a like space of time, or by placing one foot on each horn of the frame the mechanic can so use the weight of his body as to get the engine swinging up and down in such a manner that the kerosene will be splashed over the interior parts of the engine and wash down a considerable amount of dirt accumulation. (Use care to protect the paint in this operation.) 7. Remove the drain plug again and drain oflf the kerosene. Shake the car by the above mentioned method to keep the dirt from settling while the kerosene is being drained. 8. Allow the drain plug to remain out while the new supply of oil is slowly poured into the oil filler tube. 9. When the oil starts to flow clear and without signs of any more kerosene the drain plug is replaced and the engine filled to the proper oil level. 10. Where oil strainers are in use they should be removed each one thousand miles and thoroughly cleaned. JOB 73. DRAINING OIL FROM PACKARD ENGINE. Drain and flush the crank case of the Packard Twin Six each 500 miles in the winter and each 750 to 1000 miles of service in the summer months. 1. Remove the oil plugs from the bottom of the crank case and from the oil pump housing. Oiling Systems 191 2. After the old oil is all drained off the crank case is flushed out by- running kerosene through the oil filler. 3. Thoroughly clean the oil pump and strainer but do not run engine. 4. After the kerosene has been drained the crank case should be filled with two and three-fourths gallons of oil which is the amount required to bring it to the oil pet cock level. 6. Do not fill above the oil pet cock level. JOB 74. DRAINING OIL FROM HUDSON ENGINE. 1. Remove the drain plug from the bottom of the oil reservoir, draining off all old oil. Shaking the car will frequently bring down more oil after all has seemed to have drained. Note Fig. 209. i\ 1 , K «* i jf • 1 Fig. 209. Draining off Dirty Oil. Fig. 210. Pouring in Kerosene (Hudson). 2. Remove the valve cover plates and pour about a quart of kerosene into each tappet compartment. Fig. 210. 3. Crank the motor with starter for about 30 seconds. Do not allow the motor to operate under its own power. This will wash down all sediment and dirt from the inside walls and oil troughs. 4. Remove the drain plug and drain off all kerosene, allowing at least 3 minutes for draining. 5. Pour clean oil into the tappet compartments. As this oil is poured into the compartment slowly, it runs into the oil troughs and displaces the kerosene left from the previous operation. This kerosene is allowed to flow out of the drain before the drain plug is replaced. The plug is only replaced after the lubricating oil starts to flow from the drain in a clean stream. 6. Refill with seven quarts of clean new oil. JOB 75. CLEANING AN OIL PAN. Even with the care given an oiling system as suggested previously, the continuous use of the car from month to month and season to season will cause an accumulation of dirt and sediment in the oil pan which is difficult to remove without actually removing the crank pan or oil pan. This is an operation for which only general directions can be given. 1. Remove the pan bolts and drop the pan down, having first drained away the oil. 2. Take the pan to the bench or cleaning trough and carefully remove the sediment, and clean each and every nook and corner. 3. Blow out the oil passages and make certain that nothing impedes the ilow of oil through them. 4. Clean the oil strainers and any other parts attached to the pan. 193 Automotive Trade Training Fig. 211. Cranking Motor 30 seconds (Hudson). 5. Use compressed air to blow out all oil lines left on the engine. 6. Inspect and clean the interior of the engine. Wash out with kerosene. See that all oil holes to bearings are clean and free. 7. If the bearings are loose they should be put in shape at this time; however, the need of bearing adjustment is postponed indefinitely in many cases simply by properly caring for the oiling system. 8. Replace the pan and make all connections as formerly. 9. It may be necessary to use new oil pan gaskets to insure a tight joint. Fig. 212. Refilling with Cleau Lubricating Oil (Hudson). CHAPTER 8 COOLING SYSTEMS There are two types of air cooling systems in use today. These are direct and indirect. Direct Air. — The Franklin is the best example of direct air cool- ing. Here the air is drawn in through the hood, passes into a cham- ber over the cylinders, then down along the cylinders which have cooling vanes cast on them, and is thrown off or out at the rear of the engine through the flywheel fan. The cooling is more or less 'Radiator Cap ■Filler Neck ■ Top Tank "Splash Plate "Overflow Tube 'Kadiator Tubes 'Kad Inlet Cona 'Cyl Outlet Hose 'Hose Clip „_ .--^ Cylinder Head Cylinder Casting Cylinder Inlet Connection Fig. 213. Ford Thermo-Syphon Cooling System. independent of the car speed, being controlled almost altogether by the engine speed. Low speed gear work does not seem to overheat the motor as is often the case in the indirect air-cooled systems. Indirect Air. — In this case the engine cylinders are jacketed to carry a supply of water. The main supply of water is carried in the radiator. As the engine is operated the water around the cylinders is heated, after which it is circulated upward to the top of the 194 Automotive Trade Training radiator, from which point it is passed downward through the radia- tor tubes, or cells, and the heat, extracted from the cyhnder walls by the water, is now extracted from the water by the air in contact with the large surface area of the radiator cells or tubes and vanes. When the cooled water has come to the bottom of the radiator it is again passed or circulated upward through the cylinder blocks where it is again reheated, thence on to the radiator where it is recooled ; and so on as long as the engine is running. In this system the water is used as a medium of transmitting the heat from the engine to the air, instead of having the air come in direct contact with the engine cylinders. Fig. 214 Buick Cooling System. Water Cooling. — The indirect air is known as a water cooling system. Here again we have two general classes, each with its peculiar advantages. Thermosiphon. — The thermosiphon is the most popular for the lighter cars. Its use does away with the necessity of a pump with its attendant parts and. troubles. Circulation here is established by the action of a natural law. When water is heated, those portions of it in contact with the heat expand, become lighter, and rise to the top. Portions on top and cooler will settle where they in turn are heated to a point above that of the water now on top, when it is displaced and returned to the bottom for more heat. Circulation is continuous so long as heat is applied. The word "thermo" meaning heat, and "siphon" to draw out, might be said in this instance, to mean. to' draw out the heat from the engine. To facilitate a rapid circula- tion in this case, the radiator inlet and outlet is made large. An advantage of this type is that an engine will warm up more readily Cooling Systems 195 than one where the pump is used, as the water does not start circulat- ing until it is heated. One disadvantage is that the water may freeze, in cold weather, in the lower parts of the radiator before circulation is fully established. Forced or Pump Circulation. — In this case the water circulates in the same manner as in the thermosiphon, but a mechanically driven pump is used to keep the water circulating. The pump is used to draw the water from the lower part of the radiator and force it into the lower part of the cylinder block, from which point it follows the usual path. Circulation is established immediately and positively. Smaller water connections and hose are used than in the case of the thermosiphon. Fig. Iil5. Packard Truck Cooling System. Note the thermostatic control which keeps the water passage to the radiator closed until the water within the cylinder block has come to a temperature allowing eflBcient operation of the engine. As the engine continues to run after reaching this point in temperature the thermostat gradually opens until sufficient water flows to keep the engine at this point of greatest efficiency. Cooling System Care. — The careful driver or mechanic never fails to give the cooling system daily inspection. Usually a s^mall quantity of water daily is sufficient to keep all working smoothly. The sudden and unusual disappearance of water means trouble ; it may mean a leaky radiator hose connection or something more serious, as leaking cylinder head gaskets, a broken or damaged radiator, or other parts. Whatever the trouble is, it should be located and remedied immediatelv. r 196 Automotive Trade Training Radiator Hose. — Owing to the fact that the automobile is in use on uneven as well as smooth surfaces, there must be a degree of flexibility between the various units. To permit this movement be- tween the radiator and engine, rubber hose is used to form the water connection. Hose bands or clips are used to bind the hose in posi- tion. Occasionally shellac is used to make a tight joint, but should not be used unless the leak cannot be stopped otherwise. Rubber Hose Troubles. — Due to the moisture, heat, vibration, bending and twisting to which the hose is subjected, it will wear out and need to be replaced occasionally. Length of service is no indication of condition. The hose may last two weeks, two months, or two years. One year may be a conservative average. Usually the hose peels away on the inside first, and this inner rubber lining break- ing lose may cut off all circulation through the hose. Again it may be carried into the vital parts of the circulating system and clog I^adiator ran t?e/r adjustment Pack/nq <:f/ands Tyater out/ef Water infet JVater pump Fig. 216. Reo Water Circulation System. Arrows indicate the direction of flow of the water. Cooling Systems 197 them. Naturally less resistance is needed to retard circulation in the thermosiphon system than in the forced circulation. Steaming Radiator. — This is an indication of lack of water or failure to circulate. Failure to circulate may be due to a frozen radiator or passages, or a broken down rubber hose or pump. If a radiator filled with water starts steaming on a cold day the trouble is obvious, likewise the remedy. Leaving the car set with the radia- tor covered will often thaw out the troublesome spot. If this does not avail, it will be necessary to get the car into a warm garage. Fig. 217. Packard Twin Six Cooling System. Thermostat in Detail. If the trouble is in the hose it may be detected sometimes by exerting pressure on the outside of the hose. , This is not always true however and the hose may have to be removed and inspected. When this fails, inspect other parts. The impeller on the pump shaft, may have worked loose, or other mechanical trouble may have developed. A systematic search must be made and the trouble cor- rected. Radiator Mountings. — To prevent unusual jars and twists being transmitted to the radiator, springs, swivels or bufifers of some kind are provided. A radiator not so provided, as in older types, may be protected by having a piece of rubber mounted under the supports. Radiator Types. — In designing radiators having large surface areas exposed to cooling drafts of air as it is drawn through the radia- tor core, several distinct types have been developed. Very thin copper is used to construct the vanes and tubing or cells, to insure 198 Automotive Trade Training rapid radiation of the heat from the water. The types in use are the tubular and the honeycomb or cellular. Tubular Type. — This is the most common type of radiator. Usually round tubes are used. To assist in rapid radiation of the heat from the water as it passes down through the tubes, they are mounted in thin metal vanes or fins. Air passing over these fins cools them relieving them of the heat they receive from the tubes. In this construction the tubes run from the top straight to the bottom. Tubular radiators are constructed from fiat tubes, from corrugated Fig. 218. Packard Truck Fan in Section. Fig. 219. Packard Truck Engine Water Pump io Section. tubes, and tubes of many styles. In some cases they are straight and in others they are bent into such shape that when mounted they resemble the honeycomb but are not true honeycomb types. Honeycomb or Cellular Type. — This type is of more delicate construction, is more expensive, and generally considered a little more efficient. Tubes of round, square, or hexagonal cross section, are mounted in a core with the cells a slight distance apart, the ends opening towards the front and rear of the radiator. The air passes Cooling Systems )199 through the tubes or cells, while the water is passed around them in its flow from the top to the bottom of the radiator. In the tubular type the water passes through the tube and the air around it, or just the reverse of the honeycomb or cellular. Radiator Troubles. — As a rule, the apprentice or mechanic is not required to make more than minor repairs on a radiator. He should feel no hesitancy in making the repairs, such as soldering a super- ficial break or a loose overflow tube or making any repairs where the trouble is easily reached. Badly damaged radiators should be turned over to the radiator repair expert or replaced with new ones. To make an efficient repair on a badly damaged radiator requires special appliances and equipment for doing the work, as well as making proper tests. Types of Pumps. — Gear pumps similar to the oil gear pumps, rotary pumps similar to the rotary oil pump, and centrifugal pumps are used for circulating the cooling water. The last named is most generally used. This pump is designed on the same principal as any centrifugal pump. The water is taken in near the center of the pump case or impeller hub. The impeller turning causes the water to be thrown to its rim, where another opening is provided to permit it to escape into the other parts of the circulating system. Advantage is taken of the natural flow of the water. Pump Drive. — The timing gears are usually used to drive the pump. The pump shaft runs through the pump case to the distri- butor, generator, or whatever other units of equipment it is desired to drive. The Oakland deviates from this practice by driving the pump with the fan belt. Pump Troubles. — As a rule a pump gives little trouble, but the packing nuts on the shaft are in need of care to prevent them from leaking. It is good practice to place a grease cup on each pump bushing, or bearing, in which graphite grease or cup grease is used. These should be turned up regularly to keep grease in the bearings. If water starts working through, rust develops, the shaft becomes pitted, and it will be impossible to prevent leaking as the packing will wear away as fast as replaced. When there are no turns left on the packing nut, it will have to be backed off, (one is a right-hand thread, the other left, and both turn oflf counter to the direction of drive of the shaft), and new packing substituted for that worn away. Replace with pump packing furnished by the manufacturer, if pos- sible. If this is not available, hempen cord well graphited and wrapped on the way the nut turns will make a more or less perman- ent repair. Impeller Troubles. — Occasionally, after considerable service, the pump bushings may wear away permitting the impeller blades to strike or rub on the pump case. This will cause wearing and trouble 200 Automotive Trade Training in time, such as loosing the impeller on the shaft. It will be necessary to remove and rebuild the pump in a case of this nature. A point of prime importance is to have the impeller assembled on its shaft correctly to throw out, or pump water. Cooling Fans. — A fan is mounted just back of the radiator core and used to draw, through the core, the air needed to carry away the heat radiated from the water coming from the engine jacket. The fan is of more importance when the car is standing, with the engine Operating, than when being driven. In driving the air is forced Fig'. 220. Stutz Cooling System. Note fan and fan belt adjustment, also fins cast on the exhaust manifold as an aid in cooling. through 1)y the speed of the car as well as the draught of the fan. The fan is also more essential on low and intermediate gear speeds than on high. Fan Care. — Other than keeping properly lubricated and belt tight, little attention need be given the fan. If ball bearings or roller bear- ings are used, a few drops of oil every thousand miles will suffice. If bronze bushings are used the grease cups will need to receive the same attention as other grease cups. Fan Belts. — Since flexible drive is used on fans, the proper tension must be kept on the belt. Too loose permits too much slippage, while too tight prevents any slippage and causes wear on bushings if these are used on bearings. A fan delivers most air at certain fixed speeds and not a corresponding amount always with the increase of speed. For instance, the Liberty Motor gives most Cooling Systems 201 power at 1800 R. P. M., the propeller gives most power at 1400 R. P. M. This leads to the use of reduction gears to obtain the proper working speed for each. Some manufacturers introduce a friction joint in the hub of the fan to permit of some automatic adjust- ment of the speed to the power. A loose or broken fan belt will permit the engine to become overheated and a steaming radiator is sometimes the result. Tighten or replace with a new belt. Fan Belt Adjusting. — An adjustment for the fan belt is always provided ; loosening the set screw and swinging the eccentric arm until proper tension is obtained, then resetting the screw is all that is needed to take up the belt slack. In placing on a new belt, pro- vision should be made for future tightening. Changes of Temperature. — If the car was always operated at a fixed engine speed with the temperature of the surrounding atmos- phere always at a fixed point, it would be a comparatively simple engineering feat to de- sign cooling apparatus which would keep the motor at just the proper temperature for efficient operation (170 degrees Fahrenheit). Since the temperature of the at- mosphere, which is the real cooling medium, varies as much as 130 degrees Fahrenheit at diflferent seasons of the year, in some communi- ties, it is necessary for the designer to provide for the average temperature, and to arrange special features to take care of extremes, especially ex- treme low temperatures. In the summer it is sufficient to have the fan belt properly adjusted, radiator properly filled, ventilating shutter and covers open. 'I-n some extreme cases remove part of the hood or floor boards, in case of truck engines give them every possible chance for cooling. In the winter, however, provisions must be made tr shut out Fig. 221. Radiator Equipped with Shutters This permits of readily controllinjr the heat of the engine. A hand control for the shutters is provided on the dash. Shutters in Horizontal Position When Wide Open. 202 Automotive Trade Training s^^^si^^sa ^^ss^ss v'v.^'v^'^vvvvvv'v'v^^vv^vvr;^ 7..J)))JJJ))j>n^ffff. V/y>^/y>^^y>///A Cro»t Section Thermoitat Arrangement. A, Radiator coupling; B, B]r*paM coupling; C, Pi*ton valTes; D, Themottat; E, By-pas* teat. Fig. 222. Diagram of Thermostat mechanism. some of the cold air, and in come cases to control the circulation of the water. Hood and Radiator Covers. — In some cases manufacturers are providing a ventilating shutter for the hood, which may be controlled either by a thermostat or a dash control. The Hudson is a good example. Thermostat Control. — In other cases manufacturers are provid- ing thermostatic control of the w^ater circulation: A thermostat in the water pump intake pipe controls a valve which permits the water to circulate through the cylinder jackets so that the engine is operat- ^^^^^^^^^^^r^ ....-.-...-.., "^"^l^S^I I^^^R^^^ 1 *r-' 1 Fig. 223. Cadillac 8 Engine. Cooling Systems 203 ing at the most favorable temperature at all times. The thermostat D in Fig. 222 is made similar to an accordion and is filled with a liquid which vaporizes on being heated to a certain comparatively low temperature. The pressure that this gas exerts on the retaining walls of the thermostat causes enlongation of it and this action in turn operates the valve C which permits the water to flow from the radiator. The water is not permitted to circulate from the radiator to the engine until that in the water jackets and pumps and the bypass has been brought to the correct operating temperature. When this has been accomplished the thermostat gradually opens the passage to the radiator. Cooling Solutions. — Radiators need but little care in the summer except occasional drawing off of water and flushing out to prevent sediment obstructing circulation. In winter, in addition to this, the use of a non-freezing solution is recommended to prevent freezing and consequent injury of parts. Water alone will do very well when warm garages are used providing the radiator can be prevented from freezing while the car is in use. This is rather difficult unless all parts exposed are carefully protected from cold drafts of air, as for instance, the lower water passage from the radiator which frequently freezes, due to the cold draft striking it. A radiator usually freezes on the bottom first when the car is in opera- tion, and on top first if standing in a cold place for any length of time. Non - Freezing Solutions Recom- mended. — The best solution to use is wood alcohol. Denatured grain alcohol is second as it will require a greater quantity than of the wood alcohol, with a corresponding reduction of temperature of the solution. Alcohol and glycerine is ranked perhaps as second choice after the alcohols. The glycerine having a high boiling point counteracts the low boil- One bad feature of the glycerine is its tendency to attack rubber, but this tendency is offset to a certain extent by the alcohol. Glycerine is also more expensive to use than alcohol. Calcium chloride solutions are very largely used. They form the nearest ideal solution in point of reduction of freezing temperature and low boiling point, but there are several points which make their use somewhat risky. The solution is acid by nature and acids are Fig. 224. Cadillac S Pump. ing point of the alcohol 204 Automotive Trade iRAiiiiifG PACKIMG hUT FOnP ItlPCLLCR Fig. 225. Note Double Bladed Fan Construction and method of drive. Cooling Systems 205 known for their ability to corrode, eat away and destroy certain metals. It is necessary to have the acid neutralized by the addition of soda ash or some other alkaline substance. When properly neutral- ized the solution is not supposed to be particularly dangerous. To test, place a piece of the blue litmus paper in the solution. If it Fig. 226. Packard Twin Six in Section. Note fins cast on bottom of crank case or oil pan. These assist in keeping the lubricating oil cool. turns red, free acid is present and more soda ash should be added. A large number of brands of the calcium chloride preparations or similar substances are on the market. Some are particularly harmful to aluminum parts, and if used in a cooling system having an aluminum pump case for instance, it will so eat it or pit it as to make 206 Automotive Trade Training replacem-ent necessary. Manufacturers of this type of product are rather conscientious^ and if directions for the use of their product are followed, little trouble need be expected. It might be worth the student's while to know, too, that since the solution is acid and comes in contact with metals of various kinds that electrolytic action is likely to take place, thus weakening joints. Over Heated Motors. — In order that the driver may know at all times that his engine is not overheating, various devices showing the operating temperature have been perfected. Boyce Motometer. — This is the most popular device for the purpose. A thermometer is arranged to show the driver the safe Fig. 227. Continental 7R. Note water jackets around cylinder. operating temperature and the danger point as represented by the heat within the radiator. The danger here is that the driver may become so accustomed to the perfect operation of his engine that he will not notice a sudden rise of the mercury or approach of the danger point. Recognizing An Overheated Motor. — The careful experienced driver needs no special device to tell him his engine is overheating. His ear has become so attuned to the natural hum of his engine that any unusual sound is quickly recognized. Overheating will give rise to these unusual sounds, the main one of which is a pounding or knocking sound, as in overloading the motor on a heavy grade on a hot day. Instead of a smoothly running sound the engine seems to labor, to give out a harsh more grinding sound as of parts running- Cooling Systems 207 without lubrication. This is very likely to be true as the oil is likely thinned out and burned up due to the unusual heat. Steaming at the radiator filler cap and the sound of boiling water may or may. not be noticed. Causes of Overheating. — Hot weather is perhaps the most fre- quent cause of overheated engines, as it has such a direct effect on the cooling of the water in the radiator. This need not result in burned out bearings or scored cylinders if due care is exercised to have the cooling system in good condition, as having the fan belt tight and the radiator cleaned of all dirt and sediment and properly Fig. 228. Continental 7K. Note Water Pump, Oil Pump and Fan Adjustment. filled ; also the oiling system in good condition and an oil of the high flash test in the engine. Needless to say, the oil must be clean and free of carbon or other foreign matter. Refer to the chapter on oiling systems to get the essential points. Cooling the Overheated Engine. — Ordinarily the overheated engine will be quickly cooled if the bad stretch of road is passed and the engine relieved of its overload, as topping the bad hill and coming onto a level stretch. Here the air rushing through the radiator will quickly right the trouble. This cannot always be done as in pulling through bad gravel, mud and sand, or climbing long heavy grades. Then it is best to allow the motor to stand idle until the water has had a chance to cool off the engine. Raising or removing the hood will always help. Filling An Overheated Engine. — In the overheated engine the water in the radiator may have boiled, away so that it will need refill- 208 Automotive Trade Training ing. The great danger here is that the sudden introduction of cold water on cylinder walls, heated to a red hot heat in some cases, may cause them to suddenly contract and crack, thus making their replace- ment necessary. If there is any likelihood that the water is all gone from the cylinder blocks, time must be given to allow the extreme heat to be radiated and then water added very slowly. Non-Leak Solutions. — The radiator being made up from so many thin parts and subjected to constant jars, hammering, twisting, and straining, small leaks are likely to develop. These are likely to occur in either new or old radiators and often are in places very hard to reach to repair with the soldering iron. It is sometimes advisable to use a non-leak solution in the radiator. All serious leaks should be soldered if the repair is to be made permanent. Use of Cereal Preparations. — Plain cereals such as corn meal, ground flax seed, bran, etc., will serve as a temporary repair even in a rather serious leak and a knowledge of the fact may enable the driver to get out of a very trying situation. The practice is to be discouraged as a general thing since 'the excess will settle in the radiator, or in the water jacket, and tend to obstruct circulation and radiation. These cereals clog the leak because in attempting to pass through they are caught and as the water affects them they are swelled to fill the opening. Use of Liquid Preparations. — The liquid preparations may be recommended more highly. X liquid (a trade name) is a good example. It is placed in the radiator with the water. The solids in it remain in solution indefinitely, unless they are carried p\xt or steamed out through the leak, when they are left in it, or on it as a hard insoluble deposit. In a short time, ten or twenty minutes, the leak will be sealed. To facilitate the heating of the water it is well to cover the radiator for a time. This solution cleans the radiator of scale and is claimed to be beneficial in this respect. Cleaning the Radiators. — All radiators must be flushed out occasionally. A strong alkali such as soda will remove scale and tend to seal small leaks. JOB 76. RADIATOR HOSE CARE. The radiator hose connections are very frequently the source of trouble. Leaks develop around the hose bands and the rubber disintegrates on the inside stopping the flow of the water. 1. To stop a leak about the hose, use a screwdriver to draw the clamp bolt tighter. 2. Failing this, it may be necessary to renew the clamp if it should be found in poor condition. 3. The hose itself may be rotten or broken in such manner that it must be renewed. 4. If the hose is in good condition, and drawing on a clamp, likewise in good condition, fails to stop the leak, shellac may be resorted to. Remove the Cooling Systems 209 hose. Coat the inlet with shellac and allow same to dry until tacky. Replace hose and tighten. 4. Where the hose must be replaced the first step is to release the clamp. 5. Grasp the hose in the hand and give a good pull and twist at the same time. If this will not loosen it the screwdriver blade may be used to run under the hose and thus work it loose. 6. Whenever the hose shows signs of breaking out on the inner lining or rubber it should be discarded. 7. In fitting the new hose it is not shellaced unless this is found the only means of stopping a leak. 8. Be very certain to avoid any kinks in the new piece of hose as it is applied. A kink interferes with the ready passage of the water. Particular care must be used to keep the passages free. 9. In adjusting the fan be very certain that the blades do not come into contact with the rubber hose. Sometimes a fan adjustment fails and the hose is cut by the blades. 10. It is a good plan to change the hose at least once each year. JOB 77. RADIATOR CARE. Since the water passages in the radiator are very small, it is quite essential that they be kept open. The use of any water bearing such matters as lime m solution will lead to a partial stoppage of the passages and overheating of the engine. To remove sediment collections it is well to flush out the radiator at least once each season and preferably every month or so. To do this proceed as follows: 1. Place the car on the washstand, or elsewhere, where the water may flow from the radiator and be carried off properly. 2. Start the engine running at a moderate speed. 3. Open the drain cock. 4. Place the end of the hose in the radiator and turn on the water. Allow the water to run into the top of the radiator just a trifle faster than it runs out of the pet or drain cock. The overflow tube will care for this trifle of excess and the water need not run over the outside of the radiator. 5. Allow the water to run with the engine running for from 15 to 30 minutes. JOB 78. REMOVING A RADIATOR. 1. Drain the water. If a non-freeze solution is in use, save the solution for refilling. 2. Remove the engine hood. 3. Remove the stay rod if there is one. 4. Loosen the radiator bolts where the radiator shell is fastened to the frame of the car. 5. Loosen the radiator hose bands. 6. Make certain that the radiator hose is loosened from the water inlets on the radiator. 7. Lift oflf the radiator. 8. If it is desired to remove the radiator from the shell, this is done by removing the small bolts used in most cases to hold the two together. JOB 79. TESTING A RADIATOR FOR LEAKS. 1. Remove radiator. (Job 78.) 2. Solder a piece of brass or other sheet metal over each of the outlets. (Hose connection pipes and overflow tubes.) 3. Fill with water. Turn on radiator cap. 210 Automotive Trade Training 4. Using a foot pump with air line slipped on over the drain cock, force in a slight pressure of air. Not over five pounds pressure should be used. 5. This will cause the water to run, or in cases of a decided leak, to be sprayed out from the points where the radiator is leaking. 6. Locate the several leaks and mark their position after which the radiator is soldered. SECOND METHOD. 1. Place the radiator with all the outlets soldered shut into a trough or tub of water. 2. Force air at a pressure of not to exceed five pounds into the radiator noting the points at which the bubbles arise and marking them for repair by- soldering. 3. In the case of a bad leak there may be no need of following either of the above methods as the leak is easily located before removing the radiator from the car. 4 After repairing, either of the above tests may be applied to learn the condition of the job. 5, If there is time, the radiator should be filled, placed in an upright position and left over night to learn whether or not the repair is complete. JOB 80. REPAIRING A RADIATOR LEAK WITH A LIQUID COMPOUND. The liquid preparations on the market for use in repairing radiators are all similar in nature. They are placed in the radiator and as they are steamed through the leaks they solidify on coming into contact with the air. They are safe to use. X-Liquid is a sample of this. 1. Drain and flush the radiator as recommended in Job 77. 2. Fill the radiator within a quart of full, using clean soft water. 3. Start the engine running. Make certain that the oil m the crankcase is up to the "full" mark. 4 Throw a blanket over the radiator leaving the filler cap off and the filler tube exposed so as to note when the water comes to the boiling and steaming pomt 5. Put in the required amount as directed on the container. 6 Continue to operate the motor until the radiator shows dry under the blanket This is possible because of the fact that as the leaks are sealed the watei ceases to seep through. Any water on the radiator is quickly dried off due to the fact that the water on the inside of the radiator is at the boiling point. Since the action of the compound is dependent on the heat, it is just as well and perhaps better to do the work on the floor where the temperature ot the engine may be watched than it is to attempt to do it on the road when the engine may or may not reach the required temperature. If the engine is held at that speed which will just boil the water and the proper amount of oil supplied to it there is no danger ot burning it out JOB 81 REPAIRING A RADIATOR. 1. Remove and test the radiator as indicated in Jobs 78 and 79. 2. Solder all the leaks appearing on the outer surfaces and about the reservoirs and overflow tubes. This work is readily done with the regular iron. Treat the parts with soldering salts or acid. If the solder refuses to take, , wipe the part while still hot with a rag saturated with the acid. Continue heating and treating the parts until the solder does take. Of course, the major part ot the dirt and corrosion is scraped from the parts before attempting to solder them, but even then difficulty is frequently experienced in getting the ■ Cooling Systems 211 solder to take and run properly. The acid steamed off the hot part will be of material help. 3. The soldering of the leaks on the inner parts of the core or tubes is an operation requiring skill and patience. Very frequently the large iron will not reach the point where the leak is. In such a case the workman must devise other means of bringing the heat to the point where it is needed. 4. A lead burning flame will do the work in some cases. 5. A safer method for the small leak is to use a piece of copper rod of a size suitable to get to the leak and make of it a soldering iron. In some instances the work can be hastened by using the lead burning or other flame on the outer end of this small rod, the heat then being conducted to the point through the rod. This does away with the trouble experienced in having the rod cooled so rapidly that the solder cannot flow. 6. In the case of certain cells of the cellular type leaking, it. is sometimes possible to make a repair by soldering a small piece of sheet metal over each end of the cell. This is a repair recommended only for very old radiators or for temporary repair to hold until the repair can be brought to a radiator expert. 7. As a rule the radiator work of a serious nature should be left to the mechanic and shop well fitted and equipped for this class of work. The auto mechanic should attempt only those jobs which are rather easily reached. JOB 82. OVERHAULING A WATE^ PUMP. It very frequently happens that failure of the ,coaling system can be traced to the failure of the water pump. Where the p|iimp is suspected proceed as follows: • '.r 1. Remove the pump from the engine. 2. Take it to the bench and open it up. Use care in this operation, noting carefully the proper relation of parts. In working on a water pump, difficulty is frequently experienced with screw threads due to the fact that the water has rusted them. Unless care is utilized, it is quite possible to have the set screws broken off in thecastings. 3. Inspect all parts for wear, particularly the impeller. If this is worn considerably at points where it comes into contact with the case it should be replaced. 4. Inspect the shaft to see if the water has pitted and rusted it. Replace if necessary. 5. Inspect the shaft bearings which are of the bronze metal type in most instances. If worn badly, replace. 6. If the pump is generally in bad condition the entire unit should be replaced with a new one. Aluminum pump cases are particularly subject to the action of certain non-freeze solutions which cause the inside of the pump to be eaten away in an alarming fashion. The same is true of certain water supplies in which impurities are found. 7. The most frequent pump trouble is the loosening of the impeller on the pump shaft. Make this secure in reassembling the job. 8. Reassemble and replace the pump on the engine. 9. Test. JOB 83. PACKING A PUMP. The pump shaft very frequently runs through both sides of the pump case and is supplied with two packing nuts or bushings. These must be maintained in proper condition to prevent leaking. 1. Fig 229 shows the National Sextet engine and pump. Directions are also given for tightening the nuts. 212 Automotive Trade Training 2. The nuts are always tightened by turning them in the direction of rotation of the pump shaft. 3. When the nuts have been turned all the way into the case they will perhaps no longer retain all of the water. In this case they will need to be repacked. It is better to repack than to attempt to force the nut a bit farther. This is likely to result in a broken pump shaft housing. 4. Back off the packing nuts. Fig. 229. Packing a National Sextet Pump. 5. Secure the proper pump packing from the car manufacturer, or failing this use some felt or woolen yarn to wrap the shaft with. Even hempen or cotton string may be used, although any packmg to give the best service must not be too hard. Use graphite grease to pack the packing in. 6. Turn the new packings down snugly. 7. Operate the engine and then give the packing nuts a further turn. 8. See that the grease cups are properly filled and turn them down until grease starts oozing from the packing nut. If no leaks show, this should complete the job. CHAPTER 9 FUEL SYSTEMS GASOLINE SYSTEMS There are three types of gasoline systems in general use. These are the gravity, pressure and vacuum. This applies more especially to the method of bringing gasoline to the carburetor from the main supply tank. More recently, however, the term gasoline system has come to mean all methods and units or parts used in storing, feeding and supplying the fuel to the engine ready to be compressed. Gravity System. — This system was formerly used very exten- sively on both trucks and passenger vehicles. The vacuum system has largely replaced it for passenger car use. For this system to work satisfactorily it is necessary that the supply tank be placed at a point considerably higher than the carburetor. As gasoline is drawn from the carburetor, more is permitted to flow from the supply tank to the carburetor bowl through the feed line. The tank is either carried on the dash under the front seat, or on the deck as in the case of the roadster or speedster. The supply tank in this case need be only of medium strong construction. The cover must always be provided with a vent to permit air to enter as gasoline flows out to the carburetor. This vent must be of such a nature as to prevent the gasoline being splashed out. This system is pretty certain to require a low hung carburetor and a long intake pipe, especially so where the tank is placed under the seat. In the case of the tank under the cowl it has the disad- vantage of having the tank immediately in front of the driver and very close to the engine. This is likely to result in poor body design. The fumes from the gasoline are frequently annoying to passengers. Dirt and grease will accumulate about the tank due to frequent fill- ings. Since the instrument board is always located on the cowl the tank under the cowl makes the adjustment of the wiring and instru- ments rather difficult. The great advantage is the short feed line and the ease with which any trouble within the feed line is located. Pressure Feed. — This requires the gas tank to be heavy enough to resist or withstand a light pressure. No vent is provided. On the contrary, the tank must be sealed air tight to prevent the air pumped into it escaping. A pump operated by the engine when it is running is provided to keep the pressure in the supply tank up to a point where the gasoline flows to the carburetor as it is used. A hand pump is used to provide initial pressure in starting after the car has stood a time, or if for any reason the gasoline level falls too 213 214 Automotive Trade Training low in the carburetor. This would be the case if the tank was not sealed properly, if the automatic pump failed, or the carburetor was drained. Since the tank in the pressure feed is carried in the rear, one serious disadvantage has always been the number of long air lines and gasoline feed lines to keep in repair. The two pumps are also likely to give trouble and the tank is hard to keep tightly sealed. Vacuum Systems. — This system is used almost altogether for ;:iid^^^|H fiHf TO^ ^mU 'mm^ ^EhI |j(r r VRpP '1 1 Fjff. 230, Packard Liberty Aeroplane Motor Equipped with Fuelizer. passenger car work and in a large number of commercial cars. The supply tank is placed on the rear end of the chassis, while the vacuum tank is placed under the hood on the dash or on the engine. Gasoline is fed by gravity from the vacuum tank to the carburetor. It is drawn from the supply tank to the vacuum tank. The supply tank is carried on the rear of the chassis and must be lower than the vacuum tank. This system utilizes the best features of each of the other systems. One disadvantage is the number of air and gas lines to be kept free and in service. Fuel Systems 215 Vacuum Tank. — The vacuum tank is so designed as to auto- matically lift the gasoline from the supply tank to the vacuum tank. A small supply, about half a gallon, is carried in the vacuum tank, from which, as stated, it is fed to the carburetor as needed. For the student to grasp the action of the vacuum tank it is Fig. 231. Packard Twin Six Pressure Peed Gasoline System. necessary that he understand the vacuum principle. It is commonly said that nature abhors a vacuum. That is, nature seems to make provision that if one element is withdrawn or removed from a certain space or place another element is always on hand ready to move into the place vacated. This may be observed in relation to water. Suppose a brick is placed in a pail and covered with water. Remov- ing the brick does not leave a hole in the water, rather the space occupied by the brick is filled immediately by the water. However, if the water did not fill the space and no air were permitted to enter to fill the place a vacuum would be the result. Again, a dipper may be used to remove part of the water from the pail. Neither does this cause a vacuum as air immediately rushes in to fill the space formerly filled by the water. Having these things in mind, it will be easier to grasp the action of the vacuum tank which is dependent on a natural law for its unfailing response under all conditions. The upper part of the vacuum tank is connected with the intake manifold of the engine as may be seen in the cut showing the Reo gasoline system, Fig. 232. As the piston travels down in the cylinder on the intake stroke, a suction is created which draws air out of the upper chamber of the tank. Since thevf'air from the outside cannot en- ter the vacuum tank due to the air va|vve being held closed, a vacuum is formed or a place in which there is neither air or gasoline. No air can enter the tank except through the main supply tank and here all the gasoline must be forced out of the way. In attempting to 216 Automotive Trade Training Fuel Systems 217 enter the vacuum tank through the gasoline supply tank the gasoline IS carried ahead of the air. If no more gasoline is placed in the supply tank the air will eventually succeed in getting to the vacuum tank, but only after the gasoline has all been forced up to the vacuum tank, or after the gasoline is all used. As the gasoline is carried into the vacuum tank it first fills the upper chamber and then flows into the lower chamber. When both chambers have the proper level of gasoline in them the float rises to cut off the suction from the cylinder. At the same time the air valve or vent to the upper tank is opened which action permits the gasoline to feed to the lower tank. This lower chamber is always vented through the curved vent pipe. This arrangement insures a supply of gasoline to the carburetor while the upper tank is filling. However, as the gasoline flows from the upper chamber to the lower chamber, the float falls with the gasoHne level. At a predetermined point the spring together with the float action causes the air valve on the upper tank to close and the suction valve to be reopened, thus permitting more gasoline to flow into the upper chamber. The above operations are continually being repeated. While the engine is running and gasoline is being used, the operations occur at rather regular intervals, the action being automatically controlled by the rise and fall of the float within the upper chamber. The Stewart vacuum tank is illustrated. All vacuum tanks work on the same principle. Stewart Vacuum Tank Parts. — Figs. 233, 234 and 235 illustrate the Stewart vacuum tank in section and in detail. A careful study of the illustrations and the text will give the student or mechanic a clear idea of the manner in which it op- erates. A is the suction valve for opening and closing the connection to the manifold, and through which a vacuum is extended from the engine manifold to the gasoline tank. B is the atmospheric valve and permits or prevents an atmos- Fig. 233. Stewart Vacuum Tank in Section. 218 Automotive Trade Training pheric condition in the upper chamber. When the suction valve A is open and the suction is drawing gasoHne from the main reservoir, the valve B is closed. When valve A is closed then valve B must be open as an atmospheric condition must be present in the upper tank to allow gasoline to flow through the flapper valve into the lower chamber. C is the pipe connecting the tank to the manifold of the engine. D is the pipe connecting the vacuum tank to the main gasoline supply tank. E is the lever to which the two coil springs are attached. This lever is operated by the movement of the float G. F is the short lever which is operated by the lever E, and which in turn operates the valves A and B. G is the float which operates the valve mechanism as it rises and falls with the gasoline level. This flapper valve .is, held closed by the action of the suction whenever valve A is open. How- ever, it is forced open by the weight of the gasoline when the float valve has closed valve A and opened valve B. A petcock for drawing water or sediment out of the reservoir is provided. It may also be used for drawing off a small quantity of gasoline for priming the engine or for other uses. A line to the carburetor is extended on the inside of the tank to form a pocket for trapping water and sediment. A channel space is provided between the inner and outer shells which connects with the air vent, thus admitting an atmospheric condi- tion in the lower chamber at all times. This is necessary to permit of an even flow of fuel to the carburetor at all times. M is the guide for the float. N is the vacuum check valve. P is a pipe line leading to the vacuum pump on the dash. This is not always provided. It is very useful for priming the vacuum tank should it for any reason become empty. It is not necessary to Fig. 234. Float and valve mechanism of Stewart Vacuum Tank, Fuel Systems 219 GASOLINE INLET f OUTLET OR "FLAPPER VALVE TO PFilMER PUMP DRAIN TO Vacuum pump AIR VENT AIR RELIEF VALVE TO ARBURETOR Fig. 235. Stewart Vacuum Tank Operation. 220 Automotive Trade Training turn over the engine, but merely to pull the plunger in the vacuum pump two or three strokes which will create sufficient vacuum or suction to draw gasoline from the main supply tank. R is an air vent over the atmospheric valve. It also provides the opening to permit air entering the lower chamber as described on page 218. PRINCIPLES OF CARBURETION The act of charging air with a supply of fuel (gasoline) is called carbureting or carburetion. The instrument provided for maintain- ing the proper mixture at all engine speeds is called a carburetor. The student must understand the principles of vaporization to under- stand carburetion, as it is only when the fuel is vaporized that it can be mixed with or incorporated in the air as a fuel charge which is an explosive mixture. Evaporating Liquids. — A great many liquids may be evaporated and caused to float in the air. Water vapor may be seen leaving a river or lake on cold mornings. Fog is water vapor visible to the eye. Steam is a water vapor visible to the eye when first released into the air. It is visible for only a short time, however, although it still remains suspended. Setting a pan of water in the air will cause evaporation to start immediately which process continues until all water is gone or evaporated from the pan. The vapor coming off is not visible to the eye, but does continue steadily, as regular measurements will show. Clothes hung on the line dry rapidly because the water Is evaporated quickly when large surfaces are exposed to the air. if the sun is shining the heat from it will greatly assist in drying them. The evaporating process is always hastened by heat. On the other hand, the sun may not be shining but the wind blowing, in which case the action is again hastened. Clothes dry faster in sum- mer than in winter due to the greater amount of heat, likewise more quickly when more air is brought in contact with them. However, the clothes may be frozen stiff almost immediately on being hung on the line in the winter. This does not prevent them from drying, however, as evaporation still continues although very much slower. All of these observations will help the student to gain an under- standing of carburetion. Volatile Liquids. — If a pan of lubricating oil be placed in a room the smell or odor from it may be detected only when close to it, if at all. If a pan of kerosene is placed alongside of the other pan the fumes from the latter may be detected more easily and at a greater distance. If a pan of low grade gasoline is placed in the room it will be detected by the odor of the fumes at a still greater distance, Fuel Systems 221 222 Automotive Trade Training and a pan of high test gasoline at a still greater distance. In other words, one liquid is more easily and readily evaporated than another. It is only the natural vaporization or evaporation which causes the fumes to rise into the air where their presence is detected by their odor. The gasoline is spoken of as being more volatile than the kerosene. Alcohol, benzine, and certain other liquid fuels are also very volatile meaning that they easily float away on the atmosphere. Heat. — If it is desired to vaporize large quantities of water with- in a short space of time, heat is applied to it until it boils and steams. The greater the heat applied, the faster it boils and steams away into the atmosphere. The same is true of the volatile liquids, or in this case of the volatile liquid fuels. The less volatile, or the heavier the fuel, the greater the degree of heat required. Hence, the terms low grade and high test fuels. Vacuum. — A common laboratory experiment is to place a quantity of water in a glass flask. Exhausting or drawing off the air from over the water, or in other words, creating a vacuum in the upper part of the flask will cause the water to start boiling even though the temperature of the water is that of the atmosphere of the room. The boiling temperature of water is 212 degrees Fahren- heit. This is with normal atmospheric pressure at sea level. Water boils more quickly on the mountain top than at sea level. This is due to decreased air pressure on the surface of the water. Reduction of pressure hastens vaporization or evaporation. This was evidenced when the water in the flask started boiling at a temperature less than 100° ; but it requires that practically all pressure be removed from it. Spraying. — If a quantity of liquid is sprayed into the atmosphere from a nozzle it will be broken up into very fine particles. The finer or smaller the nozzle the finer will be the spray. This results in atomization, that is, the small particles of liquid are separated from each other. The more complete the atomization is, the more com- plete is the process of vaporization, and the more highly is the air charged with the liquid. Vaporization and Carburetion. — The student has had his atten- tion focused on these matters with which he is already more or less familiar in order that he may understand the manner in which these natural laws and principles are made use of in carburetor design. By utilizing these principles of vaporization and evaporation gasoline is added to air in proper proportion to give an explosive fuel, and carburetion is completed. Air bearing heat is drawn up through the carburetor where, in a partial vacuum, the volatile fuel is sprayed into it. All principles and features of carburetor design harmonize and cooperate to make vaporization and carburetion almost instantaneous. Carburetor Design. — Carburetors are so designed and built as Fuel Systems 223 to make use of all the features, principles, and natural laws enumer- ated and explained above. Air is drawn in through a stove where it is heated. Next it is drawn into a venturi tube arrangement called the mixing chamber. Here, due to its velocity, it creates a vacuum which in turn draws or sucks gasoline from the spray nozzle. As 224 Automotive Trade Training this gasoline leaves the nozzle it is atomized. Vaporization is com- pleted by the vacuum and heat. When the proportions of air and gasoline are correct the carburetion of the fuel is completed. Car- buretion might be defined as the act of spraying a volatile fuel into the heated air of a partial vacuum in such proportions that the vapori- zation effected gives a mixture which may be compressed within the engine and exploded with a clean blue flame. Explosive Mixture. — A mixture of gasoline and air is explosive only in certain proportions. In speaking of and considering the proportions of air and gasoHne they are considered with reference to weight and not volume. One part of gasoline mixed with ten or more parts of air is barely explosive. It burns with a reddish yellow flame. One part of gasoline mixed with twenty parts of air again is barely explosive. This mixture burns with a whitish flame. One part of gasoline mixed with fifteen parts of air might be said to be the best proportions. This mixture burns with a clean blue flame. With the very high test gasoline the correct proportion may run as high as seventeen to one while with the very low grade as low as thirteen to one is correct. In order that the student may understand carburetor adjustment care and repair, there are given below certain conditions which he must be able to recognize. These will be evident from the action of the engine under varying conditions, especially those having to do with speed, power, and condition of exhaust with reference to its sound and the color of exhaust gases. Rich Mixture. — A rich mixture is indicated by a sluggish motor uneven in operation. It has less than normal power. Exhaust gases may show black smoke. Response is slow on opening the throttle. Over-fed conditions are evident. The engine does not choke quickly, but will die a slow lingering death. The condition may be remedied by adding to the air supply cv permitting more air to enter by making proper air valve adjust- ments. It may also be remedied by cutting down on the gasoline allowance. Either action will result in leaning the mixture. Lean Mixture. — A starved condition is evident here. If the engine runs at all, it will run faster than the over-fed motor. Again, it has less than ndrmal power. Its surest indication is popping at the carburetor due to premature ignition, commonly called pre-igni- tion. With this condition present black smoke never will be noticed iit the exhaust. Usually, when the mixture is leaned out too much, the engine will speed up for a few seconds and then come to an abrupt stop. With a very rich mixture the engine may continue to chug along for quite a time. This condition is remedied by enriching the mixture. To do this, close off some of the air supply by adjusting the air valve spring. Fuel Systems 225 Or, the same result may be arrived at by opening up the gasoline needle until enough gasoline is added to the air to give the proper proportion for the mixture. Correct Mixture. — When the correct mixture is reached from either of the two extremes explained above, it will be evidenced by a smooth running engine and a return to normal power. In the case of a return to normal power from an over-rich mixture some little time will be needed to drive out the logged gases and burn the spark plugs clean of soot and smoke, which is bound to be left in the cylinder and on plugs by an over-rich mixture. The proper mixture would be evidenced by a clear blue flame if it could be seen. If the student is familiar with the gasoline stove or torch he will recognize this flame immediately. As the student has doubtless noticed, an imperfect mixture in the use of a gas or gasoline stove usually burns yellow and smokes. This is the condition in the rich mixture in the engine where the smoke and soot are deposited as carbon. Power. — The motorist says he has great power, has no power, or has just average power and speed. As a rule this means good, bad, or average combustion of the gases within the cylinders, which is the real source of all power developed in the car. Other conditions may be present which cause mechanical troubles, or poor ignition, but the most frequent cause of loss of power is poor carburetion. A properly mixed charge of fuel explodes with great heat and tremendous expanding force. This forces the piston down into the cylinder with decided force and power. A mixture containing too much fuel burns slowly rather than exploding. The gases form slowly and push the piston down as they form. Their expanding power is vastly less. The mixture which is too lean explodes quickly. The volume of gases formed by the explosion is insufficient to fill the entire com- bustion chamber with high pressure gases. It might be characterized by comparing it with an attempt to drive a heavy nail with a tack hammer. Not enough energy can be developed. Venturi Tube. — Practically every type of carburetor utilizes the principle of the venturi tube to hasten vaporization of the gasoline. This tube comprises an important part of the mixing chamber. The venturi may be detected in any of the carburetor illustrations as that part having a contracted neck or portion with the spray nozzle ending in the throat. The velocity of the air passing through the throat or neck is increased. After it is through and there is more room, the air expands thus forming a partial vacuum. The gasoline is sprayed into this neck. This action might be likened to a column of soldiers marching through a narrow portion of the roadway. After passing through the narrow portion they maintain the same speed but spread out to occupy a greater space on the road. In other words, they are 226 Automotive Trade Training farther separated. In the case of the air, the same quantity fills a larger space, but the particles are farther apart, or a partial vacuum has been caused. Nozzles. — Many types of nozzles are used, some fixed and some adjustable. In the case of the fixed nozzle the auxiliary air valve is adjustable. Where no auxiliary air valve is provided the nozzle is always adjustable. Where the nozzle is made adjustable it is done by providing a needle valve within it. By controlling the size of the opening, the amount of gasoline permitted to flow under any and all conditions may be regulated. Gasoline Level. — This is maintained at all times just below the top of the nozzle in the venturi tube. Whenever, for any reason, the level comes higher, the carburetor is said to flood. About y^" is correct. If too low, that is more than 3/16", great difficulty will be experienced in starting the engine. It is also liable to give trouble when operating at low speeds due to the fact that the suction within the venturi is insufficient to lift the gasoline from such a low point. Float and Needle Valve. — A float, either hollow metal or cork, is provided to maintain the gasoline at the proper level. The opera- tion is automatic. The gasoline enters the bowl from the feed line, the float rises on the gasoline until at a predetermined point the needle valve is forced down on its seat thus shutting ofif the flow of any more gasoline until some has been used out, at which time the float again falls permitting gasoline to flow until the proper level is again reached. The action of the float and the needle valve is continuous while the motor is in use. In time the valve and valve seat will become worn to such an extent by this continuous action that it will be found necessary to replace them or reseat them in order to prevent the gasoline leaking through. Float Troubles. — A common fault of either type of float is log- ging. By this is meant that gasoline has found its way into the float and has made it heavy. In the case of the cork float the shellac is penetrated and the porous part of the float is filled. In the case of the hollow float it develops a small leak from which air escapes and through which gasoline enters the float. Dirt may lodge under the needle valve and thus fail to control the flow from the feed line, but if the float sinks to the bottom of the carburetor bowl and fails to give a lively response when submerged the indications are those of a logged float. If the float responds as it should but gasoline continues to flow, the trouble is with the needle valve. This dirt may often be washed out of the valve by holding the float down, thus allowing the gasoline to wash out the valve as it rushes in. The carburetor shoulJ be drained occasionally to remove any sediment which has collected in the bowl. This also removes the water which has collected at the bottom of the bowl. Fuel Systems 227 Hot Air Stove. — Heat is added to the air as it passes on its way to the carburetor. The hottest exposed part of the engine is the exhaust manifold. On this or on the exhaust pipe the designer fits a sheet metal cover having air passages arranged in such a manner that the air going to the carburetor is drawn in and around the exhaust pipe, and after being thus heated passes through the flexible metal tube to the carburetor. Stoves are cast integral with the mani- fold in some cases. Hot Spot Manifold. — With the use of lower and still lower grades of gasoline it has been found necessary to increase the amount of heat provided to the incoming charge. ' This is due to the fuel being less volatile as explained previously. It insures better com- bustion and economy of operation. The incoming charges pass along a wall heated by the outgoing exhaust gases. The heat from the one chamber is transferred through the wall to the gases in the other. A variety of forms of manifolds are in use but the principle is the same ; that is, heat is added to insure vaporization. The manifolds are cast together. In some cases pins are cast on either side of the separating wall so that the exhaust gases. heat these pins and the incoming charge cools them and is in turn heated. The plan is being adopted rather generally. Hot Water Heat. — Carburetors and intake manifolds are some- times water jacketed to increase the amount of heat available to the incomxing fuel charge. The greatest fault with this system is the slowness. The car will travel from several miles upward before the proper temperature is secured to stop spitting of the carburetor and to insure economic operation. The great fault of ail carbureting systems is that the raw gasoline drawn in, in warming up the gaso- line, finds its way down past the pistons into the crank case there to work all manner of harm. The water heat is clean and will insure a smooth running motor when the proper temperature is reached. This is about 170 degrees. Another method of utiHzing the heat from the water to do this work is to cast the intake manifold integral with the cylinder head. The water in this case is circulated around the manifold. This construction is not apparent to the casual observer. Manifolds cast in heads which are not cooled as thoroughly as was the former practice are also in use. Here the direct heat from the gases burning in the cylinders is used to heat the incoming fuel. Exhaust Gas Jackets. — These are used in remedying carbureting systems of the older cars. A jacket is provided around the intake manifold. The ingoing charge passing through the manifold absorbs the heat through the intake manifold wall which is heated by the exhaust gases flowing through the jacket. Only part of the exhaust from the engine is conducted through the jacket. The repairman can often fit up a car of an older type with this system to good 228 Automotive Trade Training advantage. Each case has to be handled individually but results are assured. Some carburetors are provided with jackets through which part of the exhaust gases are shunted to heat the gasoline in the bowl. The greatest difficulty encountered here is to keep the jacket free of carbon deposits. Choke Valves. — When starting a cold engine, no heat being avail- able, the vacuum principle plus the atomizing effect of spraying the charge from the nozzle must be depended on entirely for vaporization. To increase the vacuum the air intake line has a butterfly valve placed in it which may be closed to choke off the air supply, thus causing a richer charge of gasoline to be drawn into the mixing chamber where the increased vacuum helps vaporization. From this greater supply of gasoline, or richer charge, enough gasoline will be vaporized to get the initial explosion and to start the motor running. Immediately the engine has started to run under its own power, it is necessary to release the choke valve to admit more air, or the engine will be choked by the over-supply of gasoline. Too much gasoline in the engine cylinders or the combustion chamber is spoken of as flooding the engine. On stopping the engine many drivers partially or wholly choke the engine to insure ready starting. This is a good practice for extremely cold weather. In warm weather a flooded motor may be the result. The spring provided to hold the choke valve open should be in- spected occasionally to insure its being maintained in proper condi- tion. It should be held wide open at all times, excepting only when its use is desired. If it becomes loose and swings about, the engine is certain to run unevenly. Air Valves. — In order to maintain the proper mixture of air and gasoline that is 15 to 1 by weight at all speeds, it has been found necessary to equip the carburetor with some device which will auto- matically maintain these proportions after the spray nozzle has been adjusted properly. This is handled differently by the various car- buretor designers. One method long popular requires that an auxiliary air valve be placed in the carburetor in such manner that it may be acted on as the inrush of air or suction becomes greater at the higher engine speeds. This auxiliary air valve is shown in a number of the illustrations of carburetor sections. Its position should be studied carefully. It serves the one purpose of maintaining the proportion of air and gas no matter what its design, location, or method of control may be. Were it not for this air valve the fuel charge would become too rich, thus causing the motor to operate unevenly. The most common type of air valve is the one whose action is controlled by a coil spring. The tension on this spring is adjustable through a thumb nut arrange- ment which increases or decreases the tension on the spring. This Fuel Systems 229 adjustable feature is necessary to insure the action of the valve at just the position required to prevent the mixture becoming too rich. The springs used are very sensitive and are especially wound for this work. If, for any reason, the spring becomes damaged, it is best to replace it with a new one. A repaired spring is likely to give an uneven jerky action to the valve thus causing the motor to run very unevenly. Neither may these springs be secured at random, but the spring furnished by the carburetor manufacturer should be used. The straight coil spring is not used very largely for this work. Either two springs of varying tension are used, or a spiral wound spring is furnished. Adjusting Air Valve. — If there is a low speed adjustment, it should be set to obtain the best idling speed for the engine while the air valve has enough tension on it to insure its remaining closed. When the proper setting for the slow speed nozzle has been secured the mechanic may proceed to adjust the air valve. First turn the thumb nut until the tension is greater than needed. Open the throttle quickly. The engine will give forth the usual indications of too rich a mixture, will be found to be sluggish, and black smoke may possibly be seen coming from the exhaust. Next release the tension on the spring, testing each little turn of the thumb nut as suggested above. Continue the operation until a point is finally arrived at, at which the carburetor pops when the throttle is quickly opened. Next increase the tension on the spring until, when the throttle is opened instantly, the engine picks up at its best speed without pause or backfire. With the setting at this point the car should be tested for speed and power. A little varia- tion may be necessary as indicated by lack of power or sluggishness. Air valves are not always controlled by spring tension. In some cases they are made to operate by gravity in which case they are not readily adjustable. The suction of air draws the valve from its seat allowing the proper amount of auxiliary air to enter to maintain the mixture in proper proportions, 15 to 1, for all speeds. As speed and suction decrease, the air valve drops back on its seat forced down by its own weight. Since the air valve cannot be adjusted, all adjust- ments must be made on the gasoline nozzle. Adjusting Gasoline Nozzle. — This operation is performed in much the same manner as the adjusting of air valves. The results arrived at are the same. A proper mixture is secured. The mixture should be made too rich by opening the nozzle to a point where, when the throttle is opened suddenly, the engine is sluggish and fails to respond in a lively manner. Other signs of a too rich mixture are present. Next close the adjustment a trifle making the test of opening the throttle. Continue this until the best running point is arrived at and passed. When the lean point is noticed by the nooning at the car- 230 Automotive Trade Training buretor, the adjustment must quickly be enriched or the motor will stop. Continue increasing the supply of gasoline until again the motor operates at its best speed without popping and without pause when the throttle is opened instantly. Test the car on the road as before and adjust finally as need is shown. These instructions are given to acquaint the student with the principle of carburetor adjust- ment as applied to simple carburetors. Under the description of special makes of carburetors will be found directions for adjustment of same. Throttle. — The throttle is a butterfly valve located in the top of the mixing chamber of the carburetor. Opening the throttle means opening this valve until, at a wide open position, the valve stands in each case in a position to allow the maximum amount of air to flow past it. Closed throttle means that the valve rests almost straight across the top of the mixing chamber. A very small opening is left for the passage of air on a closed throttle. In a closed position the engine is said to run at an idling speed meaning it is carrying no load. Closing the throttle does not stop the engine as in the case of a steam engine, but permits it to continue at the idling speed until the spark is turned off. In some models of carburetors a gasoline nozzle is introduced at the point of closing of the throttle to provide a spray of gasoline for slow speeds and starting work. Special devices and attachments are at times used by designers in conjunction with the butterfly valve to provide the throttling mechanism. Metering Pin. — This device is used to control the amount of gasoline entering the mixing chamber. It may be used either as the principal adjustment or merely as an auxiliary feature. It consists of a long metallic pin fitted into a nozzle in such a manner that it carefully measures or meters the amount of gasoline permitted to flow by it at various speeds and settings. In some cases it is actuated with the throttle in fixed relation to the opening and closing of the same. In other cases it operates in conjunction with air valve dash pots. The metering pin in its relation to individual design is brought out in the illustrations. Dash Pot. — The dash pot is a separate gasoline chamber, or bowl, in which the gasoline level is maintained at the same level as that of the carburetor bowl. This is done by the float and needle valve arrangement which controls the level in the bowl. A passage- way connects the bowl and pot. When the auxiliary air valve is drawn down the dasher within the pot forces up a quantity of gasoline which is sprayed into the auxiliary air to insure acceleration. The dasher, which is connected to the air valve, tends to hold same steady and prevent fluttering. The student will study the action of the metering pin in the designs utilizing it as described and illustrated in the succeeding pages. Fuel Systems 231 Plain Tube or Compound Nozzle Type. — Here is found perhaps the simplest carburetor in point of moving mechanical parts. Natural laws and principles are substituted for mechanical devices. The student was shown how the low speed mixture grew too rich when the throttle was opened and the suction increased. To compensate for this an additional feature is provided so arranged that the fifel charge is always too weak or lean. The two combine to maintain at all speeds the proper mixture. The regulation of the amount of gasoline <— AmnmKE SPEB>ADJUSTHENr Carbureror Assembly Fig. 238. MaxweU Carburetor in Section. to the amount of air is held at 15 to 1 automatically. Adjustments for high or low speeds may or may not be provided in carburetors using this principle, which is called the Baverly principle after its discoverer. Air-Bled Jets. — In the air-bled jets a small quantity of air is admitted through and with the gasoline. This tends to break up the gasoline and make atomization more complete as it is sprayed from the nozzle into the mixing chamber. JOB 84. MAXWELL CARBURETOR. Several styles of carburetors have been used on the Maxwell 25. The photographic reproduction shown in Fig. 239 is the earlier type. The gasoline adjustment is shown as the needle valve. This valve is controlled from the 232 Automotive Trade Training instrument panel within certain limits. If the carburetor has been dismantled .and is being reset, the needle valve should first be turned all the way to its seat. Next it should be opened to about three-fourths of a turn, after which the needle valve handle binder screw should be locked. This should be with the dash control on center. Throwing this handle to the one side, closes the needle valve giving a leaner mixture. Throwing it to the other side gives a richer mixture because the valve is opened. The lean position should be in use for driving on the level, while the neutral or rich position will have to be used for hard going. This is the only adjustment on the carburetor. The auxiliary air valve is a hollow brass ball which is raised from its seat by the Gasoline Shut Off Cock Gasoline Line Hot Air Stove Throttle Lever Drain Plug Gasoline Tank Outlet and Settling Chamber Float Valve Screw Cap Float Valve Needle Valve Handle Hot Air Stove Door - Needle Valve Handle Binder Screvi/ Needle Valve Gasoline Line Packing Gasoline Line Packing Nut Air Choke Valve Float Cfcamber or Carburetor Bt ! ioat Chamber Drain Cock Fig. 239. Maxwell Carburetor and Fittings. increased suction to admit additional air. This ball may be seen in the. center of the cut. MAXWELL 25 — 1919. A section of the 1919 carburetor is shown in Fig. 2r58. This is provided with two adjustments. Proceed as follows to adjust this carburetor. With the engine idle turn both idle screw and high speed screw to their seats. Set the throttle lever stop screw to the approximate idling position. Next open the high speed needle one and one-half turns. With these adjustments made the engine should be started and run until it is as warm as actual service conditions would make it. Next place the spark control in a retarded position and open the throttle until a driving speed of twenty to twenty-five miles is reached. Next turn the high speed needle to the right or close it until the engine tends to stop from too lean a mixture. Turn it open or to the left until the engine shows signs of too rich a mixture. The engine will roll and show signs of slowing, choking, and stopping. Next turn the needle to the right again and at a point about midway between the two extremes will Fuel Systems 333 be found the point of greatest speed as well as of best mixture. Now the idle adjustment screw should be set. The throttle should be closed at this time. Should the engine fire unevenly, turn the idle screw to the left to enrich the mixture, or to its seat to make the mixture lean or poor. The approximate position for this screw is one-half turn out. The throttle as well as the spark should be fully retarded. JOB 85. PACKARD TWIN SIX CARBURETOR. Single Jet. The Packard carburetors are of the single jet or spray nozzle type. This nozzle is located in the center of a mixing chamber or venturi. As Fiir. 240. Packard Car Carburetor. noted in the illustration. Fig. 240. both the primary air and auxiliary air act on the one nozzle. The primary air comes through the usual type of air passage provided with a choker which is used only for starting or cold weather work. The action of mixing and vaporizing is the same as previously explained for this type of carburetor. Heat is secured from the hot water jackets around the cored intake and from the exhaust manifold. The single jet is not adjustable, but all adjustment is secured from the auxiliary air valve. Auxiliary Air Valve. The illustration shows this in a housing forward of the mixing chamber. It is controlled by two springs, one within the other. At low or idling speed this valve admits very little air. The air supplied comes through the other passage and up through the mixing chamber, past the nozzle, where it picks up the gasoline. To prevent too rich a mixture, the auxiliary air valve opens with increased suction allowing the needed air. This insures the correct mixture at all speeds, as the greater the suction the greater the 234 Automotive Trade Training action of the air valve. Changing the spring tension affects the quality of the mixture. Cams placed beneath these springs are controlled from the dash. Pulling the air control button out will increase the tension on the springs thus giving a richer mixture. The proper setting of the button, for ordinary- running, is flush with the dash. If, for any reason, these cams are disassembled the greatest care should be exercised to see that they are reassembled in their original position. In warm or hot weather it is possible to so flood the engine by use of the choker that the mixture cannot be fired. This is a trouble experienced frequently by the inexperienced. Throttle. This is of the butterfly valve type. As in all cases the valve is provided with a set screw which is adjustable for idling speeds. The throttle is so adjusted that there is always room for sufficient mixture to pass to keep the engine running when the control is all the way back. Except for this provision the engine would stop whenever the control or accelerator were returned to either a normal or ofif position. To increase the minimum speed, loosen the lock nut and turn the screw forward. To decrease the minimum or idling speed, turn the screw backward or out. This should be done with the Fig. 241. Tillotson Carburetor, engine running in order to note the eflfect on the engine, and that the mechanic may know from the sound of the motor when the best idling speed is reached. Be quite certain to lock the screw with the check nut when the adjustment is completed. JOB 86. TILLOTSON CARBURETORS. Instructions for Adjusting. All models of Tillotson carburetors are equipped with the automatic air valve not adjustable. The gasoline only is adjustable, and that is regulated by adjusting the primary needle valve adjustment on the primary fuel supply nozzle. To secure the correct adjustment, first warm up the motor. Next, close the throttle so that the engine will run reasonably slow. Then turn the adjustrnent to the right or up a little at a time until the motor commences to slow down as a result of being starved of fuel, and then turn the needle back to the left about one-eighth of a turn. This should give the correct mixture, and if all other conditions of the motor are normal, the results obtained should be a maximum of power at the best economy of gasoline used. Fuel Systems 235 Automatic Air Valve. — The design of the air valve provides a small opening through which the air enters when the motor is running at slow speeds. The area of this opening is so designed as to equal the requirements of the motor 236 Automotive Trade Training at closed throttle. The area of the opening is gradually increased by the yielding of two flat steel reeds which are opened by the atmosphere pressing against them from the outside when suction or a vacuum is produced on the inside of the carburetor. The vacuum corresponds to engine speeds, likewise the opening of the reeds. The reed cage provides a seat for the reeds which should normally lie fiat on the seat thus sealing the valve. The maximum partial vacuum will only open the reeds a small portion of their maximum elasticity thus insuring long life for the reeds. The amount of air required by the motor at any and all speeds being predetermined, the correct mixture is obtained by the placing of the fuel supplying nozzles in the path of the air and supplying an adjustment to regulate the amount of gasoline to be drawn through the nozzles. The position of the secondary nozzle is such that it supplies gasoline at the higher engine speeds only. Since the primary nozzle supplies gasoline at all speeds an adjustment of it covers both nozzles, or rather the mixture for any engine speed. If the primary nozzle adjustment is made correct, for slow engine speeds, then the secondary nozzle, being of correct size and design, will supply the correct amount for the higher speeds. The student will note that the secondary nozzle commences to deliver gasoline at partially open throttle and leaves ofif again when the throttle has reached a like point in the closing operation. Warm Air. — Warm air is essential to the proper operation of the Tillotson carburetors. Hot air stoves should always be provided. A screen is provided at the gasoline inlet connection. This will have to be cleaned from time to time to insure the free flow of gasoline to the float bowl. The cold air shutter should be used during periods of extreme heat. The choker valve should be closed for starting only. "When the motor is warm the choker must be wide open to insure greatest power and economy. Attention to choker springs is necessary at times to insure the proper working of the choker valve or strangler. JOB 87. BUICK CARBURETOR. The carburetor is the instrument which measures the fuel charges for the motor, and mixes them with the proper amount of air to form a combustible gas. At a high rate of speed the velocity of the air entering increases until the air valve is lifted from its seat and an additional amount of gasoline spray is taken from the high speed nozzle. Since more air is admitted the quality of the mixture going to the motor remains the same as the demands increase or decrease. The float maintains the gasoline level in the usual way. The spray nozzle is located in the mixing chamber, and is regulated by a needle valve which constitutes the gasoline adjustment of the carburetor. It is surrounded by the venturi tube through which a portion of the incoming air passes at a high velocity, picking up gasoline from the end of the spray nozzle. The mixing chamber also contains the air valve and high speed nozzle. The air valve is held to its seat by an adjustable spring which forms the air adjustment. At a high engine speed the velocity of the entering air increases until the air valve is lifted from its seat and an additional amount of gasoline is taken from the high speed nozzle. The air enters the carburetor through a three-way valve controlled by the regulator on the dash. By means of this arrangement the* air may be taken from the heater under the exhaust manifold, or directly from the atmosphere. By means of the choke position the carburetor is made to draw excessively rich charges for starting. The throttle is the usual butterfly valve type. Exhaust Heater.— The upper end of the mixing chamber and the venturi Fuel Systems 237 tube which houses the slow speed nozzle are surrounded by jackets through which some of the exhaust gases pass. This is the arrangement previously mentioned as assisting in vaporization. A damper valve controlling the amount of exhaust entering the jacket is controlled by the throttle levers, working in conjunction with them. At low throttle speeds the throttle is wide open permitting the greatest possible amount of heat to enter. At high speeds, when the air velocity and vacuum is great and less heat is needed, the damper is closed. This system of exhaust heat to carburetor is controlled by the Season Adjustment Valve or Carburetor Exhaust Heat Jacket Shut-Oflf Valve. This valve is located on the exhaust heat inlet tube at the end next the motor. In warm weather, or with high test fuels this valve should be closed. This shuts ofif all exhaust heat from the carburetor, thus preventing loss of power and overheated motor. In cooler weather this valve should again be set open. It is best to keep it open always unless loss of power may be attributed to it. Proper handling of it makes for greater fuel economy. ADJUSTING BUICK MARVEL CARBURETOR. 1. Turn the gasoline adjustment to the right until the needle valve is closed. 2. Set the air adjusting screw so that the end of the screw is even with the end of the spring above it. 3. Open the gasoline adjustment by giving, the screw one full turn. 4. Start the motor as usual, allowing it to run with the regulator on the hot position until the motor is warmed up. 5. With the spark lever fully retarded turn the gasoline adjustment to the right, closing the needle valve until the motor idles evenly. 6. Advance the spark lever and turn the gasoline adjustment to the left until the motor begins to miss or skip, indicating too much air; then turn to the right again until the motor again runs smoothly. To test the adjustment leave the spark lever advanced and open the throttle quickly. The motor should accelerate instantly. If it skips or pops back, open the gasoline adjustment a little by turning to the left. Do not touch the air adjustment again unless it should appear absolutely necessary. The best possible adjustment has been secured when the gasoline adjustment has been turned as far as possible to the right and the air adjustment as far as possible to the left, letting the motor run smoothly and accelerate quickly when the throttle is suddenly opened. Care should be exercised to keep the exhaust heat tubes and carburetor jacket clean to insure heat circulation, which enables the motor to run better and give greater efficiency. No attempt should be made to adjust the carburetor until certain that the motor has good compression in each cylinder; that a good hot spark occurs in each cylinder at the proper time; and that gasoline is reaching the carburetor regularly from the vacuum tank. JOB 88. KINGSTON CARBURETORS MODELS E AND L. Model L. To Adjust— 1. Retard spark fully. Open the throttle about five or six notches on the steering post. 2. Loosen the needle valve binder nut on the carburetor until the needle valve turns easily. 8. Turn the needle valve in until it seats lightly. Do not force it or the size of the nozzle may be changed. Adjust it away from the seat one and one- half turns. This will be slightly more than necessary, but will assist in easy starting. 4. Start the motor and adjust the throttle position by the quadrant or hand 238 Automotive Trade Training control until the motor runs at a fair speed. Do not run too fast. Allow the motor to run long enough to warm up to normal service conditions. The final adjustment may now be made. This carburetor has but the one adjustrnent, that of the needle valve. Close the throttle until the motor runs at the desired idling speed. This can be controlled by adjusting the stop screw orji the throttle lever. Fig. 243. Kingston Fuel Strainer and Carburetor. Fuel enters strainer at point A, is strained by the fine gauze wire B, and, cleared of all sediment and impurities, is taken into the carburetor at point C. At the base of the strainer is a pocket to catch water and sediment. By turning the cock E the water can be instantly drained at the small port D. The strainer can be easily cleaned by removing the cap nut F. taking out the strainer and its cage, cleaning it and putting it back in place. This strainer, which will do away with many carburetor troubles, can be attached to any Kingston Model L or Model L2 carburetor. 5. Adjust the needle valve toward its seat slowly until the motor begins to lose speed indicating a weak or lean mixture. Now adjust the needle valve away from its seat slowly until the motor attains its best and most positive speed. This should complete the adjustment. Close the throttle until the motor runs slowly, then open rapidly. The motor should respond strongly without popping or hesitating. Should acceleration seem slightly weak or sluggish the needle should have such slight further adjustment as to remedy Fuel Systems 339 Fig. 244. Kingston Dual Model. this trouble. When final adjustment is secured lock the adjustment or binder nut. Care o£ Carburetor. — The bowl of the carburetor is provided with a drain cock and should be drained frequently to remove sediment and water. Gasoline leaks should receive prompt atten- tion. Flooding is a sure sign that the float valve is held from its seat by dirt or foreign matter of some sort. To remedy this, re- move the needle valve cover and by means of a small screw-driver give the needle valve a few turns. The top of the valve is pro- vided with a slot for the use of a screw- driver. The needle valve is held in place in relation to the lever by means of a ball and socket joint. Care should be exercised to see that the joint is not binding. It is always worth while to filter the gasoline being used. Failure to do so will give the mechanic work in cleaning out the carburetor as the dirt finding its way into the carburetor will clog fuel passages and nozzles, causing irregular operation of the engine. Trouble of this nature is rather difficult to find at times, A very frequent cause of trouble is a clogged fuel line. Model E. The construction as well as action of this carburetor is apparent from the drawing shown in Fig. 244. Gasoline is admitted at 24 and continues to flow until valve 22 is seated due to the bouy- ant action of float 5, The attention of the student is particularly called to the shape of the spray nozzle 8 which forms a cup around needle valve 7 above its seat. The gasoline level is 1/32" below its top. This excess of gasoline is avail- able for starting and furnishes a very rich charge. After the well is emptied it does not refill until the engine is again stopped. The regulation of the aitiount of gasoline is by means of the needle valve 7 seating at the bottom of the slight well. Both common and auxiliary air is supplied from the one source pass- ing by the controller or choke throttle 11 located in the air intake, after which it divides. Constant air passes down through constant air passage 3, thence up through the venturi tube at which point it becomes thoroughly impreg- nated by a gasoline spray from nozzle 8. From the nozzle it then continues up where it is reunited with the auxiliary air admitted by bronze balls 2. These balls comprise the auxiliary air valves and admit air as required by the varying motor speeds. These balls, after being lifted from their seats, remain floating in the air as long as the vacuum or suction is sufficient to carry their weight. When the Fig. 245. Kingston Model E. 240 Automotive Trade Training suction decreases with the motor speed they return to their seat thus shutting off the auxihary air which is not needed at the lower engine speeds. The controller or choke is so placed that it is possible to cut off nearly the entire supply of air. This makes starting in extremely cold weather possible due to the high degree of vacuum produced at the venturi and the rich mixture which is consequently drawn in. Facts to Remember. — It is essential that the level of the fuel in the bowl is constant and of proper height; that is from 1/32" to 1/16" below the top of the fuel nozzle 8. This may be ascertained by removing the two caps No. 1 and balls 2 opposite each other to permit light to enter one of the holes. Under no circumstances use an open flame for this inspection. The level may be seen through the side opposite the one the light is reflected in. Needle valve 7 should be removed before attempting to check up the gasoline level. Should the level be found too high, bend the float lever 4. If too low, raise it in the same manner. The main reason for keeping the level rather closely adjusted is to assist in easy starting. Fig. 246. Reo Rayfield Carburetor and Heater. JOB 89. RAYFIELD CARBURETOR MODEL L L 3P. The illustration of the carburetor and manifold, (Fig. 246), is the equipment used on the Reo Car. The Rayfield Carburetor is provided with two gasoline adjustments, but no air adjustment. The student or mechanic should bear in mind that both adjustments are turned to the right for a richer mixture as indicated on the adjustment screw heads. As in all cases, the mechanic should make certain that there are no obstructions in the gasoline lines, that manifold connections are absolutely tight and free from air leaks, that valves and ignition are properly timed, and that there is a hot spark in each cylinder. x\lways adjust the carburetor when the motor is warm as in service conditions and have the steering column control set at run position. Low speed adjustments must be completed before attempting to set high. Adjustments made for high speed will not in any way affect the low speed adjustments. A low speed adjustment i^UEL Systems ^41 must not be used to secure a high speed mixture. The adjustments of the Rayfield once set can not change as they are positively locked. Adjusting Low Speed. — With the throttle closed and the control on run position, close the nozzle needle by turning the low speed screw to the left until the block U slightly leaves contact with the cam M. Then turn to the right for about three complete turns. Start the motor (see starting instruc- tions), and allow it to run until warmed up to a temperature of about 170 degrees. After the motor has become thoroughly heated, push the control lever all the way over on the run position. Then, with retarded spark, close the throttle until the motor runs slowly without stopping. Now, with the motor thoroughly warm, make the final low speed adjustment by turning the low speed screw to the left until the motor slows down and then turn to the right a notch at a time until the motor idles smoothly. If the motor does not throttle low enough turn the stop arm screw A to the left until it runs at the lowest number of revolutions desired. The quality of the mixture can be tested as follows: With the shutter of the heater body open, it is possible with the finger to press gently on the air valve so as just to unseat it and admit more air into the carburetor. If the motor begins to pick up in speed it indicates that the mixture is too rich. Turn the adjusting screw a notch or two to the left for less gas. Open the throttle, allow the motor to speed up, then close the throttle. After tlie motor steadies, repeat the operation. If the motor begins to die immediately when the air valve is opened in the manner outlined above, the mixture is too light. Turn the screw a notch or two to the right for more gas. Wait a few moments until the new mixture has had time to enter the motor and repeat the operation again. When the mixture is right the motor will hold its speed for several seconds after the air valve is opened in this manner before it begins to die gradually. Adjusting High Speed. — Advance the spark about one-quarter way. Open the throttle rather quickly. Should the motor backfire it indicates a lean mixture. Correct this by turning the high speed needle adjusting screw to the right about one notch at a time until the throttle can be opened quickly without the motor backfiring. If loading or choking is experienced when running under a heavy load with the throttle wide open it indicates a mixture too rich. This can be overcome by turning the high speed adjustment to the left. Starting Engine With Rayfield Carburetor. — Close the throttle and hold the carburetor control all the way over on the starting position. When the motor starts firing, open the throttle slightly and return the control to the running position as fast as the operation of the motor will permit. If returned too quickly before the motor has warmed up the lack of heat and consequent poor vaporization will cause backfiring and popping at the carburetor. When the motor is warmed up the lever must be set and left on the run position, or the rich mixture drawn in will cause trouble with the lubricating system. This trouble is due to the excess or unburned gasoline finding its way down past the pistons into the crank case and thinning out the oil. Where this condition does obtain, the oil should be drained each 500 miles and replaced with fresh oil. Priming for Starting. — When the lever is in the starting position it is advisable to inspect the carburetor from time to time to determine that the steering column control when set at start pulls the eccentric arm on the carburetor back far enough to depress the small primer plunger on the carburetor. This plunger, when down, opens a bypass to the float chamber, thus permitting the motor when starting to draw gasoline directly from the bowl. The student will readily understand the reason for keeping this closed when the car is in service, as the vaporization of the low grade gasoline in use 242 Automotive Trade Training is very difficult except with the proper amount or degree of vacuum, heat and atomization as explained earlier in the chapter. General Information on the Rayfield. — The nozzles should never under any circumstances be changed. The float level rarely needs attention. The automatic air valve is always closed at low speeds or when the engine is not running. Never adjust a carburetor unless the motor is hot. The float chamber should be drained occasionally through plug Y to remove water and sediment which may have accumulated. Also occasionally flush out the dash pot through the drain cock X. To clean the strainer trap at the bottom of the float chamber shut oflf the gasoline supply and remove the nut S. Next remove and clean the gauze. In replacing the trap be certain that the gaskets are in place and that the nut is drawn up firmly to insure a tight joint. The trap may be drained only by shutting off the gasoline supply and removing the plug. Hot Air Regulation. — As stated previously, the present fuel conditions require the application of heat to the carburetor. More heat is needed in winter than in summer if perfect vaporization of the fuel is hoped for. The upper automatic air valve opening of the Rayfield carburetor is connected to a heater which is provided with a shutter for controlling the air temperature. The heater body is marked in raised letters Winter and Summer. During warm weather the shutter should be turned to the Summer position. When so turned the shutter cuts off the heater and allows the air to be drawn through the sides of the heater body. When the shutter is moved to the Winter position it seals the sides of the heater body and compels the air to travel through a channel formed in the exhaust manifold. It is obvious that the temperature of the air is greatly increased by passing through this stove or heater. An opening is also provided for the constant air supply in the hand hole cover which is connected to the carburetor by a tube. JOB 90. ZENITH MODEL L PLAIN TUBE COMPOUND NOZZLE. The Zenith Model L is designed on the principle discovered by Baverly. It consists of a float chamber, a carburetor or mixing chamber, a system of nozzle and air passages, and a hot air sleeve and regulator. Gasoline from the tank or feed line enters the body through the strainer D, passes through the filter screen Dl, enters the float chamber through the needle valve seat S, lifting the float F. As soon as the gasoline reaches a predetermined height in the float chamber the metal float F acting through the levers B and collar G2 closes the needle valve Gl on the seat S. From the float chamber the gasoline flows through three different channels in various quantities and proportions according to the size of the nozzle, speed of motor, and degree of throttle opening. With the throttle fully open most of the gasoline flows through the channel E and main jet G. Some flows through compensator I which is located at the bottom of a well open to the atmosphere. This well is left open to atmospheric pressure in order that the suction may have no direct effect on the amount of gasoline coming from the compensator I. This amount is just what will flow through a hole of fixed size and not what might be forced or drawn through. From this point the gasoline flows through the channel K to the cap jet H which surrounds the main jet. The main jet and cap jet work together to furnish the proper mixture whatever the speed of the motor may be. Idling Device.— At low speed when the butterfly valve T is nearly closed, the main jet and cap jet give little or no gasoline. However, since there is Fuel Systems 243 Zenith Carburetor Section. considerable suction on the edge of the butterfly the gasoline is drawn through the idling device. This device consists of the idling tube J withiti the secondary well P inserted in the first well, at the bottom of which the compensator I is located and which is open to the atmosphere through holes provided a small distance below the idling screw O. Gasoline from the compensator I flows through the calibrated hole in the bottom of the secondary well P. This is open to the air through the idling screw O and idling seat N. The idling tube J leads to a hole located at the edge of the butterfly throttle valve where the suction is most strongly felt. This suction lifts the gasoline through the idling tube. This amount of gaso- line combined with the air passing the butterfly valve forms the idling mixture. Air Sleeve. — The air sleeve is provided with an air strangler and temperature regulator. The two large rectangular holes can be closed partially or wholly by the brass band held together by a knurled headed screw. In P'ig. 248 the regulator is shown half open. The air •strangler or choke is operated by a lever from the instrument board and has a coiled spring integral with it to return it to open position when its use is not desired. Fig Zenith Air Sleeve. Adjustments. — The choke X, main jet G, com- pensator I, and secondary well P, need not as a rule be disturbed. Their adjustment consists or 244 Automotive Trade Training finding once for all the different sizes or settings for air or gasoline passages suitable for the motor' in question. These passages never vary and once correct will stay correct. Where the Zenith is furnished as stat.dard factory Fig. 249. Zenith Model O. equipment the settings are correct. This applies particularly for the high speed adjustments. Slow speed Adjustment. — The only adjustment vi^hich may be useful is the slow speed adjustment. The strength of the suction in the idling tube can be low SPEED ADJUSTMENT Pig. 250. U. S. A. Standard Military Truck Class B Carburetor. Fuel Systems 245 decreased by turning out screw O, thus admitting more air. Turning in the screw O increases the suction thereby causing the jet to flow more gasoline, making the mixture richer. It should be remembered that this effects the idling speed only and has no effect on the high speed adjustment. Care of the Carburetor. — In any car, especially the new ones, the gasoline lines and tank may give off scale rust, etc., which will accumulate in the filter causing a stoppage of gasoline flow and consequent popping and missing of the motor. Water will also cause trouble. In. this case the carburetor and pipes as well as the supply tanks must be cleaned thoroughly. The carburetor must be completely dismantled to give it a thorough cleaning, but in the case of the Zenith there are no adjustments which can be affected by so doing. If cleaning is necessary be certain to have the float cover well seated, the needle valve seat and various jets screwed down tight as well as the butterfly throttle fastened properly on the shaft, so that it may open fully. When closed, the lower edge of the butterfly throttle should close the idling hole. To see if there is gasoline in the carburetor remove the needle valve cap C 1. If the needle valve can be depressed with the finger, there is no gasoline in the carburetor. JOB 91. U. S. A. STANDARD CARBURETOR. This, carburetor shown in Fig. 250 is used on some of the Standardized Military Trucks, Class B. It is of the plain tube Compound Nozzle type. The Stromberg Plain Tube and the Zenith were also used on these trucks. The principle of operation is similar to that of the other plain tube types. The section shown illustrates the method of assembly as well as the type of nozzles and gasoline passages. JOB 92. CADILLAC CARBURETOR. This carburetor is a distinctive Cadillac design. It is located in the channel between the two cylinder blocks and is of the single jet type. The float bowl is directly under the mixing chamber and mi nethod of 9hou)in<^ o non-inductive coil. (/l/$o usad to 5houj inductive coil cuhen thero i$ no donK^er of co«/u5ion) -H n jT Usedfor resiston^e onlu. HH^-* C ontoc-t pointa. ' ^Tovnd connections iro frame o/cqv^ ^ Sujffch r) Motor Brush Su»ifch \/\r Print a-rij 1 -fyyyyy*- SeeondarJ C onde nser — >TV— ' Crossed ujires ( Not connected; # Connected uuires(fllso os«d for terminafa.) Fig. 267. Method of illustrating conventional electrical characters, the pressure or voltage is very high. In the case of the nail, if the driving force is great enough, it may be forced through a thin piece of sheet metal, but it is folly to try to drive it into a casting or the anvil. In the case of the electric current, if the voltage, pressure, 268 Automotive Trade Training or force is great enough, it may be made, to penetrate or pass through a non-conductor. This point will want to be held in mind by the student as it has a particular bearing in relation to the subject of ignition. It also has a more general application -to insulating or non- conducting materials. Ohm, for whom the law of electrical resist- ance is named, found that certain rules govern the relation of the amount of current resistance and pressure, or in other and electrical terms, in the relation of volts, amperes and ohms. For instance, he learned that the number of ohms resistance was equal to the pressure or voltage of current divided by the amperes or amount of current. An example of this is given. A pressure of 12 volts will carry 2 amperes through the head light bulbs. The ohms resistance is 12 divided by 2 equals 6; or, knowing the ohms resistance and the amperage, we can find the voltage by 'multiplying ohms times amperes as 6 times 2 equals 12; or, knowing the voltage and. the ohms resist- ance, the amperes flowing may be found by dividing volts by ohms as 12 divided by 6 equals 2 amperes. Accordingly, in the shortest terms the law is: Volts divided by amperes equals ohms or E-hI=R or 12-^2=6, or ohms multiplied by amperes equals volts or RXl=E or 6X2=12, or volts divided by ohms equals amperes or E-^-R=I or 12^6=2. Abbreviations or Symbols. — E as used to designate volts comes from the term Electro-Motive Force. The abbreviation or symbol I comes from *the International Electrical Congress of 1893, and the name in full is International Ampere, written I. The Ohm is the unit of resistance so the symbol R is easily arrived at. Rating Electrical Power. — The units of energy necessary to do a piece of work are computed by multiplying the voltage by the amperage. Referring to the former problem of lighting the bulb, we find that 12 volts times 2 amperes gives 24 units of electrical energy needed to perform the work. The discovery of this law is attributed to Watt and these units of energy are called watts, so this might be written, volts X amperes = watts, or EXl=W, or 12X2=24. Since the watt is such a small unit its use is cumbersome and the kilowatt, written kw., meaning 1,000 watts is used in its stead. Since all power ratings are by horse power, the student would do well to learn that 746 watts are rated equal to one horse-power (1 H. P.), since 746 watts will suffice to raise 330,000 pounds one foot in one minute. Conductors.— Conductors of electrical current are present on all hands. All metals are conductors. Water and some other liquids as electrolyte are conductors. The earth itself is a good electrical con- ductor. The human body is a fairly good conductor as is evidenced by the ease with which a shock may be obtained when touching a heavily charged body. Copper is used almost universally as the cheapest good conductor. Iron wire is much inferior to cooper wire Fundamental Electrical Data 269 ?.s a conductor. Larger sizes must be used to carry a like amount of current. Non-Conductors or Insulators. — Air, stone, mica, porcelain, glass, paraffine, sealing wax, rubber, vulcanite, and certain other substances as silk, cotton, shellac and insulating enamel are good non-conductors, or as generally termed, insulators. By this is meant that they prevetit the passage of electric current from one conductor to another. Positive and Negative. — Batteries are furnished with two ter- minals or posts to which conductors may be attached to obtain the electric current therefrom. One of these is always termed a positive terminal, marked + (Plus), and the other a negative terminal, marked — (Minus). Current flows out from the positive and through the FijT- 26S. Around every wire carrying an electrical current there is a magnetic whirl. This is always around the wire and at right angles to its axis- The wire run- ning in many directions shows this. A 12 volt current caused the iron filings to be arranged as shown on the glass. Wire is under the glass. conductors and instruments returning to the battery through the negative terminal. Some instruments are marked similarly, or they may be marked with the abbreviations Pos. and Neg. The carbon on the dry cell is the positive, while the zinc can, or shell, is the negative. Methods of determining the terminals will be noted from time to time. Magnetism. — Magnetism should not be confused with electrical current. Magnetism is a property possessed by certain materials which causes that material to attract to it other materials. In certain cases the action is one of repelling rather than attracting. The earth iself is a huge magnet. Lines of force emanate at all angles from the magnetic north pole, passing north over the earth's surface at all points to the south magnetic pole where they re-enter the earth. 270 Automotive Trade Training These lines of force are flowing at all points at all times and are readily detected by the magnetic needle. Not all materials may be magnetized. Natural lodestones are found in certain localities and these exhibit the same characteristics as the bar or horse shoe magnets. Steel may be magnetized as may also iron. Brass, copper and aluminum are some of the non-magnetic metals. Producing Magnetism. — Magnetism may be produced within steel or iron, or these metals may be said to become magnetized. Iron may be magnetized by the process of winding several coils of wire about it and sending a current of electricity from a battery through it. The magnet so produced will be found to attract bits of steel as nails, screws, iron filings, etc. Trying it with a box of nails it is found that a certain number of nails cling to the magnet directly while other nails cling to those attaching themselves to the magnet. Quite a group may be picked up in this manner. Breaking the electrical connection from the battery to the wire coil about the bar of steel will cause the nails to drop away, and a test will show that practically all of the magnetic strength of the bar is gone. In other words, since it no longer possesses magnetism it is not a magnet. If any, even a very little magnetism is left, it is because the bar is not pure soft iron but has some degree of hardness. Residual Magnetism. — This is the amount of magnetism remain- ing in an iron core after the current is broken off. The softer the iron and more nearly free of foreign substances or alloys, the less residual magnetism is left after the core has been magnetized and the current broken. This type of magnet is called an electro- magnet because the magnetism is present only when the current is flowing. A good electro-magnet loses its magnetism immediately the current is broken. Electro Magnets. — Electro-magnets may be in many forms such as the straight bar or the U bar, or the many forms of pole shoes used in electrical machines. In every case the electro-magnet is made by winding coils of wire around a piece of iron or steel which is the core of the magnet. The number of lines of force emanating from the magnet is directly dependent on the number of turns of wire and amperage passed through the coil. Much of the work done by elec- tricity is dependent on the magnetic properties of steel and the laws of magnetism. Magnetic Poles. — While with electrical current we have positive and negative terminals, with magnetism we have north and south poles. The magnetic North Pole is said to be some distance to one side of the geographical South Pole. Likewise with reference to the South Pole. In the case of magnetic poles, in iron or steel, like poles repel and unlike attract. If two magnets of like strength are brought Fundamental Electrical Data 271 together they will repel each other, as two north poles or two south poles. If two magnetic poles, one a south pole and one a north pole, are brought close together they will swing together and cling tightly Fig. 269. Lines of force about ends of single magneto magnet. Fig. 270. Double Magneto Magnets, like poles together. Fig. 271. Single Magneto Magnet. Fig. 272. Double Magneto Magnets, unlike poles together. to each other unless some means is used to reverse the polarity of one or the other when the two will repel each other. Magnetic Needle. — The magnetic needle works on the above prin- ciple. The needle itself is a magnetized steel bar, large or small. The 272 Automotive Trade Training lines of force travelling over the earth's surface from south to north cause the needle to fall in line with them so that the point toward the north is the north pole of the needle, and vice versa. While the magnetic needle is made to serve the mariner or traveler through the compass, it may be made to serve the student or mechanic in indicat- ing polarity of magnets for him. The same rule is operative in both cases. Permanent Magnets. — The magnetic needle retains its magnetism indefinitely. This is because it is made from a high grade of steel Fij?. 273. Double Magneto Magnots. Like poles together. Fig. 274. Double Magneto Magnets. I'lilike j)oles together. hardened to a high degree of temper. Once a piece of hardened steel is magnetized it retains its magnetism as a permanent quality. It is thereafter called a permanent magnet. Lines of force flow con- tinuously from its north pole to its south pole through the air or other medium. In a good magnet, well cared for, these lines of force seem to lose little strength from year to year, although they may be performing a great deal of work as in the case of the magneto magnets. Fundamental Electrical Data 273 A number of illustrations, Fig. 269 to Fig. 276, show the flow of the magnetic lines of force. The student, in studying these, will want to remember that like poles repel, and unlike poles attract. All illustrations were made with iron filings sprinkled over a glass or directly onto the magnets. Magnetizing Steel for Permanency. — In order to produce a permanent magnet it is necessary to have the steel first formed to the desired shape and then hardened. After hardening the usual method of magnetizing is to bring the ends into contact with a powerful electro-magnet. A permanent magnet may be used. The lines of force flowing through the body of the steel will cause certain changes to take place within the steel which result in the steel retaining its magnetism, thus making the commercial permanent magnet. No. 275. Two stove bolts serve to deflect the flux in much the same manner as the armature core. Fig. 276. Several bolts were placed be- tween the pole shoes. Note how the cen- ter of the field is built up. The bolts serve the same purpose as the iron in the magneto armature. The flux follows the metallic path rather than the air gap. The Molecular Theory. — The theory of the difference of the permanent and electro-magnets is one of the nature of the structure of iron. The molecules of iron or steel are similar. They may be said to have a certain slight freedom of motion within the soft iron, the softer the iron the greater the freedom of motion. On the other hand, the molecules of the steel have been fixed in position by the hardening process, having no power of themselves to move into posi- tion. In magnetizing either metal the molecules drop into line with the lines of force because of the force of the magnetic action. In other words, the student may consider the infinitely small particle, the molecule, as having two ends. One end becomes a north pole and the other end a south pole. Now these molecules might be com- pared to the nails formerly mentioned. The north pole of one attracts 2U Automotive Trade Training the south pole of another, and so on all the way through the magnet. All molecules being aligned with the axis of the magnet, all north poles point one way and all south poles of these molecules point the other way, until one end of the iron or steel bar is said to be a north pole and the other a south pole. Instantly, however, the outside mfluence is removed the molecules within the soft piece of steel fall back into a mixed position without any form or line of concerted action. Not so, however, with the hardened steel. These molecules are not free to move of themselves. The magnetic lines of force as applied changed their position and aligned them to form a magnet and they will retain the magnetism permanently simply because they &///) or Collector Fig. 277. Simple A. C. Motor or Generator, must 'retain their position until disturbed by some outside influence. This theory is strengthened by the fact that when magnetizing a steel magnet, jarring it with a block of wood helps to increase the strength of the charge taken. Note also the fact that jarring a magnet in service will cause it to lose some of its strength. These facts would seem to indicate that the molecules being disarranged by the jar fall out of line and the strength of their bit of magnetism is lost to the magnet as a whole. The jarring or tapping seems to help the mole- cules in aligning themselves with the lines of force when charging and to help them fall back into their original position when not being charged. Saturation. — Steel or iron always reaches a point where no more magnetism may be put into it. A sponge is completely saturated with water when no more water will be taken up by it. A magnet is completely saturated" when no more lines of force will flow through Fundamental Electrical Data 275 it because all are already flowing for which there is room. While this point is equally true of either type of magnet it has a peculiar appli- cation to the electromagnet. In this case the magnetism is induced by the current flowing through the wire wrapped on the core. A slight current gives slight magnetism, more current more magnetism, and so on until the saturation point is reached after which point an increase in current does not result in an increase in magnetism gen- erally speaking. Flux. — Magnetic flux or field is the condition of magnetisfn resulting between the poles of a generator or magneto where the lines Pig. 278. Simple D. C. Motor or Generator. of force are flowing. Magnetic lines of force constitute the magnetic flux, or flux as it is commonly called. Current Generation. — The student has seen how the electric cur- rent may be used to produce magnetism where none existed before and will now be shown how the reverse may be accomplished. If a permanent magnet is so placed that a loop of wire may be mounted between the ends of it and caused to rotate on a central axis, it is made to cut the lines of force or the magnetic flux. Cutting these •lines of force induces current in the wire. This current will flow trom one end of the wire toward the other end of the wire and if slip nngs and brushes are provided this current will flow from wire, to ring, to brush and oflf into an external circuit, from which point pro- vision must be made to return it to the other slip ring and internal circuit, This internal current will continue to be generated as long 276 Automotive Trade Training as the wire is in motion and an external circuit provided to handle it. Instead of two slip rings only one may be used. In this case the other end of the wire is grounded, as is also one end of the external circuit. Internal Circuits. — The internal circuit is that formed by the wire on the armature, the rings, etc. The external circuit is that used to perform the work on the outside as lighting the lamps, charging the battery, etc. Induction. — Whenever a loop of wire is made to cut magnetic flux it causes a current, or sets up a current within the wire. In other words, it may be said to induce a current to flow. The process is called induction. This reversal of ends in contact with the brushes has the effect of causing the current in the external circuit to flow always in one direction. Instead of having two pulses of current in different directions for each turn or revolution of the inductor, there are two pulses of current in the same direction. This is indicated in Fig. 279. To the beginning student it may seem an impossibility to have current traveling in two directions over the same wire but it does not travel in both directions at the same time. Current travel is very rapid. It would travel nearly eight times around the world in one second so reversal may be said to be almost instantaneous. In the case of direct current it is not one continuous even flow but might be compared to a series of pulsations following one another over the wire in the same direction, while the pulsations in the alter- nating current flow in opposite directions. By increasing the number of coils on the armature, the number of bars on the commutator also being increased, the current flow while still of a pulsating nature, is far more steady. This is due to- the fact that in the bi-polar armature there are two zero points. From these zero points to the peak of the pulsation and down again to zero as illustrated in Fig. 279, represents one-half revolution. In the next half revolution the same effect or result is secured. When many bars are used, it is only when the current is approximately at its peak that the brushes are in a position to take it off to the external circuit. Consequently the flow of current in the external circuit is at the approximate maximum pressure or voltage at all times. Armatures. — The H or shuttle type of armature is the one where the slip rings are used resulting in an alternating current. By this is meant that it will flow first in one direction and then in the other through both circuits. Alternating Current. — This is written and spoken of as A. C. current. As mentioned above, alternating current flows first in one direction and next in the reverse direction. When cutting the magnetic flux the inductor or coil is brought first into close proximity to the north and the south poles. In the next half revolution that Fundamental Electrical Data 277 portion of the inductor close to the north pole is brought close to the south pole, and the part which was close to the south pole is likewise brought close to the north pole. This reversal of position of parts of the coil or inductor results in reversal of the direction of the flow of the induced current. There are two complete reversals of cur- rent within the wire each complete revolution as the armature is kept turning. A. C. current is quite suitable for certain classes of work, but is absolutely unsuited for other classes as, for instance, charging i?torage batteries. For those uses requiring direct current the generat- ing machine must be so changed as to produce it. AfaximiWf V(ilue IweS^ TL /I C Current l/Vayes Maxfmam \/aJue Lne . D C Current Wa)/es. Fig. 279. Direct Current. — This is written and spoken of as D. C. current. Current coming from batteries is always direct current. In order to generate it mechanically the slip rings must have a commutator sub- stituted for them. In this case, as in the simple bi-polar machine vv^ith only one coil and two segments to the commutator, the separate ends of the coil are each brought to and soldered to the commutator segments. These segments or bars are separated from one another by some form of insulator. As the wire loop or coil is turned the end attached to any one of the segments is brought first into contact with one brush giving the pulsations from zero value to maximum value each half turn. This is equipped either with slip rings for A. C. current or with an armature for D. C. current. The invention of the drum type armature has made possible the steady flow of current described in the preceding paragraph. Illustrations of both the shuttle or H type as well as the drum type are shown in Fig. 266. The student will be interested to know in what machines each is used. This information will appear at a later point. 278 Automotive Trade Training In actual generator or magneto work a coil of many turns is substituted for the single loop shown. This coil is wound on a soft iron core, the whole being mounted on a shaft in its center, on which it is revolved. Either one or two slip rings are used while for the D. C. current a commutator is substituted. In the drum armature a number of coils are used. As stated previously the voltage depends on the number of lines of force being cut, and the rapidity with which they are cut. For higher voltage the speed of the armature must be increased or the number of turns of wire increased. Commutator. — The commutator usually has as many bars as Fig. 280. Voltmeter. Fig. 281. Ammeter. there are coils on the armature, although at times two coils will be attached to the same segment. The segments or commutator bars are insulated from each other. For this purpose mica is the standard material. It is a very high class non-conductor. Commutators and slip rings being subjected to wear require some attention. The matter of their care and repair is treated at a later point. Field. — That part of an electric machine which has the essential parts so arranged as to produce and maintain a magnetic flux for the armature to revolve in is called the field or fields. Usually the field is stationary, but may be in motion. In the case of the magnetos the permanent magnets with their everflowing lines of force are made use of in building up the field. In the case of generators the electro- magnets constitute the field. The wires or conductors are called the field windings. The field windings in modern practice are mounted Fundamental Electrical Data 279 en the poles themselves although at times they may be found on the yokes of the field castings. Current Control. — External control of the amount of current fxow- ing may be had similar to the control of other sources of power. A large steam pipe is needed to carry steam from the boiler to the locomotive cylinders. A smaller pipe is needed for the smaller en- gine. The pressure per inch may be the same in either case, but the amount of steam flowing through the smaller pipe is less than that flowing in the larger pipe. The same is true of the amount of work done. Similarly in the case of the cur- rent flowing from a battery. The larger the conductor and demand the more the amount of current which will flow. The smaller the conductor the less the amount of current which will flow no matter how great the demand. According- ly a large heavy cable is used to con- nect the starting motor which may draw up to 300 amperes momentarily while starting the engine to turning. The voltage or pressure can be no more than that of the battery, in most cases six or twelve volts. For lighting and ignition very light cables are used as the current consumption is seldom over six to eight amperes. Necessarily the voltage is the same as for the work consuming the greater amount. However, even these lighter wires or lighting cables would carry a great amount of current if there were not provision for cutting it down. Within the lamp bulb the filament is heated because of its natural resistance to the flow of current. The student is, of course, familiar with the fact that the filament is ordinarily mounted in a vaccum, or that there is no air in the bulb. In the case of the nitrogen bulb it is filled with nitrogen gas. However, in either type the filament is heated by its resistance to the passage of current until the bulb is made to glow brightly. At the same time, however, only a certain amount of current or amperage can pass through the filament. If more light is desired, more filament is added. This necessarily requires more current to light it or heat it to an incandescent heat. Larger candle power bulbs «.lways impose a heavier drain on the storage battery. This is just the same as the large steam cylinder which uses more steam than that on the engine having less power and less size to the cylinder. Fig. 282. Voltammeter, a combination instrument for measuring either volts or amperes. Automotive Trade Training Resistance Units. — While the lamp bulbs might be said to be resistance units serving to regulate their own current consumption vhrough their size, other units of automotive equipment are supplied w^ith separate and individual resistance units. It has been explained previously that all metals are conductors of electricity. Platinum, silver, and copper are the best conductors. Iron is only about one- seventh as efficient as copper. Certain other metals are even much poorer. Some of these composed largely of nickel, michrome, or German silver are sold under the trade name of resistance wire, Fig. 283. Internal mechanism of Electrical Measuring Instrument, as voltmeter or ammeter. because of their remarkable resistance to the passage of electric current. Ignition units or coils are usually provided with a resistance unit or coil which protects the coil winding from excessive amperage and consequent damage. It serves to regulate the amount of current flowing in such manner that the spark produced is approximately the same for all engine speeds. A quality of resistance wire to be remembered is that the resist- HiGH Tension TtRMihfiL Fig. 284. Resistance Unit on Coil. Fundamental Electrical Data 281 ance to the passage of current increases with the amount flowing. The student has noted in the case of the lamp bulb that it is resist- ance which causes the filament to be heated and glow. In the case of the resistance unit this is also true. A continuous flow of current will heat the resistance unit. As it heats, its resistance increases. The hotter the wire, the greater the resistance. This causes the cutting off of the flow of current at least partially, and this in turn allows the resistance wire to cool a bit when more current starts flowing again. It is a safety valve or governor for the coil. This feature prevents the ignition coil being burned up when the ignition switch is left on and the engine standing still with contact points together. Fuses.— The student is now familiar with the fact that electricity flowing through a conductor is likely to heat the conductor. The •imount of heat developed is dependent on the amount of current flowing, as well as the size of the conductor. It may even heat the conductor or wire to a point where the insulation will be burned off, or in extreme cases melt the conductor. SIDE|OR DIMMER \ DASH^ BEAR Fig. 285. Switches with Fuses mounted on the back. To prevent damage to expensive units of equipment practically all systems are equipped with fuses. The fuse is a protector. If an excessive amount of current flows the fuse is burned out or melted out. Fuses are made from metal with a low melting point. They are designed to form the weakest point of the electrical circuit so that there will be no doubt about which part will be burned out first. When a fuse burns out it opens the circuit just as the opening of a switch would. Thus, a unit costing a few pennies is made to protect one costing many dollars. Needless to say, a burned fuse should be replaced with another of like capacity. Metals which cannot be burned 282 Automotive Trade Training out should never be substituted, neither should very much heavier fuses be used. The trouble causing the fuses to burn out should be located and corrected before replacing the fuse. Ground. — Presumably from the fact that the earth or ground is used for return circuits in many cases of electrical installation, or for the protection of others from over-charge, has come the practice of terming the frame or superstructure of the auto- mobile the ground. Automotively speaking, to ground a circuit is to attach one end of the wire forming the circuit to the frame or other metal part of the car, allowing the frame to act as the return circuit. A magneto may have one end of the pri- mary winding or internal circuit grounded through the bearings; similarly the generator. The high tension or secondary current as used in the spark plugs is always grounded. One terminal from the storage battery is very frequently grounded giving oifc'i^t. ^^Note^ailo method of ground- ing battery to car frame. what is constituted the one wire or grounded sys- tem. LOOSE CONNECTION Terminals and Poles. — The polarity of a magnet is dependent always on the direction of the flow of the current around the core. Reversing the direction of flow of current in the case of an electro-magnet will reverse the polarity of the magnet. If no magnetic needle is at hand to determine the polarity of the magnets, that of the electromagnet may be determined as follows: To determine the polarity from the direction of flow of current, first learn the direction of flow of current through the wire. Next, place the right hand so that the fingers point in the direction of the flow of current. The palm of the hand would be next to the coil. The thumb pointing at right angles to the hand will point to the north pole. Direction of Induced Current. — To deter- mine the direction of the flow of an induced current as generated in a magneto or genera- tor, or the positive and negative terminals of the conductor in which current is induced, it is necessary first to determine the polarity and direction of lines of force or the magnetic flux. Knowing this, set the thumb of the right id to point in this direc- Fig. 287. Open Circuit due to Loose Connection. Fundamental Electrical Data 283 Q ^ @ ® ® ® @ ICR. - CONTACTS I 5W1TCH TERMINAL I CO. SHU NT WINDING- CUT OUT P01NT5- CaSERIES WINDINC- w T o BAT TERY I IGNITION AMMETER" ETER\^/ -+ BRU5H -■wO* 5TArV|NG SWITCH STARTING MOTOR ^^ OTD Fig. 288. Technical Wiring Diagram. 284 Automotive Trade Training HEAD LIGHT SIDE LAMP I IF SIDE LAMP „ . .^.^ ., ^■■.,.... -fc-L. BATTERY Fig. 289. General Wiring Diagram. Fundamental Electrical Data 286 tion. It should also be at right angles to the index finger. Next set the second finger at right angles to the palm of the hand, and pointing in the direction of the conductor travel as it cuts the lines of force. The index finger pointing straight indicates the direction the induced current will flow. Solenoid. — A solenoid is a coil or a helix of wire. It might be said to be an electromagnet without an iron center or core. It has the general characteristics of an electromagnet although the pull will naturally be less. The magnetic poles north and south are in evi- dence. The south pole will be that in which the current flows in a clockwise fashion when the observer is facing it. The same rule applies to electromagnets. Condenser. — It has been learned that it is possible to store up a charge of electricity which may then be drawn off for use in perform- ing work. The storage battery is a device used for this. The con- denser is likewise a device used for storing current, but in the case of the condenser there is no chemical action and in most cases the charge is held only momentarily. The condenser is made up of paraffined paper and tinfoil. The paper is laid between the layers of tinfoil and the whole wound into convenient form and pressed into the desired shape. This form or shape depends on the housing designed for the condenser. The capacity of the condenser depends on the number of square inches of the surface of the dielectric which is the paraffined paper. The tinfoil serves to conduct the current to and distribute it over the surface of the dielectric where it is held. The condenser is used in the ignition coil circuit. Its action is described further at a later point. CHAPTER 11 BATTERIES AND BATTERY CARE As indicated in the previous chapter, the storage battery can generate Httle or no electrical current or energy without first being subjected to a charge from an outside source. It might be compared to a tank for storing compressed air. A stream of air under pressure is forced into the tank until the gauge registers, say 100 pounds per square inch. This air may be drawn off through an air line for use in inflating tires. After one tire has been inflated, there is less pres- sure registered on the gauge. After two tires are inflated, less again, and after three tires still less, and so on. Very shortly, unless the compressor is started to work and the tank refilled, the pressure will be too low to inflate any more tires properly. Fig. 290. A group of Starting and Lighting Batteries. (Cincinnati.) The case of the battery is very similar. If the starter is used frequently the battery will quickly become exhausted. However electricity is not stored in the battery as air is stored in the tank. The same air which is run into the tank is later drawn out to inflate the tires. In the case of the battery being charged the current flow- ing through the battery drives the acid from the plates into the solu- tion. When the external circuit of the battery is closed the battery is said to discharge. That is, current is now flowing from the battery to the starter, ignition, or lights. This current being taken out is not the same as went into the battery when it was charged. In charging a battery the current flowing into it sets up certain chemical action. When the external circuit is closed the current flowing from the battery is due to the reaction within the cells. Battery Rating. — While storage batteries are rated by ampere hour capacity when on discharge, we find that automobile starting and lighting batteries are given the capacity rating when discharged at the five ampere rate. Therefore, a battery discharged at the rate 286 Batteries and Battery Care 287 of five amperes for twenty hours would have a capacity of 100 ampere hours. As the rate of discharge is increased the ampere hour capacity is lessened, or as the rate is decreased the ampere hour capacity will be increased. For example: The 100 ampere battery at the five ampere rate would have a capacity of only about 80 ampere hours when discharged at ten amperes, or in other words, it would discharge at ten amperes for eight hours. If the same battery were discharged at one ampere it would give ofif current for about 120 hours, therefore having a rate (if 120 ampere hours. It will be seen that the battery could be com- pletely discharged in a very short time if the discharge rate were Filling riuff Valve Level of Electrolyte Cell Connector Sealing Nut Post Gasket Negative Post Negative Strap Postive Post Positive Strap Wood Separator Positive Plate Negative Plate Rubber Jar Wood Case Fig. 291. Battery Cut Away to Show Construction. 200 to 300 amperes as is the case in cranking the motor with the battery. In fact the discharge rate runs even higher under particu- larly unfavorable starting conditions. Every second the starting motor is running means great drain on the battery. The student will note likewise the fact that the slow, steady, con- tinuous drain as that of the Hghts burning with the engine idle, or ignition switch left on will deplete the battery. Automotive engineers have designed the generator as part of the electric system. Its duty is to send the current through the storage battery and cause such 888- Automotive Trade Training electro-chemical action there that the battery is always ready to give off energy in the form of electric current. Battery Wear. — One of the greatest problems meeting the battery manufacturers is that of educating the users of automobiles and other electric equipment with reference to the storage battery. An air tank may be charged and discharged many times a day and over a space of many years without showing signs of depreciation. Not so with fhe battery. Each charge and discharge produces wear within the battery. The vibration to which the battery is subjected contributes to wear. This is natural wear but serves nevertheless to shorten the life of the battery. In this respect the battery might be com.- pared to the automobile tire. Every turn of the wheel as the tire travels over the road means one turn nearer the final one. So much service has been had by the car user. Of course, the user, by driving Fig. 292. Storage Battery Name Plate. carefully and keeping proper air pressure in the tire, will get many miles of service from the tire. The miles of service bear a very direct relation to the amount of care and the pressure carried. Just so in the case of the battery. It must be kept fully charged so as to have a reserve to withstand the demands made upon it for current. Careless handling, failure to provide the proper amount of distilled water, complete discharge, failure to bring to a state of complete charge and like faults will as certainly limit the service a battery will give as running a tire flat, or under-inflated, will limit the service the tire will give. The user of the battery must learn to care for his battery as he has learned to care for his tires. There are certain things he may do and should be taught to do by the battery man. Then, when the battery has served its life-time, it will be easier for the battery service station to deal with the user. He will understand that the battery is not like a piece of steel to which there is no wear, but rather like the tire it returns service for understanding care. BATTERY CONSTRUCTION Battery Box. — The battery box is carefully made from good wood. It is designed of such size that the cells will just fit into it with room for proper sealing. Handles are attached in such manner that there is no danger of the screws or bolts coming into contact Batteries and Battery Care 389 with the jars, in a manner likely to break them. The bottom of the box, in some instances, is provided with an expansion joint to care for the natural expansion and contraction of the wood. It also serves the additional purpose of allowing any moisture such as might come from spilled water or electrolyte getting down between the cells as is possible in certain types of assembling. The box is always covered with acid resist- ^^^- ^^- battery Box. ing paint to protect it from attacks of the acid in the electrolyte. Cell Jars. — For automotive equip- _^ ment the cells are always made of a specially prepared hard rubber. This is an insulating material and at the same time will stand some slight strain without breaking. The cells vary in size, being designed to just receive the element when it is fully assembled. No appreciable movement of the ele- ment within the cell is permissible be- cause of the rapid depreciation and wear which would occur. The bottom of the cell has ribs moulded across it for the plates to rest on. The space below the tops of these ribs receives the sediment from the plates as it is worn from them. Element. — There are always two groups of plates in each cell. These are insulated from each other by means of the separators. 294. Battery Section. Note Cell Jar Construction. (Willard.) Fig. 295. Complete Element. (Exide.) Fig. 296. Positive Plate. Fig. 297. Negative Plate. One group of plates is called the positive and the other is called the negative. When properly assembled and insulated with the separa- tors the entire assembly is called an- element. Positive Plates. — All plates are built up of socalled active 2:90 Automotive Trade Training material, pasted into the grid which is the frame or backbone of the plate. The grid is made from a stiff lead and is so molded that the itctive material is held in between light bars of the metal. The posi- tive plates rriay' lj>e known by their chocolate color. Negative Mates. — ^These are known by their slatish gray color. The active material is pasted into the same type of grid as that used for the positive ones. Active Material. — In-order to insure the rapid and ready action of the active material pasted into the plate grids, it is made up of lead oxides mixed with certain other materials. Red lead is mixed with certain other materials and electrolyte to form the paste for the positive plates. The litharge, another lead oxide, is mixed with certain other materials and electrolyte to form the paste for the negative plates. The exact composition of the materials and the Droportion of each kind used are trade secrets which are carefully guarded. Not all companies use the same formula, nor are the methods of handling the plates in forming the same in all cases. From long experimentation each company has arrived at the best formula for its own purpose and that best suited to its method of manufacture. Forming Plates. — As suggested above the methods of forming plates are not the same in every instance. All green plates are care- fully dried before forming. The forming is the final process of plate manufacture. Fig. 298. Cell Jar Cover. One method of forming plates is as follows : After the plates are pasted and dried, they are placed in tanks, positive and negative plates alternately, there being usually about 80 plates per tank. All positive plates in each tank are connected, while all negative plates are similarly connected. The negative plates of one tank are then connected to the positive plates of an adjoining tank, there being only enough tanks in the circuit so that the voltage from the plates will not exceed the voltage of the charging circuit. The tanks are filled with a low density of electrolyte which covers the plates, allowing Ihe current to pass from plate to plate during the forming process. Another method of forming the plates is as follows: After the plates are pasted and dry they are assembled in groups by lead burn- ing, just as they are to be used in the battery. Next, the positive group is assembled with a durrimy negative group, with separators between, and set into a cell. When the cell has been filled with Batteries and Battery Care 291 1250 electrolyte the positive group is connected to the positive lead from the charging circuit and a current sent through the element. This forms the positive plates in approximately 48 hours. The nega- tive group is assembled with a positive dummy and formed in the same manner excepting the time required which is 72 hours. After the forming process is completed the positive plates, due to the electro-chemical action, are lead peroxide, while the negative plates are sponge lead. In the forming process, it is necessary that the plates which are to be formed into positive plates be connected to the positive lead of the charging source. This is at point of vital significance in the charging of a battery. If the battery is put on the line with the negative terminal connected to the positive lead of the charging equipment, the battery plates will have to be reformed before the battery will take a charge. The change is certain to result in disaster and too much emphasis cannot be laid on the matter of putting the battery on charge correctly. Methods of determining polarity are given elsewhere in this chapter. Separators. — The separators are made from some insulating material such as specially prepared rubber or wood. The latter material is the most popular with manufacturers, inasmuch as it is the cheapest and most easily handled. How- ever, it does not always give the longest service. Where wood is used the acetic acid is removed to render the separator impervious to the attacks of the electrolyte. This special treatment also leaves the separator porous which is essential to all separa- tors, as it allows the passage of the electrolyte. The separators must be insulating material, otherwise short circuits would be developed immediately within the battery and it would be impossible to charge it. Whenever the insulators wear out or break down, the battery will develop short circuits which prevent it taking a charge. The average life of a set of wood insulators or separators is about one year. Some will give less than this amount of service and in many cases more. Unusual cases of three and four years are on record. The rubber insulators and separators such as the Willard Threaded Rubber as a rule give considerably more service. Here again the battery might be compared to the tire. A fabric tire, while well worth while, will not as a rule give as much service as the cord tire. This does not mean the fabric tire is not worth the money invested in it but does mean that the greater Fig. 299. Wood Separator. Fig. 300. Wood Separa- tors, worn out by over- heating, undercharge or overcharge. Automotive Trade Training amount of money invested in the cord can be expected to make a greater return to the user, in the amount of service. Cell Covers — One of the hardest problems the battery manufac- turers have had to solve is that of properly securing the element in the cell and sealing the top of the cell so that the electrolyte is not spilled out when the battery is in service. The hard rubber cover is designed to care for both the holding of the element in position and sealing the top of the cell. It also has the filler cap or vent plug fitted into it. Holes are molded into it, so placed that the posts will come up through them and permit of the terminals and straps being burned on above the cover. The cover is designed always with the idea of perfect sealing in mind. Various methods are used by the manufacturers, and the student will need to understand something of this construction before attempting to dismantle any particular style. Sealing Compound. — The sealing compound is a tar or pitch- like preparation which is heated in a pot or dipper until it is melted, when it may be poured around the cell covers to seal the jar and cover together. It is also used in certain types to seal the posts and to seal the cells into the box thus preventing any moisture gettin-^ between the jars, as well as shaking about of the cell jars in the cas? or battery box. The sealing compound may be purchased from tho .supply houses. Directions for its use appear at a later point in this chapter. Fig. 301. Fig. 302. Fig. 30.3. Standard Thimbla Standard Taper Straiglit Clamp Type Terminal. Plugs and Screw. Lug Terminal. Terminals and Straps. — There is some difference in the style ot terminal used by the battery manufacturers and car builders. The corrosive effects of acid make it necessary to lead coat all brass Fig. .304. ('oil Connector. parts or make the entire terminal from lead alloy. Figs. 301 to 303 show some of the most popular forms in use. The prime requisite Batteries and Battery Care 293 in their use is cleanliness which is best secured through the use of a baking soda solution used to clean them and neutralize the acid. This prevents the terminals from being constantly enlarged as is the case where a knife blade is used to scrape them clean. Do not allow any of the cleaning solution to get into the cells. Fine sandpaper is often used to advantage. When properly cleaned a thin coat of vase- line or light cup grease will serve to protect them. The straps or connectors are used to join the negative post of one cell to the positive post of another cell. These, like the terminals, are usually attached by burning them to the posts. BATTERY CARE As suggested previously proper care of the battery* is essential to service. Even with proper care there is a limit to the normal Hfe of the battery. Neglect of the two fundamentals, a proper charge and the addition of distilled water always materially limits the life of the battery. Distilled Water. — Every storage battery is dependent on the. electrolyte surrounding the plates for its electro-chemical action. Electrolyte is made up of two elements or liquids, water and sul- phuric acid. The acid is not subject to evaporation. The water is. This accounts for the fact that acid does not need to be added to a battery to bring the solution up to the proper level, while it is neces- sary to add water at regular intervals. Only pure or distilled water should be added to the solution since w^ater bearing any impurities will introduce them into the battery where, due to the chemical action, they may do serious harm. Metal vessels or containers should not be used for the distilled water. In- stead, glass or glazed earthenware should be used. It may be secured from the supply houses or drug stores. In adding distilled water the plates within the cell should be covered to approximately one-half inch above their tops. The electrolyte should not be permitted to drop below the top of the plates at any time. Water added to a battery remains separated only so long as it may be necessary for the motion of the car and the charging action of the generator current to mix it with the electrolyte. For this reason some care must be used in adding the water in the winter time. In this case it should be added just before the car is to be operated so that the water and electrolyte may be thoroughly mixed. In case of any water being spilled on the battery top it should be dried with a cloth. To prevent spilling when filling use a syringe or glass funnel. It frequently happens that a battery which has been filled carelessly will become discharged without apparent reason. This is due to the fact that the spilled water and electrolyte have established a short circuit throti^h which the battery discharges as fast as the generator charges it. 294 Automotive Trade Training Battery Freezing. — This is not likely to happen even in extreme temperatures if the battery is properly charged. Sulphuric acid will not freeze. Water will freeze. By keeping the two mixed in the form of electrolyte the water will not freeze. As stated previously, however, when the battery is discharged the acid has practically all tl mZM: t.l.t.i.i.i.l.l.l X"^ )CD Fig. 305. Hydrometer. entered into the plates. This leaves only the water surrounding them, consequently the reason for a discharged battery freezing is evident. Bringing the battery to a full charge will drive the acid out of the plates into the water again, thus bringing the electrolyte up to its proper strength. The specific gravity of a fully charged Fig Using Hydrometer to Test Battery. battery will read between 1.275 and 1.300. At this point it will not freeze except at extremely low temperatures as approximately 80 Batteries and Battery Care 295 .1300 degrees below zero. On the other hand a fully discharged battery will freeze at zero or above. Hence the necessity of keeping well charged during the cold winter. Testing Battery. — The reliable test to use in judging the state of charge of a battery is the hydrometer test. Just as the scales will show that a piece of lead will weigh more than the same size of a piece of aluminum and not only that, but the exact difference in weight, so the hydrometer will show the weights of liquids. Water is taken as the standard fluid and all other liquids are judged as they are heav- ier or lighter than it. For the sake of a starting point water is said to have a specific gravity of 1.000. Sulphuric acid is almost twice as heavy having a specific gravity of 1.835. Hydrometer Reading. — With a M B^J-HSO little practice the hydrometer is read- ily used and properly read. In tak- ing the specific gravity of the bat- tery it is placed with the rubber tube end in the electrolyte having first deflated the bulb. Next care- fully release the pressure on the bulb and the electrolyte will be drawn up into the body of the in- strument. In this portion of the instrument is placed the hydrometer proper, the other parts really being a syringe arrangement. With the electrolyte in the body of the syring. '^''tuSf-.^ll^m^^o) '1^'^Ts- the hydrometer will float. The . charged (iiso) more nearly the battery is to a full charge the higher the hydrometer will float. The graduations are read at the upper level of the elec- trolyte. To do this properly it is necessary to bring the level of the eye even with the level of the liquid within the hydrometer. It is also necessary to see that the hydrometer is actually floating, without the top touching the upper end of the chamber or the bottom resting on the bottom of the chamber in which it is contained. After the electrolyte has been drawn into the instrument to the proper level to float the hydrometer nicely, a little pressure should always be given the bulb to relieve any vacuum in the upper part of the chamber, otherwise the reading will be too high. On the hydrometer, or within it, appear the graduations which are used to indicate the state of charge. These graduations usually run from 1.150 to 1.300. The first figure indicates complete exhaus- for ^96 Automotive Trade Training tion or discharge. The second figure means that the battery is fully charged if the hydrometer is carried by the electrolyte with this point even with the surface. It is the practice of the hydrometer manu- facturers to mark the instrument for the vital points. A gravity reading of 1.150 indicates fully discharged. A gravity reading of 1.220 indicates half charged. A gravity reading of 1.280 indicates fully charged. The student will understand, as he becomes familiar with bat- teries and methods, of judging tl;ieir condition, that it is possible to have a battery fully charged at readings either above or below the figures given depending on the original strength of the electrolyte. This is explained fully in the following paragraph covering battery charging. Battery Charging While in Service. — The owner should either inspect his battery with reference to water and state of charge at legular intervals, or take the car to the service station where the work is generally done free of charge. If the battery is maintained between the points of 1.250 and 1.275 by the generator it is an indica- tion that the system is properly adjusted for the type of service expected of that particular car. If the battery shows a continued tendency to become exhausted it should be given a special charge. If this does not remedy the trouble and the battery is in good condi- tion, the charging rate should be adjusted to give a higher output from the generator. Care must be used not to exceed the rated out- put of the generator or to injure the battery by an excessive charge rate. If the battery shows a tendency to become overcharged the charging rate should be lowered, or if the trouble is thought to be cf a temporary nature the lamps may be burned in the day time or while the car is housed in the garage over night to reduce the charge and the specific gravity. The same result may be obtained more quickly by operating the starting motor for a short time, say from three to eight minutes. The slower discharge is the better. For summer touring extreme care must be used to prevent overcharging and breaking down the battery due to overheating. Overheating causes the plates to become buckled and the active material to be- come loosened from the grid. Again the battery may be compared to the pneumatic tire in that the hydrometer shows the amount of current in the battery as the tire gauge shows the amount of air in the tire, Using a battery when it is nearly exhausted is just as bad as running a tire with very low pressure over a rough street. Putting an excessive amount of air into a tire is very likely to produce disastrous results. When the tire blows out it may be beyond repair. Overcharging a battery is likely to do the same for it. When it finally fails it is ruined beyond repair. Batteries and Battery Gare HOW TO RECOGNIZE BATTERY FAULTS AND GOOD AND DAMAGED BATTERY PARTS As indicated previously, natural wear and usage limit the life of the battery. Abnormal usage makes the life of the battery very short in many cases. How to detect incipient cases of trouble and correct them was mentioned in the previous section of this chapter. , To detect and remedy the more serious cases of trouble is the work of the battery service station. In most cases this means the opening of the cells to permit of visual inspection of the plates and separators. Tests Which Indicate the Need of Opening the Battery. — If a battery refuses to take a charge or runs down in a short time after having been charged the indications are those of internal trouble. If the battery runs down quickly when in position on the car, but holds a charge when charged separately and left oflf the car, the trouble is likely with the external car circuit which should be inspected for grounded or short circuited leads. Tests for determining trouble in. the starting, lighting and ignition circuits are given in Chapters 12 to 15. If, however, the battery will not hold a charge even when oflf the car no more time should be lost before it is opened and inspected. Inspection will show whether it is advisable to repair or not. If a battery is known to have been frozen it is advisable to open it. If a battery has been overheated it is advisable to open it up. If the electrolyte shows red or muddy it is an indication that the active element is dropping from the grids. The battery should be opened for inspection. If the battery has one or two cells which are always lower in point of gravity reading and water level it is an indication that the cell jar is leaking. If, however, the cell which always has the low solution level shows the highest gravity reading, it is possible that the heat of the higher charge is evaporating more water from it than from the others. If the crack in the jar is large the loss o: electrolyte is evident from the fact that the battery box and container are wet, as well as the fact that the electrolyte cannot be main- tained at the proper level. The methods of opening batteries are described at a later point. Before proceeding with that and actual repair methods, the stu- Fip. 308. Negative dent should know how to recognize plate con- Plates Sulphated from j:^:^^ ^„a ,r«1,,^ too low a level of Eiec- dition and valuc. *^"^y^*^- Sulphation. — In the mind of the novice the term sulphation means a condition which is certain to ruin the Automotive Trade Training battery. This is not always the case, by any means, since the normal action of the battery is dependent on sulphation. When a battery is. discharged, or rather when the chemical action within the battery, which is responsible for the flow of surrent from the battery, is going on, the sulphuric acid or sulphur within the electrolyte is leaving it and entering the plates causing sulphation. When the battery is charging, the sulphuric acid is being driven out of the plates leaving the positive plates lead peroxide, and the negative plates sponge lead. The current production of the battery is dependent on normal sul- phation. Lack of a full or proper charge allows the plates to sulphate abnor- mally or to an excess degree. When this condition obtains the plates become coated with a grayish substance, which covers the surface sealing the pores, thus destroying in part the activity of the cell. This is evident if a voltage reading is taken. In a badly sulphated cell the voltage drops off very materially. A cell or battery which has been left for some time in a badly sulphated condition, which is the case in partially or wholly discharged batteries, is very difficult to charge. The acid in the plates has sealed them and it is hard for the electric current to drive it out in charging. Sulphation may be due to a low electrolyte level which has per- mitted the upper part of the plates to stand above the solution as well as to the lack of proper charge. Fig. 308 shows sulphation due to too low a solution level. Overheated Plates. — Charging a badly sulphated battery at other than a very: low rate is practically certain to cause the plates to buckle and warp. In some cases the force is sufficient to break the cell jars and loosen the covers. This is due to the rapid and unequal expansion of the active element. Unless suffi- cient time is given for the strains to be neu- Fig. 309. Warped piatea tralized within the active material itself warp- ing is certain to result. Fig. 309 shows a group of warped plates. Damaged Separators. — It is seldom, if ever, advisable to use old wood separators the second time. It is far better to replace them with new ones inasmuch as a cheap unit is made to protect the plates which are the expensive parts of a battery. In the case of separators such as the Willard Threaded Rubber and certain other ones, it is possible to use them as long as they are not damaged in any way such as being cracked or torn, or if they are not worn through from use between the plates. As stated before, the separator must be an insulator as well. If all or part of a separator is missing from its position between the plates there is certain to be a short circuit Batteries and Battery Care 29» developed at that point. It is just as though two wires carrying current were permitted to touch each other. Fig. 300 shows the effect of wear and usage on wood separators. Frozen Plates. — The plates from a battery which has been badly frozen are readily recognized by the fact that there is little left but the grids. The active material falls from the positive plates in chunks. In other words, the active material with which the grids were pasted is all falling or has fallen out of them. In this respect it resembles the plate which has been subjected to continuous over- heating and overcharging. The overheated plate disintegrates a bit more naturally than the frozen one. Knowledge of conditions of service will help the student to differentiate between the two. Judging the Value of Positive Plates. — If the active material is practically all in place and seems fairly hard when tested with the blade of a knife, Fig. v310, the plate will give enough additional service to warrant the ex- pense of reinsulating and reassembling. However, if the active material is loose and considerable of the surface gone it is best not to use it. Judging the Value of Negative Plates. — Negative plates very seldom wear out before the positive group. Sulphation is more Fig. 310. Testing a Posi- tive Plate. Fig. 312. Terminals damaged from Corrosion. Fig. 311. Straightening Plates. marked in their case. A slow charge will usually remedy this. Care should be used to keep the negative groups from unnecessary expos- ure to the air. If left exposed to the air for more than an hour the negative plates dry out, heat and harden. If necessary to leave the battery in a dismantled condition the separated groups should be left in water or weak electrolyte. Judging the Value of the Battery Case.— Unless the case shows aoo Automotive Trade Training signs of rotting around the upper edges it is usually sound. The rapid depreciation of some cases is due to the electrolyte being spilled on them. The acid in the electrolyte attacks the wood once it has penetrated the paint. The case should always be cleaned and painted with asphaltum or other acid resisting paint, both on the inside and the outside. If in a state of saturation from the acid the case should first be washed in a baking sOda solution, after which it is permitted to dry before painting. Judging the Value of Jars and Jar Covers. — The hard rubber jars are subject to physical dam a,c:c from blows as from the sudden drop- m. Pig. 313. Battery Covered with Wet Cloth before Lead Burning. ping of the battery. Heating the jar in boiHng water leaves it a bit more pliable and this is sometimes advisable in assembling. The least sign of a flaw should be sufficient to cause the jar to be dis- carded. The covers are very frequently damaged in the process of disassembling a battery, especially those which have the element in a buckled condition. Wherever this is the case the damaged cover must be replaced with a new one. JOB 101. OPENING BATTERIES FOR INSPECTION AND REPAIR Removing Connecting Straps and Term- inals. — While the construction of batteries differs somewhat, practically all types have the connect- ing straps and the terminals burned to the group posts. Consequently in opening a battery the first thing to do is to centerpunch a hole in the exact center of each terminal and connector head. The next step is to drill each of the con- Fig. 314. nectors and terminals as indicated in the illus- tration Fig. 314. This work may be done with the brace but where there is considerable to be done the usual practice is to install a light power drill with Batteries and Battery Care 301 adjustable stop so that the holes may be drilled quickly and to a uniform depth. Where there is a power drill available for general service this is frequently used. The depth to which the hole is drilled will vary from Y^" to Y^". If the connectors do not come loose after drilling to thi^ depth they may be loosened with the lead burning flame. While applying the flame have the strap gripped with a pair of pliers and lift as the lead is softened. Usually no heat is needed as the straps will lift off easily. Softening Sealing Compound Around the Covers. — There are three methods of doing this work. Formerly the method illustrated in Figs. 315 and Pig. 315. 316 was used to a considerable extent. More recently the steam boiler with its individual tubes for each cell has met with much favor in the service stations and repair shops. Where the amount of work handled is not so great the gas flame is used. Hot Water Method.— The top of the battery should be thoroughly cleaned of lead borings and dirt after which the vent plugs are removed. The battery is placed upside down on the wash trough Fig. 315 and the electrolyte allowed tQ drain. A tank of hot water is provided. This may be a large pan heated over the gas flame. There should be sufficient water to come to a point at least 2" over 316. Fig. 317. Fig. 318. 302 Automotive Trade Training the sides of the case. If the water is boiling, five minutes will leave the com- pound soft enough to work. The battery may now be placed on its side on the table, and while holding with one hand the workman gives a series of pulls on the posts, using a pair of gas pliers and alternating from one post to the other until the element of that cell is broken loose and pulled out. Refer to Fig. 317. Steam Method. — If the entire battery is to be opened, the vent plugs are removed and the steam jets are placed one in each vent. It is not necessary to remove the electrolyte in this case. Allow the steam to flow until the compound over the covers is quite soft. Refer to Fig. 318. After the compound has softened the elements may be lifted from the cells as indicated in Fig. 319. Use gas pliers to grip the posts. If the battery is Fig. 319. held in a vise the work is made easier. If no vise is available it may be necessary to place the battery on the floor and hold it with the foot while pulling on the posts. Gas Flame Method. — With an ordinary gas flame heat the compound around the edges of the cover. It is necessary to keep the flame moving so that the cover is not burned. The compound should be removed with a narrow, heated chisel. In doing the work in this manner the operator contin- ually heats the chisel with the gas flame to prevent the compound from sticking to it, and assist in speeding up the work. If a flame is used it should be yellow since this is not as hot as the blue flame from the lead burning torch. If no other flame is available, the heat from a gasoline torch may be used but this is Fig. 320. an operation requiring extreme care. Refer to Fig. 320. Since the steam boiler outfit is to be preferred, it is well for the operator Batteries and Battery Care 303 Fig. 321. to provide himself with a boiler. If nothing else is available, an old can or tea kettle may be used. The tubes used to convey the steam are rubber. In the case of the tea kettle they m^y be attached to the spout. Since no pressure is required the lid will be all the cover necessary. It also serves as a safety valve. Cleaning Parts of Compound. — With a putty knife or chisel'all the surplus compound should be removed from the covers and around the posts. Be certain to get every part quite clean. The method of cleaning the post wfell with a screw-driver is shown in Fig. 321. Remove any compound from the top inside edges of the jars as shown in Fig. 322. If this is not done trouble will be experienced in refit- ting the element and cover. Removing Sediment. — As explained in the forepart of the chapter, as the active material wears a sediment collects at the bottom of the cell jar between the ribs on which the element rests. To clean this sediment out of the jar the box is placed on the washstand and a stream of water is thrown into it which washes all the parts clean. Refer to Fig. 323. Care of Elements and Electrolyte, — When the element is first withdrawn it may be set on top of the jar, as shown in Fig. 324, where it is al- lowed to drain. When thoroughly drained it is separated for inspection and repairs. The elec- trolyte should be tested for specific gravity in order that less trouble is experienced in re- charging when refilled after the repairs are made. The old electrolyte may be used although new is better. If the old is to be used it should be poured from the jars into an earthenware or glass vessel and allowed to settle. When replacing carefully pour off and use the clear portion only. Fig. 322. Pig. 323. Cover Sealing. — A number of special types of covers are in use. The point in the cover through which the post projects is the hardest part to seal. With the idea of making the part leak-proof the several manufacturers have 304 Automotive Trade Training developed special methods and designs of manufacture and sealing. Jobs 102, 109 and 110 give the method of opening and resealing the Willard, Exide, and Cincinnati types, since these are fairly representative of all types. *^- Fig. 324. JOB 102. OPENING WILLARD TYPE "SJWN" AND "SJRN" BATTERY 1. Cut off the terminal posts as illustrated in Fig. 325, using a hack saw. This applies for the clamp terminal, with a 13/16" drill. If burned on terminals are used drill off Fig. 325. 2. To remove the top connectors, place drill jig Z72 over the top of the connector head drilling with the same drill as for the terminals. Drill to a depth just sufficient to remove the connector or strap from the posts. Refer to Fig. 326. 2r7-f. Fig. 326. 3. Use a coarse file to smooth off the post extensions left by operation 2. This leaves a flat surface on the top of the insert in the special Willard cover. Batteries and Battery Care 306 making it easier to center the drill for the next operation. Refer to Fig. 327. 4. To release the posts from the insert where they are burned together Pig. 327. just at the insert top, it is necessary to use a 57/64" drill. The Jig Z94 is made with a slight variation of internal diameters so that one end will fit over the insert. For method of use refer to Fig. 328. Z^^ Fig. 328. 5. With post builder Z93 all connecting strap posts are built to a height of 1 5/16" above the top of the connecting strap which holds the group together. After removing the post builder the- top of" the post is beveled to permit of easy assembly of the cover. The .bevel is indicated at A, Fig. 329. Z-93 / Fig. 329. 6. The elements, having been repaired, may now be replaced in the jars so that the positive terminal is to the front when the name plate end is to the right. 7. File and clean the cover inserts at Point A, Fig. 330, to a point 3/16" A A B\ \ / ^ B Fig, above the cover. Be certain to remove any roughness caused by the pliers at point B while handling. 306 Automotive Trade Training 8. Replace the covers so that their top edges are ^" above the top edge of the jars, tapping lightly with the hammer. Refer to Fig. 331. ] Fig. 331. 9. To weld or burn the post and insert together and form a perfect seal, the burning form Z87 is first placed over the post and insert and then the flame is applied. Refer to Fig. 332. 2-87 Fig. 332. 10. Thoroughly brush and clean the top of the post with a wire brush. Build up a stub post using burning form ZSS on positive posts and Z89 on the negative posts. Refer to Fig. 333. 1 B^-T. 88 -Z Fig. 333. 11. Proceed with the job finishing it up as indicated in Job 103. JOB 103. REASSEMBLING THE BATTERY. 1. Having made all repairs the elements may be reassembled in the jars and the covers sealed in place. In order that the covers may be placed quickly and a fit insured they are taken one at a time and carefully fitted to the jar and ele- ment they are to cover. Remove the covers taking care to place them so that they are not mixed in replacing. Next use the gas flame to warm the cover well about the post. This will also insure the parts being dry, which is abso- lutely essential to a perfect seal. Refer to Fig. 334. Fig. 334. Batteries and Battery Care 307 2. After warming the well of the post with the gas flame, pour in melted sealing compound until the well is nearly full. While still hot the cover must be pressed into position. This insures the parts being sealed tightly. The method of pouring the well is shown in Fig. 335. Fig. 335. 3. Using a gas flame as indicated in Fig. 336A, the workman should carefully dry the space between the jar edges and the cover. With a pouring Pig 336A. dipper, Fig. 336B, pour the space between the jar and cover about one-half full of sealing compound. , After this first amount has had an opportunity to cool Pig. 336B. Fig. 336C. and set, the space is filled a little more than full of the sealing compound. A steady motion is needed in pouring in order that the job has the appearance of careful workmanship when it is finished. With a heated putty knife, Fig. 308 Automotive Trade Training 336C, the portion of the compound above the cover and the jar may be care- fully removed. The heat in the blade will leave the job smooth. 4. If care has been used in removing the terminals and the straps, the posts will need but little cleaning to permit the strap and terminals to come to their correct position one-fourth inch above the cell covers. The post and connector may be burned together in the manner indicated in Fig. 337. If the post in any case is too short to permit of proper assem- bly, it should be lengthened by building up. To do this place a post builder, which is nothing more than a piece of iron with a proper size hole in it, over the stub, use the lead burning flame to melt the lead into the mold, and fuse it with the top 'of the stub post. In this way the post may be built to the desired height. After the post is right the connectors are burned on in the usual manner. Refer to Fig. 338. Very frequently the clamp instead of the burned type of terminal is used. In case of this construction the old post is very frequently undersize and otherwise imperfect. In such case the old one should be removed and a new one built up. 5. Fill the battery immediately it is assembled, with specific gravity of the proper density. This as indicated pre- viously will be the same as that removed. Where new wood separators are used the electrolyte may be 25 to 50 points higher. Be certain to have plenty of solution above the plates but do not fill too full. A sectional cut of a battery shown in Fig. 339 will show the proper level. Fig. 337. 90 2-91 Fig. 338. Fig. 339. Batteries and Battery Care 309 JOB 104. ELEMENT REPAIR AND INSPECTION. 1. With the battery open the separators are removed from the element in order to permit of plate inspection. If the cover has been removed the positive and negative groups are also separated. The method of doing this is illustrated in Fig. 340. Fig. 341 shows the method of removing the separators in this case, after the groups have been pulled apart. 2. Inspect all plates as suggested in forepart of the chapter. Also inspect separators, cells and case. ■ 3. In case one or two plates of a group are bad ~v(^hile the others are judged fit for further ser- vice the bad ones should be removed. To do this, use a hack saw making a cut through the strap on tach side of the defective plate. Place the new plate in position, having all of the group assembled dn the burning rack. With the lead burning flame burn the parts together. 4. A very frequent cause of trouble with a single cell is a bad insulator, which permits of a short circuit. 5. Another cause is defective burning in Fig. 3^0. It trouble may be of a nature hard to locate until develops in service. P>. When part of a group of plates is worn out in normal service it is not as a rule advisable to rjeplace them with new ones. Rather the entire group should be replaced. If it is a case of all groups being practically worn out the battery should not be rebuilt but replaced with another. ;. W^hen the groups are in good condition they are cleaned and reas- sembled ready for the separators. Fig. 343 shows the method of placing the positive and negative groups together. Fig. 341. Fig. 342. Fig. 343. 8. Fig. 343 shows the element complete except for the separators. The negative group always has one more plate than the positive. This permits of the negative plates forming the outside plate in every case. 9. Fig. 344 shows the method of placing separators in the element. One separator is placed between each two plates. The ribs on the wood separator always go next to the positive plates. In cases where other forms of separators are used the same principle holds. They should be assembled to allow as much of the positive plate surface free as is possible. The repairman 310 Automotive Trade Training Fig. 344. should .make , certain that the separators project slightly on the sides and top. Since the element rests on the cell ribs the bottom is left flush. 10. Fig. 345 shows the element complete ready for placing in the jar. 11. In placing the element in the jar use rea- sonable care that it does not bind at any point in such manner that the jar is likely to be broken. Fig. 346 shows a jar broken as the result of care- less handling. A battery will not stand being dropped from any height onto a hard surface. To drop it an inch may result in broken jars. Fig. 345. Fig. 346. 12. To remove a broken jar it is necessary to heat it with hot water or steam for at. least five minutes. It may be poured full of boiling water, after which it should be removed by pulling up on it with two pairs of pliers as shown in Fig. 347, 13. Before replacing the new jar it is well to heat it in the same manner as the old one. In the meantime remove any sealing compound which might obstruct the placing of the new jar. When the jar is in position it is sealed in the same manner as the old one. This varies somewhat for different batteries. In some cases the jars are not sealed at all, in others they are sealed at the top edge, and in still others they are sealed all around. 14. The use of hot water to soften all hard rubber parts is recommended to the student mechanic. This leaves the covers and jars in a semi-pliable state with the result that there is less likelihood of their being broken as they are handled. 15. The three most common methods of grouping cells in the battery boxes are shown in Fig. 348. Fig. 347. JOB 105. BATTERY SHOP REPAIR METHODS. General Test to Determine the Condition of the Storage Battery. — The first test to be applied to the battery when it comes to the repair shop for charging or repair is one to determine the voltage on open circuit. This should be six volts or a little higher for a three cell battery, correspondingly more for ether types. An instrument similar to the Weston Model 441 Faultfinder should be used for this test using the 30 volt range. Having made the test on open circuit, i. e., without the battery discharging, a resistor for making a discharge test reading on the voltmeter is then connected across the battery terminals. Batteries and Battery Care 311 The resistor is made from nine feet of No. 16 soft iron wire. The inherent resistance of the iron will prevent more than a certain amount of current I'l : — II f J @ @ 1 1 <==r-^ 1 6 volt (3 cell) battery. assembly I @ @ C:^ @ CI b(0)@ 1 , SI 1 L ■4 1 H 1 6 volt (3 cell) battery assembly 2 dBldSl .qpl Fig. 348. M 12 volt (6 cell) battery assembly 1 flowing. Connect the resistor and instrument as shown in Fig. 349. If the voltmeter is now below five volts the battery is either discharged or in poor physical condition. Allowing the resistor to remain as before, the instrument is connected to make a reading on the three volt range while testing the individual cells. If a/rrrer Fig. 349. 312 Automotive Trade Training Fig. 350. all are about equal, the battery is likely discharged. If one or more of the cells give readings exceptionally low it is possible that these have defective plates. Next make a test for the specific gravity of the several cells. If the gravity readings are low in all cases this indicates that the battery is exhausted from continued discharge. Charge the battery and then make the same test as just indicated. If there are no defects in the cells the voltage registered with the resistor in place and current flowmg will be about two volts per cell. If, however, the voltage drops considerably the plates are likely defective in the cell showing the drop. JOB 106. MAKING AND USING A TEST OUTFIT FOR READING VOLTAGE OF INDIVIDUAL CELLS WITH CLOSED CIRCUIT. First secure two fiive-inch spike nails. Grind the ends of these to a sharp point. Next take a blo^k of fiber or hard wood four inches long and approxi- mately one inch square as a support for the spikes Drill holes through the wood block one-half inch from each end m which mount the spikes. To secure them in position use the hand drill to drill a #2" hole through them as they are in position. Place a rivet pm or cotterkey through the holes to lock the parts together In the center mount a file handle to serve as a handle for the instrument Refer to Fig. 351. Some form of terminal must be mounted on the spike heads to which the terminals from the instru- ment (voltmeter) may be readily attached. The resistor is made from one foot of Nichrome resistance wire one-eighth inch in diameter. The ends of the wire are soldered to the spikes. When the spikes are firmly pressed into the cell terminals approximately 50 amperes will flow across them through the resistor. The voltage reading should be made at the time the current is flowing If the voltage does not read 1,6 or more with this dis- charge, the plates are not in healthy condition. The cells failing must be repaired. /~N Fig. 3r.i Batteries and Battery Carh 313 JOB 107. CADMIUM TEST. The purpose of the cadmium test is to determine which group of the plates in a cell which is known to be bad is at fault. Since the fact remains that if one group is at fault the battery must be opened, little value can be attributed to the test. Unless the operator is one well versed in the theory and action of the storage battery the test may be very misleading. For the expert battery repair man the test may be of value in showing which group contains the defective plates and in that way save some time in making the repairs. For those who desire to undertake the test the following instructions may be a guide: Have the battery in fully charged condition. The lead attached to the spike havmg the cadmium stick should be connected to the voltmeter terminal marked three volts. Connect the lead attached to the other spike to the terminal of the voltmeter. Insert the cadmmm stick into the vent hole of the cell under test, Fig. 352, taking care that it does not come Fig 352. in contact with the plates. Press the other spike into the positive terminal of the cell and with the finishing rate of charging current passing into the cell observe the reading of the voltmeter. The cadmium stick should be kept in the electrolyte sufficiently long before taking the reading until the voltage does not show any changing. If the positive plates are in good condition the reading will be between 2.35 and 2.45 volts. If the reading is less than 2.35 volts it is probable that the positive plates arc defective. Transfer the spike from the positive terminal to the negative terminal. The reading this time will be to the left of zero for a fully charged negative in good condition and should be between 0.1 and 0.2 volt. If the reading jipproaches zero, or if it is to the right of zero, the negative plates are probably defective. If the test on both the positive and negative give readings which approach zero, the battery is short circuited. In general it is understood in the case of a battery on charge that if the cadmium test to the negative plates does not give a minus reading the battery is not up to capacity, but on the other hand, a minus reading is not proof that the battery is up to full capacity. This can be determined by making a discharge test. The battery should be discharged at its normal discharge rate until the voltage per cell is 1.8 volts with current flowing. Keep a record of the time in hours required to do this. Then with a discharge current of five amperes flowing the cadmium tests should be repeated. The reading of the positive plates should be about 2.05 volts and the negative plates should show 0.25 volt to the right or plus. If the reading to the positive group is much below two volts, it is certain 314 Automotive Trade Training that the positive group is defective. If the reading to the negative plates is greater than 0.25 plus, it is probable the negative group is defective. When the readings indicate defective plates, it is best to open the cells and make a further inspection of the plates. Upon reaching the voltage of 1.8 volt per cell the battery should have given its rated ampere hour capacity. This is determined by multiplying the ampere discharge rate by the length of time rated in hours, w^hich has been necessary to discharge the battery to that point. If the full capacity of the battery has not been given it is probable that the plates are defective, and the cells should be opened up and the plates given further inspection. When the cadmium tests show the plates to be in fully charged condition, the gravity of the electrolyte should be determined. This should be between 1.275 and 1.300. If it is not, it should be corrected until it does show the proper density. If the density indicates a fully charged cell, but the cadmium readings do not show fully charged plates, the charge should be continued to see if the cadmium readings will not become what they ought to be. If not, the plates are probably defective. The battery should be opened up and receive the necessary repairs. ' JOB 108. GROUNDED BATTERY. As mentioned previously, the grounded battery is usually due to spilled electrolyte. This electrolyte, coming in contact with the metal box or battery container, will produce a circuit between the container and one or more of the battery terminals. If the system used is the single wire or grounded return this new circuit will cause a short circuit on the battery. For a short circuit to develop on the two-wire system both the positive and negative terminals must be grounded simultaneously. To test the grounded return system, first remove the ground connection. Connect the 30 volt range of the Fault Finder between this terminal and the frame of the car. Any indication on the instrument will be due to a short circuit to the car frame from the other battery terminal. In the two-wire system each battery terminal should be tested for ground to the car frame. In all cases it is very important to remove all moisture from the top of the battery. This will often remove the cause of the ground. In some instances the battery case is so saturated with the electrolyte that it is hard to remove the cause of the short circuit. Cracked cells may be the cause of short circuits. JOB 109. REMOVING AND RESEALING EXIDE SINGLE COVER TYPE COVERS. 1. Remove the lead straps. These may be bored with a five-eighths inch wood bit as indicated in Fig. 353. Just under the lead straps the special form of lock nut is visible. These nuts are used to seal the joint where the post comes through the cover. The section of an Exide battery, as shown in Fig. 354, indicates the secure manner in which the parts are locked together. Tke sealing compound locking the elements in the jars may be softened by one of the methods indicated in Job 101, after which the elements may be removed from the cells. 2. To remove the sealing nuts the special wrench shown in Fig. 357 should be used. 3. After repairs are made to the element it is assembled in the cover and the sealing nuts are tightened part way, using only the fingers for this work. Batteries and Battery Care 315 Fig. 353. Boring Connector. Be very certain to have the soft rubber washers in place in order to make a tight joint and protect the cover. With the groups on edge, as indicated in Fig. 355, the separators are inserted making certain that the flat side of the wood is against the negative plates. Section of Battery — Burned Connections, Single Plan&e Cover Fig. 354. 316 Automotive Trade Training 4. With the separators all in place and projecting equally on each side the sealing nuts are locked tight using the special wrench. 5. The sealing nut should be locked in position as indicated in Fig. 356. Pig. 357. Sealing Nut Wrench. Fig. 355. Inserting Separators. A center punch or nail may be used to punch several points to prevent the nut working loose. J^^UM e.s.B.co.izzs Fig. 356. Locking Sealing Nut. JOB 110. OPENING CINCINNATI BATTERIES. Fig. 359 shows the patented feature of the Cincinnati storage battery cover hacking device. On the group post, just above the point where the cover fits, Batteries and Battery Care 317 Fig. 358. Cincinnati Storage Battery. is a threaded portion. Projecting above this threaded portion is a round smooth post. The nut which is used to lock the cover to the group has a nipple-like ar- rangement on its top which fits over the smooth part of the post when the threaded portion of the nut locks over the threaded por- tion of the post. To dismantle, proceed as follow: 1. Centerpunch the centers of the connecting straps and termi- nals over the post. 2. Drill with a ^" drill to a depth of one-fourth inch and re- move the straps and terminals. 3. Inspect the post tops to learn if the line of separation be- tween the inner post and the nu( is evident. If not apparent it is useless to attempt to turn off the nut. Use a file to file off the top of the post and nut until the line or circle between the two appears. 4. Place a socket wrench over the hexagonal portion of the nut and turn or back it off the post. 5. After loosening the nut it may be desirable to turn it back in position until the covers are loosened in the usual manner by steaming, hot water, or gas flame. 6. When the element is finally removed the cover is quickly removed by releasing the nuts. In reassembling be certain to use the soft rubber washers under the nuts. 7. After repairs have been made to the element, it is assembled in the cell jar and the cover placed in posi- tion, where it is locked under the nuts, and the outer edges of it are sealed to the jar. 8. In burning the con- necting straps and terminal Sleeve And Post Fuses TOGETMni ) Fig. 359. Cincinnati Storage Battery- Cover Locking Device. posts in position the upper edge of the nut will again be burned to the inside post. This insures the nut remaining permanently in position. JOB 111. MAKING AND USING ELECTROLYTE. Electrolyte, as explained previously, is made by adding sulphuric acid to distilled water. The water should never be added to the acid, but in mixing the acid is always added to the water. If the operation is reversed the water striking the acid is very likely to cause such violent action as to throw the 318 Automotive Trade Training solution from the receptacle in which it is being mixed. The amount of acid added to the water determines its specific gravity. Making Electrolyte. — In making up the electrolyte, glass jars or earthen jars should be used. Metal containers outside of burned lead vessels may not be used. It is well also to have a glass funnel and syringe available. The syringe may be an old hydrometer case with the hydrometer removed. -. When mixing the acid and water they are figured not by weight, but by volume. For electrolyte of varying specific gravity consult the following table. The student will remember the specific gravity of water as 1.000, and of pure sulphuric acid as 1.835. In purchasing the acid it must be ordered from the chemical company or supply house as C. P., H.,SO^, which is chemically pure sulphuric acid. The distilled water may be secured from the same source. 1.150 Sp. Gr. equals one part sulphuric acid to 6 parts distilled water. 1.200 Sp. Gr. equals one part sulphuric acid to 4 parts distilled water. 1 250 Sp. Gr. equals one part sulphuric acid to 3 parts distilled water. 1.285 Sp. Gr. equals one part sulphuric acid to 2 5 parts distilled water. 1.325 Sp. Gr. equals one part sulphuric acid to 2 parts distilled water. Allow the electrolyte to cool below 90 degrees F. before putting it into the cells of the battery. Filling the Battery with Electrolyte. — All cells should be filled with electrolyte up to one-half inch over the top of the plates. If the elements have been out of the jars long enough to allow the plates to dry out, the battery must be left tor at least eight hours after filling before placing on charge. Determining Strength of Electrolyte to Use in a Repaired Battery. — If the plates are new the electrolyte used for filling should have a specific gravity of 1.325; if they are old plates badly sulphated, the electrolyte should be 1.150 specific gravity, while if old plates, and any doubt about their condition is held by the workman, the electrolyte used should be 1.200. To the student it is now apparent that if the specific gravity of the electrolyte drawn ofif were known it would be easier to know just what specific gravity to fill the repaired battery with. All acid which may be in the plates will be foi-ced out when the battery is charged and will increase the strength br density of the electrolyte. This is true of all old plates, but in the case of new plates the gravity drops slightly since some acid is always retained in the plates. This is the reason for using the 1.325 electrolyte when filling over new plates. Adjusting Electrolyte. — A fully chargecj battery should show a specific gravity of 1.280 to 1.300. If, after the cells are fully -charged, the electrolyte is not of the proper density, the proper correction must be made. If too high, the cell must have a portion of its electrolyte drawn off with the syringe and a like amount of distilled water added. If too low, a quantity ot the electrolyte is drawn ofi and electrolyte of 1.400 specific gravity is added After the change is made the charge must be continued for a time and then final tests and adjust- ments made. JOB 112 CHARGING A REPAIRED BATTERY. The battery should be placed on charge at a low rate, approximately that of the finish rate stamped on the name plate. It may be continued on charge until there is no further rise in gravity in any of the cells. A reliable thermom- eter must be used to check up the temperature. It at any time the battery heats to 110 degrees F., the current must be reduced until the temperature is below 90 degrees. When no further rise is noticeable in the gravity readings for two to five hours, the gravity must be adjusted to read between 1.280 and 1.300. Acid must never be added to bring up the gravity of a cell unless it shows no rise whatever over a period of from two to five hours. The cadmium test Batteries and Battery Care 319 is sometimes used to determine if the plates are fully charged. If a part of the cells are fully charged while others do not show a full charge, the low ones should be charged individually in an attempt to bring them to the proper gravity reading. It is only when this has failed to bring the cell above the fixed point after several hours of charging that the repairman may feel free to make adjustment of the acid. It must be definitely understood that batteries cannot be recharged by adding acid. Acid is added to the electrolyte only after all is driven from the plates by charging and then only to insure having the proper amount in the cell, that its future action may be correct as fixed by the generally accepted standards. CHARGING BATTERIES AND BATTERY CHARGING EQUIPMENT. The prime requisite- in charging batteries is a D. C. current. A. C. current, as explamed m Chapter 11, may not be used for this work. Other essentials are methods of controlling the voltage and the amperage and instruments to measure the voltage and amperage. There are many devices and methods in use for the work of battery charging. Some are simple and inexpensive. Others are very elaborate and quite expensive. The number of batteries to be cared for and the type of current or power available are determining factors in deciding on equipment as well as method. Where 110 volt D. C. lighting current is available it is comparatively simple to use it. Where it is desired to use the A. C. current some form of transformer or rectifier must be used. Charging a Battery from a 110 Volt Lighting Circuit. — It is possible tc charge from one to fifteen 6-volt batteries by this metbod. By "referring to Fig. 360 the student will learn the method of wiring for a single battery. The / T> flO VOLT/OO yVATT l.^MP3 ^^2 o.p carbon /Go. Technical wiring diagram of Typical Battery Ignition. (K W Ignition Co.) which is what the core of iron wire with its primary coil really is, the current sets up lines of force or flux which flow from the north pole to the south pole and there enter the iron core flowing back to the north pole through the core. Again, they come out and flow from the north to the south pole through the air and thence to the north pole from the south through the core, the action being a continuous, one as long as the current is flowing through the primary winding from the battery. However, there is this point to be remembered : When the primary current first starts flowing through the primary coil the lines of force emanate or come from each coil of the primary winding. This happens all along the length of the primary winding after which, however, they all flow as described above as long as the current is not broken. According to the same rule, when the current is suddenly broken these lines of force flowing about the coil do not continue to the end of the core to re-enter it, but drop immediately to it from all points, thus cutting the conductor wound around the Battery Ignition 327 primary coil and known as the secondary coil. It is this action of the lines of force, as they cut the conductor composing the secondary coil as they return to the core, that is usually counted on to induce the high tension current for use in ignition. Sometimes the current is induced when the lines of force come from the core. However, this action is usually less forceful and in general practice is not used. Magnetization as a rule being slower than demagnetization, the making of contact of the switch will cause some current to be induced in the secondary coil as the lines of force leave the core, but the voltage or current is not sufficient to cause the current to leap- the air gap at the spark plugs. When the switch is opened, however, the demagnetization is made Fig. 366. Section of Typical Battery Ignition System. (K W Ignition Co.) quite rapid through the use of the condenser. Breaking these lines of force causes them to collapse or break down very rapidly, and in such volume that a very high tension or pressure is induced within the secondary coil which they are cutting as they drop back or col- lapse. This pressure, varying from 15,000 to 30,000 volts, is so high that it will jump the air gap at the spark plug points. The direction of flow of the induced current is the same as that of the primary current. Air Gap. — Several air gaps are in use with reference to the igni- tion system. One is the air gap provided in the spark plugs. This air gap should never be more than 1/32". Failure of some other part of the ignition system, such as the loss of the spark plug wire from one of the plugs, might result in the high tension winding of the ignition coil being broken down and the insulation punctured if a s:afety gap were not provided. This safety air gap is usually Y^ to y^' long and is built into the coil. Ordinarily the high tension spark is carried through the distributor and from there to the plug but the 3^8 Automotive Trade Training Fig. 367. Adjusting spark plug air gap. safety gap is always ready to care for the emergency. It is made of sufficient size to insure the spark going to the plugs under normal conditions. FOR TURNING CONTACT SCREW 6 LOCK NUT Pig. 368. Adjusting Distributor Points and testing with thickness gauge. The resistance of the air gap increases with the compression in the cylinders. Since air is a non-conductor, it is natural that if four times normal air pressure is induced, as is the case in the cylinder, the gap will be harder to jump. Fig Remy Distributor Head. Battery Ignition 329 Timer-Distributor. — The student is familiar with the facts of engine design with reference to the four-stroke 'principle, and the firing order. The distributor is generally built to include the primary breaker points as well as the means of distributing the high tension current. The purpose of the timer-distributor is to make the electri- cal connection on the primary winding of the ignition coil, thus per- mitting the magnetic flux to build up. Next it must be broken at just the correct moment to permit the secondary current induced to be carried back to the distributor, and from the distributor head to the plug in the cyHnder then under compression, and waiting to be Pig. 371. Section of Atwater Kent Distributor Cap and Kotor. Fig. 370. Remy Apperson Igni- tion Distributors. fired. Here it jumps the gap, due to its tremendous pressure or volt- age, and ignites the charge. It will be noted that two distinct func- tions are performed. The first is making and breaking the contacts for the completion of the primary circuit which might be said to be switching off and switching on of the primary circuit. Normally the current is on, thus permitting the magnetic flux to build up to a high value in the coil. However, the distributor shaft has a cam on the upper end. On this cam are machined as many lobes as there are cylinders to the engine. This cam turns at one-half engine speed so that each lobe opens and closes the breaker points once for each two revolutions of the engine. Each time the switch or breaker points are opened, a cylinder is fired. Accordingly there must be an equal number of high tension 330 Automotive TradI: Training Fig. 372. Wagner Distributor Cap. wires running from the distributor cap to the engine cylinders. Just under the distributor cap is a rotor which distributes the high tension current. This rotor receives the high tension current on the center where it is usually in contact with a spring, and sends it to that plug- wire under which or with which it is in contact. The next break of the primary current induces another high tension spark which is distributed or sent to the next plug-wire in line. The next break sends the current to the next plug-wire, and so on and on, all the way around the cap, four breaks for the four-cylinder engine, six breaks for the six-cylinder, and so on. Needless to say the firing order of the engine must be considered in running the wires from F'ig. 373A. Stutz Engine with Double Distributor. I Battery Ignition 331 the cap. As far as the cap is concerned the sparks follow one another without any irregularity, but the cylinders may be fired in any one of several orders. All that is necessary is to find the proper lobe for Fig. 373B. Stutz Engine with Double Distributor. the first cylinder and then wire it accordingly. After that take the next wire from the cap to the next cylinder to fire, whichever it may be. Spark Control. — On the speed of the engine depends to a certain 332- Automotive Trade Training extent the point at which the spark should occur. By means of the ?park manual on the steering column the distributor head may be swung through a short arc. This constitutes advancing or retarding the spark. In a motor running very rapidly the charge should be fired earlier than on the same motor running at a slower speed. This has relation to firing before, at, or after T. D. C, as explained in valve timing. In some cases the hand control is depended on alto- gether to control the spark advance. In other cases this is all con- controlled automatically, no hand control being provided, or a com- bination of the two is used. Switches.— The make and break mechanism of the car has been compared to a switch, and such it is, but operated in fixed relation to the strokes of the motor. Unless the motor happens to stop with one of the lobes under the breaker point arm, thus holding the con- tacts apart, the current will continue to flow through the coil. The student will now grasp the need of the resistance unit being inserted in the primary circuit. If it were not for this unit and the current continued to flow, great damage would be certain to occur. With this measure of protection the greatest possible care should be used in all eases, when stopping the engine, to turn off the switch provided. This switch usually takes the form of a key arrangement on the dash used to make the primary circuit complete, or to break it when igni- tion is not desired. Condensers. — In a general way the action of the condenser has been explained. As stated previously, a condenser is necessary for the proper performance of the ignition unit. The action of the con- denser in the case of automotive ignition is as follows : The con- denser serves two definite pur- poses. Current from the bat- tery is always flowing through the ignition coil primary winding except when the points are separated by action of the cam lobes. Since this a direct current flowing V^^^^^^^^^^^^^^^^^W through the coil it tends to keep on flowing when the points are opening. This tendency to jump the gap would create quite a spark were it not for the condenser. The condenser is connected Fig. 374. Condenser mounted in ease. across the contact points. (Wagner.) That is, a wire is run from one side of the condenser to one of the contact points, and another wire from the other side of the condenser Battery Ignition 333 to the other side of the contact mechanism. Novv, when the points separate, the current, instead of flowing ahead and creating a spark PS it attempts to jump the gap between the points, is sent into the condenser which acts as a storage reservoir. There is no electrical con- nection through a condenser when it is in good condition. If there is a circuit through it then the condenser is useless. As the points open and the current rushes into the condenser, one side of it is charged positively and one negatively at a rather high potential or voltage. This is due to the fact that as the points open the lines of force collapse, cutting the coil windings. These lines of force, which must collapse to give the spark at the spark plug, will also cut the primary winding and induce a rather high voltage in it. It is this induced voltage as well as the primary voltage which, faiUng to jump Fig. 375. Spark Controls, High Tension Cables from the Distributor and Oiling Directions. (Allen.) the contact points, rushes into the condenser and charges it. The voltage of this charge is variously estimated at from 100 to 150 volts. This charge, however, does not remain within the condenser. The potential is high. There is a path open for it to discharge through. This path is back through the battery and the primary winding to the other side of the condenser. Consequently the condenser is no more than charged until it discharges back through the circuit includ- ing the primary winding of the coil with the very desirable result of causing the lines of force, which are collapsing about the core, to collapse very much faster. Since the voltage induced within the secondary winding is dependent on the rapidity with which these lines of force cut the many turns of the coil, the result is a very high tension current giving the desired spark at the plug. The student will want to understand that -the difference of potential between the 334 Automotive Trade Training two sides of the condenser is what causes it to discharge back through the circuit. In shop parlance the current is kicked back through. The current being kicked back through the circuit, which is in the reverse direction from the initial current, causing magnetism of the core, is a great help in completely demagnetizing the core, since it overcomes the residual magnetism and helps to quickly return the molecules to their original position within the core. This entire action following the opening of the points is instantaneous, the various steps following each other so closely that no time may be said to elapse between them. Reference to the illustrations will show methods and positions of condenser installation. Spark Timing. — In most cases the timing of the spark to the engine is not a difficult matter where battery ignition is used. The first thing to do is to remove the distributor cap. Next remove the distributing arm and loosen the set or cap screw which appears. After this tightening device is loosened, the cam may be rotated on the stem, or shaft, in either direction desired by the operator, and as far as he desires. It is well to remember that a movement of a few degrees or a very small fraction of an inch is sufficient to adjust or put in time, unless the trouble is quite serious and the motor refuses to run at all. In a case of this nature it would be necessary to bring cylinder No. 1 onto the top dead center compression stroke, and then to set the distributor so that the rotor arm when in position would, be so located as to bring the high tension spark to the wire running to cylinder No. 1 just as the cam lobe was br-eaking the points. Therefore, if the car on the road gave evidence of too great an ad- vance, or appeared sluggish from too late a spark, the proper adjust- ment might be secured by lo,osening the binding screw and moving the cam as would seem necessary. VIBRATION COIL IGNITION Principle of Vibrator. — The vibrating coil is identical in con- struction with the non-vibrating coil, with this one exception. For mmm^m^^^^msk, Fig. 376. Fordson Vibrat- Fibre Inj? Coils. (K W Ignition Co.) Put) Rod ConneoiMi Case Thumb Nut Contact Poinr Roller Arm Brush Engine Cover Pig. ."iTT. Ford Timer. Battery Ignition 335 the breaker points within the distributor head which are worked mechanically and in fixed relation to the firing order, the vibrating coil utilizes a vibrator mounted on the coil. The vibrator consists of a set of springs and conductors, and a set of contact points, fre- quently called vibrator points. When contact is made within the timer, which takes the place of the distributor, a primary current is sent through the primary winding of the coil. This causes a mag- netic pull at the end of the iron core and thus attracts or pulls to it the steel spring on which is mounted one contact point. When this point is pulled away from the other, the primary circuit is broken or interrupted just as happened when the contact points were opened in the distributor head. The consequent action again is similar. Fig. 378. Oiling Ford Timer. That is, the breaking of the primary circuit causes the lines of force to collapse, inducing a high tension current in the secondary winding which is carried to the spark plug, there to ignite the fuel charge. However, as soon as the magnetic effect of the iron core is broken down due to the breaking of the points, the cessation of primary current, and the condenser kicking back through the primary coil, the steel spring snaps the contact back in plkce, again permitting ihe primary current to flow. This again causes the contact to be broken, another induction of high tension current to take place, and another spark to be delivered to the same plug. These actions or operations follow each other so rapidly that there is what appears to be a continuous flow of high tension current jumping the spark plug points as long as the roller within the timer is in contact position. Since this system is that in use on the Ford car, the student is likely more or less famihar with it. Timer. — A timer instead of a distributor is used. This is some- times called the commutator. A roller with spring tension is mounted 336 Automotive Trade Training on the cam shaft where it travels at one-half crank shaft speed. Within the timer head are mounted four (in the case of the Ford, this depends on the number of cylinders) strips of metal or contacts. The roller makes contact and electrical connection for the primary s 1^3 Sir 3 oQQCoaO u 5 — PM r^ T»- C ft> «C b: t: fc is •^ <^ nn rJ\ rA Gt oOSt^S\"2<^^ 2 2 3:3 *=-^-.-2opc.^ op ooE« current through these strips. Each timer contact is connected to a separate coil on the coil box carrying primary current from the magneto to it. As the roller rolls around on the inside of the timer head, one after the other of the coils are connected to it through the segments. As each one in turn is brought into action the high ten- Battery Ignition Z31 sion current is Induced through the action explained above. Each coil is connected to one spark plug only. Whenever the roller is in contact, and for as long as it is in contact with its segment, that coil sends a spark to its plug. The essential difference between the vibrating and non-vibrating coils is that the last mentioned gives one pulse of high tension current to jump the spark plug points while the vibrating coil gives a series of pulses of high tension current to jump the plug points for each firing effort. In the case of, the non-vibrating coil, the break of the contact points depends on the mechanical operation of the breaker points, a cylinder fired for each break. In the case of the vibrating coil the break of the points is entirely automatic, but at the same time this automatic action is con- trolled by the roller within the timer head. Timing the Spark. — The timing of the spark as mentioned previously is largely dependent on the rolling of the roller within the timer, in relation to the cam shaft speed. Advance and retard of the spark are obtained from rotating the timer-head forth and back on its seat. Needless to state, the wires connected to the coils are made flexible and permitted to move with the timer-head. As to the method of securing the spark in the proper cylinder: In this case the primary wires must be led from the timer to the proper coil to give the high tension spark in the desired cylinder. That is, coils and timer must be connected in relation to coils and cylinder. The whole must be in proper relation to timer roller and compression stroke. JOB lie. ATWATER KENT IGNITION SYSTEM, TYPE CC. This system as used on the Maxwell car is of the closed circuit type differing radi- cally from the K-2 system. The amount of current consumed for ignition is very much greater. Inasmuch, however, as the gener- ator is producing current at all times this drain is not serious. The closed circuit sys- tem for battery ignition is used to such an extent that it might be said to be the stan- dard battery system. The coil and the contact maker and distributor constitute the CC system. ' Contact Maker. — The contact maker consists of an exceedingly light contact arm made from steel. The end of this arm rests lightly on the hardened steel cam which is driven at one-half crank shaft speed. The cam has four points opening the contact points four times for each two revolutions of the engine which is necessary for firing Fig. sm. Atwater Kent Type ^he four-cycle engine of four cylinders. "CC" Ignition Unit. Each time the pomts are opened the primary 338 Automotive Trade Training circuit is broken, thereby inducing a high tension current in the secondary- winding, ' which is led through the distributor to the spark plugs. The con- denser is mounted directly on the contact maker. This construction tends to simplify the construction and increase the life of the contact points. The high tension distributor forms the top of the instrument. The high tension rotor takes the jump spark current from the center terminal and distributes it to the plugs in proper firing order. Coil. — This is of the usual non-vibrating type of construction. An iron icore has two windings on it. The coarse winding or primary is next to the iron core. Over this are wound the many turns of fine insulated wire forming Fig. 381. Maxwell Atwater Kent Ignition System. the secondary winding. The amount of current used is automatically regulated by the resistance unit in the top of the coil. The coil is carefully sealed to exclude moisture. Setting and Timing the Type CC System. — First make certain that all advance rods and electrical connections are complete. Advance rods must be so adjusted that the full advance movement of the distributor is possible*. With these precautions first taken, proceed as follows: 1. After wiring is complete remove the plugs and lay them on th< cylinder head. Have the plug wires attached. Do not permit the termina ends of the plug to touch the casting. Battery Ignition 339 z. Turn on the ignition switch and crank the motor over slowly using the hand crank. Note that each of the plugs sparks in the proper firing order. For the Maxwell this is 1-3-4-2. When this is checked, turn off the ignition. 3. Set the spark lever on the steering wheel quadrant one and one-fourth inches from the full retard position. 4. Loosen the ignition coupling so that the knurled collar on the hori- zontal shaft may be easily turned. 5. With the hand crank turn the motor over until the piston in No. 1 cylinder is on exact T. D. C. between the compression and power strokes. 6. Turn the ignition on again. 7. With the fingers or the point of a screw driver move the knurled collar away from you or toward the engme, very slowly and carefully until a spark is seen to jump plug No. 1. Do this so carefully that the knurled collar stops the instant the spark occurs. If not certain of the operation, move the collar back one-quarter turn and try again. 8. Stop exactly as the spark occurs. Maintain the parts in this position until the adjustment can be secured by locking the hexagonal screw on the coupling clamp. The motor is then timed so that the spark occurs on dead center when the spark lever is placed one and one-fourth inches from full retard. This allows of ten degrees retard for safe starting and about twenty degrees advance for high speeds. Adjusting Contact Points. — If convinced beyond doubt that the contact points are at fault, they should be adjusted. The normal gap between the points should not be less than .005" nor more than ,008". The standard setting is ,006". The contact points are made from purest tungsten and are much harder than platinum iridium previously used. JOB 117. ATWATER KENT IGNITION SYSTEM K-2. In this system which operates on the open circuit principle there are three units. The Unisparker which combines the special form of contact maker which is the basic principle of this system, and the distributor for the high tension current. The Coil, which consists of the usual primary and secondary winding, i.s imbedded in a special insulating compound. The coil is Fig. 382 View of contact malver showing of the non-vibrating type. The places to be oiled.— Type K2. . •, ■ .1 • •^- -^ i. other unit is the ignition switch. Principle of Operation. — The operation of the system is illustrated in Figs. 384, 385, 386, and 387. A notched shaft is provided, one notch for each cylinder. This shaft travels at one-half engine speed so as to provide the four sparks for each two revolutions of the engine. A lifter or trigger is operated by the rotation of the shaft being pulled forward. A spring attached to the trigger pulls it back to position. A hardened steel latch and a pair of contact points complete the instrument. In Fig. 385 the lifter is being pulled forward by the notched shaft. When pulled forward as far as the shaft will carry it, the lifter is snapped back into its original position by the spring. In returning, it strikes against the latch throwmg this against the contact spring, thus closing the contact points for a wt -■Pr^^'ySff 'Fic l.^ I 1 OIL tlGHTLY SEE THAT CONTACT-POINTS ARC FREE FROM OIL 340 Automotive Trade Training wwv— BATTKRV CONTACT MAKER Fig. 383. Atwater Kent Wiring Diagram— Type K2. very brief instant. The contact is made for such a small space of time that the eye cannot follow the action. This is quite different frorri the closed circuit type where the contact is made and considerable time, is allowed for building up the magnetic field about the coil core. Fig. 386. Contact Made. Fig. 385. Contact Still Open. Fig. 387. Contact Broken. In Fig. 387 the lifter has dropped into the second notch. The student will note that the circuit is closed only during the instant of the spark. No current will flow at any other time not even if the switch is left on with the motor standing idle. The engine speed has nothing to do with the speed with which the contact is made and broken. No matter how fast the engine may be operating the Battery Ignition 341 spring will always return the lifter at the same speed. This return speed is the vital factor in making and breaking the primary circuit. Contact Points. — The contact points are the only parts adjustable and they require this at infrequent intervals. The normal gap is from .010" to .012", never closer. These points are made from pure tungsten. When working properly, small particles of tungsten will be carried from one point to the other, sometimes forming a roughness and dark gray color on the surface. This 9Arrrnm Fig. 388. Wiring Dia- gram, Type "K-2" or "H", with Plate Switch or Kick Switch Coils. Fig. 389. Wiring Dia- gram, Type "K-2" or "H", with Underhood Coil Re- versing Switch. roughness does not in any way aflfect the working of the pomts owing to the fact that the rough surfaces fit into each other. However, if it becomes necessary to adjust the points the rough parts must be removed. To do this remove the contacts from the Unisparker and file the points with a fine file. When reassembled, the mechanic will want to see that the points have a proper bearing over their entire surface. Oiling. — The other parts of the contact maker — the latch, the lifter, lifter spring and notched shaft are not subject to wear if they are properly cleaned and oiled at intervals of a few weeks. Under no circumstances permit oil to get on the contact points. Refer to Fig. 381 for oiling instructions. i 342 Automotive Trade Training Setting and Timing. — First put piston No. 1 on top dead center com- pression stroke. Loosen the clamp holding the Unisparker in position. Next turn the instrument backward, contrary to the direction of normal rotation, until a click is heard. This click occurs at the exact instant of the spark. Maintaining the Unisparker at this position it should again be secured by tightening the clamp. The distributor cap is now removed and the terminal in contact with the distributor block is connected to cylinder No. 1. Connect the other cylinders in their proper order of firing. JOB 118. NORTH EAST IGNITION SYSTEM FQR DODGE CARS. MODEL O. Fig. 390. Dodge North East Ignition System. The ignition distributor is mounted on the right-hand side of the engine, being held in position by four bolts. There are two shafts, one a horizontal driven from the engine, and the other a vertical driven from the horizontal one. The latter is driven from the pump shaft through a flexible coupling. It is driven at engine speed. The vertical shaft travels just one-half as fast, the Fig. 391. Dodge North Bast Ignition System. Battery Ignition 843 reduction of speed being through the spiral gears. The complete distributor unit consists of three self-contained assemblies. The^e are the ignition coil, the breaker box and distributor head assembly, and the distributor base assembly which includes the automatic spark advance mechanism. Any one of the three elements may be removed from the distributor unit without disturbing the other two. Ignition Coil Assembly. — This is illustrated in Fig. 394. It is so con- structed and designed as to operate on the twelve-volt starting and lighting circuit. The coil is not likely to cause any trouble and when this does occur the entire assembly is usually replaced. For tests on coils refer to Jobs 122 and 130. Breaker Box and Distributor Head Assembly. — If for any reason the distributor head and breaker box is to be removed, ficst place the distributor in full retard position. Next remove the distributor head. Mark the exact posi- tion of the distributor rotor on the edge of the box. This njark should be made with special care, because it has to serve as the sole guide for the correct position of the vertical shaft when the assembly is put back in place on the distributor-base. Moreover, while the breaker-box assembly is separated from the base, the horizontal shaft in the base must not be turned from the position it occupied at the time when the location of the rotor was marked. If either of these precautions is neglected, the correct relationship between the several moving parts of the system will very probably be disturbed to such an extent that a complete retiming of the distributor will become necessary. The breaker box contains the condenser as well as the breaker contacts and breaker cam. The distributor head covers the entire box excluding water, cil and dirt. Fig'. 392. Breaker- Box and Distribu- tor-Head Assembly. -Fig. 393. Distributor-Head. Fig. 394. Ignition Coil Assembly. Breaker Contacts. — The breaker arm carrying one of the breaker contacts is mounted on a pivot from which it is thoroughly insulated by a fiber bushing. The coil spring, which is attached to the lug at the pivot end of the arm, holds it in such position as to keep the points closed, making the system a closed circuit system. The fiber block mounted near the center of the breaker arm is struck by each lobe on the breaker cam, in turn, and the points are separated. This produces the four interruptions of the primary circuit necessary to the production of the four high tension sparks, for each two revolutions of the engine. The second contact is carried by the stationary contact stud which is adjustably mounted , in an arched support. With this stud properly adjusted, 344 Automotive Trade Training a^VAV^A the distance between the contact points when they are fully separated by the cam is .020". Replacement of Breaker Contacts. — The proper method is to replace the Battery Ignition 345 . Fig. 396. Model O Ignition Distributor. entire breaker arm and stationary stud assemblies. The breaker arm can be removed by simply lifting it off its pivot after its pigtail has been disconnected from the breaker-box binding post. The spring attached will slip off of its own accord as soon as the arm is raised sufficiently from its normal position. After the breaker arm has been taken off, the stationary contact stud can be removed by releasing its lock nut and unscrewing it from its support. Reverse the operations to replace. Fig. 397. Breaker-Box. Automatic Spark Advance. — Combustion does not follow instantaneously on the occurrence of the spark, however, because a small interval of time is always needed for the gas in the cylinder to ignite. Consequently, unless soma means were provided for offsetting the lag between the spark and combustion, the explosion of gas could not always be made to take place at the right moment under the varying speeds of the motor. The centrifugally actuated mechanism shown in Fig. 399 is designed to care for this by automatically advancing and retarding the time of the spark in exact accordance with the speed at which the engine is running. 346 Automotive Trade Training Manual Spark Control.— This works independent of the centrifugal device. It is used principally for starting or idling the engine, or to facilitate carburetor adjustments. In normal driving the correct method of use is to advance the manual control as far as the engine will permit without knocking and permit it to remain at that position. . The actual regulation of the advance and retard is then cared for by the automatic device. When properly set with reference to the cam position the retarding of the spark lever permits the spark to occur eight degrees past top dead center. With the spark lever advanced the spaik will occur fifteen degrees before top dead center. Timing the Distributor.— First bring the piston in No. 1 cylinder to top dead center, and advance the hand crank caVefully until it is just starting down. Fig. 39S. Ignition Distributor with Test Lamp Attached — Ground Return System. Rotor in position for Spark to occur in No. 1 Cylinder. To be certain of this it is best to do the work with the cylinder head removed. The mechanic may use some method which does not require the removal of the head but should be certain that the position is correct. Next, remove the control from the breaker-box arm and retard it fully by moving it as far as it will go in the direction of rotation of the vertical shaft. With the ignition switch in off position, the distributor head and distributor rotor may be removed. The breaker-cam nut may be backed off by means of a screw driver with a blade wide enough to catch both sides of the nut at one time. This wHl leave the cam free to rotate on its shaft. Next replace rotor and turn the cSini slowly until the breaker points just begin to open when the rotor occupies the position where it normally makes contact with the No. 1 distributor terminal. Refer to Fig. 398 which Shows the distributor and rotor in this position. m Fig. 399. Automatic Advance Mechanism on Shaft. This adjustment can often be facilitated by turning the cam forward to separate the contacts, and then back agai.i slowly until the contacts just come together, at which point the cam should be allowed to remain. When the proper position for the cam is assured the rotor should be removed again and the cam locked in position by tightening the slotted nut which holds it. Replace the rotor and rock the vertical shaft back and forth as far as the slack in the gears will permit, noting carefully the action of the breaker contacts. The setting must be so accurate that as the gears are rocked forward to take up the slack the contacts will just separate, and yet when the gears are rocked backward the points will actually close. Using Lamp Bulb to Check Timing. — A convenient method of verifying the ignition timing is to use a twelve to sixteen volt bulb connected as shown in the illustration, Fig. 398. When the contacts separate, the bulb will light. When Battery Ignition 347 the contacts are closed the current all passes through the ignition unit and the lamp does not light. The instant of opening and closing of the points is very evident as indicated in the bulb. This test may be applied to any battery system if care is used in selecting the correct size of bulb and the points of connecting the wires to put it into circuit across the contact points. In general it might be said that when a grounded return is used one cable is grounded, while where a two-wire or insulated return is used the proper terminals must be located and used. JOB 119. HUDSON DELCO IGNITION. The ignition unit is located above the timing gears of the Super Six motor. It is driven by spiral gears from the pump shaft. The distributor head is of A3.i. t,T'NG NU LOCKING SCREW CONTACT POINT SCREW FOR CAM ADJUSTMENT BREAKER ARM CONDENSER RESISTANCE UNIT Fig. 400. Hudson Delco Distributor. the usual constant contact type. Beneath the distributor head and rotor is the timer. By loosening the screw in the center of the shaft it is possible to time the ignition. By moving the cam in a clockwise direction the timing is advanced, and by moving the cam in a counter-clockwise direction the spark is retarded. The proper gap for the contact points is .018". If it should be necessary to clean the contact points use a strip of fine sandpaper pinched between the points. A top view of the timer mechanism is shown in Fig. 400. In this figure the rotor and the distributor head are removed. A side view of the unit is shown in Fig. 401. Note the automatic spark advance. Timing and Ignition. — Set the spark lever on the steering wheel at the top, making certain that all parts are in proper working condition for full movement of the advance and retard mechanism as effected manually. 348 Automotive Trade Training Open the priming cocks and set piston No. 1 on top dead center of the compression stroke. No. 1 cylinder is due to fire in advance position when the mark A on the flywheel reaches the pointer attached to the crank case. This may be observed through the inspection hole on the flywheel housing, left side motor. Mark "A" is one-half inch before top dead center. Top dead center is marked D. C. 1 and 6. Loosen cam and set to break at this point. Make certain that the adjusting screw is set properly so as to prevent a change in timing. The spark occurs the instant the contact points open. In checking the timing hold the cam on tension in the opposite direction of rotation in order that all backlash be removed from the gears. CONTACT BUTTON Fig. 401. Hudson Delco Automatic Advance Mechanism. After retiming and rechecking the timing of the opening of the breaker points, the head may be replaced. Place a bit of vaseline on the rotor track so that no wear may occur. Coil. — The coil is of the usual non-vibrating high tension induction type. It is mounted on the dash. I JOB 120. BUICK DELCO IGNITION. The distributor timer is mounted on the front end of the motor generator. It is driven by a spiral gear which is cut in the outer face of the generator driving clutch. The driving gear is operated by the pump shaft at one and one-half times engine speed. This in turn drives the vertical shaft of the distributor at one-half engine speed. The vertical shaft carries the breaker cam, the rotor, and the automatic advance mechanism. Battery Ignition 349 ADVAf/CE^EVEH Z.EAOTO COIL B/TEMKEROin OILER. tONTRCT ftRn CENTER CONT/ICT. l^OTO/f. ROTOf? BOTTOM. BALL BERRINQ^ Fig. 402. Buick Delco Ignition Unit. 360 Automotive Trade Training Spark Control.— The distributor is equipped with both manual and auto- matic spark control. The manual control is used for retarding the spark in starting and very slow idling, as well as the necessary advance for low engine speeds when the automatic advance is not operative. Adjusting Timing Contacts. — The contact points when fully open should measure just .018". The adjustment is effected by loosening the adjustment nut and screw shown in the top of Fig. 402. Make certain the lock nut is properly tightened after adjustment is completed. Timing the Ignition. — First place, the spark lever on the steering wheel in the fully retarded position. Next turn the engine to the seven-degree mark which is practically one inch after top dead center with engine on compression stroke for cylinder No. 1. The timing adjustment screw in the center of the distributor shaft is loosened and the breaker cam is turned so that the rotor button will be in position under high tension terminal No.l when the distributor head is properly located. This determines the proper lobe of the cam to use for timing. In attempting to locate the point at which the cam must be set use the following plan. Set the cam so that when the slack in the distributor gears is rocked forward the contacts just open. When the slack in the gears is removed by rocking backward the contacts will just close. Tighten the adjustment screw with the parts in this position. Replace the rotor and the head. The firing order is 1-4-2-6-3-5. Test all high tension wires to see that the proper wire leads to each cylinder in turn. Resistance Unit.— The resistance unit is mounted on the forward end of the ignition coil. It consists of a special resistance wire wound on a porcelain spool and connected in series with the primary winding. This connection appears in the circuit diagram Fig. 395. It serves the purpose of preventing an excessive discharge from the storage battery when the engine is not running, and the ignition switch is on with the contact points closed. It also, through current regulation, insures a more even spark at the varying engine speeds. JOB 121. PIERCE ARROW DOUBLE DISTRIBUTOR. The Pierce Arrow car uses a T head motor and provides double ignition. The ignition switch is so arranged that either double or single ignition may be used at the option of the driver. Two sets of plugs, condensers, breaker points, transformer coils, etc., are used. The double system is used except when testing one system independent from the other or when the battery may be very low. The idea of the double ignition application to the Pierce engine is to have the charge within the cylinder fired at two points simultaneously thus insuring rapid and complete flame propagation. An automatic advance is provided, the action being similar to the auto- matic advance for the single distributor head. Care and Maintenance. — The battery breaker points KL and EP, Fig. 403, should be set to open .015". These points are of pure tungsten. They require little attention. If they do not give perfect contact after adjustment they may be put into service and in a little while will true themselves up as they wear. Before putting a new car in service, and occasionally thereafter, it is advis- able to place a bit of vaseline on the track of the contact buttons within the bakelite head. Remove any surplus with a dry cloth. The fiber cams F and J will wear a bit during the first 1000 miles and it may- be necesary to adjust the points to remedy this. Thereafter very little wear will occur at this point. Battery Ignition 351 C D E FG H I Fig. 403. Pierce Arrow Double Distributor (Delco). If it is desired to make the points open a bit nearer exact synchronism it can be accomplished by loosening the screws D, D, and D, Fig. 403, on the sub- base to which the breaker mechanism is attached. The equalization is then effected by moving the sub-base about until the desired result is obtained. It may be noted by examining the bakelite distributor tops or heads that the firing order is imprinted on them, with the proper cylinder number opposite each terminal. Timing the Spsirk. — For timing this double ignition unit to the engine, first place the flywheel so that the indicator is over the ignition mark on the 352 Automotive Trade Training flywheel as shown in Fig, 404, being careful to have the engine on the com- pression stroke for cylinder No. 1. The distributing arms in the Delco Unit, Fig. 403, should then be in position to fire cylinder No. 1, as marked on the head of the distributing units. With the spark fully retarded on the quad- rant, both sets of points should just be on the point of opening. In this posi- „. .^. „. . ^. . ., J- ^ -u ^- V 1 ij 1 ^^S- 404. Pierce Arrow Timing tion the distributing unit should be Diagram. connected to the driving flange on the pump shaft. To make a slight adjustment of the timing, to make the points open a bit earlier or a bit later, the instrument is not disconnected from the pump shaft coupling, adjustment being made by loosening the adjusting screw G instead. With this screw loosened the cam may be adjusted to make the points break at the proper time. Care should be used to see that the cam is not moved through more than a very slight angle. If it is moved any considerable amount, the spark timing will be out very much. It is quite possible to move the cam until the break occurs, when the distributing arm or rotor is under the high tension wire leading to some other than cylinder No. 1. JOB 122. REMY IGNITION. The Remy Battery Ignition Units are standard equipment for a large number of motor cars. The matter of care and adjustment is similar for all motors. Where possible, the instruction book for the particular model being worked on should be consulted. Contact Points. — The points should be inspected regularly each 1000 miles to see that they are main- tained in good condition. If they show signs of un- even wear fold a strip of OO sandpaper and place same between the points in such manner that the sanded surfaces are in contact with the points. By working this forth and back between the points they may be cleaned and any irregularities overcome. The points should be maintained with a break of .020" to .025". To adjust the gap loosen the lock nut next to the post and turn the contact screw until proper clearance or gap is obtained. Lock the nut on the screw to maintain the setting. Timing to the Engine. — Place the piston in cylinder No. 1 on top dead center. This may be accomplished through the aid of a gauge in the spark plug hole or by noting the fly wheel marking whgre such is given. Work with the piston on compression stroke. Place the distributor advance lever on full retard. Remove the distributor cap. Remove the rotor or distributing segment. This lifts up. Unscrew and remove the nut appearing. Next loosen the cam from the taper on which it is fitted. Use a screwdriver to pry up on it, rapping it lightly at the same time. Use care to prevent damage to any of the parts. The cam may now be reset by moving it in the direction in which it rotates until the points are just opening, the engine being maintained in the position noted above. Since the spark occurs just as the points separate, it will occur Pig. 405. Remy Ignition Distributor. Battery Ignition 353 with this setting at exact top dead center. It is safe to have the piston in cylinder No. 1 just a bit over top dead center on the power stroke since the spark control is fully retarded. Advancing the spark with this setting will give the required range for efficient engine operation. The distributor rotor may now be replaced and the distributor cap like- wise. The high tension cable leading to cylinder No. 1 must be that one which attaches to the distributor cap terminal immediately over the rotor within the head, since it is to that terminal high tension spark will be conducted when the points break. The other cables must be led from the distributor cap in order, but RESISTANCE^ UNIT HIGH TENSION TERMINAL, run to the cylinders in their proper firing order Fig. 40G. Kemy Coil Assembled. WIRES TO PRIMARY WINDING WIRE to CONDENSEI iron:core CONDENSER' COIL WINDINGS WIRE FROM SECONDARY WINDING Pig. 407. Details of Remy Coil Construction. 354 Automotive Trade Training ROTATING CONTACT TO ''-J^'~\\ TIMER COVER POINTS i i /\ ^H^^9^^^ ^-- ■■ L ^ l;/;^:- ^ ^^B ^^,^ SECMENT SPRING CONTACT / ^H^^ POINT TO TIMER COVER ^^Gi m^r ^f,' Fig. 408. Remy Chalmers Timer with Distributor Bloclc in Place. CONTACT POINT LEVfR m '^ te POINT OF CAM ^P ^ 1 CONTACT POINT GAP H 1 _ __^ -/ PL TIMER CAM CONTAC? POINT / ADJU:iT>NG 5CPEVV ^ •■ ^^5^ ^■1? Fig. 409. Remy Chalmers Timer. JOB 123. CONNECTICUT IGNITION SYSTEM. Connecticut ignition apparatus uses unrestricted current from the battery for ignition. This insures a good spark at all times for use at the plugs. The system is able to use this flow of current without danger of battery drainage or coil burning because of its automatic switch arrangement. A thermostatic device is arranged to break the circuit in the event that the motor is stopped or stalled with the ignition left on. Igniter. — These are provided for use on four, six, or eight-cylinder engines. The main constructional difference is the number of cams milled on the upper end of shaft A, Fig. 412, which shows the working parts of the igniter. Fig. Battery Ignition 355 No. 410. Connecticut Coil and Igniter. Fig. 411. Section Con- necticut Coil. 410 shows an external view of the Igniter and Coil. Fig. 411 shows a sectional view of the Connecticut coil. In Fig. 412 the shaft A extends through the instrument. The lower end is driven from the engine at the required speed. The cams B, milled on the upper end, operate the breaker arm C and point E which it carries. G is a roller on which the cams operate the arm. The point E operates in conjunction with point F. The spring H returns the point E and arm C to position after the cam passes the roller. Fig. 412. Connecticut Igniter with distributor cap removed. 356 Automotive Trade Training It is during the period of contact between the points E and F that the coil saturation takes place. The more complete the saturation, the better the spark. The system is designed to give all the time possible for this operation. Breaker Points. — The breaker mechanism of this igniter is very easily removed and replaced. It was so designed to enable the user to make a complete replacement should there be occasion to do so. It will be found Fig. 413. MOTOR RUNNING. CURRENT FLOWING. THERMO- STATIC ARM IN POSITION MOTOR STOPPED, EXPANSION OCCURRING IN THERMO- STATIC ARM.WHICH IS JUST ABOUT TO RELEASE PLUNGER. Fig. 414. Connecticut Automatic Kick-off unit as used witli Connecticut switclies. advisable to replace the complete breaker plate rather than individual points. The successful operation of the coil will be hindered by any ir- regularities of the point adjustment and in time this may do serious in- injury. Unless the points ir^ prop- erly adjusted, arcing and burning is bound to occur. Automatic Switch Feature. — Connecticut switches incorporate an automatic cut-out feature in the various designs. The principle of operation is the same for the several styles of switches. In fact, the part known as the K unit is designed into switches of several dififerent types. The latest Connecticut switch is operated on the toggle principle. In this switch, too, the automatic device is differently designed, but j the principle is the same. ■ To secure the automatic kick- off of the current in case the engine is left idle with the ignition switch ■ on, a thermostatic principle is taken | PLUNGER OFF. CURRENT STOPPED-PUSH IT BACK WHEN YOU WANT TO START AGAIN Fig. 415. Connecticut Automatic liick-off device. advantage of. One form of the device is shown in Fig. 414, Another form is shown in Fig. 415. The action is as follows: r Battery Ignition 35? As soon as the motor stops running and the interruptions of the ignition circuit cease, the flow of current increases and heats up the wire ribbon about the arm A, Fig. 414. This arm is so constructed that when heated it bends down until it makes contact with post B. The current then flows down post B through the wire which connects B and C, up C into the ribbon around D. Arm D is constructed similarly to A, but is arranged to bend upward when e^ e^ I BATTETSY 10 TQ CQIU. CONOENSER REASE CUP Fig. 416. Connecticut Switch and Igniter Wiring Diagram. heated. This upward bend or movement releases the latch which holds the plunger E in the "On" position, causing it to kick out and break the ignition circuit. It requires a short interval of time for this action to take place so that it does not interfere with the normal duties of the system, but does protect the battery and coil when the ignition is on and the engine idle. JOB 124. WAGNER IGNI- TION. The Wagner ignition is de- signed to give a hot spark for low speeds and at the same time to efficiently take care of the maximum speed of which the engine is capable. The timer distributor and coil are both dust and waterproof. Coil. — The coil is of the non-vibrating type. It is en- closed in a hermetically sealed case, thus protecting it from moisture or mechanical injury. The coil illustrated in Fig. 420 has a safety spark gap incorpor- ated in it. This gap serves to protect the coil from excessive electrical strains in event of failure of some other part of the high tension circuit. The action of the spark gap as the current crosses it in such a case will be noticeable through the mica window. Fig Complete Wagner Timer Distributor. 358 Automotive Trade Training The internal arrangement of the Wagner coil is different from other coils. The high tension current is brought out in the center at the top, through a bakelite insulator which is molded into the steel case. This construction makes the case very sturdy. The construction of the coil case helps to prevent injury to the windings and misfiring during wet weather. Distributor Head. — The Wagner timer distributor is shown in Fig. 417 completely assembled. The system will operate over a wide range of battery voltage. A satisfactory spark for ignition can be obtained even when the battery is too low to crank the engine. Starting in this case is effected by hand cranking. The cover for the distributor is molded from bakelite. When the high tension wires are properly assembled the head is water-proof. Revolving Distributor. — The revolving distributor carries the high tension current from the center of the cover to the terminal connected with the cylinder to be fired. The metal plate carrying the current does not make actual contact with the distributing pins, but passes within ten-thousandths of Fig. 418. Setting cam on Wagner Head. an inch of them, thus permitting the spark to jump to the pins in the same manner as the spark jumps the plug gap. A special grade of tungsten is used for the contact points. It requires no cleaning or filing, and will operate best if left entirely alone until the tungsten is nearly worn away. Fitting New Contacts. — If new contacts are necessary, first replace timer lever KC-335 and contact screw KC-313 with new^ parts.* Adjust the contact screw until the points separate .020" to .025", after which the screw is secured by tightening the lock-nut. Next note if the points are square with each other and touching over their entire surface. If not, loosen the nuts holding the contact support. This can then be moved sufficiently to line up the contacts properly. Tighten and lock all nuts. The timing lever is lubricated by a small wick contained in the hollow spindle underneath the spring clip. Three drops of oil in this wick once a season is sufficient. The grease cup on the distributor shaft should have one- half turn each 500 miles of service. *The marks KC-335 and KC-312 appear stamped on new parts. Battery Ignition 359 Setting the Ignition. — If the timing of the ignition has been disturbed and it is necessary to reset it, this can be accomplished by loosening the cam screw, the cam lightly on its seat, and turn it in the direction in which it rotates, until then raising the cam off its taper on the shaft by prying it up with a screwdriver. (See Fig. 418.) To reset the cam: First set engine with cylinder No. 1 on T. D. C. compression stroke. Retard the spark fully. Rest the slot B is opposite the timing lever C, and the point of the cam in line with the slot is just starting to open the contacts. Tap the top of the cam lightly with the butt of the screwdriver. This wili hold it until the adjusting or clamping 360 Automotive Trade Training might en si 01^ mStSTANCE LOW TENSION TEHMINAL — i(TO Oe CONNCCTEO TO S WITCH) SAFETX 6A/> WITH MICA WINDOW LOWTENSIONI ERMINAL BE CON- NECTED TO TIM en lead) Fig. 420. Wagner Spark Coil, screw can be replaced. Test after tightening the cam screw to see that the setting has not been changed. Wiring Diagram. — The wiring diagram shown is for the Elgin 6. but may be considered as typical of the Wagner system. The student will be interested in tracing out the high and low tension circuits. JOB 125. Open Circuit in the Primary of the Ignition Coil. — To test for an open circuited primary, a 6-volt battery is connected to the terminals of the primary Fig. 421. Battery Ignition 361 winding of the coil with the ammeter in series as shown in Fig, 421. In most coils the current flow will be about ten amperes if the winding is in good condition. (Consult the coil manufacturer to find out the actual value or try- out several coils known to be good.) Refer to Chapter 14, Job 160, for instruction on the use of the Fault Finder Test Set. Fig. 422. JOB 126. Open Circuit in the Secondary of the Ignition Coil. — To test for an open circuited secondary, connect the thirty-volt range of the instrument in series with the battery and the secondary winding of the coil as shown in Fig. 422. An open circuit will be indicated when the reading is zero. For a good winding the reading will be about three volts. FR/MA/ey mi^ Fig. 423. JOB 127. Open Circuit in Ignition Coils vdth Connected Windings. — In some coils the primary and secondary windings are connected together with the coil as 362 Automotive Trade Training shown in Fig. 423. When this is the case the test can be made on the secondary, as shown by the full line connection, and on the primary by chang- ing the connection as indicated by the dotted line. The thirty-volt range is used. Zero reading in either case indicates an open circuit. JOB 128. Short Circuit in the Primary of the Ignition Coil. — To determme if the primary winding is short circuited, connect the ammeter in series with the windinsf and the battery as shown in Fig. 421, Job 125. A short circuited winding will be indicated by a reading on the ammeter in excess of the normal current for a good coil. (Consult a coil manufacturer for the normal value of a current.) Fig. 424. JOB 129. Short Circuit in the Secondary Winding of the Ignition Coil. — Connect the thirty-volt range as in Job 126, Fig. 422. A completely short circuited coil is denoted by the voltmeter indicating C0N0£A/5£e ^ ^>'^^ Fig. 425. Battery Ignition 363 the battery voltage. Partial short circuit will result in a value less than the battery voltage but somewhat higher than three volts. JOB 130. Ground Between Primary and Secondary Windings. — Connect the battery and the thirty-volt range of the instrument, as shown in Fig. 424, to one end of the primary and one end of the secondary windings. If the coils are grounded on one another an indication will be obtained. Note: — This test cannot be performed on coils having internally connected windings. JOB 131. Grounded Condenser. — Connect a six-volt battery and the thirty-voIt range of the instrument in series as shown in Fig. 425. Connection is made to only one terminal of the condenser, the circuit being completed through the metal case of the condenser. If the condenser plates under test are grounded to the case, an indication will be obtained. No indication denotes absence of a ground. Change the connection from terminal No. 1 to terminal No. 2 and repeat the test on the other set of plates. JOB 132. Short Circuited Condenser. — Connect a six-volt battery and the thirty-volt range of the instrument in series to the terminals of the condenser. Fig. 426. No indication will be obtained if the condenser is good. If short circuited, an indication will be obtained. C0ND€/^5Eie Fig. 426. CHAPTER 13 MAGNETO IGNITION This type of automotive ignition is divided into tv^o general classes. These are low tension magneto and high tension magneto. Low tension, being the most closely connected to battery ignition, will be described first. Much of the matter given with relation to the low tension is applicable to the high tension magneto. Low ten- sion magnetos, excepting the type used on the Ford car, are con- sidered obsolete for automobile use. FiJ,^ 427. Electrical system on I'ackard truck. Low Tension Magneto. — By a low tension magneto is meant a machine generating current in a mechanical manner, but of insuffi- cient pressure, or voltage, to cause it to jump air gaps on spark plugs. The machine is used to produce the current, while coils are used to step it up to a high tension point where it will jump the plug points. The voltage of the low tension magneto is about six volts in most cases. The Ford magneto generates about eighteen volts. Magnetos generate A. C. current only. The action of coils is not materially influenced by this fact since the magneto is usually timed so that the one-current impulse as generated in one-half revolution is used to produce the spark in each cylinder. While the current does reverse in the armature and consequently within the coil, it does not alternate in producing any one spark. It is rather only in the direction in which the separate or successive sparks flow that there is reversal 364 Magneto Ignition 365 of direction. In other words one spark will follow the high tension wire to the plug and return to the coil through the engine frame, the next due to the reversal of direction within the magneto will go through the ground to its plug and return to the coil through the wire. To illustrate more fully. When A. C. current is used to light the bulbs in house lighting, the direction of flow of the current through the filament reverses a number of times per second. Although an A. C. machine is used to generate the current which is stepped up and used to ignite the fuel charge within the cylinder, it flows in only une way since only one wave is used to produce any one spark. Each succeeding wave, although in different or alternate directions, is used to produce one spark and ignite one and a separate charge. The current waves do not alternate back and forth in producing the spark in any one cylinder where the shuttle or H type armature is used. H or Shuttle Type Low Tension Magneto. — Where this type of armature is used for low tension magneto work there is but one winding on the armature. In constructing the magneto the usual design is to mount the armature between two pole shoes on the out- side of which are bolted or screwed the permanent magnets. The permanent magnets are used to produce the magnetic flux or field. Brass or bronze bearing supports are mounted across the ends of the pole shoes to carry the armature. Thus the armature is rotated on its bearings within the magnetic field, cutting the lines of force or magnetic flux, and taking off through its windings the primary cur- rent thereby induced. Inductor or Stationary Coil Type. — In this type of magneto the coil or winding is made to remain stationary, while the magnetic flux IS made to cut the winding either through a rotating inductor or a rotating field. These points are brought out more fully when the various types are considered. Magnets. — The nature of magnets as well as the methods of con- structing, charging, and caring for them was described in Chapter 10. In the practical application of magnets to the magneto certain forms are standard. In lighter magnetos either a wide single magnet is used, or two lighter ones side by side. In heavier machines where more is demanded of them the magnets may be made to fit one over the other, and as many as four, six, or nine are used in a group. Whatever the number used, the purpose served being the same in all cases, they maintain a permanent magnetic field from which may be induced a primary circuit to feed the coil and produce a jump spark. Pole Shoes. — In the nature of the magnets the lines of force are stronger at or near the ends than elsewhere. To facilitate this flow of the lines of force and to insure a proper field of magnetic flux for the armature to turn in, much attention is given the design of the 366 Automotive Trade Training pole shoes. Each manufacturer gives special attention to this and the slight differences will be evident in the illustrations and in the models the student comes into contact with. Aside from the special magnetic duty which they perform, the pole shoes are used very often to build up the other units of the machine. To them are fastened the magnets, the bearing supports, dust covers, and base. Non-Magnetic Metals. — Owing to the fact that the magneto must be very compact and carefully enclosed to exclude all dust, dirt, grease, etc., as well as the fact that it is usually mounted directly on the engine, care must be used in its mounting and construction to Fig, 428. Eisemann High Tension Magneto. prevent any disturbance of the magnetic field. By this is meant that nothing must be allowed to come in contact with the magneto which will divert the flow of the flux from the north pole to the south pole of the field. For this reason the base, bearing supports, armature ends, and certain other parts are made from non-magnetic metals such as bronze, brass or aluminum. In some cases screws of brass are used, and where this is the case iron should never be substituted. By non-magnetic metals are meant those not attracted by the mag- netic lines of force as are iron or steel. To avoid troubles hard to locate, use extreme care in rebuilding a magneto. Armature. — The armature of the H or shuttle type shown in Fig. 484 and elsewhere is commonly used in both low and high ten- sion magnetos. No shaft runs through it. As mentioned before, non-magnetic metals are used to hold the ends of the armature together and to support the stub shafts on which the armature turns. Magneto Ignition 367 Bearings are usually ball bearings. The magneto must be very care- fully assembled since very slight clearance is allowed between the armature and the pole shoes. Sometimes the apprentice will allow the screws used for holding the parts together to become mixed, with the result that the ones which are a bit too long may project through the pole shoes and damage the armature. Slip Rings. — The nature and purpose of the slip ring was pre- viously explained. One or two may be used on the magneto. If only one is used the one end of the primary winding is led to it and fastened in direct contact. On this slip ring a carbon brush rides and carries the current to the external circuit. The other end of the primary winding is grounded through the shaft and bearings, or some special form of ground connection may be used. This furnishes the Fig. 429. Magneto Firing Order- 1-2-4-3. Other connection to the external circuit. Where two slip rings are used one is provided at each end of the armature. The current may be taken ofif direct, but the one on the rear of the armature is fre- quently grounded through a small carbon brush in the dust cover, or within the base. Sometimes the end within the magneto is grounded through a brush onto the bearing support. This takes the place of a slip ring. In the case of the low tension magneto the slip rings conduct only low tension current as there is no high tension current within the armature winding. Breaker Points. — In magnetos of the shuttle armature type the machine must be driven in fixed relation to the engine speed. In a magneto for a four-cylinder engine the armature turns at crank shaft speed that is one to one. If the engine is a six-cylinder one, then the armature turns at one and one-half crank shaft speed or one and one-half to one. This the student will note provides for one-half of one revolution for each cylinder fired. This is absolutely essential as two sparks are available for each revolution of the armature. In 368 Automotive Trade Training other words, the machine is so designed that at two points in each revolution of the armature the maximum number of Hues of force is being cut by the armature windings. When this condition is present the current wave is said to be at its peak, and this is the time to open the contact points. When the current wave is at its peak the mag- netism of the coil will be at its maximum, and as the points open there is the maximum break of magnetic lines of force, and conse- quently the maximum intensity of high tension spark at the plug points. This means that as the points open the armature would be close to the position shown in Fig. 449. A retard and advance range of about 35 degrees is available with this type armature. That is, the peak of the current wave is great enough or long enough to permit of advancing or retarding the opening of the points within the range mentioned, and still have sufficient voltage to produce a spark at the plug by aid of the step-up or transformer coil. Periods of no, cr zero, current are reached twice during each revolution. At this point the direction of current is reversed. Transformer or Step-Up Coils. — Several distinct methods of step- ping up the current in the external circuit are in use. Each requires the use of an ignition coil, or in other words, a transformer coil to transform the current from low to high tension. The difference in the two systems is the position occupied by the contact point. Contact Points in Series. — By this is meant that the breaker or contact points are connected in series with the armature winding and the primary winding of the step-up coil. In other words, the arma- ture takes the place of the battery as the source of current, and, the action is exactly similar to the standard battery system. The current generated by the magneto flows into the primary coil of the trans- former, thence back again to the armature. The contact points, being- closed, permit this flow. When opened they check or stop this flow. This causes the lines of force about the coil to drop back to the core. The collapse and quick return of these lines of force is insured by the condenser action. The induced current within the secondary coil, due to the rapidly falling lines of force, is high and is used to jump the plug points. It will be seen that the induction is dependent on the rapidly collapsing lines of force. The second method is exactly the reverse in action. Rapidly built up or out-going lines of force are depended on in this case for high tension induction. Shunt Current Interruption Induction. — The same coil and low tension magneto with condenser and interrupter is used. However, instead of taking the current from the magneto armature where it is generated through the primary winding of the coil and then back to the magneto, it is led through a shunt and directly back to the arma- ture through the magneto points which are closed at this time. This insures a high pressure being built up within the magneto armature. Magneto Ignition 369 When the armature is in a vertical position, or position of greatest voltage, the interrupter points are opened. The condenser is across the points so that it is charged instantly, but the primary circuit of the coil is also across the points so that it affords a second path of travel for the current being generated. Since, however, the shunt affords an easier path, little will flow to the coil until the points separate. When the points separate, the condenser is charged at the same time that current from the armature surges through the primary wind- ing of the coil. The discharge of the condenser aids the current surg- ing through the coil from the armature, and both together produce Fig. 430. Method of Wiring in a Switch. such a rapid or instantaneous building up of magnetism that the rising or outgoing lines of force cut the secondary coil with such rapidity and in such numbers that a spark is available from the in- duced current, to ignite the charge within the cylinder. The student has seen that this is the exact reverse from the method used in the battery and in the other method of utilizing the low tension magneto, in that the induction of secondary current takes place on magnetizing the coil rather than on demagnetizing it. After the first spark is delivered and the points have closed again, the armature will start building up for the next spark which will occur as the points are opened after one-half revolution from the point of first break and spark. Each half revolution a spark is delivered to the engine. Two of these sparks are from the action of one of the breaker lobes, the other two from the other lobe. Sometimes a car having magneto 370 AuTOMOTufi Trade Training ignition seems to "hit" better on two cylinders than on the other two. This can often be traced to imperfect breaker lobes or cams. Distributing High Tension Current from a Low Tension Mag- neto.— The current is generated within the magneto, is taken out of it to the transformer coil where it is stepped up through the induc- tion method from about six volts to fifteen or twenty thousand, when it is returned to the magneto to be distributed to the proper cylinder on the engine. It enters the center of the magneto distributor on a high tension wire, and then is carried to the proper contact within the distributor cover by the distributor brush. The distributor on the CoJitroi Bus' nk IMug d Wife Magnf-to Fig. iol. Magneto Installation. magneto is similar in action to the distributor head for battery igni- tion. Sparks are distributed to each segment in turn, but the wires running from the segments must be carried to the proper cylinders to give correct firing order. Timing Spark on Low Tension Magnetos. — It has been shown that the magneto armature of the H type runs at a fixed speed rela- tion with reference to the engine crank shaft. The one to one rela- tion for the four-cylinder engine is used here for an illustration. Two sparks are generated each revolution, four sparks are produced in two revolutions. Four sparks are needed to fire the four cylinders of the engine in two revolutions. Driving the armature of the magneto at crank shaft speed cares for the proper number of sparks but pro- vides no speed fitted to distribute them to the cylinders at correct time. Accordingly a gear is fitted onto the armature or armature Magneto Ignition 371 shaft which drives another gear carrying or turning the distributor brush. The gear ratio is two to one. The armature gear is smaller and turns twice while the distributor gear turns once. The desired result of distributing the four sparks to the four cylinders is thus secured. For a six cylinder the distributor brush is slowed down to turn once to three turns of the armature, but the armature is driven at one and one-half crank shaft speed so that the distributor gear and brush still travel one turn to two of the crank shaft. However, six sparks are produced and delivered in two turns of the crank shaft, thus firing all cylinders. This is the working out of the ignition for the four-cycle engine no matter how many cylinders. This was ex- plained in Chapter 7. If a magneto is removed from the engine it may be replaced on the engine out of time. Care should be used to observe proper markings and timing of valves with reference to com- pression strokes. Magnetos dismantled may have their internal tim- ing disturbed unless due care is used. These matters are treated in detail elsewhere. Dual Ignition. — By dual ignition is meant not double, but rather two kinds of ignition using the same set of plugs, spark plug wires, and distributor units. In connection with the low tension magneto, dry cells are used as the source of current supply for starting, after which the switch is thrown in such position as to permit of operating the engine on the current generated by the magneto. A storage battery may be used in lieu of dry cells. Dual Ignition Switch. — The switch for the dual system is arranged to substitute the battery as the source of current supply for the magneto, and vice versa. One throw of the switch performs the operation of cutting out one source of supply and cutting in the other, thus making the operation of starting on battery current and running on the magneto practicable. If the change is not quickly made the engine will stop. Push Button Starting. — Where dual ignition is used it is general practice to place a push button in the switch. This push button may be made to take the place of the interrupter or contact points. Vibrat- ing the push button with the fingers causes a spark to be produced within the cylinder on compression. If a fuel charge properly com- pressed is present the engine will start when this spark occurs. The uncertainty of the engine stopping with a cylinder ready to be fired makes the system an uncertain proposition. Along with the other parts of the low tension magneto this, while still found, is considered obsolete. Low Frequency Inductor Type Magnetos. — In the low frequency inductor type the magnets and pole shoes constituting the field are very similar to the armature type. However, instead of the armature 372 Automotive Trade Training with its slip rings and revolving winding, an inductor of the nature of that shown in Fig. 441 is used to carry the flux through a stationary coil. The -inductors are so designed that in certain positions they act as a bridge' to carry or conduct the magnetic flux from the north pole to the south pole. However, the inductors are so made and mounted that a coil rests between them over the shaft. When the magnetic flux flows through the inductors, it is made to cut the wind- ings of this coil. The more flux flowing through the inductors and coil the more current induced. As in the other type, there are zero points to the current. The current is alternating. The current waves reach a peak and it is at this peak or as near the peak as practicable that the points must be set to break. The current is a pulsating A. C. current for the following reason. On one position the flux flows from the north pole through the one inductor, through the coil, through the other inductor, and then into the south pole. With the next half revolution of the inductor the other inductor arm is at the north pole. Consequently in this case the flux flows into this one through the coil and out of the other one. The flux has cut the coil windings first in one direction then in the reverse direction. The current induced, as previously explained in Chapter 10, bears a definite relation to the direction in which the flux cuts the coil or the coil cuts the flux. No Brushes. — Since the winding is stationary, there is no need . cf making any provision for slip rings or brushes in this type of magneto. The ends are either both led to terminals, or one grounded and the other provided with a suitable terminal. As the current is taken off it is A. C. current, but here again the machine is run in fixed relation to the engine. Only one current wave or pulsation and only the peak of that is used to produce a spark. As previously explained, each of these waves in turn is carried to the step-up transformer and used to induce the high tension jump spark current which is led along one wire to the plug for a certain cylinder. While the output of the machine is A. C. current, the single wave used for any one spark as well as the induced current is D. C. current. There IS in reality no difference in the action of this type of magneto and that of the shuttle or H armature type, excepting only in the manner in which the flux cuts the coil windings to produce the low tension current. Each is provided with breaker points or interrupter for breaking the low tension current, and a distributor for distributing the high tension current to the plugs as it is brought from the trans- former coil where it has been stepped up. One advantage of the inductor type is that the current will raise to a peak and hold that value for some little time before it drops back toward zero value. The armature type, having reached maximum potential or value, starts dropping down immediately. The result is that the armature Magneto Ignition 373 type will not give quite as hot a spark on retard as it will on ad- vance, while the inductor type will, approximately the same value of current being available for the entire range. Being a low frequency machine the inductor type must be driven as is the armature type at a fixed speed relation with the crank shaft. That is a one to one ratio for a four-cylinder engine. High Frequency Inductor Type Magnetos. — These may be on the general principle of the above if more inductors are added. The Ford magneto is of the high frequency inductor type. With the armature type or low frequency type the current waves must be timed with the engine speed. This is necessary to insure the peak of a current wave available at the proper time. This does not apply Fig-. 432. Typical Magneto Wiring- Diagram. (Wired without reference to firing order.) to the Ford Magneto since there are sixteen pulsations or waves of current for each revolution of the magneto, which is built into the flywheel and necessarily rotates at engine speed. Taking this into consideration, the frequency of the waves is so high that current may be said to flow at all times. Accordingly, in timing the engine it is not necessary to make allowance to have the spark occur at the peak of the current wave, as this point is arrived at so frequently that it would be difficult to find a point on the timer contact when the spark would be delayed more than a few degrees due to the lack of a high enough pressure or current. It is a matter of fact, however, that there may be a little variation of the timing of the spark due to the lack of a sufficiently high voltage from the generator or magneto. The spark may occur a few degrees early or a few degrees late. Method of Generating. — Current is generated or induced to flow in the armature, or the inductor of the machine, by the field of perma- 374 Automotive Trade Training SEARCHLIGHT DASHtt-OeTTEO LINE INDICATES LIGHTING CmCUITA DOTTED LINES INDICATE BATTERIES WHICH ARE NOT fJECESSA/fr. CONNECT AS SHOWH IF USED. GROUND TO ENGINE FRAME. Fig. 433. K W Inductor Type Low Tension Magneto witli Ignition and Liglit in Circuit. Battery Current for Starting. nent magnets rotating in front of it and in close proximity to it. One thirty-second of an inch is allowed as clearance between the two. With sixteen magnets mounted with their like poles together, cut- ting past the sixteen inductor coils, it is seen that when the two north poles of a group are over the core of an inductor the flux will enter it and flow to the core of an adjacent inductor coil, from which it will Magneto Coil Spool Copper Wire End of Ribbon 1 Grounded Here J To Coil Magneto Coil Support Magnet Flywheel Magnet Clamp Ford Magneto. emerge to enter the south poles over it. This flow of the magnetic lines of force or flux induces a wave of current within the coils of the i Magneto Ignition 375 inductors. Simultaneously with this action the same process is going on in seven other sets or groups of magnets and inductors. However, when the two north poles have advanced to the inductor over which the south pole stood, the magnetic flux flows into its core where it previously came out. This results, of course, in an alteration of the direction of flow and the second pulse of current is in the reverse direction through the inductor coils. When the next inductor is reached the direction of flow is again changed, and so on all the way around the inductors of which there are sixteen mounted on the one magneto coil assembly frame. Sixteen times in one revolution the Fig. 435. Section High Tension Magneto. direction of current is changed, because of a reversal of polarity in the inductors. Eight waves flow from the magneto into the external circuit in one direction, and eight others in the reverse direction. These waves follow each other so closely that there is a current flow even enough to be used for lighting as well as for the vibrating coils. External Circuit on Ford Ignition. — One terminal of the low ten- sion armature is grounded. The other is connected with the terminal mounted on the center of the top of the transmission cover case. Between this terminal and the ground or metallic parts of the car, all electrical units using the low tension current must be arranged. As described under battery ignition, the Ford ignition system brings the low tension current to the timer roller and from there to the timer segments as it rolls over them, then to the separate vibrating coils connected to the timer segments or contacts. The contacts within 376 Automotive Trade Training the coil box are connected to the magneto terminal which completes the external circuit with reference to ignition. The coil box switch naturally must be considered as being placed in the circuit to open and close it, otherwise the engine might be cranked at any time with reference to the spark and would have to be choked to stop it. The distribution of the high tension current was explained under the battery ignition. It is well to have in mind the fact that instead of one coil four are used, doing away with the necessity of distributing the high tension current through a special distributor. Any plug will receive a spark only when its respective coil is vibrating and the coil vibrates only when its respective segment in the timer is in contact with the rollers, and this roller can only be in contact with that segment when the cylinder to receive the spark is on the finish of the compression stroke. The only other type of high frequency magneto is the one having the drum armature wound with a number of coils. This type may be used for lighting lamps, but not for charging a storage battery since only D. C. current may be used for this. HIGH TENSION MAGNETOS High tension magnetos are so called because the machine is com- plete within itself, and is able to deliver a high tension jump spark to the plugs without the aid of any outside help. No transformer coil of any nature, and no external units whatever are required. Fig. 436. Typical Magneto Construction. All units for ignition either low tension or battery are still required, but all are built into the magneto itself. The manner of building in the high tension coil condenser distributor, etc., is of interest to the student. High Tension Armature Type. — In this machine the arrange- ment of magnets, pole pieces, frame and general design are very Magneto Ignition 377 similar to the low tension of the same type. The main difference in principle of operation is the addition of the secondary or high tension coil over the primary or low tension coil on the armature. Other necessary units are also built in so as to make it self-contained. Low Tension Circuit in Armature type. — In the high tension magneto the low tension or primary current is generated just as in the armature type low tension magneto. Not as many turns of wire are used due to lack of space on the armature. Two waves of cur- rent are generated again, one for each half revolution. These again are alternating. Just as the peak of the current wave is reached, Fig. -±37, Engine Timing Gears and Magneto Drive. which is just as the armature shoe edge leaves the pole piece, the breaker points are opened. The action is the same as for the low tension or battery system. When the points open the lines of force collapse or fall back, cutting the primary winding which induces a higher voltage therein, which rushes into and charges the condenser. The condenser is mounted in the end of the armature. This con- denser charge is immediately kicked back through the low tension circuit, thus assisting in completely demagnetizing the coil core and assisting in breaking down the lines of force. The final collapse is very rapid. This rapid collapse of the numerous lines of force causes 378 Automotive Trade Training the induction of a very high tension current within the secondary v^inding. This is used to ignite the charge vi^ithin the cyUnder. It is taken off of the collector or slip ring, and is carried to the center of the distributor head by means of the pencil brush or distributing bar. The student v^ill note, however, that there is another feature which makes the high tension magneto superior to the low tension. While a current wave is being induced in the primary winding, one is being induced in the secondary winding even stronger than the first mentioned. This is induced by the secondary coil cutting the lines of force, just as the primary current is induced. The voltage or pressure generated by this method is not sufficient to jump the spark plug points, but it is there within the secondary winding attempting to flow along the wire to the collector ring brush and pencil, and by way of the distributor to the spark plugs. The pres- sure within the secondary coil is thus fairly high when the contact points on the primary circuit open. The opening of the points in- duces additional current and this is high enough to cause the current to break down the air gap momentarily. Once the gap is broken down and the current flowing, the voltage, which is generated within the secondary coil by the magnetic lines of force passing through the field from the north pole to the south pole, is sufficient to keep the current flowing in the form of a heavy burning spark. It is readily seen how this current flowing for a longer length of time (about 30 to 40 degrees of armature travel) will produce better ignition of the fuel charge within the cylinder. High Tension Inductor Type. — In this type the general con- struction follows the low tension machine , of the same type. An additional coil of fine wire is placed on the coil over the coarser primary winding. In this finer winding the high tension current is induced. The coils are again stationary over the inductor shaft and mounted between the inductor arms. These inductors or arms form the path for the magnetic flux to follow as it flows from the north pole to the south pole through the coil. Except for the fact that the coils are stationary, and the absence of brushes and slip rings, the action is the same as for the armature type. When the breaker points open, a cur- rent is induced within the coarse or primary winding. This charges the condenser. The condenser discharges back through the Fig. 43,s. High Tension primary coil. The rapidly collapsing lines of Magneto (Dixie Aero). f^j.^^^ jnduce a high tension current within Magneto Ignition 379 the coil of fine wire which is sufficient to jump the spark plug gap. Following on this comes the current induced by the flux, flowing through the high tension winding from the one inductor to the other. Just as in the armature type this current, while not sufficient to jump the spark plug gap of its own force, will continue to flow across the points once the gap has been jumped and the resistance overcome. The condenser is mounted within the base or at some other point convenient to the general type of construction. JOB 133. K-W LOW TENSION MAGNETO GENERATOR All K-W magnetos are of the inductor type. The winding is stationary, the magnetic flux being conducted through the winding as it passes from north Fig. 439. K-W Low Tension, Model DL pole to south pole. The rotor carrying the inductors is the only moving part. The full action of the inductors is explained in Job 134 on the high tension type. The low tension magneto is of the high frequency A. C. type. This instrument is used to provide current for vibrating coils or for the lighting system. Friction or belt drive is used. It is not necessary to have the Fig". 440. K-W Low Tension Magneto. Note Inductors. 380 Automotive Trade Training magneto timed to the engine. The speed of the low tension machine is from 2000 to 3000 R. P. M. Since the direction of flow of the magnetic flux changes four times per revolution instead of twice as in the H or armature type, the current pulsations per revolution are twice as many or four instead of two. This will give four times the rotor speed, changes, alternations or pulsations of current per minute, in actual figures from 8,000 to 12,000 pulses per minute. Since one-half of these are in one direction and the other in the other direction the current is not satisfactory for charging storage batteries. Fig. 441. Inductors and Stationary Coil Winding. The rotor which is illustrated revolves in two sets of the latest improved ball bearings. It does not rub against or touch any other parts of the generator as all other parts stand still. No brushes or slip rings are needed. Winding. — The winding shown in position on the rotor consists of a strip of copper wound spirally around the core of the revolving rotor. Terminals K-W MAGNETO CROUNO TO CNCINC FBAMC Fig. 442. Low Tension Magneto with vibrating coil. of the winding extend through the top of the pole pieces in which the rotor revolves. They are securely attached to the binding posts found at the 'end of the generator. The wiring diagram shows how the magneto is wired in connection with a quad dash coil for ignition on a four-cylinder engine. JOB 134.— K-W HIGH TENSION MAGNETO. Principle of Operation. — The K-W high tension magneto is used very largely on heavy duty motors, as trucks and tractors. The same principle is Magneto Ignition 381 Fig. 443. K-W High Tension Magneto. used as in the high frequency low tension machine. The rotor is the same general style. However, the high tension machine is fitted with the usual circuit breaker and distributing mechanism. It must be driven as are all high tension machines in fixed relation with the engine. Flexible drives such as friction or belts cannot be used. Winding. — The primary winding is on a soft iron core. Refer to Fig. 444. ^ I > -^ — ^ CWCUIT . IRUKM Fig. 444. K-W Magneto. Arrows indicate path of Flux. 382 Automotive Trade Training The primary winding forms the core for the secondary winding, which is much shorter than in the armature type. The core of the winding is located in the direct path of the greatest number of lines of force flowing from the north pole to the south pole. These lines of force are indicated by the arrows in Figs. 444 and 445. The winding is stationary. Inductors, Rotors and Pole Shoes. — The inductors are part of the rotor. They are made from soft iron machined to a close fit and placed on the rotor shaft at right angles or ninety degrees apart. The pole pieces or shoes differ from the usual armature type and are mounted on the ma- chine at a ninety degree angle with respect to each other. This harmonizes with the rotor construction and accounts for the four current waves per revolution of the rotor. Fig. 445 shows the pole shoes in section. The path offering least resistance to the magnetic flux is in- dicated in the same figure. It enters one extension of the rotor and from it passes into and through the core and coil windings, after which it fol- lows along another arm or extension of the rotor to the south pole. The next extension of the rotor to come into close range of the north pole is one on the opposite side of the coil or winding. Consequently the next wave of current will be in the opposite direction. The change of direction producing A. C. current is desirable, as before a current wave can be built up in a reverse direction the core and winding must have reached a 2ero point. In other words, the reversal hastens the collapse of the lines of force about the winding which is very much desired in producing a hot intense spark. Fig. 445. K-W Magneto. Arrows indicate path of Magnetic Flux. Fig. 446. Simms "C4" 4-Cylinder Magneto. Magneto Ignition 383 Fig. 445 shows three vital positions of the rotor. At A, the first position, the lines of force come down through the wing of the rotor, pass through the core, and then up through the opposite wing or extension. In B the rotor has been rotated to the next position, while in C the position indicated is the one occupied as the spark is produced at the plug. The high tension spark is delivered the instant the contact points open so that the position C indicates the point at which the maximum current would be generated in the primary. JOB 135. SIMMS HIGH TENSION MAGNETOS. Fig. 447. Simms "C4" Magneto, with Impulse Starter. Simms magnetos are of the true high tension type. High tension current is developed directly within the armature without the introduction of any exterior devices. This in itself is a considerable advantage over the low tension magneto, where a transformer coil is used to step up the low tension current, as there is a certain amount of current and time lost in this operation. The result is a weaker spark in the case of the low tension. A great deal of rather complicated wiring is re- quired for the low tension magneto while the high tension requires only one cable to each plug and one ground wire con- nected through a switch. Pole Shoes. — A distinct fea- ,gg ture of the Simms magnetos is their slow speed characteristic. They will give a heavy spark even when rotated at speeds of less than 40 R. P. M. This fea- ture allows starting the engine on the magneto even where the cranking speed is necessarily Pig. 448. Full back view showing driving end. ^low. An inspection of the cross Arrow indicates direction of rotation. section of the pole shoes and 384 Automotive Trade Training armature will show the student why the construction used will make for easy starting even on a retarded spark. Since the amount of current produced is dependent on the number of lines of force cut, this pole shoe is so designed as to cause a large number of lines to flow just as the armature breaks from the retarded position. Contact Breaker. — The contact breaker is so designed that at high speeds the action is assisted, and not retarded by the centrifugal forces developed. Thus, there is never any danger of the ignition cutting out at high speeds. Armature. — The high tension armature consists of a few turns of heavy primary wire over which are wound many turns of fine secondary wire. Enamel insulated wire is used and each layer is further insulated from others with sheets of oiled silk. After being completely wound, the armature is first placed in a tank under pressure. The tank is filled with insulating liquid. Next the armature goes into a tank under vacuum. As this operation is continued, first compression, then va- cuum, all air is worked from the arma- ture and all pores or small openings are filled with the insulating liquid, or dielectric. The armature is next baked in ovens to drive off all traces of mois- ture. Winding. — One end of the primary wire is grounded on the armature core, and the other end is brought out to the breaker points. The condenser is con- nected in parallel to prevent the points burning. The grounded end of the secondary is connected to the primary, forming a continuation of the same. The other end of the secondary is kd to the slip ring, then through the conducting bar to the distributor, spark plugs, and ground on the engine, to the magneto base and back into the grounded end of the secondary. Fig. 449. Showing relative position of armature at both full retard and full advance with American Simms Patented Extended Pole Shoe. As breaker points open at the fully retarded position the air space is but 1 m/m. At this point the maximum current is produced in the primary, thus explaining the American Simms easy starting feature. Fig. 450. Wiring Diagram for Simms High Tension Magneto. Four-Cylinder. Magneto Ignition 385 When the contact points are closed the primary circuit is also closed. Rotating this coil through the magnetic flux induces a low tension circuit in the primary coil. The primary circuit is then broken, inducing a high tension current of extreme intensity in the secondary winding, which is distributed to the spark plugs as rnentioned above. Driving. — The magneto must be positively driven by gears or chain. If the latter method is used provision must be made to take up the slack due to wear. For a four-cylinder four-cycle motor the magneto is driven at engine Fig. 451. Wiring diagram for Sims Six-Cylinder Magneto. Speed. For a six-cylinder motor the magneto is driven at one and one-half times engine speed. The magneto will operate only in the direction shown by arrows on the driving end plate. Timing. — To time the magneto to the engine turn or crank over until cylinder No. 1 is on the compression stroke. This is the top dead center with valves closed. It is the beginning of the working stroke, and the connecting rod should be swung on the downward stroke side. Remove the contact breaker cover with the distributor cover or board. Turn the magneto armature in the direction which it must run until the contact points are just opening. The timing lever must be in full retard position. To secure retard, the lever must be pushed down with the direction of turn of the armature. The distributor brush must at the same time be in a position to touch the distributor segment serving cylinder No. 1. The driving gear or coupling should then be securely tightened onto the magneto armature driving shaft using the key in the key-way provided for same. If it is a case of retiming the magneto this work is likely already done. With the engine in the position given and the magneto set as stated, the two are in proper position to be connected. Care must be exercised to see that they remain in their relative positions until finally secured together in this proper relation. It must always be remerabered that the distributor brush rotates in the opposite direction to the armature. Terminal No. 2 on the distributor does not necessarily lead to cylinder No. 2, but must lead to that cylinder firing second. The same applies to cylinders and termnials 3 and 4 as well. The magneto has a timing range of 30 degrees, crank shaft travel. Any advance or retard desired more than that available from the action of the 386 Automotive Trade Training Fig. 452. Simms Type K4 Magneto. timing lever must be secured on the engine alone by advancing or retarding the engine timing gears, but in no case must the setting of the magneto distributor or internal armature gears be disturbed, as these have a certain fixed relation to each other. Any different setting of these two gears will seri- ously impair the efficiency of the magneto. If neces- sary to disassemble these gears, make certain the proper marks are on them to insure proper reassem- bly. Oiling Magneto. — The magneto should be oiled every two weeks or 1000 miles run, with four or five drops of light machine, not cylinder, oil in each of the oil holes, which are located _ ,^.. _ „ over the armature driving Fig. 453. Simms Magneto, Type "CK6", Two Spark. , r^ ^u ^ r ^u shaft near the top of the distributor board. The contact points should never be oiled as it may cause serious trouble and undue wear of them. Care of Contact Breaker. — The platinum points should be set to open on each cam about 1/64". They should be kept free of oil and clean. They should make even contact over their entire surface. The contact breaker lever should pivot freely in the bushing, and should be inspected occasionally and freed of any oil or dirt accumulations. The points should be filed only if absolutely necessary and then with a fine flat file. Distributor Board. — Cable connections should be kept tight and the inside of the board wiped occasionally with a dry cloth to remove any oil or dirt. I Magneto Ignition 387 The distributor carbon brush should at all times press firmly against the distributor board. Safety Spark Gap. — The safety spark gap is to protect the insulation of the armature from injury such as might be the case if excessive voltage were built up. This condition would be present should a high tension wire become loose or broken. The high tension spark will then jump the gap. If sparking should be detected in the safety gap which is located just over the driving spindle, the high tension wiring should be gone over thoroughly at both the magneto and spark plug ends. The distributor carbon brushes should be examined to see if they are in condition and making contact with the brass segment on the distributor rotor. If sparks can be obtained at the safety gap, it is an indica- tion that the magneto is generating and that the trouble is likely in the wiring or spark plugs. Removing Coupling. — If it is necessary to remove the coupling, great care should be taken that not too much force is used in the operation. The hard rubber slip ring just inside the housing is easily broken. On no account should any violent blows be struck on the end of the armature shaft. The garage press, or better still, the properly adjusted gear puller should be used if there is a tendency for the coupling to stick. Spark Plugs. — The plug points should be set from 1/64'' to -h." apart. The first mentioned, or just a bit over, is recommended. If the distance is too great, it is possible that the motor will be hard to start. It must be borne in mind that while a spark will jump the points when the plug is lying on the cylinder, it does not follow that a spark will occur when the plug is in the cylinder. The reason for this is that the resistance of the gases under compression is greater than that offered by the atmosphere. If the insulation of the plug is cracked or broken, if the plug points are oily, or if the insulation is covered with carbon, the desired results will not be obtained. A cracked porcelain is often hard to detect. The easiest way is to insert a new spark plug or one known to be right. If this overcomes the trouble, it is then known to be with the plug. Refusal to Start. — Should difficulty be experienced in starting after tests have proven the plugs are in proper condition, the wire connected to the contact breaker box should be removed. If this seems to correct the trouble the switch should be examined and any corrections necessary should be made. The wire removed is for the purpose of short circuiting the primary current when desiring to cut out the ignition and stop the motor. JOB 136. BOSCH MAGNETOS, DU TYPES. The types DUl, DU2, DU3, DU4, and DU6 magnetos are of the high tension series and are used respectively on one, two, three, four, and six- cylinder engines of the automobile type in motor car, marine, tractor, and stationary service. The type DU magnetos are usually used as sole ignition on an engine, or in some cases in connection with a battery system operating on a separate set of spark plugs. The DU magnetos are also used to provide battery and magneto ignition with one set of plugs. This is without alteration and is accomplished as indicated in Job 142 describing the Bosch Vibrating Duplex Ignition System. Generation of Current. — The high tension current is generated within the armature, without the aid of any step-up coil. The timer and distributor are integral. The armature winding is composed of two sizes, one heavy and the other comparatively fine. The heavy wire is used as the primary or low tension circuit, while the very fine wire is the secondary circuit. The rotation of the armature between the poles of strong permanent magnets sets up or 388 Automotive Trade Training induces a current within the armature primary circuit. This is further augmented at regular intervals in the rotation of the armature shaft by the abrupt interruption of the primary circuit by means of breaking the magneto interrupter points. At the opening of the primary circuit the resultant dis- charge of current from that circuit induces a current of high voltage within the secondary winding of the armature. The high tension current thus induced is collected by the collector ring on the armature and passed through the collector brush, then to the various magneto distributor terminals, each of which is connected by cable to the spark plug of its respective cylinder. The operation will be more completely understood by referring to Fig. 454 which shows the complete primary and secondary circuits. I^^•ERRUPT£R Fig. 454. Circuiit Diagram Type DU4 Bosch Magneto. Primary or Low Tension Circuit. — The beginning of the armature primary winding is in metallic contact with the armature core. The other end of. the primary winding is connected, by means of the interrupter fastener screw, to the insulated contact block supporting the long platinum contact on the magneto interrupter. The interrupter lever, carrying a short platinum contact, is mounted on the interrupter disk which, in turn, is electrically connected to the armature core. The primary circuit is completed or made whenever the two contacts are brought together, and interrupted when the cams on the breaker mechanism cause these points to separate. The separation of the points is controlled by the action of the interrupter lever as it bears against the steel cams secured to the inner surface of the interrupter housing. The high tension current is generated in the secondary winding only when there is an interrup- tion of the primary circuit. The spark occurs the instant the platinum points are opened. Secondary or High Tension Circuit. — The armature secondary circuit is a continuation of the armature primary circuit, the beginning of the secondary being connected to the primary, while the end of the secondary is connected to the insulated collector ring. This is mounted on the armature shaft just inside the driving shaft end plate of the magneto. The collector brush, which is held in contact with the collector ring by the brush holder at the shaft end of the magneto, receives the high tension current collected by the collector ring, and by means of the conducting bar under the arch of the magneto, passes the current to the metal contact in the center of the distributor plate. From the latter point the high tension current passes to the distributor brush which is held in a brush holder mounted on the distributor gear, and consequently rotates with the gear. Magneto Ignition 389 Distributor. — Metal segments are molded into the distributor plate, and as the distributor brush rotates it makes contact successively with these segments. The segments in turn are connected with the terminal studs on the face of the distributor plate. The latter are connected by cable to the spark plugs in the various cylinders. In the cylinder the current, in the form of a jump spark, ignites the fuel charge and then returns to the magneto armature through the engine castings. This completes the circuit. Safety Spark Gap. — In order to provide protection for the armature and other current-carrying parts the magneto is equipped with a spark gap called the safety gap. Under ordinary circumstances the current will follow its normal path to the spark plugs, but if for any reason the electrical resistance in the secondary circuit is increased to a. high point as when a cable becomes disconnected, or a spark plug gap too wide, the high tension circuit will discharge across the safety gap. Otherwise it is inoperative. The current should never be allowed to pass across the safety spark gap for any length of time. If the engine is to be operated on an auxiliary ignition system, the magneto must be grounded in order to prevent the production of high tension current. The switching off of the magneto switch will accomplish this by grounding the primary' circuit. The snapping sound by which the passage of current across the safety gap may be noticed should always lead to an immediate search for the difficulty. The safety spark gap is arranged on the dust cover over the armature, and consists of two short pointed electrodes supported a short distance from each other. One electrode is set on the dust cover itself and enclosed by a metal and wire gauze housing. The other electrode which is the insulated one is set in a steatite cover of the safety spark gap housing and is connected in the secondary circuit of the magneto. Timing Range. — The magneto interrupter housing is arranged so that it may be rotated through an angle of 35 degrees with respect to the armature shaft. The movement of this housing in one direction or the other causes the interrupter lever to strike the steel cams earlier or later in the revolution of the armature. This causes the spark to occur earlier or later with relation to the stroke of the piston. The spark can be advanced by moving the interrupter housing by means of the timing control arm in the direction opposite the rotation of the armature. To retard it, move in the direction of rotation of the magneto armature. The armature rotation is indicated by the arrow on the oil well cover at the driving shaft end of the magneto. Cutting out the Ignition. — Since high tension current is generated only on the interruption of the primary circuit, it is evident that to cut out the ignition it is necessary merely to divert the primary current to a path which is not affected by the action of the magneto interrupter. This is accomplished as follows: An insulated grounding terminal is provided on the magneto interrupter housing, with its inner end, consisting of a spring with carbon contact, pressing against the head of the interrupter fastening screw. The outer end of the grounding terminal is connected to a switch. Low tension cable is used for this. The other side of the switch is grounded by connecting it to the engine or other metallic part of the chassis. When the switch is open the primary current follows its normal path across the platinum interrupter contacts, being interrupted at each break of these points. However, when the switch is closed the current passes from the head of the interrupter fastening screw through the grounding terminal cable and switch to the engine and thus back to the armature. Since the primary current 390 Automotive Trade Training Fig. 455. Bosch Magneto. is not Interrupted in this flow no high tension current is generated or induced within the secondary winding. Oiling. — Aside from keeping the magneto clean externally about the only care needed is oiling of the bearings. There are two ball bearings supporting the armature and a plain bearing supporting the shaft of the distribu- tor gear. Any good light machine oil may be used for this, but cylinder oil should not be used. Each of the bearings should receive two or three drops each 500 miles run. This should be applied through the oil ducts under the covers marked "oil" located at each end of the magneto. The interrupter is intended to operate without lubrication. Oil on the platinum breaker points will pre- vent good contact causing sparking and burning as well as misfiring. Care should be exercised to prevent oil entering to these parts. Starting the Engine. — When cranking a motor equipped with the D.' U. magneto as sole ignition, the spark lever should be advanced a slight distance. In some cases of properly timed magnetos the advance may be one-third the full advance for hand cranking, and as much as one-half for starting motor work. This will permit easier starting. The most effective point for starting is quickly learned from actual experience. In hand cranking full advance is very likely to result in injury to the operator, and in starting motor work may result in injury to the apparatus. Ignition Troubles. — Ignition troubles with the Bosch magneto may be divided into two classes. The first of these is spark plug trouble, the second, comparatively infrequent, magneto trouble. In the case of defective ignition the first pomt to determine is whether the trouble is with the plugs and external circuits, or within the magneto itself. In general, when only one cylinder misfires, the trouble is with the plug. Plug Gap too Wide. — The distance between the electrodes of the spark plugs varies according to the individuality of the engines, but normally this distance should not be less than one-fiftieth inch. On the other hand, however, too wide a gap increases the resistance and interferes with the proper genera- tion of current at low speeds. Difficulty in starting an engine and missing at low speeds are very often due to the spark plug gaps being too wide. As the actual use qf the plugs shows a tendency for the spark to burn the plug gap wider, it is well to inspect the plugs from time to time to make sure that the gap is not too great. Readjusting the electrodes will remove any gap troubles. Unless quite experienced, the mechanic should test his work to see that all plugs are adjusted equally. If not, the motor will operate unevenly. Plug Short-circuited. — This is usually caused by a cracked or porous insulator. Any of these conditions will cause misfiring by permitting the current to stray from its intended path. Cables. — Misfiring of one cylinder, either continuous or intermittent, may be due also to a chafed or broken cable, or loose cable connection. The cables should receive careful examination, special attention being paid to the insula- tion. The metal parts of the cables must not come in contact with any metal Magneto Ignition 3"9l parts of the engine or magneto, except those designated as being correct in the instructions preceding this. Ignition Fails Suddenly. — A sudden failure of the ignition may indicate a short in the low tension cable. This condition may be caused by the presence of moisture or dirt, defects in the cable or cable insulation, or to faulty connections at the switch or even a short-circuited switch due to the failure of the switch mechanism. A test for trouble in the switch and low tension cable is quickly made by removing the cable from the grounding terminal on the cover of the magneto interrupter housing, and then attempting to start the motor on the magneto. If the engine runs with this wire disconnected, but stops when the wire is replaced, it is evident that the magneto is in good order and that the trouble is due to some fault in the switch or grounding wire, permitting the same condition to exist as is designed and used to stop the engine by cutting out the low tension current from the breaker points. Irregular Firing. — If the cables and plugs are in good condition and the ignition is irregular the trouble probably is with the magneto. First carefully examine the interrupter. It should be seen that the interrupter moves freely on its pivot, that the hexagonal headed fastening screw in the center of the interrupter is properly tightened, and that the two platinum interrupter contacts are properly fastened in position. If the interrupter lever does not move freely on its pivot, which is some- times possible, particuarly with new magnetos, the hole in the fiber bushing, in which the lever pivots, may be slightly enlarged. Either a reamer or small round file may be used to remedy the trouble. The reamer is to be preferred to the file, but no matter which method is used the work must be very carefully done or the hole will be made too large. A very little reaming accomplishes the desired result. Platinum Interrupter Contacts. — The platinum interrupter contacts should be examined for the correctness of their adjustment, and they should be so set that they separate 0.4 of a millimeter, or about one-sixty-fourth of an inch., when the interrupter lever is resting on either of the segments in the interrupter housing. The strip of steel attached to each magneto wrench is to be used for this test. A wrench is furnished with each new machine or may be purchased from the dealer. The adjustment of the platinum points may be made by loosening the lock nut of the long contact screws, which passes through the interrupter contact block, and turning the head of the screw with the magneto adjusting wrench. When the proper adjustment is made care should be used to tighten the lock nut firmly. The platinum contacts of the interrupter should be clean and in proper alignment with each other. Any oil or grease accumulating on them should be removed as should any form of dirt. If contacts are in bad condition, or uneven, they may be smoothed by means of a fine flat jeweler's file. The platinum contacts should be kept clean. When in that condition and given proper attention, a maximum amount of service may be expected from them. They should not be filed unless this is found to be absolutely necessary. Removing Interrupter. — The interrupter may be taken out as a unit by removing the interrupter housing and then the interrupter fastening screw in the center of the interrupter. The magneto wrench fits this screw head. Should the interrupter stick on its seat, it may be pried loose by means of two small screw drivers inserted back of the interrupter disk, one on each side. When replacing the interrupter care must be used to have the key on the interrupter disk fit into the keyway in the armature shaft. Damaged Insulating Parts. — As it sometimes happens that brush holders and other insulating parts are damaged through accident or carelessness, these 392 Automotive Trade Training parts should also be carefully examined, for possible disarrangement or damage of the insulation which might permit leakage of current. Summary of Ignition Troubles.— In brief, granting that the magneto is properly timed to the engine, trouble due to ignition may be as follows: Engine will not start. Switch is closed, switch or switch wire short-cir- cuited, interrupter lever sticks, defective plugs or disconnected cables. M V N L Fig. 456. Vertical Section of B4 Magneto. D^ Q M T S R W Fig 457. Horizontal Section B4 Magneto Type. A. Armature. B. Condenser. C. Distributor rotor. I>. Collector ring. E. Collector brush. F. Collector brush-holder. G. Armature gear. H. Distributor gear. I. Distributor rotor shaft J. Shaft adapter head. K. Distributor block. L,. Terminal nut. M. Interrupter disc. N. Contact block. O. Interrupter fastening screw. P. Contact screw — long. Q. Rear end-plate. R. Interrupter lever. S. Interrupter operating spring. T. Interrupter housing. U. Interrupter housing control arm. V. Interrupter cam. W. End cap. X. End cap contact spring with brush. Y. Holding post spring. Z. Distributor brush. Engine stops abruptly. Switch is closed, switch or switch wire short- circuited. Misfiring at slow speeds is usually due to a too wide spark gap. Misfiring at all speeds. Spark plug may be dirty or defective, improper Magneto Ignition 393 spark plug gap, cable insulation chafed, cable connections loose, brush holder defective, platinum interrupter contacts dirty or oily, interrupter lever sticks. Timing the DU Magneto to the Engine. — The crank shaft must be rotated to bring" the piston in cylinder No. 1 to top dead center on the compression stroke. The piston must be maintained in that position. The magneto is then to be secured in position on its bracket on the engine. The timing control lever must be placed in retarded position. Next remove the distributor plate by withdrawing the two holding screws, or depressing the two catch springs as the case may be, thus exposing the distributor gear and brush.' The cover of the magneto interrupter housing should next be removed to permit obser- vation of the interrupter. Next rotate the armature in the direction the engine will turn it, which must in all cases correspond to the direction indicated by the arrow on the oil cup cover. To rotate this, the distributor gear may be used. Continue to rotate the armature until the contact points are just about to separate, which occurs when the interrupter lever begins to bear against one of the cams, or steel segments of the interrupter housing. The armature should be held in that position until the magneto drive is connected to the engine, due care being taken that the piston of No. 1 cylinder is as previously placed, exactly on top dead center of the compression stroke. The installation is completed by replacing the breaker box cover and the distributor plate. To wire the plugs proceed as follows: Wiring Spark Plugs. — With the engine and magneto set up and connected as just suggested, the next step is to observe which brass segment in the distributor plate will be in contact with the carbon distributor brush as the points break. A high tension cable or spark plug wire is to be run from that segment, or rather from the terminal stud representing that segment to the plug in cylinder No. 1. The terminal stud next to receive a high tension current will be determined by the direction of rotation of the magneto. In all cases of gear-driven distributors this direction is just the reverse of that of the travel of the armature. Having determined which one of the terminal studs receives the second spark, the cable must be led from it to the next cylinder to be fired. The third segment in order of rotation must be connected to the third cylinder to be fired and the fourth segment to the fourth cylinder, and so on if more than four cylinders are used. Wires should be put on in workman- like manner and carried through some form of support which will protect them from heat, oil, dirt, and accident. JOB 137. BOSCH HIGH TENSION MAGNETO B4 AND B6 TYPES. These magnetos with the exception of the distributor are the counterpart of the DU types previously described, and are illustrated in Fig. 459. The cable showing on the side carries the high tension current from the collector ring to the center of the distributor from which point it is distributed to the separate cables leading to the plugs. Fig. 458 shows the wiring diagram for the B4 type. The winding as described for the other Bosch types applies equally here. The safety gap is a threaded electrode projecting through the top of the magneto frame into the magneto just over the collector ring. Figs. 456 and 457 are in section. The names of the parts as shown here are applicable to the other Bosch high tension types. The placing of the distributor in the upright position is a distinct advantage 394 Automotive Trade Training 0ISTRIBUT09 Fig. 458. Circuit Diagram Type B4 Bosch Magneto. Fig. 459. . Bosch Type B4 and B6 Magnetos. and makes for cleanliness and ease of inspection. Wiring is also simpler, since there are fewer angles to carry the wires through. Another distinct advantage of this type over the earlier types is the unit frame construction which renders the parts fully dust and water-proof. Fig. 460. Bosch BT4 Magneto With Impulse Starter. Battery Ignition 395 JOB 138. BOSCH HIGH TENSION MAGNETOS, TYPES ZR4 AND ZR6. These magnetos are for use on the four and six-cylinder engines. They are used as independent ignition. They are also used in connection with the separate battery system. The battery and magneto systems have nothing in common, each being provided with its own set of plugs, etc. The action of the magneto is closely related to the DU4 and DU6 described in Job. 136. Primary on Low Tension Circuit. — The end of the armature primary circuit winding is in contact with the armature core. This provides a ground connection. The other end of the primary winding is connected by means of the interrupter fastening screw to the insulated contact block supporting the long platinum contact on the magneto interrupter. The interrupter lever carrying the short contact is mounted on the interrupter disk, thereby grounding it. The primary circuit is completed whenever the two platinum contacts are brought together, the magneto armature being in motion. Likewise it is broken or interrupted when the points separate. The separation of the platinum contacts is controlled by the action of the inter- rupter lever as it bears against the two steel segments mounted within the interrupter housing. At the instant the interrupter points break, the collapse of the lines of force about the secondary winding is sufficiently fast to induce the required high tension current to jump the spark plug gap. Secondary Winding. — The secondary winding is a continuation of the armature primary winding. The beginning of the secondary is connected to the primary, while the other end of the secondary is connected to the insulated collector ring, or slipring. The high tension current is taken ofif the slipring by the slipring or collector ring brush. The conductor bar under the arch of the magnets carries the current from the brush to the center of the distributor Fie:. 461. Bosch ZR6 MaernetC- INTERRUPTER Pig. 462. Circuit Diagram Type ZR4 Bosch Magneto. Note — Spark plugs must be connected in accordance with firing order of engine. 396 Automotive Trade Training plate. The metal brush carried by the distributor gear has one end in contact with this solid metal center. As the gear revolves, the other end is brought into contact with the first one and then another of the metal segments embedded in the distributor plate. There are either four or six of these seg- ments depending on whether the magneto is a ZR4 or a ZR6. The segments in turn are connected with the terminals on the outside of the plate. High tension cables connect these terminals with the proper plugs. Safety Spark Gap. — The usual safety spark gap is provided. Under normal conditions the current will follow the spark plug cable to the plug, but if for Fig. 463. Shaft end view with hood ix-moved. showing slipring brush holder and safety spark gap. any reason the electrical resistance in the secondary circuit becomes too great, as when a cable becomes broken, or disconnected, or the plug gap too wide, the high tension current will discharge across the safety gap. The current should never be allowed to pass across the safety gap for any length of time. To permit this is likely to result in serious damage to the winding. The fact that it is jumping the gap is detected by the snapping sound. The gap consists of a pointed metal electrode projecting from the mounting flange of the slipring brush holder, inside the shaft end plate hood. The tip of the electrode is extended to within a short distance of the metal part of the connecting bar running between the collector ring brush and distributor plate. Timing Range. — The magneto interrupter housing is so designed and constructed that it may be rotated from 34 to 37 degrees with respect to the Fig. 464. View with distributor plate and interrupter housing removed showing distributor segments, distributor brush, interrupter, etc. Magneto Ignition 397 rotation of the armature shaft. The rotation of this housing with the direction the armature turns causes the spark to occur later or to be retarded with relation to the point the piston is in, and to the top of the cylinder at the time the spark occurs. Rotating the housing toward the turning armature, or in the direction opposite to which it is turning, will advance the spark. By this is meant that the spark will occur earlier with reference to the travel of the piston within the cylinder. A fully retarded spark occurs after the piston has passed top dead center. A fully advanced spark occurs before the piston has reached top dead center. The arrangement for advancing or retarding the spark is in two sections. The interrupter housing and segments constitute one segment, while the timing control arm is the second part. The construction is such as to permit the timing control arm to be set in any desired position on the interrupter housing. This facilitates the adjustment for advancing and retarding the spark. Further Instructions. — Cutting out the ignition, care and maintenance, magneto troubles, adjusting platinum points, and the installation and timing of the ZR magnetos is very similar to that of the DU types. The student should refer to Job 136 for instruction covering these and other points of desired information. JOB 139. BOSCH NU4 HIGH TENSION MAGNETO. This magneto is suitable only for engines of the four-cylinder automobile type, rated at or under about 30 H. P. This magneto may be used as the sole ignition or in cojunction with the Bosch Vibrating Duplex Coil, thus giving battery ignition for starting. The magneto is of the Shuttle or H armature type, the entire current generated within the armature being delivered to the spark plugs without loss or lag. The sparks so delivered are of sufficient intensity to insure the combustion of relatively poor mixtures. The distinct gear driven distributor common to other high tension types is omitted in the NU4 magneto and in its stead is a double slipring combining the functions of current collector and distributor. The result is a considerable reduction in the number of moving parts, with a corresponding lessening of the possibilities of wear and noise. It is also of less weight. As in other types, the current is in- exhaustible and is available at low speeds. The wiring is the simplest possible. Aside from the switch wire the only cables used are those running to the plugs. , Secondary or High Tension Circuit. — The primary circuit is very similar to that of the DU magnetos described elsewhere. The secondary winding is in- sulated from the primary. The two ends of the secondary wind- ing are connected to the two metal segments in the slipring mounted just inside the driving shaft end plate of the machine. ^^_ Fig. 465. View of Double Brush Holder. NU4 Magneto. 398 Automotive Trade Training The slipring has two grooves each containing one of the two metal segments. These segments are set diametrically opposite each other, i.e., 180 degrees apart. The segments are insulated from each other as well as from the armature and magneto frame. Four Slipring Brushes. — These brushes are part of the secondary circuit and are supported by two brush holders, one on each side of the driving shaft end plate. Each holder carries two brushes so arranged that each brush bears against the slipring in separate grooves. On rotating the armature one brush Pig. 466. Showing tlie Interrupter of the "NU4" Magneto. makes contact with the metal segment in one groove, while a brush in the holder on the opposite side of the magneto makes contact with the segment in the other groove. The marks 1 and 2 appearing on the brush holders mean pairs of brushes receiving simultaneous contact. Those marked 1 constitute one pair, and those marked 2 the other pair. A Spark Caused at Two plugs Simultaneously. — It is important to note that as two of the four slipring brushes receive contact at the same time, and as each is connected by cable to a spark plug in one of the cylinders, the Fig. 407. Wiring diagram of "NU4". Magneto Ignition 399 secondary circuit always includes two plugs. The spark occurs in two cylinders simultaneously. Timing Magneto to Engine. — It should be taken into consideration that, since at each interruption of the primary circuit a spark occurs at two plugs, the four effective sparks required for the four cylinders each two revolutions of the crank shaft are accompanied by four surplus sparks. Each cylinder Fig. 468. Showing Position of the Slipring Brushes With Relation to the Slipring. receives alternately one effective spark and one surplus spark, the latter occurring exactly 360 degrees behind the former. In coupling the magneto to the engine care should be taken that the platinum points do not separate too late in their relation to the stroke of the piston. Should this happen, the surplus spark will occur after the inlet valve has opened. With the magneto correctly timed, the spark al- ways occurs during the exhaust stroke. With the average four- cycle engine, the inlet valves of which open when the piston is at top dead center, or slightly past that position, the proper results are obtained by timing the magneto as follows: Piston No. 1 is brought to exact top dead center of the compression stroke. While maintained in this position, the interrupter housing is placed in retarded position. The magneto may be bolted to its seat on the bracket. Next remove one of Fig. 4r>9. Method of Removing Brush holders. With the Spring Pushed Down, the Holder Slips Out. 400 Automotive Trade Training the brush holders, Fig. 469, to permit observation of the slipring. The arma- ture shaft is now rotated in the direction in which it will drive until the begin- ning of the metal slipring segment is visible in the slipring groove corresponding to Fig. "1" of the brush holder which has been removed. Next remove the cover of the interrupter housing. Further rotate the armature until the plati- num points are on the point of breaking. This point is reached when the interrupter lever bears on the steel cam or segment of the interrupter hous- ing. The armature is held in that position while the magneto drive is con- nected to the engine piston No. 1, being as formerly placed. Next carefully replace the brushes and brush holder. Replace the breaker box cover. Next connect the cable from one of the No. 1 brushes to cylinder No. 1, and the other No. 1 brush to cylinder 4. The other two cables go to the other two cylinders, that is cylinders 2 and 3. It should be noted that while these direc- tions will care for the average four-cylinder engine, experiments will show the best timing. Frequently, instructions for timing the magneto to a particular engine are available. In this case they should be followed as closely as pos- sible. Attaching Cables to Brush Holders. — The brush holders fit into plates in each side of the driving shaft end plate, being held in place by the L plate catch springs. These springs are pivoted at one end, and at the other, or rounded end, carry a small boss which, when in position, rests in a notch in the brush holder and secures the holder in place. A slight downward pressure and outward pull of the rounded end of the spring disengages the spring and permits the removal of the brush holder. To connect the spark plug cables to the magneto the brush holder^ are removed and the brushes withdrawn. At the base of each of the brush recep- tacles is a pointed cable fastening screw. Remove this with a narrow bladed screw driver. Do not force a large blade into the insulator or it will be cracked or broken. Next in- sert the cable end. This is cut off square and the end has no insulation removed. Replace the screws. As they are turned in they pierce the cable and make perfect electrical contact while securing it. Troubles and Remedies. — The instruction given with reference to the DU types applies equally as well to the NU type. Fig. 470. Bosch High Tension Magneto Type "NU4". JOB 140. BOSCH DUAL IGNITION SYSTEMS. Dual ignition means not two independent sets of ignition equipment, but rather two independent sources of current. The one set of plugs, and certain other parts as the distributor and cables, are used for the application of the current from either source to work or duty of igniting the charge of fuel within the cylinder. The Bosch Dual Magneto is of the armature type common to all Bosch instruments. It produces its own current and times it through the interrupter points and breaker mechanism. As in the independent types, the breaker Magneto Ignition 401 points are carried on a disk which is attached to the armature shaft. The segments which serve as cams to break the points are attached to the housing in the usual Bosch design. In addition the dual magneto is provided with a steel cam having two projections which is built into the interrupter disk. This cam acts on a lever that is supported on the interrupter housing, the lever being so connected in the battery circuit that it serves as a timer to control the flow of the battery current through the coil. These parts are illustrated in Fig. 473. Battery Current Units. — The student is familiar with the fact that when battery current is used in conjunction with the high tension magneto, the purpose is always to give easy starting. All induced current in any ignition system being dependent upon the rapidity with which the lines of force are cut by the winding or vice versa, it has been found impractical under certain conditions to secure a fast or high enough cranking speed to enable the operator to start the engine on magneto, Since the battery current is avail- Fig. 471. able at a uniform voltage it is used to give the initial current for starting. All units needed for battery ignition are required. All units required for the independent magneto operation are needed for running. The distributor cables and spark plugs are made use of for both systems. It is obvious that the sparking current from the battery and from the magneto cannot be led to the spark plugs at the same time. A further change from the magneto of the independent form is found in the removal of the conducting bar between the collecting ring brush and the distributor center. Instead, the high tension current is led to the switch, and a second cable conducts the current from the switch to a terminal connecting with the distributor center. When operating on the magneto, the sparking or high tension current flows through the switch to the distributor. When running on battery the primary circuit of the magneto is grounded, consequently no high tension current is generated. It is then that the high tension current from the coil is led to the spark plugs. This current is led from the coil to the center of the distributor on the magneto. Bosch Synchronous Coil. — This is illustrated in detail in Fig. 474. The coil consists of a cylindrical housing bearing a brass casting which serves as a mounting flange. When the engine is running on battery ignition, a single 402 Automotive Trade Training high tension spark occurs at the moment the contacts separate. The intensity of this spark, as well as its accurate timing, permits of operating the engine on battery current. Switch. — The end plate of the housing carries the switch handle. The switch mechanism is built integral with the coil. By means of the switch either the magneto or the battery may be employed as the source of ignition current. In operating the switch the entire coil is rotated within the coil housing. The inner side of the stationary switch plate is provided with spring contacts that register with the contact plates attached to the base of the coil. Independence of the Systems. — While the prime feature of the dual system is the ability to start the engine at slow cranking speeds, it is a reliable system for running in case of failure of some part of the magneto. Each system utilizes the distributor in common. This is a part seldom causing trouble or failing for any reason. Push Button Starting Feature. — For the purpose of starting on the spark, a vibrator may be cut into the coil circuit by pressing the button which may be seen in the center of the end plate of Fig. 474. Normally this vibrator is out of circuit, but the pressing of the button brings together its platinum points and a vibrator spark of high frequency is produced. If a cylinder on the power stroke is provided with an unexploded charge of fuel, pressing of the button will give the needed spark to ignite it and thus start the engine. Wiring the Dual System. — Refer to Fig. 472. It will be noted that while the independent magneto requires but one switch wire in addition to the spark plug cables, the dual system requires four connections between the magneto and the switch. Two of these are high tension and consist of wire No. 3 by which the high tension current from the magneto is led to the switch contact, and wire No. 4 by which the high tension current from either the magneto or coil is conducted to the terminal in the center of the distributor. Wire No. 1 16 ■Ground Outton. Batfary Secondary to Oist Mag See. to Snitch. Mag Grounding tVira Battery Circuit Bncktr ^ Fig. 472. Wiring Diagram of the "DU4" Dual System. (On Magnetos of the Model 4 class, the grounding terminal is located on the side of the circuit breaker housing. Magneto Ignition 403 is low tension being used to carry the battery current from the primary winding of the coil to the battery, interrupter. Low tension wire No. 3 is the grounding wire by which the primary circuit of the magneto is grounded. This occurs when the switch is thrown to the off or the battery position. Wire No. 5 leads from the negative terminal of the battery to the coil. Wire No. 7 is used to ground the positive terminal of the battery. A second ground wire No. 6 is used to ground the coil terminal. Setting the DU Dual Magneto. — The Dual magneto is so arranged that the battery interrupter breaks its circuit at approximately ten degrees later than the magneto interrupter. This feature gives the full timing range of the magneto. With the timing lever fully retarded and the switch on the battery position, the battery spark will occur after the piston has reached and passed top dead center and is moving downward on the power stroke. This feature eliminates the danger of backfire. Timing the Dual Magneto. to the Engine. — The process is similar to that for the independent type. The magneto should be placed in position on the bed plate or pad provided for it, the bolts and straps being properly secured. The driving gear or coupling, however, should be left loose on the driving shaft. The instructions given in Job 136 for timing the independent type may be followed, or the following method may be used which will give the same result. First remove the aluminum dust plate which is located under the arch of the magnets and over the armature. To remove this it will be necessary to note if spring catches or screws are used to secure it in position. If spring clips are used a screw driver may be used to spring the cover. The greatest care should be used to see that no foreign materials such as screws or washers are dropped into the armature tunnel while the dust cover is off. Next, crank the engine until the piston in cylinder No. 1 is on top dead center, compression stroke. The armature should now be rotated in the direction it will turn, clockwise or anti-clockwise until, in the position shown in Fig. 471. The correct setting for the armature is determined by the dimension marked "e". For the DU4 this should be from 10 to 15 millimeters. For the DU6 the setting should be from 12 to 20 millimeters. These -settings represent an advance of from 10 to 15 millimeters on motors with 130 millimeters stroke. With the armature held in this position and the crank shaft and pistons as placed, the magneto coupling may be secured. It is difficult to give the exact setting. This is often determined by experiment after the approximate setting has been found as above. Setting the ZR Dual Magneto. — In this case it is unnecessary to remove either the interrupter housing cover or the distributor plate in order to deter- mine the setting of the instrument, or to locate the distributor terminal with which contact is being made. First fasten the magneto in position allowing the coupling to remain loose. Bring piston No. 1 to firing position for full advance. The fly wheel markings, or the engine manufacturer's instruction book may give this. Next rotate the armature until the Fig. 1 can be seen through the window in the face of the distributor plate. The cover of the oil "well on the distributor end of the magneto is then to be raised and the armature is to be rotated a few degrees in either direction- until the red mark on one of the distributor gear teeth is brought into register with the red marks on the side of the window located between the two oil ducts. The magneto is then in time for the full advance position, and since the engine has been maintained in that position the two may be connected. Dual Coil Care and Use. — When a four-cylinder engine comes to a stop it is very likely to stop with the crank shaft in a horizontal position. The 404 Automotive Trade Training ■ g — ^ --! ^ Lock nut ^ Contact block ^ Segment Fastening screw to. [^ppv |^^hji^\j0^^^n ^ Long platinum screw Contact block -^ Wri r^V^ufl ,^ Fastening screw for spring • >- Short platinum screw nbre block ^, Segment,^ lim " x'^^^^^^ \ >^ Interrupter lever Auxiliary sprinu ^ 0km ft'^'-^fcs iZP*' ^HK m^ >- Auxiliary spring Short platinum : ■ . " J^ ^1 z!^i0^SWm 1^^ ^ ^ Spring |5ost Long platinum serf.-.- ^ ^1 |V^c^/t~^ fliliomcLtiO ,Cut-oui "^^o/Tta cts flatomaiic &eN^R^TOR ^/^TTtRy Fig. 508. Inserted Resistance Control. Current Circuit used on Coil. Automatic Cut-out in Circuit. che output of the generator is controlled by the magnetic action of the vibrating controller. The device consists of a soft iron core with either a voltage or a current coil wound on it. In some cases it is supplied with both. In the latter case the automatic cut-out is in- corporated with the controller relay. The student must not confuse these two instruments. A casual glance would lead to the conclusion that they were the same as each is equipped with contact points held in position by a spring. In the cut-out the points are normally open, allowing current to flow only when they are drawn together by the magnetic action of the core. Just the reverse is true in the case of the relay controller. The points are normally held together. When the current flowing through them becomes equal to the desired gen- erator output for battery charging or lighting use, the action of the controller is so arranged that the strength of the spring holding the Starting Motors and Generators 433 contacts together is overcome by the magnetic action of the core and winding, thus drawing the points apart. As the points separate, a bit of resistance wire is inserted into the circuit which regulates the strength of the field. The resistance cuts down on the amount of current permitted to flow to the field circuit. As the strength of the field is thus decreased, the amount of current generated within the armature is necessarily likewise decreased. As this output is decreased, the magnetic pull of the con- troller core on the soft iron part carrying the movable contact point is decreased to such a point that the pull on the spring is greater than the magnetic pull and the points return to normal position. The resistance which really controls the output is thus cut in and cut out many times a second. It is usually brought into action at from Carre/fi Cfrcutt ^ij ■ ■ ^ ^a t-^ut Coff tacts ^ Fig. 509. Inserted Resistance Control. Voltage coil only used on regulator coil. Automatic Cut-out in Circuit. fwelve to eighteen miles per hour. The device may be used either in connection with the voltage or the amperage of the generator. If the current or amperage is depended on, the controller core is wound with wire heavy enough to carry the entire output of the generator. If voltage or pressure is depended on for regulation, the wire may be very light and the ends of it connected across the generator brushes in a plain shunt. The student does not want to lose sight of the fact that the out- put of the generator is actually controlled by the inserted resistance and that the relay is made to insert and withdraw this resistance automatically, and in such degree that the amount of current flowing to the battery and lighting circuit is maintained at a uniform value no matter what the operating speed of the engine. As the field builds up, the output increases. Armature speed, one of the three controll- 434 Automotive Trade Training Cui-Oat Cofiiach Fig. 510. Inserted Resistance Control. Cut-out and Regulator combined with both current and voltage coils assisting in the operation of each part of instrument. ing factors, is responsible, as part of the current taken off from the armature through the brushes is shunted into the field to build that. Consequently, to offset the speed factor the magnetic field strength is decreased by preventing the return to the field, w^inding the normal proportion of armature output. The insertion of the resistance accomplishes this. As stated before, the usual practical application of this method is through the combination of the automatic cut-out and vibrating relay. Both w^indings, the heavy current circuit and the light or fine w^inding shunted across the brushes, thus influence the action of the instrument. As the voltage starts building up when the genera- tor is driven by the engine, the cut-out points are closed. When closed the current starts flow^ing through the current winding to the battery. This adds to the magnetic pull affecting the closing of the cut-out points and helps to hold them securely together. Both coils acting together, since they are wound on the core in the same direc- tion, affect the action of the vibrating points. The spring tension controlling the separation of these points is regulated to increase or decrease the output of the machine. Increasing tlie tension on the spring means that more current must flow at a higher voltage before the contacts open and the resistance is inserted. Decreasing the tension on the spring means that there is less voltage and less current flow required to separate the points and insert the resistance. As a consequence the output is increased or decreased at the desire of the mechanic. Differential Compound Wound or Bucking Series Field. — It is presumed that the student is familiar with the terms shunt and Starting Motors and Generators 435 series as applied to the winding of generators and motors. The action of the type of regulation depending on the bucking series field is easily understood if it is remembered that winding an electro- magnet with many turns of wire will, when current is sent through the wire, make one end of the electrom.agnet north and the other end a south pole. Reversing the direction of the winding will reverse the polarity. That is the pole formerly north is then a south pole, and vice versa. If, on the other hand, a number of turns of wire are wound on in one direction and then the direction of winding is reversed and a like number of turns put on in the opposite direction, it is evident that there will be a bucking effect between the two coils GENERATOR Fig. 511. Bucking Series Field with Automatic Cut-out in Circuit. as the current is run through them. One coil would attempt to make a north pole out of a certain end of the core, while the other coil would attempt to make the same end into a south pole. If the coils were just equal there would be a complete neutralization of the magnetic effect and there would be no decided polarity evident. The magnetic field or flux would be destroyed. In the bucking series field regulation this is the basis of the con- trol. Part of the output of the armature is run through the field to build it up. This is called a shunt field. If all the current passing through the armature winding were passed through the field that would be series winding. In this case the shunt winding which is the longest is wound in one direction about the pole shoes to form the electromagnet and set up the magnetic field. The charging cur- rent also taken from the armature brushes is run about the pole shoes in the opposite direction in its circuit, and before it is carried through the automatic cut-out and ammeter to the battery. Consequently, as the output grows, more and more current will pass around the pole shoes in the opposite direction to that building 436 Automotive Trade Training up the field. This current bucks or neutralizes the magnetic flux or field by attempting to build up a field of reversed polarity, with the result that the stronger field is bucked or partially neutralized. Since the magnetic field is one of the determining factors of all generators it vi^ill be seen that the neutralization of part of the field will cause a falling off of the output. The increased output, due to higher arma- ture speeds, is used to neutralize the field and reduce itself. As in the case of the vibrating controller the increase of armature speed, which is one of the three factors, is offset by a decrease of the mag- 1 h r/V//?Z7 BffL/SH 3 R^GULRTION \\ n 5 ANGLE OF F1.UX V 5 OlSTORTlONv i V z H ■^ \ ' 2} 1 \ ANGLE OF FLUX ] ^ijX \ 5 DISTORTION [ ^ oX V'^ i z H ARMATURE REACTION COMP< 5NENT ARMATURE REACTION COMF ►QiiENT Pig. 512. Parallelograms illustrating degree of flux deflection due to the armature reaction. netic field factor. The same result is accomplished by different means. This method entails no moving parts. There is no method of readily increasing or decreasing the output. If the circuit used to charge the battery and light the lamps should fail for any reason no current would be traveling in the reverse direction to buck down the shunt field circuit. This would permit the voltage to build up and up until, if the car were operated at considerable speed the field and voltage coil on the cut-out would most certainly be burned and dam- aged. Consequently great care must be used to see that all terminals are tight and the wiring complete. Third Brush Control. — In this system which is used to a greater extent than any other the governing factor is the armature reaction. When the electric current flows through the coils of the armature as it is generated it magnetizes the iron core of the armature. This Starting Motors and Generators 437 magnetism is termed cross magnetism and affects the main field magnetic flux. With the main magnetic field established at full strength by the exciting current flowing through the field coils, the lines of force will BTARTING SWITCH Fig. 513. Starter Generator not in operation. Third Bush Control. Fig. 514. Starter Generator running at 1200 R. P. M. Third Brush Control. leave the north pole, pass across the first air gap to the armature, through the armat]^re to the second air gap, and across it to the south pole. If the armature is not in motion and no current is flowing through its coils to set up the cross magnetization, the lines of force pass across from the north to the south pole in a straight path. However, with cross magnetization present, the armature flux thus 438 Automotive Trade Training produced creates a secondary field having a marked influence on the main field. This cross magnetization is at right angles to the lines of force flowing in the main field. It is this fact that is relied on to control Fiei.D Current. 23 AMPCRES Fig. 515. Starter Generator running at 2200 R. P. M. Third Brush Control. nCUa CURRENT '1.25 AnPOK» Fig. 516. Starter Generator running at 5000 R. P. M, Third Brush Control. the field flux and consequently the generator output. It is a well known fact that two forces coming together at an angle will result in the combined force following a line which is that of neither of the first two forces. If the two forces are equal the angle of distortion will be such as to bring the line of the new force half way between Starting Motors and Generators 439 the two originals. However, if there is one weaker than the other the line of distortion will form a smaller angle with the line of the main force than if they were equal. Refer to Fig. 512. In the application of this principle to the generator the main lines SHUNT ricuo COIl_- ^ POI_E STARTER -GENERATOR RUNNING AT aaOO R.P.M. rzzzzzi SERIES riCUO COIL.- + MAJN BRUSH — MAIN BRUSH omitted" + main brush "OMITTED" — MAIN BRUSH 3RO BRUSH J Fig. 517. Wiring Diagram showing Dodge Northeast Starter Generator operating at average speed. of force are those passing from the north to the south pole shoes. The distorting force is the armature flux. When the generator is idle or just starting to generate this force is negligible. However, as the output increases, the force tending to distort the field flux also increases. As this force grows stronger and stronger, the main flux 440 Automotive Trade Training is distorted more and more. When the main field flux is distorted fewer Hnes of force are cut by the armature conductors when in such position that the current can be taken off by the brushes. This results in a decrease of the output with the result that the cross magnetization and main flux distortion are also less. Again the out- put is made to regulate itself by decreasing the strength of the field, the same as in the case of the vibrating regulator and the bucking field types of regulation. The part the third brush plays is illustrated in Fig. 517. The third brush is at the point of greatest voltage value with reference to the armature coils. The armature reaction results in the greatest armature value being thrust to one side of the third brush. Since the third brush takes the current from the armature which is used to excite the field, it is evident that not as much cur- rent will be taken off by it when the distortion is greatest, thus result- ing in a decrease of the field flux. The speed factor again attempts to build up the armature output. Because of armature reaction and the third brush location the speed factor is offset by the weakened field factor. There are many variations of these three types of regulation, but the main principles involved have been explained. The variations in certain instruments are described under their respective job sheets. Cut-Out Relay. — The cut-out relay is an automatic switch in- serted in the charging circuit. The construction may be noted in a number of the illustrations, for example Fig. 511. Not all systems utilize the automatic cut-out. A number of Delco systems have had the cut-out switch in connection with the ignition switch so that when the ignition takes place the generator will start motoring and continue doing so, drawing current from the battery until the genera- tor speed is sufficient to produce an output and voltage greater than the battery voltage, at which point the generator starts charging the battery. Turning off the ignition also turns off the generator cur- rent and breaks the charging circuit. The automatic cut-out switch is dependent on the voltage coil shunted across the generator brushes, to make contact, or bring to- gether the cut-out points. This is due to the magnetic pull of the cut-out core which is made of soft iron. The magnetic pull is resisted by the spring tension. The strength of the spring must be such that it will hold the points open until the generator voltage is slightly more than that of the battery. Under this condition, when the points are closed, the current will flow immediately to the battery to charge it and no discharge is possible. Referring to Fig. 511 the student will note that the current coil is wound on the core in the same direction as the voltage coil. Accordingly when the contact points close the magnetic pull of the iron core is increased and the switch is made all the more positive in action. Starting Motors and Generators 441 The student must not confuse the vibrating control points with the cut-out points. The latter remain closed ouce the generator speed assures a sufficient voltage until the speed of the generator drops too low when they are automatically opened. The regulator points, on the other hand, vibrate rapidly, alternately inserting and cutting out the inserted resistance which is used to regulate the magnetic field, and consequently the generator output. Since the cut-out is closed automatically, it must likewise be designed to open automatically. When the voltage builds up to a certain point the contacts close and current flows as stated previously until the generator speed falls below the point where the voltage is below that of the battery. When this happens the current starts flowing not from the generator, but from the battery to the genera- tor. This reversal of current in the charging circuit attempts to reverse the polarity of the cut-out core and in so doing neu- tralizes the current flowing through the voltage coil which has no connection to the battery. In this manner the pull of the iron core is neutralized and the spring pulling on the contact causes it to be opened immediately. If the engine is being stopped the points remain open. However, if the engine has slowed only momentarily, the points will close immediately the car and engine speed again passes the predetermined point, about seven to ten miles per hour. The entire purpose is to automatically switch on and off the charging circuit in such manner that no attention need be given to the act by the operator of the machine. Occasionally the cut-out points will stick. If this happens, the battery will be discharged back through the generator. Where the system is equipped with an ammeter this fact may be detected by its action. The hand would stand at possibly ten to twenty amperes discharge with the lights and ignition oflf. Points will stick because they are burned by an excessive charge, or because of failure of the spring or other mechani- cal parts. JOB 150. WAGNER STARTING MOTOR. As used on the Studebaker cars the Wagner starting motor is rather representative of the entire Wagner line. The machine illustrated in Fig. 518 utilizes reduction gears to cut down the speed and increase the cranking power. A further reduction of speed and increase of power is secured through the use of a small sprocket on the starter gear shaft and a larger one on the crank- shaft of the engine. This latter is mounted on the forward end of the crankshaft and includes an over-running clutch in the hub on which it is mounted as part of the starting equipment. This clutch allows the engine to drive faster than the starting motor once it begins to operate under its own power. The Wagner line includes the popular bendix drive as well as the reduction gear chain and sprocket types mentioned above. Fig. 520 illustrates a bendix drive gear reduction combination, built by the same company. The single unit method of construction is employed in all Wagner equip- ment. A particular item of interest is the size of the starting motors. These 442 Automotive Trade Training Fig. 518. Wagner Starting Motor, are always small and light. Through proper design and gear reduction the very small instrument has proven equal to the task of readily spinning heavy six cylinder engines even under adverse starting conditions. Starting Switch. — From the car wiring diagram,. Fig. 557, it may be noted Pig. 519. Light and powerful starting motor, driving through chain and over-running clutch (Studebaker). that a large cable from the negative side of the battery is fastened to one side of the starter switch. This switch, shown dismantled in Fig. 521, is of the plunger type. It is so arranged that when the plunger is depressed it makes contact with the two copper contact segments located in the base of the switch Fig. 520. Wagner Starting Motor with Bendix Drive. Starting Motors and Generators 443 connecting them, thus providing a closed circuit from the battery to the starting motor. In case of any trouble with the switch it should be disassembled and cleaned. If the springs on the plunger have become bent out of shaf)e they should be repaired by springing until they will make firm contact. Be very certain not to harm or displace the insulating materials, otherwise short circuits will develop and cause battery and starter trouble. Fig. 521. Wagner Starting Switch. JOB 151. BUICK DELCO MOTOR GENERATOR. Motor Generator Operation. — The motor generator performs the three following operations: 1. Motoring the Generator. — This operation is necessary in order that the starting gears may be brought in mesh with the small gear on the armature shaft and with the teeth in the fly wheel. This motoring of the generator takes place whenever the lever on the left-hand side of the ignition switch is turned to position marked "On," thus completing the circuit from the battery to the generator windings. This discharge of current is through the shunt field windings and the generator windings on the armature. The motoring speed of the generator is slow. 2. Cranking Operation. — The cranking operation is performed when the starting gears are brought fully in mesh and the motor brush makes contact with the commutator. The brush thus brought into contact with the com- mutator after the gears are properly meshed serves the same purpose as closing a switch. A heavy current flows from the battery to the starter windings of the machine. It is very essential that all parts such as brushes, terminals, etc., make good electrical contact. 3. Generating Operation. — After the engine has been cranked and starts to operate under its own power, the starting pedal is returned to its normal position by a spring action. This demeshes the starting gears, at the same time raising the starting motor brush from the starting motor commutator, and lowers the generator brush onto the generator commutator from which it is always lifted while cranking the engine. At very low speeds the voltage generated is not sufficient to overcome the voltage of the storage battery, and a small amount of current may be discharged from the battery through the 444 Automotive Trade Training generator winding. At all normal engine speeds the voltage of the generator is sufficient to overcome that of the battery and the current flows through the battery and recharges it. The ammeter on the dash registers the rate at which the storage battery is discharging, or the rate at which the generator is charging the battery. Current Control and Output Regulation. — The current control is eiTected by the third brush system of regulation. To regulate the output the brush must be moved to the right or left as indicated in Job 156. Starting Motors and Generators 445 xr>j/ (h-^ 446 Automotive Trade Training JOB 152. DODGE NORTHEAST MOTOR GENERATOR. The instrument which is of the single unit type is mounted on the left-hand side of the engine. It is driven by the engine at three times the engine speed. It operates directly from the crankshaft through a silent chain drive. The machine employs only one commuta- tor, one set of field windings, one set of brushes, and one armature for the performance of all its functions both as a starting motor and gener- ating dynamo. Starting Characteristics. — While starting the engine the instrument acts as a cumulatively compounded motor, but while serving as a gener- ator it serves as a dififerentially com- pounded machine with its output ^^^- ^24 positively controlled by means of the third brush regulating system, supple- mented by the differential influence of the series field upon the shunt field. Generating Characteristics. — The machine is designed for twelve-volt service. When driven by the engine it normally begins to deliver current to the battery as soon as the engine speed is brought to a speed corresponding to a ten miles per hour car speed. At a car speed of sixteen to seventeen miles per hour the standard maximum output of six amperes is reached. This rate will remain practically constant until a car speed of twenty to twenty-one miles is reached, after which the charging rate will decrease gradually until at the upper speed limit of the engine it may be as low as three amperes. Whenever abnormal driving conditions are encountered, some special care to take proper account of them may be needed. Correcting Overcharge.— Where the battery seems to show a tendency to be chronically overcharged the condition may be relieved by allowing the lamps to burn dim for five or six hours to reduce the charge. To reduce the charge quickly it is a safe plan to permit the battery to crank the engine from five to ten minutes until the charge is materially reduced. In some cases the lamps may be burned dim while the car is left in the garage over night. Correcting Undercharge. — Undercharge may be corrected by having the battery charged at a service station, or by driving the generator with the engine while the car is standing. Refer to Chapter 11 on battery charging, for instruction in charging by other methods. If too much trouble is experienced in keeping the battery in proper condition, the charging rate may be decreased or increased by regulating the third brush. In making any change of the third brush setting the charging rate must not be permitted to become less than four amperes nor more than ten as a maximum figure. Method of Readjusting Starter Generator Output. — The student must always bear in mind the difference between charging rate and generator output. The latter is the entire amount of the current producd by the machine, while the charging rate varies considerably. This variation is due to the fact that the ignition always consumes part of the output and when the lamps are burning they may consume nearly the entire output. At these times then the battery is charged by that portion of the output which is left after the normal needs of the electric system are supplied. Knowing these facts, it is easy to see how the poor driver may easily exhaust the battery by continued cranking, or how the driver, who uses his car a great deal at night for short drives, will encounter the same trouble. On the other hand, the careful driver will Starting Motors and Generators 447 conserve the energy within his battery by properly setting his spark and throttle before cranking. A driver doing much touring in the daytime will likely find a tendency to overcharge the battery. If the remedial measures mentioned above are not satisfactory and the charging rate must be changed proceed as follows: ftHUNT nCLO ClOHTINa « MNITION SWITCH tJATTERY CROUND Fig. 525. Circuit Diagram of the North East ]\Iodel G Starting and Lighting System. Type 3566 Starter-Generator. Type 8100 Starting Switch and Reverse Current Cut-Out. 1. With the starter generator in position to run either on the car or on a test bench, insert a suitable ammeter in circuit to read the total output. Also connect a voltmeter capable of reading at least twenty volts across the two binding posts of the starter-generator to read the generated voltage. 2. Run the starter-generator at 1800 R. P. M. — the speed at which its maximum output is normally delivered — and note the readings of the am- meter and the voltmeter. 3. Consult the output table, page 449, and compare the current and voltage readings obtained in the test with those given in the table. In doing this take into consideration the output variations that occur as the result of changes in the counter-electromotive force (back-voltage) of the battery. To take these variations properly into account, first ascertain the approximate C. E. M. F. of the battery by measuring the starter-generator termnal voltage, which is its practical equivalent; and then, referring to the table, compare the observed current reading with the corresponding standard value of current to be ex- 448 Automotive Trade Training Fig. 526. The North East Model G Starting: and Lighting System as applied to the Dodge Bros. Motor Car. pected at the actual voltage in question. Should the test reading be thus found to differ from the equivalent standard reading, due allowance for the fact must be made in re-adjusting the machine. Starting Motors and Generators 449 Variations in Starter-Generator Output Due to Changes in Battery C. E. M. F. Starter-Generator Output Battery C. E. M. F. Starter-Generator (Starter-Generator Terminal E. M. F.) Amperes Volts R. P. M. 5.5 12 1800 6 13 1800 6.5 14 1800 7 15 1800 7.5 16 1800 PORTABLE AMMETER 1R£VERSE'CURRE>IT CUT- OUT ^A TO TO UIGiHTINQ 9t IQNITION , /+ BATTERY & \- INDICATOR Fig. 527. Ammeter Counections for taking Output Readings. 4. Refer to Fig. 528 showing the Brush Rigging. After ascertaining the true output, shift the position of the third brush until the required modifica- tion in the setting is obtained. This is to be done in the following manner: Release the third brush plate clamp (8757) by backing off the clamp screw (4069) one or at most two turns. Then turn the adjusting pinion stud (8035) slowly until the desired output is registered by the ammeter. The stud should be turned in a counter-clockwise direction to reduce the output, and in a clockwise direction to increase it. The output must never be reduced below MAIN BRUSH COPPER COUOREO 8039 THIRD BRUSH Fig. 528. Dodge Northeast Brush Rigging. 450 Automotive Trade Training a value equivalent to four amperes at 1800 R. P. M. at a battery C. E. M. F. of fifteen volts, nor must it be raised above a maximum equivalent to ten amperes at the same battery voltage. As soon as the proper setting is ob- tained, lock the third brush plate again by tightening the clamp screw. Then as a precautionary measure against having disturbed the setting while lock- ing the clamp, note the instrument readings once more after all adjustments have been secured. 5. Before the operation is to be considered finished, the starter-genera- tor, must be given a final test by running it for fifteen or twenty minutes at a constant speed of 1800 R. P. M. During this time the readings of both the instruments should be watched closely to make sure that the new setting is accurate and permanent. The machine should then be subjected to a brief varying speed test by first lowering its speed to 700 or 800 R. P. M. and then raising it to approximately 3000 R. P. M. Finally a general inspection of the entire equipment should be made to see that no other parts have been dis- turbed while the output re-adjustment was being made. ^■j W/gftKtttifttfttl^Kt p m\ M^^t-^" ,.. Jk"-':^'^^ff^*"'*^ '- 1 • # C» V.:V ■? / A w Fig, 529. Dyneto "KIR" Motor Generator, as used by H. H. Franklin Mfg. Co. JOB 153. DYNETO SYSTEM AS USED ON THE FRANKLIN CAR. The Dyneto System is of the single unit type. A light weight efficient motor is permanently connected to the engine by means of a silent chain drive which operates the generator at two and one-half to three times engine speed. The student will want to note this feature individual to this system. No over-running clutch is used to secure a starting hold for the starting motor. Neither is there a cut-out employed. The entire system consists of the starter generator, a twelve-volt battery, and the switch. The three units are connected by a very simple wiring system consisting of two wires from the motor gener- ator to the switch, one wire to the battery, and one wire from the battery to the switch. Operation. — The switch shown in Fig. 530 should be placed on "start." It is left in this position unless the battery is fully charged, or if the car is being used for long or fast runs, in which cases the switch lever is moved back to "neutral" and left there. With the switch on "start," the Dyneto operates as a starting motor spinning the engine from 125 to 200 R. P. M. After the engine starts to run under its own power and above a speed corres- ponding to car speeds of seven to eight miles per hour the voltage generated is greater than that of the battery and flows to, rather than from, the battery thereby charging it. Whenever the car speed drops below seven or eight miles per hour, the voltage from the battery overcomes that of the generator, and the current flows into the machine from the battery causing it to motor Starting Motors and Generators 451 and help drive the car. At extremely low car speeds the system prevents the motor from becoming stalled. The lower the car speed the more power available from the Dyneto system. Construction and Care. — The bearings are of the ann- ular ball-bearing type. Keep them clean and apply a little oil each week. The brushes are mounted in their holders which are in turn mounted on a molded bakelite rocker arm. This is accessible through a large hand hole pro- vided for the purpose. All parts about the unit should be kept clean and all connections tight. The brushes should be examined once in a while. If the commutator is dirty and causes sluggish action of the starter it should be cleaned with a piece of fine sandpaper. Clean the brushes in gasoline. In replac- ing them they must be returned to their original holder and their exact former position. Do not place with the wrong side up or they will not fit the com- mutator. Replace worn-out brushes with Dyneto brushes only. Failure to Start. — If the unit will not operate, turn off the switch, and turn on the lights. If, on attempting to start with the lights on, they do not dim, this is an indication of an open circuit in the starting wires. Examine switch connections, terminals and brushes; also the battery. If there is a drop in the brilliance of the lamps and the dyneto system fails to start, the trouble may be due to loose connections, a rough or dirty commutator, brushes worn- out or not well fitted to the commutator, weak springs, grounded or defective armature or field windings. Refer to tests in Job 160 to Job 188 to learn method of tracing out trouble, Failure to Generate. — The trouble will probably be found in an open shunt Fig. 530. Franklin Dyneto Switch. Fii?. 531. Franklin Engine with Dyneto Electrical Equipment. 452 Automotive Trade Training field circuit. In Fig. 533, showing the wiring diagram, the circuit may be traced out from the negative pole of the battery to post 1, through half of the series winding to the negative brush, through a part of armature winding to the third brush, through the shunt field winding to post 3, through the starting switch, if there is one, to the positive side of the battery. The shunt circuit mentioned above may be tested independently of the main circuit by removing the wire from post 2 so as to cut out the main armature circuit, and setting the starting switch on start. If the shunt circuit is complete a bright spark will be made when the wire is removed from post 3. If no spark occurs, look over all the wires and connections and an open circuit will be found. Conned the ammeter for this test as shown in the illustration. CUT OUT FRAME %^ COVER FELT CASKET 3rd OR RECULATtNG BRUSH BRUSH YOKE I BEARING ARMATURE -BEARING Fig. 532. Gray & Davis Generator and Cut-Out. JOB 154. GRAY AND DAVIS GENERATOR AND CUT OUT. Dynamo (Generator). — The dynamo is of the shunt wound type, and is thus classified because its field windings are connected in shunt with, or across, the armature. The fields are connected in series, one side being con- nected to the positive brush and the other to the third or regulating brush. The third brush system of regulation is used, thus insuring protection to the battery and lamps at high operating speeds. The dynamo cut-out is shown in Fig. 532 as it is mounted inside the machine. It closes the circuit when the dynamo output is great enough and opens the circuit when the generating speed is insufficient to charge the battery. The shunt winding of the cut-out is connected across the dynamo brushes. This is also called the voltage coil. The series or current coil assists in holding the contacts firmly together. Lubrication. — The bearings should receive oil every week or every 200 miles. Use a high grade motor oil. Place from eight to ten drops in each of the oiling places. Be very certain to replace the oil covers in order to exclude all foreign substances. Do not assume that the oil is reaching the bearings, but make absolutely certain. Overflow of oil at the oiling places is Starting Motors and Generators 453 5 2 /^S^Oi/0 no indication that the bearing has oil. At times oil passages to bearings will clog. Speed and Output. — The dynamos are designed to be driven at engine speed or one and one-half times engine speed. The first delivers its full out- 454 Automotive Trade Training Fig. 534. Gray & Davis Brush Rigging— Third Brush Type. put at 500 R. P. M. The one and one-half engine speed machine delivers full output at 650 R. P. M. In either case this corresponds to a car speed of from ten to twelve miles per hour. If the car speed is less than this, the output is also less. At speeds above this the maximum output is maintained. If no current is used for lighting, all the generated current excepting that needed for ignition is used for charging the battery and the ammeter will show prac- tically the full output, as flowing to the battery. When the lights are burning the charging current is reduced, although the output is more than sufficient to burn all of the lamps. Other causes which will result in a falling off of the amount of the charg- ing current are a sulphated battery, or one in which the battery gravity is low. 11 4 8 5 6 7. ■ \ ■ \ \ V.^^^^ ^ ^ ^- 1 Bflf^^j r'j35®^r? P r ^. ^^B^-nppi B \ 13 wv •;,ji Fig. 535. Cut-out Housed in Dynamo, Gray and Davis, Starting Motors and Generators 455 This is due to the increased internal resistance when a battery is in poor con- dition. Operation. — To determine if the dynamo is functioning properly, the mechanic should observe the ammeter carefully. With lights ofif start the engine running. Increase the speed very gradually. If the ammeter begins to register at a speed corresponding to seven to nine M. P. H., it indicates that the automatic cut-out is cutting in (closing) at the correct time. As the speed Fig. 536. Gray & Davis Cut-out— Used on Third Brush Dynamo. is increased the ammeter should register from twelve to fifteen amperes at a car speed of thirteen to eighteen miles per hour. Above eighteen miles per hour and at high speeds the ammeter will show a gradual falling off of the out- put. This is approximately ten amperes at the higher speeds. The engine speed should next be decreased as gradually as it was formerly increased all the while watching the ammeter. If, as the ammeter shows a discharge of to 2, the hand suddenly returns to 0, the indication is that the cut-out is opening the circuit properly. However, if the ammeter hand indi- Fig. 537. Gray & Davis Internal Wiring, Third Brush Dynamo. Gates a decided discharge, or should fail entirely to return to 0, the indications are at least a sluggish opening of the points and possibly burned aud stuck contact points in the cut-out. If the ammeter fails to indicate any charge when the engine is speeded up, the first point is to determine whether the cut-out, dynamo, or wiring is at fault. The wires between the battery and dynamo should be examined. The battery terminals are very frequently at fault. The brushes and commu- tator should be examined next. The brush holders are equipped with stops which prevent the brush wearing down beyond a certain point. Refer to Job 189 for further instructions. Failing to have eliminated the trouble, the next 456 Automotive Trade Training step is to connect a wire from the negative dynamo brush 13 in Fig. 537, to dynamo terminal 6. With the engine operating at a 13 M. P. H. speed the cut-out is out of the circuit. An indication of charge and discharge then appearing on the ammeter as the engine is operated would place the fault with the cut-out. However, if the ammeter fails to register the fault is in the generator. Go carefully over all brushes, terminals, fuses, and wiring. Failing to correct the trouble, the machine must be tested with the Faultfinder or some similar instrument as indicated in Jobs 174 to 188. The car must not be operated with the battery removed unless proper precautions are taken. In this case the method recommended is to raise one of the brushes from the commutator and tie it in that position. This prevents the generator building up an excessive output and voltage with the attendant dangers of burned and damaged parts. Adjusting Third Brush. — Fig. 534 shows the yoke with the two main brushes 13 and 14. The third brush is indicated by 12. When attempting to adjust the third brush to secure an increased or decreased output an amme- ter must be in line, either the one on the dash or a portable one. The battery should be fully charged. The adjustment is secured by turning pinion 11, which is provided with a slot for a screw driver blade. This is shown in Fig. 535 on the outside of the housing. A very slight turn will affect the output very materially. Turning to the left will increase the output, and to the right will decrease the charging rate. The speed at which the driver operates his car has much to do with the output. If the car is driven regularly at high speeds the tapering ofif or falling ofif due to the armature reaction may be partially overcome by setting the third brush for a low charging rate at a low engine speed. This will delay the armature reaction and the result will be that the maximum charging rate will come at a relatively higher car speed resulting in a greater output. The internal wiring diagram is shown in Fig. 537. JOB 155. GRAY AND DAVIS STARTING MOTOR TWO UNIT SYSTEM. The starting motor is the link between the battery and the engine. In cranking the engine it converts the electrical energy drawn from the battery into mechanical energy. Electrically, it is connected to the battery with heavy cables. Mechan- ically, it is connected to the engine through a gear reduction. The principal parts are shown in Fig. 539. This illustration shows the automatic pinion shift type (Bendix Drive). Mounted on the armature shaft is a sleeve having screw threads, with stops on either end to limit the travel of the pinion. The pinion has internal threads making it a smooth running fit on a threaded sleeve. The pinion is weighted on one side. This sleeve is connected to the motor shaft proper through a spring attached to a collar pinned to. the motor shaft. Normally the pinion is in a demeshed position. When the starting switch is closed, by pressing down on it, the armature of the machine immediately starts rotating. Since the threaded sleeve is connected to it through the spring, it is also set in motion. The motor pinion being weighted on one side does not start rotating immediately, but moves endwise. This endwise motion causes it to mesh with the teeth cut on the flywheel. When the limit of its travel endwise is reached, the pinion must turn with the sleeve and armature. The spring acts as a cushion while cranking against compression. It also breaks the severity of the shock in case of backfire. When the engine begins to operate under its own power, the increased speed of the fly wheel causes the engine to attempt to drive the starting Starting Motors and Generators 457 CONNECTION TO ARM. SHAFT CONNECTION TO SCREW SHAFT^ PINION STARTING SWITCH SCREW SHAFT STOP COLLAR ARM. SHAFT FLY WHEEL Fig. 538. Gray & Davis Starting Motor Application. FELT STOP/*- COLLAR BRUSH YOKE GROUND CONNECTION SCREW SHAFT ARMATURE COMMUTATOR PINION CAGE Fig. 539. Gray & Davis Motor Parts. Outboard Automatic Pinion Shift Type. motor. This results in the pinion being thrown out of mesh since no power can be transmitted backward until the pinion is against the other collar. At this point it is out of mesh. The centrifugal effect of the weighted side of the pinion causes the pinion to be maintained out of mesh until the armature has come to a stop. It is needless to emphasize the necessity of removing the foot to perrnit the switch to open as soon as the engine is operating under its own power. Lubrication. — The starting motor must be oiled regularly every two weeks. Eight to ten drops of light motor oil should be placed in each of the oil recept- 458 Automotive Trade Training acles. Sliding surfaces and rods must be oiled frequently. Use kerosene on the threaded motor shaft to keep it clean. Failure to Start. — If the starting motor cranks the engine when the start- ing switch is depressed to the full limit of its travel, but the engine fails to fire and run under its own power, the starting pedal must be released after ten to fifteen seconds. The cause of failure may be any of the following: Fuel supply exhausted. Ignition switch not turned on. Ignition wires not firmly connected. Spark plugs defective. Cylinders need priming. Cylinders flooded from too much priming. Carburetor out of adjustment. Poor grade of fuel. Reasons for Cranking Failures. — If de- pressing the starting pedal fails to cause the starting motor to rotate and the engine .to turn the fault may be any of the following: Battery weak or discharged. Loose battery terminals. Starting switch not making good contact when pedal is depressed to the limit of its travel. To remedy this press blades out slightly. Refer to Fig. 540. Crank engine by hand to see if the fault is in it. They should make good contact and swing Fig. 540. Gray & Davis Starting Switch. Examme motor brushes freely. See that commutator is clean. See that the pinion is not stuck on the threaded sleeve JOB 156. HUDSON DELCO MOTOR GENERATOR SINGLE UNIT. The Delco single unit used on the Hudson engine is typical of Delco equipment. The same armature serves for both starting and generating. However, the windings are separate and the commutator on the rear end is used only for the generator while the commutator on the front end is used only for the motor as it operates in starting the engine. A set of brushes, with which the motor end is equipped, are in contact with the commutator only while the cranking effort actually takes place. This prevents undue wear on them while the machine is used for the work of generating and recharging the storage battery. The car is not equipped with the usual type of starting switch. The raising and lowering of the brushes is the equivalent of the switch action in this case. Cranking Operation. — When the starting pedal is depressed, it causes the motor clutch to engage with the teeth of the fly-wheel and with the motor pinion gear. Connected to the pedal mechanism is the brush controlling mechanism. When the starting pedal is depressed, the brushes are allowed to come into contact with the commutator. This then permits the current to flow from the positive terminal of the storage battery to the series winding of the motor, to the upper motor brush, through the armature to the lower brush, through the lower brush and frame of the car to the negative terminal of the battery. It is seen how the movement of the starter pedal thus con- nects the motor to the engine and at the same time closes the switch which in this case is the motor brushes. The wiring diagram, Fig. 542, shows the motor brushes lifted. The cranking circuit may be traced out on the diagram. Starting Motors and Generators 459 Fig. 541 shows the actual wiring necessary to connect the motor to the battery. As stated previously the negative brush is grounded as is also the negative battery terminal. Fig. 543 shows the motor commutator and the brushes, together with their springs and operating pin. Operating as a Generator. — When the ignition switch is closed, the gener- ator will start motoring. This is due to the fact that no automatic cut-out is employed, and the action of closing the ignition switch closes the charg- ing circuit as well. Since the pressure of the battery is thus admitted to the 460 Automotive Trade Training cc 3(0E StoC ^Sju «ta WVWVhH rl"l'lh-> charging circuit, current is caused to flow to the generator from the battery. This flow of current amounting to four or five amperes is sufficient to cause the generator armature to rotate at a slow speed. In some Delco models this is evidenced by the ratchet-like noise of the over-running clutch. Starting Motors and Generators 461 The purpose of the design which incorporates the motoring armature is to insure the starting motor pinion engaging properly with the fly-wheel teeth as the starting pedal is depressed. As noted previously, the same action which throws the gear into mesh with the fly-wheel also applies the starting motor brushes to the commutator of the starting motor. A third operation is performed by this same operation, and that is opening the gener- ator switch. The generator switch which is shown in the wiring diagram, Fig. 542, as well as in the illustrations of the motor generator, Fig. 543 and 544, serves to 1 1 jBBBSiwlBBfc, jg^^^^^^^^HHHIII^^^^^H^ CONNECTS TO ^^^■■■jJI^^^^M^^^^^^^^SW^ ^^TERMiNAL 2) GENERATOR ' J^^^H^^^^^B^^^Bh^ ' SWITCH "~"~~-~-^ ! H^^S^^9|^H||^^^^|^H^^^H& > CONNECTS TO ■MK^^^^^^H^^^HPH^^^^^H^^GENERATOR BRUSH IIPPPR MHTnR . HI^^IH^^^sHHi BRUSH ^SSSBS^SB^^K^k OIL HOLE ""^ ■■^■^^^^Bmi MOTOR — — ' ^^^^^^^^^^^^^^yP^ COMMUTATOR ^^^^^^^^Hl LOWER MOTOR ^^^^^■B BRUSH — -__ |H^HKp f ^ — -PIN OPERATING MOTOR BRUSHES 1 fc W 1 Fig^. 543. Hudson Delco Motor Brushes and Commutator. connect the battery to the generator winding, on the armature, at all times, excepting only when the starting pedal is depressed and the engine is being cranked. After the engine starts operating under its own power, the generator switch is closed as the pedal is released and current flows through the charg- ing circuit. As long as the engine continues to operate above a speed suffi- cient to overcome the battery voltage the current will flow from the gener- ator to the battery. When the car speed or engine speed drops down, the current will reverse in the charging circuit and flow from the battery. To stop the flow of current within the circuit, it is necessary to open the igni- tion switch, which at the same time opens the shunt winding of the generator. Regulating Generator Output. — The Hudson Delco equipment is con- trolled by the third brush method. The position of the brush on the com- mutator controls the output. The output is regulated at the factory and should be satisfactory for the average driving conditions. If it should become necessary to increase the output, first remove the cover plate over the third brush. The next step is to loosen the two set 462 Automotive Trade Training screws in the arm of the third brush and move the brush to the right (look- ing at the front end of the generator). A small movement will make quite a difference in the charging rate. To decrease the output move the third brush to the left. Be certain to set up the screws snug and tight, to prevent parts coming out of adjustment. It is also necessary to sand in the brush in its new position. Refer to Job 189 for instructions. At nine miles per hour the charging rate should be five amperes, at twelve CONNECTS TO TERMINAL (No. 2) GENERATOR TERMINAL (No. 2) CONNECTS TO GENERATOR BRUSH GENERATOR SWITCH SHUNT FIELD TERMINAL (No. 4) MOTOR PINION MOTOR TERMINAL (No. 1) J Fig. 544. Hudson Delco Side View of Generator. miles, ten amperes, and at twenty-four miles the maximum is reached which is seventeen amperes, after which point the output drops off rather rapidly until at 42 miles per hour the output has dropped back to eleven amperes. The operator must remember that with this system the drain on the battery is two-fold if the ignition switch is inadvertently left on, since the drain is both to the ignition and the generator. JOB 157. MAXWELL SIMMS SYSTEM. This system is a twelve-volt single unit type. It is so mounted on the Maxwell engine that the one end of the armature shaft may be used for driv- ing the engine through the starter pinion and the other end receive the power from the engine which drives the machine as a generator. This arrangement is possible due to the fact that the generator drive is one of belt friction. The generator driving shaft is connected to the small end of the armature shaft by means of a flexible coupling. The forward end of the shaft is equipped with a pulley. The generator is driven at about two and one-half times engine speed by the fan belt. When the motor generator is connected to the fly-wheel pinion, however, the generator' speed is about nine times the engine speed. As this connection is a positive one, the fan belt slips on the Starting Motors and Generators 463 generator pulley during the time that the motor is used for starting or crank- mg the engine. In this manner the use of over-running clutches, or ratchets, is done away with. Starting Conditions. — Refer to Wiring Diagram Fig. 547 for the numbers and circuits mentioned. Under starting conditions the starting switch plunger is moved forward and completes the circuit between 5 and 6. The same movement connects the starter pinion or meshes it with the fly-wheel gear. This is not shown on the wiring diagram. The path of the current is then as follows: Starting at the storage batter.y from terminal 8 the current flows through Fig. 545. Maxwell Simms Motor Generator. connection 9 to contact 6, through connector 10, through contact 5, in the starting switch, then to terminal 11 at the generator through the positive brush 14 into the armature to the negative brush 15, through the series winding of the field pole, and thence to the frame or ground of car to terminal 13 and negative pole of the battery. Charging Conditions. — After the current has flowed from the battery and through the circuit indicated above, thus starting the engine to running under' its own power, the foot pedal is released, which in turn demeshes the pinion and opens the switch leaving it in the position shown in Fig. 547. The fan belt drive for the generator now becomes operative. The residual magnetism left in the field poles is sufficient to start the machine generating. Current is gener- ated between the two main brushes 14 and 15. Starting from the third brush 13, the current travels through the shunt field coils to the frame of the motor, through the series field coil, and back through the negative brush 15. This shunted current passing through the field winding produces a stronger magnetic field to be cut by the armature winding, and consequently permits the voltage or pressure to be built up and the output increased. Starting from Fifr. 54C. Maxwell Simms Yoke, terminal 11 the current flows through Complete. the small wire to termmal 16, through 464 LEFT HEAD LAMP Automotive Trade Training RIGHT HEAD LAMP V OROUND \ ^ 32 / .GROUND l^ljgHl|' GROUND \ 33 'ii^.pqi GROUND I DISTRIBUTOR Starting Motors and Generators 465 the voltage coil in the cut-out 17 to the ground. This causes a magnetic action which closes the contact points, whereupon the current will flow through 19, 20, and 21, through the coil 22, through terminal 23, through wire 24 to ammeter terminal 26, through wire 27, through fuse holder, through terminal 9, through terminal 8, through terminals 7 and 12, to the ground, then through the series winding of the generator field and back to the negative terminal, 15, of the machine. Generator Output Regulation. — Fig. 547 shows three cuts marked Slow Speed, Medium Speed and High Speed. The relative positions of the two main brushes and the third brush are shown. The lines of force are repre- sented by twelve lines for the twelve volts output of the system. These lines do not represent the winding, but the lines of force or magnetism of the field poles, yoke and armature. In the Slow Speed it will be noted that the lines of force are equally divided over the sttrface of the pole shoe. In the Medium Speed section it will be noted that the lines are distorted in the direction of armature rotation. This is due to the armature reaction as explained in the early part of the chapter. In the sec- tion marked High Speed a still greater distortion is shown which is representative of the actual condition in the field. If, as stated above, each line is said to represent approximately one volt and there is a total of twelve volts per pole, and the field coil is connected to the third or regu- F*&- 548 Maxwell Simms Brush- , . , , , ,. , , ^ Holder, Complete, latmg brush one-half way between the two main brushes, the student will see that the resultant distortion of the increase of speed causes fewer lines of force to be cut, and decreases the amount of current flowing through the field as indicated. Since the current output is dependent on the three factors, armature speed, armature winding, and field, it is evident that the increase of speed is counter- acted by the decrease of the lines of force being cut, as the distorted field insures. Consequently the regulation is inherent. The shunt field is wound for seven and one-half volts, while the armature output is approximately fifteen and one-half volts when the third brush is properly located and the armature running at approximately 1500 R. P. M. JOB 158. REMY OLDSMOBILE. As in the case of the Remy Ignition, the Remy starting and lighting equipment is built for a large number of car manufacturers. The Oldsmobile is given here as representative of the Remy line. Thermostat Control. — The student no doubt understands by this time that the thermostat control is a device of whatever nature which is so arranged to control some other feature of equipment because of certain action within itself, due to heat. In the chapter on Cooling Systems the effect of heat on the thermostat controlling the water circulation was explained. In this case the heat is produced by running a current of electricity through a bit of resistance wire wound on a metal blade. This blade is made up of two metals, one with a great amount of expansion when heated, the other one not subject to much expansion. The result is that, when the current flows through the resistance wire around the blade, they are heated. When heated beyond a certain point the blade, owing to the nature of its construction, will curve, thereby throwing 466 Automotive Trade Training the points apart and inserting another resistance unit into the circuit which will cut down the output of the generator. In the Remy this device is used in connection with the third brush control to regulate the output of the generator. It is natural that more current would Fig. 549. Remy Oldsmobile Generator with Ignition Coil and Relay mounted on it. be required in the cold winter months to open the thermostat than in the warm summer months. This is an especially desirable feature since the demand for current both for starting and lighting is much greater in the winter than in the summer. This device then helps to insure a higher charging rate in the winter to compensate for the heavy demands on the battery. The device is entirely automatic and requires no attention. In case of serious damage to it a new unit should be installed. Third -Brush Control. — The output of the generator is high and the thermostat is depended on to prevent overcharging. However, if the battery shows signs of being continuously overcharged, the output may be reduced by means of the third brush screw. This is found on the commutator end of the generator and a slight turn to the left will correct the trouble. Likewise turning to the right will increase the output. This should never exceed twenty amperes, Where the output is too low, look for brush or commutator trouble. Fig. 550. Remy Oldsmobile Starting Motor. Starting Motors and Generators 467 TO CCNERATOR FIELD fXl rf^ TO SENERATOR FIEL yvAAA/W" ^ Fig, 551. Remy Oldsmobile Thermostat. Relay. — This Is the automatic cut-out previously described. The Remy relay shown in Fig. 553 consists of the contact points, a movable arm with a spring hinge, and a simple electro magnet. The spring holds the contacts apart when the engine comes to rest. When the generator is being driven at THERMOSTAT 3RD BRUSH BRUSH RIGGING INSIDE Fig. 552. Remy Oldsmobile Brush Rigginfr with Thermostatic Control mounted on the inside. a speed sufficient to develop a voltage equal to that of the battery, the shunt coil on the relay, sometimes called the voltage coil, is energized and the arm bearing the one contact is pulled down to the other, thus closing the circuit through MOVABLE ARM CONTACT POINTS ELECTRO MAGNETS Fig. 553. Remy Relay. 468 Automotive Trade Training which the current must flow to reach the battery. The relay is provided with a series coil, through which the current flowing to the battery must pass. This insures the contact points being held firmly together. Starting Motors and Grxerators 469 Fig:. 555. Studebaker Wagrner Generator. h'ig. 55t). \v'aguer Relay Cutout. 470 Automotive Trade Training Care of Contact Points (Relay). — If the points become worn or dirty, Or show a tendency to stick, they may be placed in good condition by passing through them a piece of No. 00 sandpaper. Blow out all dust to allow a clean, flat contact. Use care not to spring the arm, or to change the opening or the spring tension. The spring tension is correct unless there are some unusual circumstances attending. The clearance of the contacts when open is from .015" to .020". Starting Motor. — This is a four pole series wound machine. A Bendix drive is used. When the starting switch is closed, the motor starts revolving at high speed. The pinion gear, by reason of its inertia, tends to lag behind the rotation of the shaft, thus being thrown into mesh with the teeth cut on the fly-wheel. As soon as the engine starts operating under its own power, the pinion is driven faster than- the armature and threaded shaft, and is thus thrown out of mesh with the fly-wheel teeth. This arrangement permits of a large starting torque, since the armature is running at a high rate of speed when the load comes onto it. JOB 159. WAGNER GENERATOR. A unique feature of the Wagner Generator in its application to the Studebaker power plant is the fact that the instrument is so designed, built, and attached as to operate in a vertical position. The Wagner Company manufactures generators which are driven in the more common horizontal position. Fig. 555 illustrates the Studebaker generator. This instrument is built along the usual third brush regulation lines. One unique feature about the third brush arrangement is that the adjustment is made at the factory and then sealed. The factory guarantee is made void if this seal is broken by anyone other than a Wagner representative in the rd 0-1 ItORN PUSH BUTTON ^-».(^ IGN. AND LIGHTING SWITCH r-STARTlNG MOTOR ■ in* STARTER SWITCH. Fig. 557. studebaker Wiring Diagram. Wagner factory, or an accredited Wagner service branch. This emphasizes the fact that a properly designed generator requires very little adjustment of output if attendant equipment is maintained and used properly. Generator Care. — See that the two oil holes receive a few drops of the best oil each 1000 miles of service. Wipe the commutator clean. It is not usually necessary to sand in the brushes, or sand down the commutator for Starting Motors and Generators 471 several seasons' service, but if the work must be done, follow the directions given in Jobs 189 and 190. Relay Cutout. — This works automatically to cut in the battery at approx- imately ten miles per hour, and the generator will give the maximum output from seventeen to nineteen miles per hour. Wiring Diagram. — Fig. 557 shows the Wagner Studebaker wiring diagram. The feature in this diagram of special interest is the junction box where all wires are brought together for proper connection and fuse protection. JOB 160. INSTRUCTIONS FOR THE USE OF WESTON MODEL 441 FAULT FINDER FOR TESTING AUTOMOBILE ELECTRIC STARTING, LIGHTING AND IGNITION SYSTEMS. Description of the Instrument. — The Weston Model 441 Fault Finder, illustrated in Fig. 558, consists of an ammeter and a voltmeter mounted in a convenient case. Connections to the instruments are made by means of cables having clips at one end and plugs with handles at the other end. The plugs are pushed in posi- tion through the holes in the marking plate through especially constructed contact clamps. The Ammeter. — The ammeter is self- contained, having a range of 30 amperes. The scale is provided with the zero at the center. There are fifteen divisions each side of zero. The value of each division is two amperes. The ammeter is protected against in- jury by burn-out by the enclosed glass fuse mounted on top of the instrument case be- tween the two instruments. This fuse is a standard 30-ampere automobile fuse. The ammeter must always be con- nected in circuit so that the full current of the circuit under test will pass through it. To make this connection, the circuit is opened at some convenient point and the test clips are attached to the two ends of the break just made. To trace the direction of the current flow in a circuit by means of the ammeter, it is only necessary to remember that the pointer deflects to the right of the zero mark when the current enters the instrument through the contact marked +, and to the left of the zero mark when the current enters through the contact marked 30. Fife'. 558. Model 441 Fault Finder. 0^ VOLTS \0/ AWEReI \<^ LO O 0(0 O) Fig'. 559. Marking Plate for Model 441 Garage Testing Instrument. The Voltmeter. — The voltmeter is a double range instrument. The ranges are 0.2-0-3 volts and 2-0-30 volts. The scale has 30 divisions above zero and two divisions below zero. Each division on the 30-volt range has a value of one volt, and on the three-volt range 0.1 volt. The voltmeter should always be connected over that part of the circuit 472 Automotive Trade Training Fig. 560. across which the voltage is to be determined. When using the voltmeter, connect the plug which is in the (+) hole of the plate on the side marked volts to the positive (+) wire of the circuit, and the other plug to the negative ( — ) wire, placing the plug in either the hole marked 30 or 3, according to the range to be used. When connected as just explained, the pointer will move to the right of the zero if the polarity of the circuit is correct. JOB 161. When the Starting Motor does not Operate. — To determine the qause, proceed as follows: Carefully examine all connections at the starting switch and at the motor. Also be certain that the brushes of the starting motor are making good contact on the commutator, and that the commutator is clean. Examine contact surfaces of the starting switch to be sure they are clean and making good contact. Having eliminated possible causes of trouble, connect the 30-volt range of the voltmeter across the battery terminal as illustrated in Fig. 560. Note the reading. Case A. — Close the starting switch. Again note the reading. If it is the same as when the switch is open, there is an open circuit either in the starting switch. Job 162, the motor field. Job 163, or the motor armature. Job 164. Case B. — If on closing the starting switch a small decrease in the reading results, there is a high resistance somewhere in the circuit, which was not located by the preliminary visual inspection. This may exist in the battery terminals. Job 166, in the motor field. Job 163, in the motor armature, Job 164. or in the starting switch. Job 162. Case C. — If, on closing the starting switch, a large decrease in the reading results, the battery may be exhausted, a short circuit may exist in the starting motor field, Job 168, or in the motor armature, Job 170, or in the wiring. Job 169. Case D. — If the reading on the voltmeter, when the starting switch is open, is very much below the normal voltage of the battery, one or more cells of the battery may be exhausted or defective, or a short circuit may exist in the wiring between the battery and the starting switch. (Job 169). Starting Motors and Generators 473 JOB 162. Open Circuit or High Resistance in Starting Switch. — Connect the 30-volt range of the voltmeter to the terminals of the starting switch, Figure 561. If the rest of the circuit is in good condition the voltmeter will indicate the battery voltage; if it does not, trouble exists in some other part of the apparatus. Close the starting switch. An open circuit will be designated by BATT£J?Y 5rA/?T/N6 5W/TCH Fig. 561. no change in the reading. A small change in the reading will indicate a high resistance. In either case, the contacts of the starting switch and all connec- tions in it, or to it, should be carefully examined. Contacts should be cleaned or repaired if found to be poor. If the switch is in good condition the indication will drop to zero o|;i closing it. JOB 163. Open Circuit or High Resistance in Motor Field.^ — Connect the 30-volt range of the voltmeter to the ends of the field coils as shown in Fig. 562. Close the starting switch. An open circuit in the field coil will be indicated by the reading of the instrument being equal to the battery voltage. Try all sections of the field. A good field will be indicated if the instrument reading is zero or nearly zero. A reading which is somewhat lower than the battery voltage and not near to zero indicates a field of high resistance. Look for loose connections between sections of the field if high resistance is indicated. JOB 164. Open Circuit or High Resistance in Motor Armature. — Connect the 30-volt range of the voltmeter to the armature terminals as shown in Fig. 563. Close the starting switch. If the voltmeter shows a reading equal to the voltage of the battery, the armature is open. A good armature will be denoted by a very low reading. A high resistance will be denoted by a reading somewhat lower than the battery voltage but considerably above zero. An open circuit may be in the brush leads. These should be carefully 474 Automotive Trade Training BATTERY 5TARTl/\/G 5WJTCH Fig. 5G2. examined. Other causes may be burned-out coils or broken wires in the coils, or brushes not bearing on the commutator because the spring tension is poor; worn out brushes; brushes stuck in the holders; poorly fitted brushes; high mica; low segments; loose or poorly soldered connections. If the open circuit is found to be in' the armature, the same should be disconnected from the field and one cell of a storage battery in series with a lamp bulb connected to the brushes as in Fig. 564. Connect the three- volt range across the brushes and note the reading. If it is equal to the battery voltage there is an open circuit in both halves of the armature. If it is less than the battery voltage, connect one of the test cables to a segment lying under a brush and the other cable to the adjacent segment as shown in Fig. 564. Move the lead on around the commutator one segment at a time, and if the deflection gradually increases to approximately the value obtained across the brushes, the half of the armature tested does not contain an open circuit. BATT£-RY STARTINS SWITCH Fig. 563. Starting Motors and Generators 475 20CAN0LE POW£^ Head L/G*^r Bulb Fig. 564. If a segment is reached on which the deflection suddenly increases to approxi- mately the value obtained across the brushes an open circuit exists in one or more of the coils included between the test leads. The other half of the armature can be tested in the same manner. In order to test the coils lying under the brushes the armature should be rotated slightly and the test repeated. High resistance in the armature circuit may be due to broken coil wires which are lightly touching at the break, poorly soldered connections at the commutator bars, poor bearing brushes, and dirty commutator. JOB 165. High Resistance in Ground Connection. — Connect the 30-volt range of the voltmeter to the terminal of the battery which is grounded (usually the BATTERY 3TAieTlNG 5WITCH Pig. 565. 476 Automotive Trade Training negative is grounded), and the frame of the car. When doing this be sure that all paint or other insulating substances are removed and that connection is made to the metal. Upon closing the starting switch no indication will be obtained if the ground connection of the car is good. If it is poor, a deflection will be obtained. To remedy this condition remove the ground connections between the battery and the frame of the car. Clean the connection lead and thfe frame where the connection is made. Give the cleaned surfaces a coating of white lead and make the connection again, being certain that it is tight. Refer to Fig. 565. JOB 166. High Resistance in Battery Terminal. — This may occur because the joint between the link connecting two cells and the terminal connected to a set of plates are poor or loose. Connect the 30-volt range of the voltmeter as shown in Fig. 566. Close the starting switch. No indication will be obtained 'if the joint is good, but if the joint is defective there will be an indication. Try all joints in this manner. '• s^rrfjey 5TA/er/N6 SWITCH Fig. 566. JOB 167. Short Circuit in Motor. — If, when the instrument is connected as in Fig. 567, an indication is obtained which is much less than the battery voltage, there is a short circuit in the motor; or if the car has a grounded system there may be a ground in some part which should be insulated. When these conditions are indicated, the field should be disconnected from the armature and the following test made: Connect a dry cell and either the Weston 6-10 Register or a six-volt twenty-candle-power headlight bulb in series with the field coils. Connect the three-volt range of the voltmeter across one of the field sections. Note the reading. If zero, the field section is probably short circuited. Repeat on the other sections. Fig. 567. Note. — To secure the best results from this test an instrument having a range of about 100-milli-volts should be used. The Weston Model 280 Garage Starting Motors and Generators 477 6 ]/. 20CP LAMP nAA/WW^ — M Fig. 567. Type Volt-Ammeter is particularly adaptable for this purpose. Refer to Fig. 578. If the field is found to be in good condition the armature should be tested for short circuited coils. This cannot be done with the model 441 Fault Finder. The test described is as made with the model 280 Garage type Volt-Ammeter. Fig. 568. Connect as shown in Fig. 568. Using the 100-milli-volt range, measure between adjacent segments of the commutator. A short circuited coil will be indicated when the instrument reading is zero or very near to zero as compared to the readings on good coils. The contact at the segments must be good, otherwise the results will not be reliable. JOB 168. Short Circuited Wiring to Starting Motor. — If the system is a two-wire, it may be possible for the insulation to become rubbed and a short circuit to result. To test for this, disconnect the wires from the starting motor, but be 478 Automotive Trade Training careful not to have the ends touch any metal parts of the car. Measure the battery voltage with the starting switch open, using the 30-volt range of the instrument. Connect the instrument cables to the wires which have been removed from the motor terminals. Close the starting switch. A reading equal to the battery voltage shows the wires are good. Zero reading, or a very small reading, indicates a short circuit. Note. — On one-wire grounded systems a ground on the one wire acts the same as a short circuit. See under wiring test, Job 173. aArreer 3TA^TWG5W/TCH Fig. 569. JOB 169. V Open Circuit in Wiring to Motor. — Connect the 30-volt range to the motor terminals as shown in Fig. 569. If there is an open circuit in the wiring there will be no indication on the voltmeter when the starting switch is closed. COMMUTATOe Fig. 570. Starting Motors and Generators 479 JOB 170. Ground in the Motor Armature.— Remove the brushes from the commu- tator and disconnect the field. Use a six-volt battery and a thirty-volt range of the voltmeter. Fig. 570 shows the connection to be made at the commutator and at the armature shaft. Any indication on the voltmeter denotes a ground. For the armature to be good the reading must be zero. Grounded armatures are usually caused by damaged insulation of the armature coils. In armatures having double v^indings. each of which is brought out to a separate commutator, each winding should be tested for grounds and then ihe connection made between the two armatures to determine if the insulation between them is defective. A reading indicates defective insulation. JOB 171. Ground in the Motor Field. — Disconnect the field so that its ends may be free and take care that they are not in contact with any metal of the car. Use the battery and voltmeter as in Job 170, making connection to an end of the field and the metal frame of the generator or motor. An indication on the voltmeter shows a grounded field. Zero reading shows a good field. On single unit systems the generator and motor fields are wound on the same frame. Test each field separately for ground to the frame, then attach the test leads to the two fields to see if their insulation is defective. A reading indicates defective insulation. JOB 172. Grounded Brush Holders. — On two-wire circuits all brush holders are insulated from the metal parts of the motor or generator. In the grounded return systems one of the holders is in metallic connection with the frame of the motor or generator. Only such brush holders need to be tested for ground as are intended to be insulated. Usually these are very readily detected by visual inspection. In order to make the ground test on brush holders it is advisable to either remove the brushes or to put pieces of paper under them to insulate them from the armature. Then with the voltmeter and battery connected as in Job 170, Fig. 570, connect the test leads to the metal of the brush holder and the metal frame of the motor or generator. If the insulation is good the reading will be zero. Any reading other than zero indicates a ground. JOB 173. Grounded Wiring to Motor. — Disconnect the wires from any apparatus they may be attached to. Be careful that the ends are not in contact with metal parts of the car. Connect the voltmeter and a battery as shown in Fig. 570, Job 170. Connect one of the test cables to the end of the suspected wire and the other test cable to the frame of the car. Zero reading means good insulation. Any other reading denotes defective insulation. On two-wire circuits test each wire. JOB 174. To Determine if Generator is Generating. — Connect the 30-volt range of the instrument to the terminals of the generator and run the engine at its normal sp'feed, Fig. 571. The voltmeter indication should build up to about seven volts on a normal six-volt system when the cut-out relay will close and the circuit through the battery be completed. If the voltmeter does not show any 480 Automotive Trade Training cur OUT ^t LAY Fig. 571. indication or one that is very nearly zero the field regulator is not working, Jobs 175 to 179, the armature may be open circuited, Job 181, the field may be open circuited, Job 180, or either may be short circuited. Jobs 182-183, or grounded, Job 184. curoun^ELAY CONTACTS , — mm-^ 3Ho/?r C/I^CUIT WIRE Fig. ^sn. ^STARTING Motors and Generators 481 If the voltage goes much above seven volts, it is an indication that the cut-out relay is not operating properly. JOB 175. Defective External Field Regulator. — With the instrument connected to the 30-volt range as shown in Fig. 572, place a short circuiting wire around the field regulator so as to cut it out of the circuit. If the voltmeter indication goes up to the proper value the regulator is defective and should be repaired. JOB 176. Mercury Tube Regulator. — When the mercury tube type of regulator is used the mercury tube and plunger should be short circuited when making this test. JOB 177. Series Field Regulator. — When the regulation is accomplished by a series field connected to produce a bucking effect, this should be short circuited as shown in Fig. 573. The instrument is connected to the 30-volt range. If the series field is open, upon bridging it with the wire the voltage will immediately be indicated. If the series field was short circuited within itself, the voltmeter would show an indication when the bridging wire was removed. The indication would increase above normal with increased speed of the engine. Caution. — If the motor is also used for starting purposes be sure that the bridge wire is removed before trying to crank the engine with the starter. cur our ^a AY r^^rtA/WWW Fig. 573. 482 Automotive Trade Training JOB 178. Vibrating Regulator. — When the regulator is of the vibrating type, bridge the resistor R with a wire as in Fig, 574, and connect the instrument to the 30-volt range. If an indication of about normal voltage value is obtained when the bridge wire is in place, either the resistor R is open circuited, or the contact blocks are not in good contact. It is well to clean the contacts carefully and make Fig. 574. CONTACTS OPEN >- ■< 1 /^E5I5T0^ - + 1 Fig. 575. Starting Motors and Generators 483 the test with the bridge wire removed. If the trouble has not been eliminated, try the resistor for open circuit. This is done with the engine stopped and a dry cell connected in series with the three-volt range of the voltmeter and the resistor as in Fig. 575. The contacts should be held open. If the resistor is not open circuited, an indication will be obtained. No indication means an open circuit. If the resistor were short circuited a voltage reading would be obtained when making test Job 174, but the voltage would increase above normal with increase in engine speed. JOB 179. Third Brush Regulation. — Failure of the generator with -this type of regulation may be caused by the brush not bearing on the commutator. An incorrect generated voltage ^would be due to the third brush being out of place. This can be corrected by shifting the brush until the proper voltage is obtained. JOB 180. Open Circuit in the Shunt Field of Generator.— Do not run the engine. Disconnect the field from the regulator and complete the circuit through the 30-volt range of the voltmeter as shown in Fig. 576. If the field is open circuited no indication will be obtained. CuroUTjeELAY e Fig. 576. JOB 181. Open Circuit in the Armature of Generator. — Apply the latter part of Job 164 forr locating open armature coils. Examine the brushes for contact and the connections to the brush holders. 484 Automotive Trade Training JOB 182. Shunt Field of Generator is Short Circuited. — Disconnect the field from the rest of the machine; connect the three-volt range of the voltmeter across the ends of the field. Then connect a dry cell across the field. If a short of any considerable magnitude exists the reading of the instrument will be zero or very nearly zero. If the field is not short circuited the indication w^ill be somewhat near that for the voltage of the cell. It will be a little lower but probably over one volt for a good dry cell. (Fig. 577.) Fig. 577. JOB 183. Short Circuit in the Armature of Generator. — This test is best performed with the Model 280 Garage Type Volt-Ammeter, as a lOO-milli-volt range is needed. The method to pursue is as follows: Disconnect the armature from Fig. 578. Weston Model 280 Garage Type Volt-Ammeter. Starting Motors and Generators 485 the rest of the machine and try for open circuited coils as In the latter part of Job 164. Then with a cell or battery connected in series with a suitable resistor, such as the Weston Special 6-10, manufactured by the Ward Leonard Electric Co., of Bronxville, N. Y., introduce a small current into the armature through the brushes. Using the 100-milli-volt range of the instrument, test between adjacent segments until the entire armature has been gone over. Short circuited coils will be denoted by a zero reading or by a reading very much less than that obtained on a coil which is apparently good. (See Fig, 568.) JOB 184. Grounded Armature or Field, or Brush Holders on Generator. — Proceed as directed under Jobs 170, 171 and 172. JOB 185. Short Circuit on Lines Between Generator and Battery. — Connect the ammeter as shown in Fig. 579 on the generator side of the cut-out relay. Run the engine at normal speed and note the reading of the ammeter. Then change the position of the ammeter so that it is on the battery side of the cut-out relay as shown in Fig. 580. The reading of the ammeter should be practically the same as before. If any large difference exists it is due to a short circuit in the lines between the battery and the generator. curour^aA'T Fig. 579. JOB 186. General Tests for Relay Trouble.— Connect as in Job 174, Fig. 571. If the relay does not operate, the reading of the voltmeter will go above seven volts for a normal six-volt system. This may be due to an open circuit in either the series or the voltage coils of the relay. 486 Automotive Trade Training carourje£LAr COf^TACTS Fig. 580. JOB 187. Open Circuit in the Voltage Coil of the Relay. — Connect the 441 instru- ment as indicated in Fig. 581. If a reading is obtained the coil is not open curooreeiAY \ Fig. 581. Starting Motors and Generators 487 circuited. If no indication is given, move the test lead to the other end of the winding. If a reading is now obtained the coil is open circuited. JOB 188. Open Circuit in the Series Coil of the Relay. — Connect the instrument as in Fig. 582. If an indication is obtained the battery connections, wiring and generator circuits are likely in good condition. Next move the test lead to the other contact point so as to include the series winding of the relay in the circuit being tested. If the winding is in good condition, the reading should be approximately equal to that in the first test. If no reading is obtained the coil or winding is open circuited. CUrOUT££LAY Fig. 582. JOB 189. FITTING BRUSHES AND SANDING COMMUTATOR. A commutator which is in good condition shows clean and bright although it may be of a purplish color. To clean, use kerosene on a rag and polish with a dry cloth. When a commutator has become roughened for any reason, it should be sandpapered with either or 00 sandpaper or cloth. ' SANDING COMMUTATOR. 1. Cut a strip of sandpaper the width of the commutator. 2. Pass this paper through under the brushes with the generator or motor in position on the engine. It is necessary in this work to remove only the inspection cover. 3. Keeping the ends of the sandpaper close together as indicated in Fig. 583, work the paper back and forth until the commutator is bright and smooth. Turn the commutator occasionally as the work progresses in order that all sides may receive the same treatment. 4. Polish the commutator with a rag and kerosene. 488 Automotive Trade Training SANDING BRUSHES. 1. This operation is similar to the above in that the sandpaper is the width of the commutator and the machine is not lifted from the engine. The sand side of the paper however is placed to the brushes rather than against the commutator. 2. Allow the normal spring pressure to be exerted on the brushes as the paper is worked under them. 3. Continue the sanding until the brushes are a perfect fit on the com- mutator. 4. This remedy will properly care for noisy squeaky brushes as well as insure the proper fitting of new ones. BRUSH 3ANO PAPER STR/P. Z BRU9H SANDPAPER SXFtlP. RldHy W/KV WRONG WAV SAND/NC BRUSHES RUSH ^ANOPAP^f^ S>TR1P WFJOfsTG V^AY fZlGHT WAV Fig. 583. Sanding Commutator and Brushes. JOB 190. UNDERCUTTING MICA. Turning Down Commutators. In service certain commutators will wear unevenly. The mica insulation between the commutator bars is harder than the copper bars and will not wear as fast. This is especially true in the case of generator brushes which, as a fule, are softer than the motor brushes. When this condition is evident the generator will not work properly, due to the fact that the mica holds the brushes away from the commutator. To correct this trouble proceed as follows. A high or low bar in the commutator will require the same treatment as tlic high mica, 1. Remove the generator and dismantle. 2. Place the commutator in the lathe. Starting Motors and Generators 489 3. Set the lathe tool to take a light cut over the surface of the commutator. Remove just enough metal to allow the commutator to come out round. 4. Sand the commutator. Run the lathe at a high speed. 5. Place a tool in the lathe which is so ground that it will undercut the mica. This tool should be held in the toolpost and cut the mica as the carriage COMMUTATOR BRUSHETS 1 1 1 COMnu-r/KT-OK START/NC G^OOVr f/N AffCA WITH 3-CO«NE.ReO FILE COMMUTATOR SL.OTTING. MICA WITH (^IE.C£ Of^ HAr.KS>/KYf 3UAOE. SEGMEIMTS SEdMEfi-rs, RIGHT WAY MlC/\ MOST- BE CUT* AWAY CL.£:/\N SETWCE/y &eGMe:/vrs>. SCOTT/NG MICA M/CA V/«0/V<3 WAY MICA MOST NOT se uePT With a thin E:a9AfP >sro/rt46£S>irr/r/?r Fig. 588. Oakland Wiring Diagram. Wiring and Lighting 495 It may, however, lead to trouble hard to locate, especially if similar g-rounds develop elsewhere in the lighting or ignition circuits. Wiring. — Since all automobile electric systems are of the low voltage type, it is very essential that all wiring be of sufficient size to carry the current readily, and that all splices in the wiring or cables be properly made and soldered. A connection a bit loose is very likely to offer so much resistance that current will not flow. Wher- ever splices are made the job should be most carefully taped to pre- vent the development of a short circuit. Where wires run close to the engine, or through points where the liability of heat, grease, or moisture affecting them is apparent, they are properly protected by loom. Loom may be of the fabricated rubber construction, or of the fiber type, or as in the case of more recent usage, of the flexible metallic type. Lighting Switches. — There are many types of lighting switches on the market. In some instances the lighting switch is used in con- nection with the ignition switch. The switch may have a separate push button for each light or set of lights, or it may be so constructed and wired to give only those combinations for which there is most need. These combinations are: Headlights full, with dash and tail lights burning, and head lights dim, with tail and dash lights burn- ing. Head Lights. — Head lights are measured by the diameter of the lens or the distance across the front of the reflector. They will vary from 8" to 10". A bulb of from 15 to 30 candle power is set at the point of focus as explained in a later paragraph, and in this way, due to the highly polished surface of the reflector, is made to throw a beam of light of thousands of candle power onto the roadway. Where no side lights are used the headlight will have either one or two bulbs. If two bulbs are used the upper one is a small one of low candle power and is used for city driving or where dimmers are needed. The large or high candle power bulbs are used for country driving, or where a strong light is needed. Where side lights are used they take the place of the small bulbs in the headlight. Where only a large bulb is in use in the headlight and no side lights are provided, two means of dimmiilg are used. The most common of these is to have the switch so arranged as to cut in a bit of resistance wire thus reducing the amount of current flowing to the headlight bulbs. The other method is to so wire the lights and switch as to throw the two bulbs in series. This will dim them quite effectually, but the same candle power bulbs must be used at all times. Dash and Tail Lamps. — These are frequently so wired and con- nected that one bulb burning out will put both out of commission. In other words they are wired in series. If a 6-8 volt system is in 496 Automotive Trade Training c u ^ ON OS u- 1— ( o « B IS S o t)c e C3 a. Q 3 rt u u n O ui u a- i-Hi" (§^ g 3 3 use the bulbs for tail and dash lights in series would be 3-4 volt. In most cases two-candle power bulbs are used. Where this system is in use the driver is aware instantly any trouble develops with the tail light. This may save him much embarrassment in night driving to say nothing of the added safety assured the motor car. Wiring and Lighting 497 498 Automotive Trade Training CIRCUIT DIAGRAM Tail and dash lights are not always in series, and when this is not the case the bulbs are the same voltage as the electric system. The candle power is two to four. Wiring and Lighting 499 500 Automotive Trade Training Spot and Search Lights. — These are designed for use as an auxiHary light. For roads not familiar to the driver and in showing up the side of the road when passing other vehicles they are well worth while. Some communities prohibit their use, but this is merely because of the unrestrained and abusive use of them. The safety of the occupants of the car is dependent on proper light on the roadway. The safety of the pedestrian is likewise dependent on proper light, but the glaring head or spot light is a source of danger to both unless the pencil of light is kept below the point of vision of the approach- ing car or pedestrian. Ammeters. — Nothing is more valuable to the driver than an ammeter which may be depended on. Its proper indication of the charging and discharging of the battery is invaluable. All current passing from the battery to the ignition or lighting circuit must first pass through the ammeter. Current used to operate the starting motor in cranking the engine is not passed through the ammeter. Fig. 593. Stewart Spotlight. Pig. 594. Stewart Searchlight. An instrument of sufficient capacity to register the output of the battery during the cranking operation would not be delicate enough to properly register the rate of charge and discharge under normal circumstances. A good ammeter such as the Weston instrument, ■with which many cars are equipped and which may be installed on any not so equipped, is shown in Fig. 609. This instrument or its equal will show the operator of the car many things about the opera- tion of his car which he needs to have exact knowledge of in order that the entire electrical system may be maintained in first class con- dition. By keeping a careful mental record of the proper reading of Wiring and Lighting 501 the ammeter the driver will be able to recognize the following con- ditions : 1. The proper discharge when the ignition switch is on and when the engine is idle or running. 2. The proper charge rate in the daytime when the lights are off and the engine driving the car at a fifteen mile rate, above or below that average point. 3. The proper charge rate at night time when the lights are being used and speeds are similar. 4. The proper discharge with the engine not running, when headlights are bright and all other lights are on. The proper amount of increase in discharge when a spot light is added to the regular lamp load. 5. The proper discharge when the headlights are dimmed. 6. The proper amount of current for operating the horn. 7. Whether there is a variable contact in the electrical circuit. 8. Whether the generator brushes are in good order. 9. v^hether the generator regulator is operating properly. 10. Whether there are certain types of leaks or short circuits in the electrical system when the car is standing idle. Fig. 595. Stewart Electric Horn. Voltmeter. — The voltmeter is not a part of the regular equipment. Its purpose is to show the pressure of the electrical circuit just as an air gauge shows the pressure in a tire or in a compressed air tank, its use in making electrical tests is explained elsewhere. Fig. 610 shows the Weston Voltmeter. Junction and Fuse Boxes. — In certain systems as employed by the car manufacturers all the wires forming the lighting and ignition circuits (low tension) are brought together at a central point in a fuse box, or junction box. At this point the proper weight of fuse is placed in circuit to protect that part of the system to which the wires lead, from injury due to too heavy a discharge of current. Not 502 Automotive Trade Training Fig:. 59G. Single C o nt a c t Bayonet Base, Standard for automobile lighting. all cars are so equipped and where not so cared for the system is frequently protected by one central fuse. Bulbs and Sockets. — The bayonet base has come to be adopted as standard for the miniature bulbs used in automotive equipment. The minia- ture bulb v^ith the screw^ base is not used to any extent for this type of work. Its use was dis- continued because of the liability of the vibration causing the bulb to work out and break contact. The single contact bayonet base is proving the most popular due to greater simplicity of the sockets and the entire wiring system. The Proper Lamp for the Service.* — In the design of miniature Mazda lamps, it is the aim to provide a product which wil] operate at an economic balance between efficiency on the one hand, and lamp life on the other. This means that the question of operating voltage must receive close attention, for both factors are very sensitive to voltage conditions ; the higher the voltage at which a given lamp is operated, the higher the efificiency of the lamp and the shorter its life. For the best performance, incandescent lamps must be supplied with constant voltage (in some cases, constant current) of the proper value. Miniature lamp service is, in general, however, such that the lamps must be designed to give the best possible operation over wid^ ranges of voltage. The characteristics of the energy supply — whether storage cells, dry cells, battery generator systems, magneto, or central station service — must be carefully taken into account. Lamps must be designed to operate efficiently and to give satisfactory life ; they must not burn out in an unreasonably^short time at high voltage and they must give fair illumination during- the time they are operating at low voltage. o JiLSO NOTANCHOHEO rUcimeni Forms Used in Miniature M/IZOfI Ump9 Fig. 597. Design of Lamps for Use with Storage Batteries. — In the design of lamps for use with storage cells, it is necessary to take into con- sideration the voltage variations which occur throughout the entire time of discharge. For example, a lead-type liquid-electrolyte storage cell, the type at present most commonly used with miniature lamps> ♦Courtesy, National Lamp Works. Wiring and Lighting 503 4* /4 „ '""^ *-- >, 1 f ) r &6 \ ) W Fig. 598A. Storage Battery Discharge Curve. has an initial open-circuit voltage of about 2.2 volts per cell. During discharge, this voltage rapidly drops to slightly above two volts, from which point the decrease in voltage is very slow and uniform for a considerable period, depending upon the rate of discharge and the capacity of the battery. As the cell approaches exhaustion, the volt- age again decreases very rapidly. Due to destructive chemical action which may take place within the cell near exhaustion, it is not con- sidered good practice to allow the voltage to drop below about 1.8 volts, and this value represents, therefore, the lowest working volt- age of the cell. The curve of Fig. 598A is typical of the continuous discharge characteristics of lead-type liquid-electrolyte cells in gen- eral. The rate of discharge and capacity of the cell afifect, of course, the voltage which the cell maintains. f^ ' t-Z *^ -^ ///n /•O '"^ --. Co^ Y^£:ic^ T"" h^ pS^^. t"^ ^ ^^ ^ - X OA M.9 HOtJR^ Fig. 598B. Typical continuous and intermittent average discliarge voltage curves for No. 6 dry cells discharging through miniature mazda lamp. 504 Automotive Trade Training Another factor which influences the design of miniature Mazda lamps is the condition of charge of the battery during the time the lamps are operating. In certain hand lanterns, for instance, the lamp operates over several complete discharge periods of the battery. In electric vehicle service, the battery is seldom allowed to discharge to a point near exhaustion, and the lamps must be designed therefore for a higher average cell voltage. With the conditions of service known, it is possible to calculate the voltage for which lamps should be designed in order to give the desired average life on that particular battery. Since these calcula- tions are somewhat involved and are influenced to a large extent by physical limitations in lamp manufacture, it is requested that those engaged in the development of new apparatus employing miniature lamps consult the lamp manufacturer at as early a stage of develop- ment as possible. Design of Lamps for Use vrith Dry Cells. — In the case of dry cells the individual voltage of the cells will vary widely, depending upon the composition of the cell. On continuous discharge, where a cell does not get a chance to recuperate, the voltage will show a con- tinuous drop from the initial voltage. When the cell is on intermit- tent discharge, the discharge curve is composed of a succession of periodic discharge curves, each succeeding curve having lower maxi- mum, minimum, and average voltage values. Due to the recupera- tive action, the average voltage of a cell in intermittent service may be considerably higher throughout the useful life of the cell than will that of one used for continuous service. Fig. 598B shows typical in- termittent and continuous discharge curves obtained from dry cells discharging through Mazda lamps. A period of at least two hours was allowed between the periodic discharges for recuperation. Experiments show that in the ordinary commercial cell after two hours* recuperation, further voltage rise and capacity increase are negligibly small. In general, for a given discharge rate, the shorter the periods of service, the higher will be the averages of the periodic discharge voltages and the longer will the cell maintain its voltage. However, when a cell is allowed to stand unused for long periods, the averages of the periodic discharge voltages may fall off even more rapidly and the useful life of the cell be actually less than with longer discharge periods and shorter intervals between such periods. Before the lamp voltage best suited to a dry battery can be determined, it is necessary to decide to what degree the illumination may decrease from the normal and still serve the purpose at hand, to express this in terms of voltage and to consider the usefulness of the battery at an end when the battery voltage has dropped perma- nently below this value. The procedure is as follows: The voltage Wiring and Lighting 605 curve of the particular type of battery in question is taken under certain conditions of load from initial voltage to the point where the voltage has dropped to 0.7 volt per cell in the case of dry cells of the standard No. 6 type or to 0.5 volt in that of flashlight cells. The voltage curve between these points, translated into terms of lamp life, forms the basis for the lamp design. The discard point of the battery is considered as that point in the discharge when the volt- age has decreased to 60 per cent of the mean effective lamp volt- age. This naturally varies considerably in different types of cells, one of the important factors being the cubical content. Lamps must be designed in a wide range of voltages to suit the different styles and capacities of dry cells in common use. The voltage rat- ings are, however, purely nominal and do not represent the actual design voltage. For example, at present, flashlight lamps for use on two-cell batteries have nominal ratings of 2.5, 2.7, and 2.9 volts depending upon the capacity of the battery with which they are to Fig. 599. Focus Adjustment on Headlamp for Standardized Military Truclc Class B. be used. Periodic tests on batteries are conducted to insure a lamp product suited to modern battery product. Referring again to Fig. 598B it is seen that for all values of volt- age higher than 0.7 volts, the average voltage curve on intermittent discharge lies above the continuous discharge curve. Hence, a greater proportion of the total energy of the cell may be utilized on intermittent service than on continuous service. Moreover, the varia- tion of voltage throughout the greater portion of the life of the bat- tery is between narrower limits and the candle-power of the lamp is more nearly constant. 506 Automotive Trade Training Design of Lamps for Use with Battery — Generator Systems. — < Lead storage batteries in combination wtih generator systems are a third type of energy source much used for miniature lamps, particu- larly in automobile and motor-boat service. There may be as much as 35 per cent difference betw^een the voltages at w^hich the lamps operate v^hen the engine is idle and the battery is near exhaustion, and when the engine is running and the battery is in a state of satura- tion. It is necessary to design the lamps for such service to give fair illumination at a low voltage and to give satisfactory life perform- ance despite the voltage variations above normal. Large numbers of tests conducted on a large number of the various makes of auto- mobiles under widely different conditions of service have made pos- Esfe'*^' ■1 fh p^^^^^ ■ 1 ^ 'Shijum M I 1 1 i \ -^^ ^^ ^,^ 1 IP^ J Fig. 600. Sectional View Cadillac Lamp. Head Fig. 601. Gray and Davis Focusing Device. sible the design of lamps adapted to battery-generator systems where the average normal voltage fluctuation is between 6 and 8 volts, 12 and 16 volts, and 18 and 24 volts. Lamps for this service are rated 6-8 volts, 12-16 volts, and 18-24 volts, respectively. Design of Lamps for Magneto Lighting Systems. — The straight magneto system of energy supply is about the most difficult system existing for which to design satisfactory lamps. The voltage varies :n about direct proportion to the speed of the magneto. The magneto speed in turn, usually varies directly as the engine speed, with the lesult that the lamp is called upon to furnish illumination over an extremely wide range of voltage. In the design of lamps for mag- neto service, the aim is to provide a lamp which will supply sufficient illumination at the lower engine speeds yet which will not burn out Wiring and Lighting 507 in an unreasonably short time when the engine is running at high speed. Lamps which meet these requirements will supply satisfac- tory lighting at the usual running speed. Some Fundamentals of Light Projection. — A large proportion of all miniature Mazda lamps are designed for use in equipments which C - SOURCE IN FRONT Of" FOCU^ Fig. 602. Beam ckaracteristics of Parabolic Reflector with light sources in three Positions. project the light in relatively narrow beams. In flashlight service, the lamp is usually equipped with a reflector or lens system which, while directing the light in a beam, does not confine it closely; in headlight and spotlight service, the beam is confined to a considerably narrower angle. In practically all cases, the desired effect is secured through the use of a polished reflector of a contour which confines the light to the desired angle. The narrowest beams of light are obtained with paraboloids, that is, with reflectors whose surface is formed by revolving a parabola about its axis.' When a source is placed at the focus of a parabolic reflector, the light rays striking the reflecting surface are projected 508 Automotive Trade Training forward in a beam, the central ray of which is parallel to the axis (See A, Fig. 602). When the source is placed behind the focus, the beams diverge as shown in B. When the source is in front of the focus, the beams converge, cross, and diverge as shown in C. Contrary to the idea sometimes advanced no light is lost by the crossing of the beams. Every point on the surface of a parabolic projector reflects a cone of light whose spread depends upon the size of the source and the focal length of the reflector, as shown in Fig. 602. It will be seen, in other words, that the spread of the beam is determined by the angle pig. eos. Appearance of which the light source intercepts at the surface ^p^^ ^""""SeSdHghts ^^''^"^^'^ of the reflector. A source which presents its largest dimension toward a part of the reflector remote from the focus will, therefore, give a narrower spread of beam than when it presents the largest dimension to the closest part of the surface. The fila- ments of Mazda lamps designed for headlight and spotlight service are condensed into as small a space as practical, and when set at the focus of a parabolic projector, provide a beam which is very highly concentrated. A position of the filament, either ahead of or behind the focus, will result in a broader beam ; but if. the filament lies behind the focal point, the reflecting surface will catch and reflect a slightly larger portion of the light emitted by the filament. Pig. e04. Appearance of Spot from Headlights with light source too far ahead of or behind focal point. Wiring and Lighting 509 The motorist should make a very careful study and adjustment ci his headlights. The adjustment can best be accomplished by standing the car on a level roadway and projecting the headlight beams, without any glare-reducing device, upon a flat surface perpen- dicular to th'" axis of the beam, at a distance of not less than 25 feet. The lamps . hould then be adjusted in the reflector by means of adjust- ing screws or other devices now furnished on all good headlights, until the smallest spots of light obtainable are thrown on the distant surface. The lamps will then be at the focal points of the reflectors. The appearance of the spot of light projected by each headlight snould in this case be approximately as shown in Fig. 603. If the lamp is too far ahead of or behind the focus, the spot should appear about as in Fig. 604. With the lamp in focus, careful measurements should be made to determine whether the centers of these spots of light are any higher than the centers of the headlights themselves. If they are, the headlights should be bent down until the centers of the beams come slightly below the horizontal. There are three general types of glare-reducing devices for use on automobile headlights : One type operates by diffusing the light, another by refracting or reflecting the light rays ; the third by cutting off the rays which would be projected upward. JOB 191. SPLICING LIGHTING CABLES. It is frequently necessary to splice a wire in order to lengthen it. Another splice is the one in which it is necessary to cut in on a circuit for a branch to some special instrument as the search or spot light. 1. In making the end splice the first step is to determine the length of end necessary to be exposed in order to splice. 2., With a sharp knife run a light cut around the wire at this point just cutting through the outer layer of cotton covering. To make this cut in a care- less manner is certain to result in sever- ing some of the fine strands. 3. Using the point of the knife, split the insulating material from the first cut made to the end of the cable. This ope- ration requires care as the knife actually cuts down to the wire strands. 4. Open the cable at the end and pull out the strands of wire through the slit just made. 5. Use the knife to finish the first cut made. This is easily accomplished since the cable strands are kept twisted together and may thus be pulled away from the insulation while same is being trimmed. Fi|r. 605. Varying the Dimming of Headlights. (Hudson.) By tying two of the coils together the amount of resistance wire in circuit on dimmer is lessened and lamps burn brighter. 510 Automotive Trade Training I^^^H^^pv 6. With an end of each length of wire free of all insulation the two are twisted together in the form best suited for the work in hand. 7. Treat the splice with soldering paste and solder carefully. Make Wiring and Lighting 11 certain that the solder runs into the strands and does not merely rest on tiie outer surfaces. 8. In making a splice where the end of the new piece of cable is joined onto the old cable, at some point other than the end, the first step is to remove the cable insulation at the point desired to tap in on the main circuit. Do this work most carefully in order that not one of the small strands is injured. Make the splice, solder and tape as suggested above. JOB 192. SWEATING OR BURNING ON A TERMINAL. It is frequently necessary to sweat or burn on a new terminal for some of the leads of the electric system. This work may be necessary in reference to the storage battery terminals or any of the numerous terminals such as are' found about the ammeter, the generator, or the starter. Burning or sweating in this case means having the solder worked while in the liquid or melted state. 1. Select the new terminal with reference to the requirements of the job. Where the old is still in such condition as to permit of comparison, the new terminal should be matched to it. 2. Prepare the cable by removing as much of the in- sulation as may be necessary to permit the strands to en- ter the terminal properly. 3. Twist the strands to- gether and tin them. To do this they must be clean. The soldering iron may be used to flow the solder onto the cable end; the end may be treated with soldering flux and dipped into a pot of melted solder, or the end may be tinned by the use of the lead burning or other light flame. 4. Next prepare the terminal by tinning the in- side of it and running it full of melted solder. 5. Keep the terminal hot. The end of the cable previously tinned is heated and the two while hot are forced together. This will crowd out some of the solder in the terminal, but it is better to have too much solder than not enough. 6. When cool, the job should be cleaned and taped if necessary. Fig. 607. Reverse side of Weston Ammeter, terminals and binding posts. Note _0 • TO rH£ UGHTtNG SYSr£M TO fGNfr/ON srsr£M /9AfM£r£/9 cur-our BATTERY ## GENERATOR f 3 Fig. 608. Sugjrestive diajrram for wiring an ammeter. (Weston.) 512 Automotive Trade Training JOB 193. ATTACHING WIRES TO LAMP SOCKETS. 1. Remove the insulation for such a distance as is necessary to expose enough cable to enter into the socket. 2. Sweat the ends of the stranded cable together. (Job 192.) 3. Carefully insert the sweated ends of the cable into the small tubes mounted in the sockets. Make, certain that the small set screw is backed out sufficiently to allow the cable end to enter. Use a small screw driver for this screw, otherwise the hard rubber socket may be broken. 4. When all is properly assembled, tighten the binding screw. 5. Never pull or jerk on the lamp wires as they are subject to injury. They may be pulled from the socket if roughly handled. The hard rubber nut fitted onto the end of the socket should always be kept turned up snug. JOB 194. INSTALLING AND WIRING AN AMMETER. 1. In some cases cars are not equipped with an ammeter. To install one, first select the instrument of a style suitable to mounting in the space available. Where an ammeter is placed in circuit instead of the "telltale" or "ofif and on" instrument the same wiring may be used. 2. Cut the instrument or dash board to permit of mounting the ammeter selected. 3. Learn the most suitable points to cut in on the circuit between the battery and the lighting and ignition leads. All current used should be made to pass through the ammeter, excepting, of course, the starting current which is very heavy. 4. Consult the wiring diagram, Fig. 608. 5. Solder and tape all splices. 6. Secure all cables so that they are free of oil, grease, or dirt and likewise of the danger of mechanical disarrangement and injury. 7. Test the instrument when all connections are made. If it shows charge when the lights are burning and the engine idle, the wires on the back of the instrument will want to be changed, or reversed. If it shows discharge, the connection is correct. Fig. 607 shows these connections or binding posts and screws on the back of the ammeter. Fig. 609. Weston Ammeter for mounting. Fig. 610. Weston Voltmeter. Wiring and Lighting 513 JOB 195. POLISHING LAMP REFLECTORS. Lamp reflectors are made from brass, silver plated, then polished very highly. The secret of keeping them bright and in good condition is keeping the air excluded. Excluding the air by means of properly fitted dust rings means that the moisture and road dust will not be carried in as is the case where the small currents of air find their way into the lamp. In case they do become dusty the best way to remove the dust is by means of blowing it away. A stream of compressed air is best for this. Where the reflector is old and tarnished it may be necessary to remove and repolish it. Hand polishing will not restore the original luster but may result in a temporary improvement. Not all mechanics nor lamp manufacturers are agreed on the proper method to follow in polishing the reflectors when this work is done by hand. The following method is the one recommended by the Gray and Davis Co. 1. Use crocus or rouge with a clean chamois. Have the chamois free of dust and retain it for this purpose alone. 2. To polish use the chamois with rouge dampened with alcohol. This will remove the heavier spots of tarnish. 3. After this is all wiped off with the first piece of chamois, a second piece is used with dry rouge, to give the reflector a very high polish. 4. In polishing use a ro- tary motion as indicated in Fig. 611. Not all workmen favor the rotary motion for polish- ing reflectors. A motion di- rected from the rim of the re- flector to the center is less likely to leave marks. How- ever, either a perfect rotary motion or a direct in and out motion should be used and no attempt made to change pro- miscuously from one to the other. Neither may good re- sults be expected if a haphaz- ard hit or miss sort of effort is made. Where the chamois and rouge are not available, good results may be obtained from the use of lamp black and a fine grade of tissue paper. Many other methods of greater or lesser value are in use. As a final word of caution it is suggested that whatever materials or polishing stroke is used that the pressure be not too great. Resilvering of the reflectors is work always handled by the lamp manu- facturers or the plating establishments. Fig. 611. Polishing Lamp Reflectors. JOB 196. None of the Lights Operate. — If none of the lights operate either the battery is run down, or there is an open circuit between the lighting switch and the battery. Connect the voltmeter across the battery as shown in Fig. 612, using the 30-volt range. The reading of the voltmeter is the open circuit voltage of the battery. 514 Automotive Trade Training UI^HMQ ^mrcH \ I I 4" and 5" tires. Fig. G24. Repair Fabric. Vulcanizing Cement, C-15. — C-15 Cement is made of the highest quality materials and is of a heavy consistency. One gallon will make two gallons of good cement when thinned down with a good solvent. Furnished as follows : Pint cans, 1 gallon cans and 5 gallon cans, 55 gallon steel drums. C-16. — C-16 Cement is the same as C-15. It has been thinned to the proper working consistency. This cement is furnished because many repair men find it difficult to obtain a high grade solvent for thinning C-15 Cement. 526 Automotive Trade Training Furnished as follows : 1 gallon and 5 gallon cans. 55 gallon steel drums. C-25. — C-25 Cement is a quick cure vulcanizing cement especially compounded for use with G-180 and G-190 Tube Repair Gums. It is also used in the application of Goodyear Cord Patches. Furnished as follows : 1 pint cans, 1 gallon and 5 gallon cans. 55 gallon steel drums. C-35. — This cement is of the finest quality and is used for apply- ing valve patches, splicing inner tubes, applying cold patches of any description and reliners. It is a self-curing cement. Furnished as follows : 1 pint, 1 gallon and 5 gallon cans and 55 gallon steel drums. ^OOD^EAR C-16 lizing Ceme '-—-J C-15 uicanizing Cem*^ ellt ! Goodyear Tire & ^^ Fig. G25. Regular Cure Vulcanizing Cement. Reliners. — The Goodyear Reliner, properly applied, acts as a new backbone to a "worn" casing and usually adds many miles to its life. Furnished as follows : 30 X 3 3 ply 30 X 31^ 3 ply 32 X 3>^ 3 ply 31x4 4 ply Goodyear Reliners are made of high grade, new American fabric. The ends and sides are stepped down to a feather edge. The ends have rubber tips which prevent chafing where the ends lap. Valve Patches. — The patches are made of tough resilient rubber. 30x3 3 ply 32x4 4 ply 35x4^ 4 ply 30x31^ 3 ply 33x4 4 ply 36x4>4 4 ply 32x3>^ 3 ply 34x4 4 ply 35x5 4 ply 31x4 4 ply 34x41^ 4 ply 37x5 4 ply Tire Care and Vulcanizing 537 reinforced in the center with two pHes of fabric. They are rigid next to the valve, but the edges stretch readily with the tube. Furnished as follows : No. 1 for 3", 3>^", 4", 4>4" and 5" tubes. Semi-Cured Retread Bands. — Goodyear Retread Bands are of the same quality and dimensions as the treads on Goodyear Tires and excel in wearing qualities, construction and appearance. Goodyear Retread Bands give exceptional service when applied with under-cover stock (G-lOO, G-105 and G-115) and are cured properly. The system of grouping sizes enables the repairman to take care of all passenger car size tires by stocking only five sizes and two styles of retread bands. These bands may be had in either the All-Weather or Ribbed Tread. Soapstone. — Goodyear Soapstone is the best grade that can be purchased. It should be used in the form of a stiff paste to preserve tread designs, and to dust over repairs to prevent them from adhering to the molds and inner tubes. Furnished in : 25 pound sacks. Fig. 626. Sectional Air Bag. Sectional Air Bags. — Goodyear Sectional Airbags are made of a specially compounded gum and high grade closely woven fabric. The inside is lined with a heavy gum tube especially compounded to retain its good qualities even after long continuous use. The bag is reinforced at each end with a reinforcement of heavy fabric. A loop of tape is attached to facilitate removing the bag from the casing. Instructions as to the proper use and care of sectional airbags are furnished with each bag. Furnished as follov^, in ^4 circle and 1/5 circle: 3';, Sy/, 4", 4^", 5" and 53^" bags. WHY REPAIRS FAIL Most repair failures are due largely to oversights and careless- ness on the part of the repairman. They happen rriainly because a detail of a process has been overlooked. Repairmen, as a general rule, are quite sure of their materials and major methods. However, if they are kept busy with customers as well as doing the actual work 528 Automotive Trade Training in the shop and are called frequent- ly from their work, the repair work is bound to suffer. Repairing re- quires careful supervision. The master repairman who is required to take care of customers should have an assistant well trained to do this supervising. 1. Cement, if not allowed to dry thoroughly, causes a porous condition between new and the old material. This condition will show up black and glossy. The pores will be small. 2. Cement, if allowed to dry too long, loses its adhesive proper- ties, thus permitting separation. This condition can properly be called "air cure" because the air attacks the cement, causing one form of cure. 3. If dust is allowed to settle on the repair before it is completed and it is riot removed, it permits separation after the cure, because the plies of raw materials do not adhere to each other. 4. Oil or grease may be in either the old tread or the casing as well as in the solvent or gasoline. This is caused by the tire standing in pools of oil or by running on oiled roads, especially when the tread is badly cut. This allows the oil to soak through and penetrate to the fabric in the carcass. 5. Lack of pressure in a cure also causes a porous condition. In most cases it can be detected by poor flow of the raw material. It is caused by leaky sectional airbags, poor bead molds or bad clamps or from sectional airbags not fitting the inside of the casing properly. 6. Buckles inside the casing, and cracks on the outside of the casing along the tread line in sectional repairs are usually caused Fig. 627. Semi-Cured Tread Bands. Tire Care and Vulcanizing 529 by too much pressure exerted on clamps in placing the casing in the cavity of the mold. The mold cavity is then smaller than the casing. 7. Clamps properly fitted should be just tight enough to form a complete mold around the casing. 8. Do not handle repair material any more than can possibly be helped. 9. In washing a repair with solvent the rag should be slightly moistened and not saturated. 10. Occasionally it is found that after curing a casing, the first layer of fabric bulges and upon opening it with an awl gas comes out. This condition is usually caused by a deteriorated condition of the carcass. SUGGESTIONS FOR HANDLING REPAIR MATERIALS 1. Raw gum and fabric should be kept in a cool, dry place. 2. If possible, the stock room should be dark. It is imperative that the raw stock should not be near an open window nor in a direct draft or sunlight. Dampness should be avoided. Raw stock should never be allowed to stand on the floor or on a table. Wherever pos- sible, they should be placed on a rack with a rod running through the shell on which the material is rolled. 3. In warm weather raw gums will sag from their own weight, even when tightly rolled on the holland. To overcome this, it is advisable to turn the stock at frequent intervals. 4. Repair gums and fabric received in cold weather sometimes appear hard and lifeless. They are merely frozen. Freezing does not affect the stock. If received in this condition it should be put in a warm room a short time to thaw out. 5. In order to get good results from a repair it is essential that the stock be perfectly clean when used. 6. Dirt and bloom, or free sulphur, always collect on uncured rubber. If this is not thoroughly washed oflf with gasoline before used in a repair, an imperfect union will surely result. 7. Gums and fabrics that have bloomed sometimes appear old and do not appear to be in condition to be used. If the bloom and dirt are washed off with solvent, the gum will give good results. 8. The quality of gums or fabric is not necessarily determined by the length of time before they start to bloom. All uncured gums are bound to bloom eventually. 9. Always save your scrap gums. They can be returned for credit. The value of this material when returned depends largely upon its condition. The gums should be kept separate and free from foreign materials. 630 Automotive Trade Training 10. All repair fabrics should be cut on the bias at an angle of 45 degress. A repair made of fabric cut on the straight becomes hard and often bulges. 11. Tread stock dissolved in gasoline or solvent does not make a good vulcanizing cement. It is also costly. 12. The most economical plan to make cement is to buy good grade cement gum. 13. Make test cures of your rav^ gum and fabric at least once a week. 14. For testing open heat and sectional repair work, build up a section on an old tire and cure in the usual manner. Cut from this cured section a piece about an inch wide and separate the different stocks wherever there should be a union. 15. By pulling these slowly, it is easy to see whether you are getting good strong unions in your cure. You can also judge as to the cure by the condition of the stock. 16. A good method of testing rubber for cure is to cut a narrow strip about 3^" wide in the edge of the piece to be tested. By pulling this, the elasticity and "set" can be determined. A well cured stock should be elastic and lively, and the strip should return to very nearly its original length. 17. When raw gums do not flow, it is a pretty sure sign of in- sufficient pressure on the inside of the casing. 18. Always inflate sectional airbags to 70 pounds pressure. If the bag or coil is not large enough to fill out the casing properly it should be padded with strips of old fabric until it fits snugly. 19. Be sure that the fabric in the casing to be repaired is dry before you proceed with a repair. Fabric separation will result from failure to heed this warning. An inside patch vulcanizer serves as an excellent drier. Temperature should not exceed 150 degrees F. in drying. 20. If extensive repairs are made on casings with separated fabric, the heat during the cure will expand the air between the plies and increase the separation. 21. When cutting rubber, dip your knife in water. It lessens the resistance. 22. The best way to repair a leaky splice is to insert a new section. 23. The life of an airbag can be greatly prolonged if the bag is handled properly. 24. Do not use an airbag as a building form. 25. Do not remove the air bag from the casing by pulling it by the stem. 26. When the tire has been placed in the mold, do not fasten Tire Care and Vulcanizing 531 the clamps down securely until after the airbag has been partially inflated. 27. Always dust the airbag slightly with soapstone before using. 28: When in use keep the sectional airbag inflated to 70 pounds pressure. 29. If a bag becomes porous, it can be repaired by forcing a small quantity of C-15 vulcanizing cement through the stem and into the bag. 30. Here is the method to use in doing this. 31. After removing the valve inside, clasp the bag between your hands, and exhaust as much of the air in the bag as possible. 32. Place the stem of the bag in the cement and release the pressure gradually until a small quantity of cement has been drawn in. Then roll the bag around so as to get the cement distributed over the inside. Allow the cement to dry. 33. Repeat the operation three times (using in all about one- fourth pint of cement). The bag is now ready for use. 34. When a tube splice is made by the acid cure process and it does not hold, it can usually be traced to one of the four following causes : 35. The cement was not dry. 36. The acid was too weak. Z7 . The splice was not made quickly enough after the acid was applied. 38. There was insufficient pressure on the splice after the union was made. 39. After an inner tube has been repaired, always test it in water to make sure that there is not another leak. PRACTICAL VULCANIZING HINTS 1. Undercuring of sectional repairs can often be traced to the molds. ' If the molds are clogged with dirt, or if air pockets are allowed to form in the molds, it takes longer to heat them and consequently, longer to cure the repairs. 2. Water collects in the molds occasionally, stopping circulation, with the result that, while the pressure may be correct, the tempera- ture of the molds will be too low to accomplish the cure in the pre- scribed time. 3. At least once a month the steam pipe should be disconnected and a strong current of compressed air should be blown through the molds. 4. A surprising amount of dirt and water will be dislodged by this process. 5. There will be comparatively little trouble from this source if your molds have a drain at the lowest point, where water is likely 532 Automotive Trade Training to collect, and a pet cock at the highest point to allow trapped air to escape. 6. An airbag that has been used in several cures becomes elongated and may extend beyond the ends of the sectional mold. This causes a ridge on the tire at the ends of the mold. To prevent this, bevel the edges of the mold back about half an inch. 7. Small cuts and fabric breaks in motorcycle tires can be repaired on the tube plate. 8. It is very important to know^ the relative degrees of tempera- ture to pounds of steam pressure. The foUov^ing table gives this information : Pounds Steam Pounds Steam Temperature F Pressure Temperature F. Pressure 227.2 5 280.6 35 239.4 10 286.7 40 249.8 15 292.4 45 258.8 20 297.7 50 266.8 25 302.6 55 274.0 30 307.2 60 This table w^ill not hold true in extreme altitudes or climates. In such cases it is v^ell to revise the table with the use of a ther- mometer so that you can- be sure of getting the required temperature^ with the designated steam pressure. 9. All metal surfaces that come in contact with the raw gum during the cure should be kept highly polished and perfectly clean. 10. Clean your molds or cores as follows: First, polish with fine emery paper or wire cloth. Then apply a solution of soap and water, or soft soap by means of a large paint brush. 11. In making cement, take a quantity of raw gum and cut it up in small pieces. Then place in a can together with a small quantity of high test gasoline and stir every hour or two until the gum has dissolved to the consistency of cream. 12. Cement should be thoroughly stirred each time it is used or the results are bound to be variable, due to the settling out of curing agents. Cement is like paint in this respect. 13. C-15 Cement, when ready for use should be of a consistency similar to that of cream or house paint. It should flow readily. 14. If C-15 Cement is found very heavy when purchased, or if it becomes very thick, it may be thinned with a good grade of gasoline (one that shows no oil residue) or benzol. 15. Where several gallons of cement are required daily, a small barrel or churn can be used to advantage for mixing. 16. During the time that C-15 Cement is being used, it should Tire Care and Vulcanizing 533 be stirred frequently. Poor results will be obtained unless this is done. 17. Never hang cemented tires in a draft or over vulcanizers to hasten the drying. Allow the drying process to take its natural course. 18. Vulcanizing Cement can be thinned by the use of a good rubber solvent. 19. Gasoline that will not leave a grease spot on white paper after it has been allowed to evaporate is a good solvent. Fig. 628. Akron-Williams Vulcanizing Kettle. 20. Benzine or energine are both good solvents and can be relied upon. 21. Grain or wood alcohol is not a rubber solvent and should never be used. The cement may appear thinner but it is of poorer quality. Instead of acting as a solvent it causes coagulation of the rubber particles. 22. So-called "high grade" or "more power" gasolines contain substances which make them unfit for use with rubber cement. 23. Low gravity solvents contain greasy residues which are de- trimental to cement. 24. Solvent should be added a little at a time and then stirred thoroughly before any more is added. 534 Automotive Trade Training Tire Care and Vulcanizing 535 25. Cement should be kept in covered containers when not in use. 26. Whenever possible cement should be stored in a cool, dry- room to prevent evaporation of the solvent. VULCANIZATION Vulcanization so changes the physical properties of rubber as to render it less plastic and more resistant to wear and mechanical strains. Vulcanized rubber is a product resulting from the chemical union of crude rubber and sulphur, and as heat accelerates all chemi- Fig. G30. Curing on hot plate. cal reactions we have employed the aid of steam to bring about a quick union of crude rubber and sulphur. It is generally known that other chemicals than sulphur are also used in compounding. These chemicals do not unite with the rub- ber but are highly dispersed throughout the mass and their presence gives to the rubber certain desirable properties such as resistance to wear and abrasion, resiliency, and strength. Sulphur and rubber combine very slowly under atmospheric con- ditions and this is what we call spontaneous cure. It takes months 536 Automotive Trade Training for this curing to materially affect the physical properties of the product, so we find this matter of little importance to the average vulcanizer. Now, according to certain laws of chemistry, an excess of any element entering into a chemical combination greatly accelerates the speed of reaction. It is for this reason that it is necessary to use an excess amount of sulphur. However, this excess, unless it is too great, does not in any way affect the physical properties of the vul- canized rubber. Rubber blooming is nothing but the excess of sul- phur in the vulcanized rubber working to the surface. It is also true that some of this excess sulphur never blooms, and as rubber ages there is a slow process of spontaneous vulcanization going on which is called "aftercure". It is for this reason that rubber when very old becomes hard and lifeless and has a tendency to chip easily. Well made repair materials are compounded with the correct amount of ingredients so that when properly cured the effect of "after cure" is reduced to a minimum. For the above reasons, to get good results it is absolutely necessary to use the temperatures and time recommended for curing the different repairs. Cures. — Following cures are recommended for curing passenger car tire and tube repairs: Tube Repairs. — The length of time necessary to cure a repair depends on its thickness. G-180, cured in thin sheets, cures in five minutes at 60 pounds steam pressure. However, when built up in repairs, a somewhat longer time must be allowed in order that the heat may penetrate and give a good cure throughout. On Tube Plate at 60 lbs. Steam Pressure: G-180 alone, five to eight minutes. G-180 with G-190 reinforcement, ten to twelve minutes, depend- ing on the thickness used. On Tube Plates at 40 lbs. Steam Pressure: G-180 alone, ten to fifteen minutes. G-180 with G-190 reinforcement, eighteen to twenty-five minutes, depending on the thickness used. Valve Patch with C-25 Cement. Cure 12 minutes at 40 lbs. Sec- tional Work (Built up as Described) : For full section and half section and quarter section. For Smooth Tread: 3", 3>4" 55 minutes at 40 pounds 4" 60 minutes at 40 pounds 41^" 65 minutes at 40 pounds 5" 70 minutes at 40 pounds Note : Add twenty minutes to time of cure when negative pad is used to preserve the tread pattern. Add fifteen minutes to time of Tire Care and Vulcanizing 537 cure when soapstone and jacket are used to preserve tread pattern. In curing a quarter section the additional time allowance for matrix or soapstone need not be added to the cure. Cure full section built in tire which has tread cut off for retread- ing: 3'\ 3y2" 25 minutes at 40 pounds 4", 4>^", 5" 30 minutes at 40 pounds Top Section: In sectional mold (2 plies stepped out). For Smooth Tread: 3", 3^" 50 minutes at 40 pounds 4", 4^" 55 minutes at 40 pounds 5" 60 minutes at 40 pounds Note : Allow fifteen minutes additional time when soapstone and jacket are used to preserve the tread ; twenty minutes when matrix is used. When top section is built in retread cure in regular manner. Side wall Cuts: Cure on hot plate or in sectional mold 50 minutes at 40 pounds when no plies have been cut out. When outer ply has been stepped out, cure as recommended for quarter section. When strengthening plies are put inside tire, cure same as retread in kettle. Cure for Negative Pad or Matrix: 20 minutes at 40 pounds in sectional mold. Tread Repairs : Cure 45 minutes for cuts about ys" deep ; 60 minutes for cuts about ^ " deep. Retread with All- Weather or Rib Tread Band: 3", 3^^", 4" 50 minutes at 40 pounds 43^", 5" 55 minutes at 40 pounds In retreading kettle. One-Third Circle Retreading: Cure at 40 pounds steam pressure: No. 1 Camel back, 3", 3^" — 55 minutes at 40 pounds steam pressure. No. 2 Camel back, 4", 4^" — 60 minutes at 40 pounds steam pressure. No. 3 Camel back, 5" — 70 minutes a.\ 40 pounds steam pressure. Cure at 50 pounds steam pressure : No. 1 Camel Back, 3", 3}^" — 45 minutes at 50 pounds steam pressure. No. 2 Camel back, 4", 4'^" — 50 minutes at 50 pounds steam pressure. No. 3 Camel back, 5" — 60 minutes at 50 pounds steam pressure. 638 Automotive Trade Training JOB 202. REPAIRING PIN HOLES AND SMALL PUNCTURES. 1. "Pick out" puncture to a small open injury. 2. Buff with emery cloth — stretch tube so that injury can be buffed thoroughly. 3. Wash with solvent to remove dust. 4. Apply two coats of C-25 quick cure cement overlapping the injury. 5. Then "drive" small "thread" of G-180 tube gum through injury so that it will form a rivet head on inside of tube. 6. Fill up injury flush with outside surface of tube — do not overlap on the outside. 7. Cure according to chart. 8. It is always well to use a piece of holland on the tube plate. Fig. 631. Correct method of stitching in gum. JOB 203. REPAIRING LARGE INJURIES AND BLOW OUTS IN TUBES. 1. Ragged edges of injury should be trimmed and thoroughly buffed. 2. Buff the side of the injury and the inside of the tube for a distance of 1'' around this injury. Wash this surface with a rag moistened with solvent. 3. Apply both inside for a distance of l" around the break and to the edges of the break two coats of C-25 quick cure cement. 4. Cut a piece of G-190 cured back tube gum with rounded corners, ^'^ larger than the injury. Insert on inside of injury with raw gum side next to the tube. 5. This inside reinforcement patch can be inserted by holding the patch with a pair of long-nosed pliers. Dip it in solvent and insert it before the solvent dries. When this is done, care should be taken to hold the reinforcing patch away from the tube on the inside, in order to allow the solvent to evaporate before stitching down the patch. 6. Fill up the injury, on outside, with G-180 tube gum, flush with the outside surface of the tube. Do not overlap at edges. This should not be Tire Care and Vulcanizing 639 filled in until the reinforcing patch has been allowed to dry for at least ten minutes. 7. Cure on tube plate, according to chart. Fig. 632. Injury trimmed out ready for repair. JOB 204. SPLICING INNER TUBES. 1. New section inserted in' the tube should be 5" longer than the old section cut out, thus allowing 2^/^" for the splice at each end. 2. The edges should be beveled to feather edge at an angle of approxi- mately 40 degrees. 3. One edge should be beveled from the outside and the other edge from the inside. 4. The edges of the inner tube itself should be beveled in the same manner as the section to be inserted. 5. Both tube and section should be buffed with emery cloth or wire buffer, 3" from each end. One end of the tube and section should be buffed on the outside and the other end on the inside. To facilitate buffing the tube may be put on a mandrel, 6. One end of the section should be lapped back 2^/^" on the female tube mandrel. 7. The end of the tube itself should be lapped back 5" and then folded back on itself 2%" on the male tube mandrel. 8. Apply two coats of C-35 acid cure cement. 9. Allow the first coat to dry twenty minutes; second coat, thirty minutes. 10. The two ends are then placed in position and acid or curing solution is applied, 540 Automotive Trade Training Fig. 633. Inserting inside reinforcement. 11. The lap on the female mandrel should be pushed quickly over the male mandrel and tightly wrapped with strips of rubber or cloth. 12. Allow the splice to be wrapped for approximately thirty minutes. Fig. 63i. Filling up injury on the outside. Tire Care and Vulcanizing 541 13. It is always well to slide the female mandrel forward so that 1%" of tube remains after cementing. This eliminates the possibility of an overlap at splice. 14. After applying acid or curing solution, the ends should be placed together and wrapped in less than eight seconds to insure perfect results. ACID CURING SOLUTION. Acid curing solution may be secured from the druggists or from the drug supply houses. The formula for this solution is given below: Fig. 635. Tube on mandrel ready to splice. 1.7 fluid oz. Sulphur monochloride (S Cl) to 1 gal. Carbon tetra-chloride (CCl). It is possible to vulcanize a splice on the tube plate. Those desiring to use this method should follow directions given in Job 305. JOB 205. VULCANIZED TUBE SPLICE. 1. Cut out the bad section of the tube to be spliced. 2. From another tube of good rubber cut a section 5" longer than the one removed. This permits of a splice at each end of 2^/4". 3. Turn back the ends of the section or tube. Roughen edges of both section and tube 2^" from the ends. Clean with gasoline. Fig. 636. Tube spliced and wrapped. 542 Automotive Trade Training 4. Cement with vulcanizing cement, two coats. The first coat should dry 20 to 30 minutes, then apply the second coat and let dry two or three hours. 5. Place about a tablespoonful of French talcum in the tube. This is used to dust the inside of the splice to prevent the edges from sticking together when vulcanizing. 6. With the talcum in the tube the ends may be evened up and the ones which have been turned back may be pulled over the other ends. Splicing mandrels may be used here if desired. 7. Secure two blocks of wood V^" narrower than the tube, but longer than the splice. Place one of these over each splice. It will take three cures of fifteen minutes each to finish the repair. 8. When cured inflate the tube after which the rough edges of the splice may be bufied off on the buffing wheel. JOB 206. COLD PATCHING. This method of repairing tubes is not to be recommended for greneral use. It is well, however, for the student to familiarize himself with the process. Fig. 637. Stitching down valve patch. The success of the work depends to a large extent on the proper roughing or sandpapering of the rubber to be joined. Always allow sufficient time for the cement to dry properly before assembling the patch on the tube. Patching cement is, at times, also used for applying reliners. 1. Find the leak. Roughen with sandpaper or rasp. 2, Clean with gasoline, and cement with patching cement. Tire Care and Vulcanizing 643 3. Secure a patch or piece of cured rubber. Prepare same as the tube. 4. Permit cement to dry from ten to fifteen minutes. 5. Place the patch over the injury and rub down good and firm. 6. In the case of a road repair the tube may be put into immediate use. JOB 207. APPLYING VALVE PATCHES OR PADS. The best method of repairing breaks in valve patches at the point where the valve stem comes through is to apply a new patch to the tube as described below. . Take all fittings off the valve and force valve back into tube. A hole is cut through the tube at the point where the patch was applied and the valve stem put in. The old valve patch is then repaired by filling the hole as described for large injuries and curing. 1. Buff, with emery cloth, surface of tube to which patch is to be applied. 2. Wash with solvent. 3. Apply two coats of C-35 acid cure cement. 4. First coat should be allowed to dry twenty minutes; second coat, thirty- minutes. 5. Apply acid solution to cemented portion of tube and immediately place patch in position. 6. Stitch patch down thoroughly, being careful to secure the edges. 7. Then wrap on the tire last or tube mandrel with strips of cloth and leave it in this position for thirty minutes. 8. Another method of applying patches is to apply C-25 quick cure vulcanizing cement in place of C-35 and curing on hot plate. JOB 208. REPLACING VALVE STEMS. 1. Around the base of the valve is a fabric reinforcement in the tube. Consequently the valve cannot be pulled out without rupturing the fabric. 2. To replace the valve stem, cut a hole in the tube large enough to remove the old valve stem, and insert the new one through it. After the new valve s«tem is inserted, repair this hole in the usual, manner, JOB 209. OUTER CASING REPAIRS. General Rules for the Preparation of Fabric Tires. — Punctures and small holes through the tires, and small fabric breaks can be repaired by the appli- cation of a built-up sectional reliner. The size and number of plies in this reliner depends upon the size of the tire and upon the condition of the plies. Four types of sections are used in the repair of large breaks in fabric tires. They are: quarter section, half section, full section, and inside section. A top section is used, but it will be taken up under the heading, "Tread Cuts and Retreading." The inside of the tire should be buffed thoroughly before the repair is torn down. After the carcass plies are stepped out the tire will be too flimsy to allow it to be buffed properly. The length of the section is determined by the following general rules, which apply to all types of sections. 1. All plies are stepped down l" in the direction around the tire. 2. Two plies are removed in the case of 3", 3^/^", and 4" tires; and three plies in the 4%" and 5" tires, unless the size of the injury warrants a stronger repair, this is, to a large extent, a matter of judgment. 3. A margin of 1^/^" is left between the last ply removed and the extreme point of injury. 4. The tread is laid back 1^/^" further than the first ply removed. 544 Automotive Trade Training Fig. RSS. Diagram of quarter section. JOB 210. TEARING DOWN QUARTER SECTION. A quarter section is used in the case of a tire being rim cut or with a broken bead, in 3", 3^", and 4" regular clincher casings. The length of the section is determined by the rules given above. It is necessary to remove- only two plies of old fabric. In the case of a quarter section, the side wall is removed 4" from the extreme points of injury. The ends are skived. . The chafing strip is removed ^" inside the point at which the side wall was removed. Remove the top ply, cutting 2^/^" outside of the extreme points of the injury and %" below the tread line. Take this ply out to the toe of the bead. Remove the second ply, stepping down l'' on the ends and Yi" on the tread side. It is also removed to the toe of the bead. Skive the edges of the injury, removing all loose fabric. After repair is ready to buff, the ends of the injury should not touch, and should taper to a feather edge. Buff thoroughly all the exposed outside surface \" farther than the longest ply stepped out, and from the toe of the bead to the center of the tread. It is now ready to cement. Clean with cloth moistened with solvent. Apply three coats of C-16 or C-15 cement as per the following directions for the application of cement. These directions are general and are to be followed in the cementing of all types of repairs: 1. Apply the first coat thin and rub in well. This corresponds to the filler coat in painting. 2. Apply the second coat heavier than the first and smoothly. This is a cover coat. 3. Apply the third and last coat thinner than the second and heavier than the first, and rub in well. This is a finish coat. 4. Allow the first coat to dry from 30 to 60 minutes, the second 30 to 60 minutes, and the last until the cement becomes tacky, which occurs in three to five hours, depending upon the humidity. Cement is not dry until all of the solvent has been evaporated. It is important that cement should not be allowed to dry too long, . otherwise an air-cured film will form which may weaken the union. JOB 211. BUILDING UP THE QUARTER SECTION. 1. Dust and dirt should be removed with a cloth moistened in solvent. All edges of the old fabric should be covered with strips of G-170 ^" wide. Fill the hole through the tire with G-170 cushion stock. Apply the first ply of HF-41 frictioned two sides, skim-coated one side, with the skim coated side down, lapping Y^," over the old fabric and extending to the toe of the bead. Tire Care and Vulcanizing 645 Apply the second ply, lapping ^" over the old fabric. This ply is made long enough to extend over the bead, and to extend up the inside of the tire to a point half way between the center of the tread and the tread line. 2. Where the new fabric passes over the bead, it should be trimmed down to make a butt joint with the old fabric. Replace chafing strip with LF-52, lapping it J4" at the ends. This chafing strip will extend over the bead and l" Fig. 639. Quarter section torn down. inside of the tire. Replace the side wall with G-lOO, G-105, or G-115. Before the last ply is stitched down on the inside a small patch of HF-41, 1" larger all around than the injury, is placed over it. Cover all edges of the new fabric with strips of G-170. 3. Dust the inside and the outside of the casing lightly with soapstone. Repair is now ready to be cured according to table. 546 Automotive Trade Training Fij^-. 040. ;->Utclihiy (K-wii plies in (laarter s^'ction. JOB 212. TEARING DOWN FOR HALF SECTION. 1. A half section is built into the tire when the injury is between the bead and the center of the tread. The length of the section is determined by the general rules. It is necessary to remove only two plies of old fabric. When the injury is large enough to warrant the removal of more than two plies, the full section must be built into the tire. 2. Lift the tread and breaker from one end, allowing the tread to hinge at the other. Remove the side wall 4" from the extreme points of injury. Skive the edges. The chafing strip is removed Y^" inside the point at which the side wall was removed. Measure back XV^" from the ends of the section and step out the top ply. The top ply is stepped out 1" from the tread line on the side opposite the break to the toe of the bead on the same side as break. The second ply is taken out \" narrower all around than the first. The ends of the tread at the point where it is cut across the tire should be skived on an angle of 45°. If there is a hole through the tread, all loose gum is trimmed out. Fig. 641. Inside of casing, illustrating plies laid back to show construction. Tire Care and Vulcanizing 547 The exposed surface on the outside of the tire is buffed. The inside of the tire is buffed from toe to toe of beads and l" longer on either end than the largest ply taken off; this should be done before the tire is torn down. Follow the general instructions for cementing. JOB 213. BUILDING UP THE HALF SECTION. 1. When the cement is dry, clean it with a cloth moistened with solvent and cover the outside of the entire exposed surface with G-170, 1/64" gauge. This gauge can be obtained by cutting the i^" gauge stock one-half the size of the surface to be covered and stretching 100%, the G-170 extending to within IJ/^" of the heel of the bead. 2. The hole through the tire is filled with G-170 cushion gum, 3. The first ply is replaced, lapping the edges of the second ply removed ^". The second ply is replaced, lapping the edges of the first ply removed ^". This ply is cut long enough to cover the inside of the tire from bead to bead. At the point where the fabric goes over the bead, it is skived so as to make a butt joint with the old fabric. After this ply is replaced, cover the entire surface of the tread with G-170, 3*2" gauge. The chafing strip is replaced, lapping the old G-105, or G-115. 4. The tread is then laid down, stitching carefully between the buttons. The "V"-shaped hole where the tread was cut is filled with tread stock higher than the original tread, the new gum is then cut out to match the pattern of the tread. Any holes in the tread are repaired in the same manner. 5. A small patch of HF-41 1" larger all around than the injury is placed over it. The last ply from the outside is carried over the bead and around the inside of the tire to within l" of the bead on the side opposite the injury. 6. The chafing strip is carried l" inside the tire. Cover all raw edges of the fabric with G-170. Dust the inside and outside of the tire with soapstone. The tire is now ready to be cured according to table. ^^.x^^^^..-^ < •Bread x^ nr.. \V ^ /^ y^ \ ^ '\^ / T \^\ /Bead Fig. 642. Diagram of half section. JOB 214. TEARING DOWN FOR FULL SECTION. 1. A full section is used in the case of a large blow-out or where the blow-out is in a position that it cannot be repaired with a quarter or half section. 548 Automotive Trade Training 2. Two plies are removed from the 3", 3^", and 4" tires, and three from the 4%" and 5" tires. This is a general rule that must be varied if the injury- is exceptionally large and the fabric around the hole must be removed on account of separation. The length of the section is determined by the general rule. 3. The inside of the tire should be buffed 2" longer than the longest ply- removed. Fig. 643. Half Section ready to be built up. 4. The tread is laid back the length of the section the same as in the c.se of a half section. 5. The side wall is removed from both sides of the tire, and both chafing strips are removed. The first ply is stepped out from toe of bead to toe of Tire Care and Vulcanizing 549 bead, and 1^" inside the point at which the tread was laid back. The other plies are stepped out l" shorter on either end than the preceding. All loose fabric and all loose gum is trimmed from the injury. Buff thoroughly all the exposed outside surface of the carcass and underside of tread and cement according to general instructions. Fig. 644. Showing method of laying in the tread. JOB 215. BUILDING UP THE FULL SECTION. 1. When the cement is dry, remove any dust with a cloth moistened with solvent. Cover the exposed surface of the tire with G-170, 1/64" gauge, to within 1^" of the bead. Replace the old plies with new HF-41, skim coated side down, lapping %'\ This applies to the underplies. If the ply taken out is trimmed to the toe of the bead, the ply replaced should be trimmed at the toe, also; thiat is, the new ply should be trimmed at the same point as that at which the old ply was trimmed. The top ply is cut long enough to cover the outside and inside of the carcass and to lap, itself %". The side walls and chafing strips are replaced and the tread is laid back ill the same manner as in the half section. 2. The last ply is then stitched over the bead. On the one side it is carried 1^/^" up the inside of the tire, and the other end of the ply carried around the inside of the tire to meet it with a lap of H"-'. At the point where the fabric goes over the bead, it is skived so as to make a butt joint with the old fabric. A piece of new fabric is cut large enough to run from toe to toe of the beads and extend l" further on either end than the ply brought around the outside. This is stitched down inside the tire over the ply which was 550 Automotive Trade Training ^< <=:S Tread Break ^ r^ W /An \V ,''^ / ^/^ / \W >s^ A A^^ \ >\- /yCBead Fig. 645. Diagram of full section. Fig. 64C. Full section ready for building up. Tire Care and Vulcanizing 561 brought around from the outside. All raw edges of new fabric are covered with strips of G-170. Dust the inside and outside of the tire lightly with soapstone. Cure according to instructions. JOB 216. INSIDE SECTION. 1. Inside sections are made to repair fabric breaks on the inside and almost through the tire, when the injury is small and it is deemed inexpedient to lift the tread. It is not used to make repairs below the tread lines. 2. It replaces the full section for small repairs. Half, or less than half, of the plies are taken out in four or five ply tires, and three in six or seven-ply tires. When two plies are removed, the first ply is taken out 2J^" from the extreme points of injury. When three plies are removed, the first ply is taken out 3^" from the extreme points. The largest ply is taken out to the toe of the bead and each ply is stepped out l" narrower than the first ply. This is buffed and cemented in the regular manner. Fig. 647. Photo showing inside of tire and method of carrying ply around from outside. 3. The first ply is replaced, lapping %'' all around. No skim coat of G-170 is necessary. All raw edges of fabric should be covered with a narrow strip of G-170. The skim coated side of HF-41 is placed down. All underplies are lapped %". The last ply replaced is lapped %" and carried to within %" of the toe of the bead. One or two over-all plies are placed over the repair running from toe to toe, and extending 1" over the last ply replaced in the tire. Dust the repair with soapstone and cure according to instructions for full section. JOB 217. REPAIRING OF CORD TIRES. The Goodyear Cord Patch is used when the cut or injury in the cord casing is no longer than 3V^" and occurring between the tread lines. 1. Buff the inside of the casing from toe to toe of bead and somewhat wider than the patch to be applied. 2. Trim the loose gum and fabric from the injury so that the edges of the plies do not touch, and the hole is free and open. Taper the hole so that the inside is larger than the outside. 3. Buff the injury thoroughly. 4. Clean with cloth moistened with solvent. 5. Cement outside of repair to be made with C-15 or C-16 vulcanizing cement. 6. Cement the inside of the casing where the cord patch is to be placed with three coats of C-25 vulcanizing cement, 562 Automotive Trade Training Fig. 648. Showing tread laid back and V-shaped cut in tread. 7. When the cement is thoroughly dry, remove the holland from the gum side of the cord patch and insert the patch using a paddle, stitching down carefully so that the patch is not bridged and no air is trapped. The oval in the patch should be directly over the injury whether the injury is in the center of the tread or not. 8. After the patch has been stitched down into place, trim the protrud- ing edge or edges. 9. Always clean uncured gum side of the patch with a cloth moistened with solvent. If any stock from the holland sticks to the G-180, it can be removed with a rag moistened with water. It is then thoroughly cleaned with solvent, allowed to dry thoroughly and applied. Fig. 649. Inside of tire, showing construction. Tire Care and Vulcanizing 553 10. After stitching the patch firmly into place, fill up the injury on the outside with G-170 cushion gum up to the top of the breaker strip. 11. The remaining part of the injury should be filled with G-lOO, G-105, or G-115 tread gum. 12. Repair is ready for cure. See chart for cure for regular sectional repairs. 13. Cord separation, on the inside only, may be taken care of by the Goodyear Cord Patch. 14. Buff thoroughly. 15. Cement with C-25 cement and insert patch over weakened part of carcass. 16. Cure on inside vulcanizer. Fig. 650. Inside section ready to be built up. JOB 218. FULL SECTION CORD TIRE. For extremely large injuries it is necessary to make a full sectional repair. Injuries that occur below the tread line, if they are too large or in such a position that they cannot be repaired with a cord patch, must also be repaired with a section. Cut the tread and breaker strip at point where injury occurs and lay tread back 5" in both directions. 1. It is necessary to tear out all of the cords in the first group on the inside and outside. 2. These are removed as follows: 3. First layer of cords allows a margin of 1" on either side of the extreme points of break and from toe to toe of bead. 4. Second ply is to be removed V2" inside of first ply. 5. Chafing strips and sidewalls should be removed for a distance of ^" beyond the point where the cords are removed. 6. The tire is then spread open so as to allow the removal of the cords on the inside. 7. The inside plies run opposite to the outside. These plies are removed the same as the outside. Chafing strips are laid back to the toe of the bead ^" farther than the widest ply taken out. 8. Bufl the inside of the casing far enough so that a "cross" of cord fabric may be inserted over the injury. 9. Buff the exposed surface of the tire thoroughly. 10. Cement both inside and outside with three coats of C-15 or C-16 vulcanizing cement. 11. Place cushion gum where the old cords have been removed. 554 Automotive Trade Training Fig. 651. Hole trimmed otit with sides tapered. 12-. Cushion gum should not be stretched and should be left full sfe" gauge. 13. New plies of cords are then inserted without lapping. 14. The injury is then filled from the outside with G-170 cushion gum. 15. Cushion gum is then placed over the cemented tread surface. 16. The chafing strip is replaced with LF-52 fabric. 17. Side wall rubber is replaced with G-lOO, G-105 or G-115. 18. The tread is then laid back and stitched down thoroughly. 19. G-170 cushion gum is then placed where the plies have been torn out on the inside. 20. The old plies are replaced with new cord fabric in the same manner as the plies have been replaced on the outside. 21. After the plies are replaced on the inside, the same number of plies of fabric as have been taken out on the inside are inserted, running at right angles to the plies removed and from bead to bead and forming a "cross." This over- all ply or plies is 2" wider than the injury and applied skim coated side down. The under ply of the reinforcement should be made Yi" narrower than the outer ply in order to avoid an abrupt change in thickness at the edges. 22. This forms a reinforcement over the injury. Tire Cake and Vulcanizing 555 Fig. 652. Showing method of inserting cord patch inside of tire. 23. The section is then cured in the same manner as a fabric tire — in a sectional mold. 24. It may be necessary to cure the section twice because of its length. 25. However, effort should be made to keep the repair short enough so that it may be cured completely with one cure. Fig. G53. Outside of section ready to be built up. 556 Automotive Trade Training 26. All cushion gum, G-170, should be used 3*2" gauge. 27. Nominal size airbags are usually too small in cross section for use in cord tires. Be careful in selecting your airbag for cord tire sectional work. For example, a 4^" sectional airbag will fit a 4" cord tire better than a 4" sectional airbag. JOB 219. CORD TIRE FULL SECTION. 1. This fnethod is used when the 45° repair is too long. 2. Lay back tread as described for fabric tire full sectional repair. The length of tread in inches to be laid back will be 6+ (total length of injury in inches) + 2 (number of plies removed from the outside — 1). The center of the section of tread laid back should correspond to the center of the break. 3. Remove the chafing strip and side walls. 4. The popular sizes of cord tires are listed below with the number of plies in each size. 30x3^^ 4 plies 33 x 4^^ 6 plies 32x3% 6 plies 34x4>4 8 plies 33x4 6 plies 35x5 8 plies 34x4 6 plies 37x5 8 plies 32x4^ 6 plies 5. Repairs of this kind may be divided in two classes: first where the break occurs between the tread lines on the top of the tire, second where the break occurs between the bead and tread line, 6. Repairs of the first type: 7. Remove one-half the total number of plies from the outside of the tire. In eight-ply tires, first ply should be cut 4^" from the extreme points of the injury. For six-ply this distance will- be 3%" and for four-ply 2^". The outer ply in all cases is cut out around the bead to the toe and the ply beneath is taken out to within l" of the heel. When more than two plies are removed the plies are stepped down l'\ ■ 8. Loose fabric and rubber is trimmed out of the break and the repair is then buffed, the inside of the tire being buffed for a distance of 4" at each end beyond the point where the outer ply was cut. 9. Cement according to general directions both inside and out. 10. Build up the inside of the repair first as follows: 11. Stitch in a ply of CF-44 skim coated side down and cords running in opposite direction to cords in tire. This ply should extend %" on each side of the points at which the outer ply was cut and to within V2" of the toe of the bead. Over this ply is placed another ply 2" longer than the first ply and extending to the toe of the bead. Fig. 654, Inside of section ready to be built up. Tire Care and Vulcanizing 557 Fig. 655. Inside of section built up with crpss. 12. This ply is only stretched down to within 2^/^" from the bead. 13. Fill in the hole through the carcass from the outside with G-170. 14. Build up the outside by covering the cemented surface with a ply of G-170 -^i" gauge. Replace the plies cut out with CF-44 skim coated side down, cords running in same direction as the original plies. New plies should overlap ^" and cords should have the same direction as those of plies replaced. The last ply replaced should be cut long enough to extend around the bead on each side and 1^" above the toe of the bead on the inside of the tire. After this is stitched down, the inside reinforcing ply should be stitched over it. 15. Where the ply goes around the bead it should lap ^" as on the rest of the repair. 16. Replace the side walls and chafing strips, lay back the tread and fill the hole with G-105 tread stock. Dust with soapstone and cure according to directions for full section in sectional mold. 17. Repairs of the second type: 18. In this kind of repair where the break occurs between the tread line and the bead it is necessary to lay back the tread and cut off the chafing strips and side wall. Remove one-fourth of the total number of plies from the outside and one-fourth from the inside. The plies are taken out from the outside the same manner as described for outside repair and the plies on the i''ig. 056. Section ready to be built up. 558 Automotive Trade Training inside are stepped out from toe to toe and are 1" shorter than the largest ply- taken off the outside. The remaining plies are stepped down l". 19. Trim out loose rubber in the break and cement. 20. Replace the plies in the manner described for the first type of repair, placing a skim coat of G-170 both inside and out. 21. Put one reinforcing ply on the inside with cords running in the opposite direction to cords in last ply replaced. 22. This ply should be stitched down over the last ply brought around for the outside of the repair. ■ 23. Cure the repair in sectional mold according to directions for full sectional cure as given in thv, chart. Fig. 657. Section built up before laying back tread. JOB 220. WIDTH OF BREAKER. Fabric Tires Cord Tires Size Tire Width of Breaker Size Tire Width of Breaker 3" 3^" 3^" 3'' 3/2" 2/2" 4'' 3^" 4" 23/4" • 4/2" 4" 4/2'' 354" 5" ^V2" 5'' 4" Splices Yi," Splices not closer than 10" JOB 221. REPAIRING TREAD CUTS. 1. Tread cuts should be repaired at once so that sand and moisture will not work into the tire and cause separation. 2. Bevel out injury down to the carcass so that it is free and open. BufT thoroughly. Clean with cloth moistened with solvent. Cement according to directions. 3. When thoroughly dry, fill injury with layers of G-lOO, G-105, or G-115, depending upon the color of the rubber in the tread of the tire. 4. The injury is built up higher than the original tread. The original tread pattern is then cut into the raw stock. Tire Care and Vulcanizing 559 5. Cure for tread cuts should be taken from the chart. 6. In repairing the tread cut it is essential that the fabric directly under the cut is free from foreign matter such as dirt and moisture. 7. If, on examination, it is found that the fabric is water-soaked and full of dirt, remove the first layer of fabric on the outside in the form of a small, square patch. 8. In building up, this should be covered with G-170 cushion gum. 9. Place a piece of HF-41, %" larger than the piece taken out, in the square made above. Place G-170 gum over the ply placed in position. 10. Then fill the cut of the tread in the same manner as described above. 11. In case of mud boils or sand blisters, cut the blister open and remove all of the loose rubber from the carcass. Buff thoroughly. 12. In case more than one ply is removed, the plies are stepped down l". 13. Then replace with HF-41 fabric, allowing J/^" lap on the under plies and }i" lap on the last ply. 14. Then place an inside reliner extending from toe to toe of the bead of approximately l" more in width than the largest ply of new fabric replaced on the outside. 15. Fill in the cut on the outside. 16. Dust with soapstone. Cure repair according to chart. Fig. G58. Filling in the Injury. JOB 222. PRESERVING THE TREAD. 1. When vulcanizing a section in a non-skid tire it is not necessary to disfigure the tire by a section on which the tread design is imperfect, due to the old design being flattened out in curing. 2. The design may be preserved by the use of a stiff paste, made of soap- stone and water. When soapstone is used the tread pattern is cut in the new rubber before the cure. 3. Another method of preserving the design is to make up a matrix or 560 Automotive Trade Training negative pad from one ply of LF-52 and two plies of -h" gauge tread gum. The pad should be wide enough to cover the width of the tread and long enough to extend about l" beyond either end of the molds with which it is to be used. 4. Soapstone the pad freely and fit it over a section of the tread that is in good condition. Insert a sectional air bag. Clamp the tire in the mold and cure. (See table.) Fig. 659. All-Weather Negative Pad. 5. The result will be a perfect mold of the tread pattern. 6. When the repair is ready to vulcanize soapstone the raw section of the tire, then take the pad and apply C-35 cement at the edges. Fit the pad over the section; the cement will hold it in place. Cure the repair as recommended. JOB 223. REPAIRING SCRAPED SIDE WALLS. 1. Side wall repairs are of three kinds: (1) Side wall rubber may be injured and no plies damaged; (2) the top ply may be injured and plies cut; (3) the side wall rubber may be chafed and several plies worn through for the entire circumference of the tire. 2. When the side wall rubber alone is injured, the old rubber is trimmed away and the exposed surface is buffed and cemented. A new side wall is inserted, replacing the old rubber, 3. When the top ply has been cut through, it is often necessary to replace this cut ply by a new ply which is built in, in a manner similar to a quarter Tire Care and Vulcanizing 561 section. The side wall and chafing strip are removed and the ply is taken out to the tread line. The ply of fabric is replaced by a new fabric extending around the bead of the tire to a point half way between the center of the tread and the tread line on the same side as the chafed side of the tire. 4. When the plies have been cut locally through only a few plies of fabric, it is often more expedient to reinforce the inside of the casing with a sectional reliner, trimming out the injury and filling in with new side wall rubber. These repairs may be cured in either a sectional mold or like a retread by inserting the coil and curing it in a kettle. Local repairs that have a sectional reliner are cured according to the chart. Fig. 660. Scraped side wall. JOB 224. RETREADING. 1. Remove old tread rubber and breaker strip froni tread line, to tread line. 2. Fig. 662 shows tire ready for retreading. 3. Buff exposed surface and cement with three coats of C-15 or C-16 vulcanizmg cement, accordmg to directions. 4. Sometimes when the tire has been run too long it will be found that one or two outer plies have been so damaged by water and dirt working through the tread that they must be removed.. In this case the injured ply or plies should be stepped out and replaced with new fabric. To do this the plies are stepped. out on each side of the broken fabric, keeping as close as possible in order to stay above the flex points. Room should be allowed for a ^" step ^62 Automotive Trade Training Fig. 661. Scraped side wall, one or more plies of fabric worn through. if the under ply is removed. In building up the HF-41 is applied directly to the cemented surface skim coated side down. A Yz" lap is made on the under ply and a ^" lap on the outer ply. 5. G-lOO, G-105, G-115 is used when applying a plain laid-up tread. The gauge should be the same as the corresponding camel back for the same size tire. (See chart for proper sizes and widths). When this tread is laid up and thoroughly stitched, all air being removed, it is placed on the carcass directly over the breaker strip. It is trimmed at the tread line. 6. Camel back may be used in place of the built-up tread. 7. In some cases it is necessary to put a section in the tire before it is retreaded. In this case remove the old tread rubber, breaker and cushion. Trim out the repair and rebuild section in the usual manner with the exception of applying the tread 8. This section should be given a semi-cure. 9. This cure is sufficient to shape the beads and side wall rubber of the section. 10. The casing is then buffed and cemented and the retread applied in the usual manner. 11. Goodyear Camel Back is furnished to eliminate the plying up of ordinary tread rubber for retreading work. 12. Camel Back is applied in the same manner as the built-up tread. Tire Care and Vulcanizing 563 Fig-. 662. Tire Buffed and ready for retreading. JOB 225. BUILDING UP THE RETREAD. 1. When cement is thoroughly dry, apply one ply of G-170 cushion gum ^^" gauge. This cushion gum should extend to within Vz" of the edges of the cemented surface. 2. Breakers should be cut "on the straight" for fabric tires and on the bias for cord tires. 3. Apply breaker strip. (See chart for width of breaker strip for various sized tires.) 4. In applying semi-cured retread bands a layer of ^" gauge tread gum is placed over the breaker strip extending from tread line to tread line, 5. The semi-cured retread band is thoroughly buffed and cemented with three coats of C-15 or C-16 vulcanizing cement. 6. When cement is thoroughly dry the band is placed on the tire. 7. A piece of clean muslin or holland should be placed over the cover- stock before the band is applied. This will eliminate the possibility of the tread band sticking to the carcass before it is centered. 8. When band is centered, remove the muslin or holland and stitch well, stitching from the center out. Stitch between the buttoms. 564 Automotive Trade Training 9. Be careful that you have removed all air blisters between the cover- stock and the carcass proper. 10. After stitching down the band, the edges should be trimmed V^" above the undercover line in 3", 3J/2", and 4" tires. Trim off ^" above the under tread line in 4^" and 5" tires. 11. Retread is ready for cure. Fig. 663. Successive steps in building up retread, showing buffed surface, cushion, breaker, under-cover and semi-cured retread band. JOB 226. CURING THE RETREAD. Kettle Cure.-^Insert steel coil of sufficient size to keef^'^the toe of the tieads 1^" apart. 1. Make a thick paste of soapstone and water and fill the cavities in the tread design if semi-cured band is used. The paste keeps the tread design from flattening out under pressure. 2. Cover the outside of the casing to just below the tread line with a heavy jacket of cotton canvas, or muslin, cut on the bias. 3. Then wrap the tire with cotton canvas strips approximately 2" in width. This should be wrapped around , with a 1" lap. Wrap twice around, reversing the direction the second time around. 4. . Use extreme pressure in wrapping the casing. 5. Use length and temperature of cure specified on chart. 6. When applying the plain tread, the entire surface of the tread is dusted with soapstone, the coil is inserted, and a heavy jacket of cotton canyas or muslin, is applied, covering the raw stock. The tire is then wrapped with strips of cotton canvas as when retreading with a semi-cured band. The tire is now ready for cure. JOB 227. THIRD CIRCLE RETREADING. 1. For one-third circle retreaders camel back stock or built-up tread gum is applied. 2. Care must be taken in curing by one-third circle retread methods to get •the best results and minimum of defects. 3. A sand bag is used in curing retreads in one-third circle retreading. Tire Care and Vulcanizing 565 Fig. 664. Laying up a tread. The pressure is secured by means of clamps and a pressure bar. The sand bag should fit snugly in the casing and should be just as long as the mold. It -should be of sufficient diameter to assure a good pressure on the side walls. Fig. 66&. Photo showing method of putting band on tire with muslin. 566 Automotive Trade Training Tig. 66C. Section of casing cut down t( apstoiu iiid uieth.td of wrapping. 4. Care should be taken that the pressure bar used'on top of the jand bag is not bent or out of shape. " 5. If the pressure bar is out of shape, flat spots will occur on the tread surface between the points directly under the clamps. The pressure bar shou'd not be too large and stiff, otherwise, the pressure will not be distributed evenly and light spots may result. The clamps should be tight?ned dT.vn .u^radualiy Fig. 6G7. Third circle retreader. Tike Care and Vulcan iz inc. 567 Rubber Knife. Fig. 668. Hard Casing Roughing Brush. 668 Automotive Trade Training from the center of the mold out, so that no air is trapped, which would cause defects in tread. Tighten clamps about ten minutes after the cure is started. 6. The tire should be kept in an upright position so that the tread design or ribs are centered evenly around the tire. 7. The edges of the tread gum, after it is applied to the tire, should be skived and stitched down to a thin feather edge so that a perfect union is insured without excessive overflow. 8. Be sure to examine the casing during the cure for air blisters at the ends of the section that is being cured. 9. If these blisters appear, they should be opened at once by means of a sharp awl. 10. Sand used in sand bags should be screened through a 20 mesh sieve. 11. It is advisable to use a small amount of fine flake graphite with the sand to eliminate any bunching or caking and assist in giving uniform pressure. JOB 228. RETREADING CORD TIRES. Retread the cord tire in the same manner as the fabric tire. After the old tread is removed, inspect the tire carefully. The tire should not be retreaded if it has ply separation. The building up and curing is the same as for fabric tires. CHAPTER 17 GARAGE SHOP REPAIR METHODS JOB 229. LIFTING AN ENGINE FROM A CAR. The use of a crane, a heavy block and tackle, or chain block is essential to lifting a motor from a car. Various types of cranes are in use. Where many cars are handled in a certain location the traveling crane, mounted overhead in such manner that the chain block may be run to any point over a consider- able area, is best. The crane mounted on the single track is rather limited m its service. The double track overhead crane which permits of side to side motion as well as movement along the track is very good. The floor crane which is so arranged that it may be run under the front axle of the. car to lift out or replace the motor is ideal for the smaller garages. Fig. 669 shows the Franklin crane of the portable type being used to replace ■ .^^r- 'v^*"^*"^ «^NI' «l w ^ 1 f r^'^^^BHB ^^^H ^Km/ , / Infi ■ '/'.-A^^^H ^^^^E yH 1^^^^^^^ IH HHm Fig. 669. Lifting an Engine with a Portable Crane, the six-cylinder engine in a Reo car frame. The particular advantage of this type of crane is the ease with which a heavy motor may be lifted out and then moved to any desired position. When in use for lifting, the front wheels are locked under the frame to prevent the crane moving. Throwing the handle controlling these wheels forward releases the wheels and permits of the crane and load bemg moved about the floor. The floor crane is also used for lifting the body or frame away from the rear axle. Care must be used in makmg the hitch to prevent the top or body being injured. In making a hitch on an engine or other load for lifting make very certain 569 570 Automotive Trade Training it is secure and safe. Ropes and wire are to be avoided for this type of work Special clamps or a good square link chain are safer and better. JOB 230. USING A GARAGE PRESS. The development of the automotive trades has led to the development of special labor and time saving equipment. The arbor press which is best fitted for limited machine shop work is not always best fitted for the wide range of work met with in the garage. The special garage presses such as the Weaver, shown in Fig. 670, are better suited. In the use of a press of this nature several points must be kept in mind. Owing to the tremenduous pressure the work must be handled carefully to avoid any damage. 1. Adjust the table to accommo- date the work. 3. Make certain that the work is to receive the pressure at the correct point. 3. Do not attempt to press while work is resting on makeshift supports. 4. Do not apply pressure with the spindle or shaft being pressed setting at an angle. 5. Where bushings or gears are being pressed on make certain the parts are entering properly. 6. It is a good plan to round the ends or edges of the bushings jusc a trifle to insure their pressing properly and not grabbing on the side of ^.the retainer. 7. Where work is too long to enter with the press setting on the floor, it may be blocked up or even be operated while laid on the side. TAPS AND DIES. In order that the student may recognize the various sizes and kinds of threads it io necessary for him to spend some time in studying them. While there are still a number of spe- cial threads in use on certain machines, standardization is along the lines of four only. U. S. S.— This is the abbre- viation for United States Stand- ard thread. This thread is a V thread with a flat edge, or an edge which just fails of reach- ing a point. It is used in all manner of machinery and equip- ment. In automotive work it is used more for studs which are set in soft metal such as bronze or aluminum or cast iron. Bolts with this thread are used for fastening on the Fig. 670. Using a Garage Press to press in ball cup. ^HkkkMiH0MMmm tut III 'ig. 671. TaptT. Plug an9/64 '/8 32 m 3/32 + 7/6 14 ,368 U + 13/8 6 1.213 17/32 + «/i4 40 .116 32 •/2 27 .464 '5/32 1'/2 12* 1.419 127/64 H4 36 .114 33 •/2 24 .460 29^4 t l'/2 6 1.338 1"/32 ^ 32 .110 35 '/2 20- .451 29^4 t 15/8 5'/2 1.448 12^64 5>62 40 .132 30 + V2 13 .425 27/64 t 13/4 5 li55 19/16 + 5/32 36 .129 30 '/2 12 .419 27/64 t 17/6 5 1.680 1"/.6 5/32 32 .126 '/8 Vl6 27 .526 "M t 2 4/2 1.783 12^ •/64 36 .145 27 V.6 M* m '/2 t 2'/8 4'/2 1.909 12^ + «yfe4 32 .141 28 + Vl6 12 .481 3^ t 2 'A 4/2 2.034 2'/3? 3/6 36 .161 2a 5/8 27 .589 15% t 23/8 4 2.131 2'/8 3/6 32 .157 22 5/8 18' .571 14.5«/» t 2'/2 4 2.256 2 'A 3/6 30 .155 23 5/8 12 .544 3^64 t 25/8 4 2J81 23/8 + 3/6 24 .147 26 + 5/8 11 i36 17/32 t 23/4 4 2.506 2 'A •3/64 32 .173 17 •'/.6 16" .627 5/8 t 27/e 3/2 2.597 2'9/32 •3/64 30 .171 '/64 + "/6 11 .599 '9/32 t 3 3'/2 2.722 22^ + 13/64 24 .163 20 3/4 27 .714 2^ t 3'/8 V/2 2.847 227/32 7/32 32 .188 13 3/4 16* .689 "/-6 t 3'/4 3/2 2.972 23/32 7/32 28 .184 14 3/4 12 .669 M^ t 33/8 3/4 3.075 3'/l6 + 7/32 24 .178 16 + 3/4 10 .653 2'/32 t 3'/2 3/4 1200 33/.^ •^ 32 J04 6 '3/,6 12 .731 ^64 t 35/8 3/4 3.325 3 V.6 •^4 28 .200 8 + '3/l6 10 .715 2^ t 33/4 3 3.425 3V<« + 'H4 24 .194 10 7/8 27 .839 27^ t 37/8 3 3.550 39/,e Ve 18' J21 5^64 t 4 3 3.675 3«'/.6 •S. A. E. Standard +U, S, Standard particularly is this true. A bit too heavy a strain on the small tap will cause it to twist and spring; the expert mechanic will detect this action immediately but the apprentice may continue turning the tap holder and attempt to force the tap to turn with the result that it is broken off in the nut or hole. The correct procedure when the tap shows signs of twisting is to carefully back it Garage Shop Repair Methods 673 out and clear out the cuttings. The general method of proceeding in the use of taps is as follows: 1. Select the tap needed for the piece of work at hand. 2. Determine the size drill needed for the blank hole. This may be determined from the table of tap and drill sizes, or by measuring the diameter of the bottom of the taper tap. 3. Drill the hole a bit deeper than the threads are expected to go, if the .work permits this. 4. Start the taper tap first and run this as far as it will go without striking the bottom of the drill hole. Keep the tap working freely. Use oil for steel or iron. Oil is not necessary on brass or cast iron. 5. Follow the taper tap with the plug tap. 6. Follow the plug tap with the bottoming tap if threads are to be run to the bottom of the drilled hole. 7. It will be found that the chips and cuttings must be removed from the hole as the work progresses. JOB 232. USING DIES. Dies are made either in one piece or adjustable. The latter are the better type since the thread may be made a bit above or below standard to fit special cases. This feature allows of some compensation for wear of the dies and also permits of their being reground. The setting of the dies from standard size should not be done, however, unless the reason is a very good one as it is likely to put unusual strains on the cutting edges. In using dies on steel or iron plenty of oil must be used. Lard oil is recommended, but failing this use machine oil. 1. Learn first the exact die required to cut the thread needed. Make certain that the diameter of the bolt is known and the number of threads per inch. Select the die bearing these figures stamped on it. 2. Start the die on the bolt properlj/;. Dies are* made with the first few threads relieved to permit of starting the work with the least effort. This provision also allowa .the work to proceed gradually^, each thread or tooth cutting a bit deeper thah th^ one preceding it. Dies are also provided with a guide which is a free fit dver the end of the bolt or rod. This insures the threads being started and kept true. 3. Avoid starting the die with the finishing face first. Where it is necessary to cut threads veiV close to a bolt head the die should be started correctly and run on as far as possible, after which it is removed and the finishing face started on first. This arrangement permits of the die being started correctly and prevents such a great strain on the finishing threads or teeth. FORGING. Practically all modern garages are equipped with a forge. This is not with the idea of making new parts but rather with the idea of facilitating repairs. The automobile is constructed with many parts mOre or less inaccessible. Some special tool or appliance may be needed in just one instance "or to do one particular piece of work. While it may take quite a bit of work to forge out this special tool, it is a saving of time and expense in the end: In other cases a small part may need to be heated for bending, or for straightening. Certain parts from wrecked cars as for instance front axles may need to be heated in the forge to permit of proper straightening. The forge is not used' a great deal for the welding about the garage. The oxygen-acetylene process is far better suited. The student should do enough forging that he may feel confident to 574 Automotive Trade j raining proceed with the making of punches, chisels, and other special tools and appliances. Carbon steels are susceptible to hardening and tempering. All tools and certain parts of the automobile are made from carbon steel or similar tool steel. Files are a high carbon tool steel, and while they may be forged into a certain shape for use as tools for certain work their carbon content is too great for work requiring much spring. JOB 233. BUILDING A FORGE FIRE. Just as in all other classes of work, so it is in forging. Certain funda- mental operations or processes are necessary to success. One of the most important is ability to control the fire properly. The following instruction will Fig. 674. Forge. clear up many points in the mind of the student as to the proper method of buildmg and maintaining the forge hre. Hand forges are in use more largely than the power blast for garage work 1. Owing to the fact that a number of men have access to the same forge it is sometimes difficult to maintain it in good condition. The first step on attempting to start a fire is to remove all the coke left from the previous fire. Coke is iron grey in color, light in weight and clean to handle. It is formed by burning all smoke and gas from green coal. Lay the coke to the side or place it in a bucket. 2. Level off the cinders remaining on the hearth. Clean any cinders away from the center of the hearth leavmg the center hollowed out down to the tuyere iron. This hollowed space should be about the size of an ordinary wash basin. The tuyere iron is in the center of the forge through which the air blast is forced into the fire, and must show at the bottom of the hollowed space. Garage Shop Repair Methods 575 3. Make certain the blast is working properly by running the fan. It may be necessary to clean out the ash pit under the tuyere iron, for which a trap door is provided at the bottom of the pit. 4. Place the kindling for the fire. This may be paper and short lengths of kindling wood. Oil soaked rags are sometimes used. 5. Light the kindling, and place on enough blast to get it blazing smartly, 6. Cover the burning kindling with the coke which was saved for this purpose. Keep the blast going and in a few minutes the coke will be glowing white hot. 7. Cover all of the glowing coke which has been heaped to a mound over the center of the hearth, excepting the very top and center with green coal, which is a good grade of smithing coal that has been dampened with water until it will pack. Leave the center open to allow the blast and smoke to come out. Use the shovel to pack the green coal tight around the sides of the mound of glowing coke. 8. The work may now proceed. The green coal is gradually dried out and coked up. By the time the center of the fire has burned out the green coal, with which it was packed, will be converted into coke to replenish the fire. At this point the smith pulls in the coke and thus replenishes the fire, which is again protected with a layer of green coal packed all around its base and open only on top. 9. When inserting the work into the fire care is used not to destroy the shape of the fire. 10 It is useless to attempt work until coke is available for heating the material. If the coke is not at hand in proper quantities, time will be saved by starting the fire and burning some of the green coal into coke. 11 It IS useless to attempt work with a fire which has green coal in it, or in one which has cinders mixed with the coke. 12. Keep the hearth leveled ofif and packed down hard with cinders. They will not burn, but serve as a fire protection to the forge. They also serve to form the basin m which the fire is held. Any surplus of cinders other than those needed for the above purpose should be removed from the hearth. Do not permit the cmder bed on the hearth to be dug up or become mixed with green coal. 13. Do not use the forge for a receptacle for tools. The hammer should lie on the anvil when not in use. The tongs should be kept on a rack, and the hardie by the anvil. The rake, poker and shovel may be laid on the nicely leveled hearth provided the iorge is large enough, otherwise keep them on a rack. 14. Keep the space about the forge neat and clean. JOB 234. FORGING HAND TOOLS. Cold chisels, cape chisels, gouges, punches, drifts, cotterkey extractors, etc., are hand tools readily forged by the beginner. After some experience, he may confidently attempt the more advanced problems of socket wrenches, end wrenches, and ihe many problems of that nature. Bearing scrapers are readily forged either from new tool steel or from old files. Old files are also adapted to forging into punches and screwdriver blades. In attempting to forge out any tools keep the following suggestions in mind: 1. Select stock suitable to the work. Cold rolled or mild steel cannot be hardened nor tempered. Tool steel may be secured from the supply houses. 2. With the stock cut to the proper length, fit a pair of tongs to the work, A link over the end of the tong handles will be of great aid in holding the work properly. 576 AuroMOTivE Trade Training 3. Heating tool steel is an operation which requires care. The proper forging heat is just below the white heat and while the steel is in the yellow heat. Forging while white hot will cause certain steels to crumble under the hammer. 4. Reheat the piece of work before the heat has dropped to a dull red. 5. When approaching the final steps of the forging heat, care must be used not to go above the hardening heat which is a so-called cherry red. At this heat the steel works nicely. Forging while red gives smooth surfaces. 6. When drawing out any work, as the work on the punch would require, do not attempt to draw the work while keeping it round. Forge the work square and keep it square until approximately the right length has been secured. The next step is to forge the punch to an octagonal shape, and the final step in the process is to forge the eight corners into sixteen and remove any trifling irregularities. Attempting to draw out a piece of steel or iron while retaining the circular form will result in a split piece of work. 7. Move the work under the hammer and not the hammer over the work. 8. Skill comes with practice. 9. Do not attempt to har^dle two pieces of work at one time. Disaster will follow. 10. If white starlike sparks are seen coming from the fire, steel or iron is being burned. Just as a piece of steel reaches the welding point it gives off a few sparks. Continued heating above that point will result in a badly burned piece of work. Iron may be forged at that temperature, but tool steel may not. 11. Be careful not to "miss the work, or the hammer will rebound from the anvil with great force. Standing well over the anvil the hammer may strike the workman in the face doing serious injury. JOB 235. HARDENING AND TEMPERING. After a piece of tool steel has been forged to the proper shape for the desired work or use, it is essential that it be hardened and tempered to with- stand the demands made upon it. A cold chisel must have the cutting edge hardened and tempered. A punch must have the small end properly heat treated. Bearing scrapers, screw drivers and wrenches require varying treat- ments to insure their proper standing up to the work. Several methods are in use for hardening tools and likewise for drawing the temper. The student will understand that tempering may not be done without the hardening having first been accomplished. The two processes are separate and may not as a rule be accomplished simultaneously. Where special methods of heat treating are in use the single operation may finish the work, but in the tempering of hand tools at tlie forge hardening to the full degree is the first step. This full degree of hardness is then tempered to the point necessary for the use the tool, is to be put to. Hardening. — After the tool has been forged to the proper shape it is replaced in the fire and heated slowly to a cherry red. A cherry red is about 1400° Fahrenheit and may be recognized as a heat lying between a red and yellow. Experience with the steel at hand will give the correct heat for hardening. When the tool has reached the proper temperature it is dipped into cold water, as much of the tool being inserted as is to be hardened. In the case of a cold chisel or punch about 1^" is correct. Allow this point to remain in the water until cold. When removed from the water the point should hold the water for a short time before it dries away. The point is now hardened. The heat remaining in the tool will be sufficient to draw the temper. With a piece of sandpaper or emery cloth polish the point of the chisel or punch until it shows bright. As the heat draws from Garage Shop Repair Methods 577 the body of the tool to the point, colors will- appear on the polished surface of the tool which indicate with fair accuracy the degree of hardness remaining, or the temper of the tool. When the proper color appears plunge the entire tool into the water. The chart gives the colors and the corresponding temperature, and notes a few tools with their corresponding colors and tempers. In case the tool is to receive the same temper all over, it is first heated properly and thoroughly hardened, the entire tool being cooled in the water bath. To draw the temper the outer surface of the tool is first polished and is then heated gradually over a piece of sheet metal over the forge fire. A gas flame may be played directly on the surface of the tool to draw the temper. The colors should be watched carefully and when the proper one is reached the entire tool is plunged into the water. Tempering Chart. Light straw 430 degrees ] Straw 450 degrees }■ Lathe tools. Dark Straw 470 degrees J Light Brown 490 degrees ( Milling cutters, taps, dies, and reamers. Dark Brown .... 510 degrees | Light purple .... 520 degrees ( Twist drills, flat drills and wood working Dark purple 530 degrees ) tools. Light blue 550 degrees { Screw drivers, punches, cold chisels, etc. Blue 560 degrees j Dark blue 600 degrees Black above 650 degrees SOLDERING. It is absolutely essential that the student of automotive trade work acquire a knowledge of soldering and be able to do a neat piece of work. Soldering as required about the motor car is frequently difficult and tedious. It is difficult because of the amount of oil, dirt, and grease which collects on the parts requiring repairs of the nature possible with soldering. Gasoline tubes and tanks, carburetor and vacuum floats and other parts, as well as parts of the electrical equipment system are those requiring a knowledge of soldering in order to make repairs in a workmanlike manner. The first essential in all solder work is absolute cleanliness. The second is proper means of heating the iron and the third is a good flux. Solder may be purchased in the bar form or in the wire form. The last mentioned is most suitable for the varied work about the garage. Fluxes. — There are a number of fluxes on the market. If the garage does not do this kind of work regularly the most satisfactory flux is what is known to the trade as soldering salts. This flux may be purchased from the supply houses in pound bottles. To use the salts they are mixed with water. The strength of the solution may be varied at will so that a piece of work requiring a strong flux may be handled as readily as a piece such as tin which requires only a weak flux. Where a considerable bit of work is done the acid preparation is recom- mended. To prepare this, secure muriatic acid from a wholesale druggist or the supply house. Place a quantity of the acid in a glass or earthenware vessel. Add to the acid as much scrap zinc as it will eat away. This is called cutting the acid. For electrical work and certain other work a paste preparation called '"soldering paste" is recommended. This may be secured from supply houses. Powdered resin forms a splendid flux for electrical and similar work. Acid must not be used in certain places about electrical equipment. 678 Automotive Trade Training JOB 236. TINNING A SOLDERING IRON. The proper care of. the soldering iron is a prerequisite to good solder work. The body of the iron is made of copper. This may be filed or it may be drawn out on the tip to the proper shape. In drawing out by hammering, the copper is first Jieated to a dull red and then cooled in water thus annealing it. The point as a rule should be kept rather long. This permits of doing better work on the small intricate parts needing repairing, in the average run of work in the garage. 1. With the point of the iron of the proper shape, it is filed bright and clean. 2. Heat in the furnace, on the torch, or by any other means. A clean blue flame is preferred for this work although the iron may be heated in the coal fire. 3. Remove the iron from the fire and dip the point into a vessel containing a small quantity of soldering salts or other flux. 4. Work the iron onto a piece of clean tin on which a few drops of solder have been melted. Continue dipping it into the flux and working on the tin until an even coat of solder is provided well back on the point of the iron. 5. While working with the iron, each time it is withdrawn from the fire, it should be dipped momentarily into the soldering flux in the vessel especially kept for this purpose. This has the efifect of keeping the point of the iron permanently bright. At the end of a day's work it will be found that a surprising amount of dirt, Cross or sediment has collected in the bottom of this vessel. 6. Acid or other flux may be used in this process of tinning. 7. The usual method of tinning the soldering iron or copper in the tin shop is somewhat different from the above. Salamoniac is used to clean the iron in this case but it is a bit more difficult to manipulate. Where it is used in a block the solder is melted into the hole caused by working the iron in one spot on the surface of the block. When used in the powdered form the point of the iron is dipped into the box containing the salamoniac and then the operation carried out as outlined for the flux. - 8. The coat of tin or solder will be burned off if the iron is heated to too great a degree. The first sign of this is a blue color to the tin which will shortly turn brown and flake off if the heat is continued. 9. It is useless to attempt even the smallest piece of work without properly tinning the iron. JOB 237. SOLDERING A LEAKY CARBURETOR FLOAT. In many cases the hollow metallic float is in use in carburetors. In the course of months of service the gasoline will in some cases find its way into the inside of the float. To correct this trouble proceed as follows. 1. The presence of gasoline is detected by failure of the float to operate properly. Remove the float. Shaking it past the ear of the workman will give forth the sound indicating a confined liquid. 2. If not certain where the gasoline entered the float place a pan of water on the stove and bring it to the boiling point. Place the float in this pan. The gasoline vaporizing at a point lower than that of the boiling point of the water will be driven off from the float in the form of bubbles. The points at which the bubbles appear indicate the points at which the gasoline entered. 3. Punch two small holes in the float on the opposite sides. 4. Blow into one of these and all of the gasoline will be forced out of the lov/er one. Garage Shop Repair Methods 579 5. After all the gasoline is out, the float may be repaired by soldering the two holes punched in the float and those located by the above method. 6. Too much solder piled on the float will take away its buoyancy. A very thin coat is sufficient to hold. JOB 238. REMOVE CARBON BY BURNING. In certain types of engines which are not fitted with removable heads, the job of removing carbon is rather difficult. Scrapers may be used but this is a tiresome tedious task. Since carbon and oxyf^en have a great affinity for each Decarbonizer Regulator. Oxygen Tank Valve. Oxweld Carbon Removing Blowpipe Flexible Brass Tip Fig. 673. Oxweld Carbon Removing Outfit. 580 Automotive Trade Training Fig. 676. Oxygen and Natural Gas Lead Burning Equipment (Oxweld). other, this fact is taken advantage of and oxygen from the welding tank is used to complete combustion and burn out the carbon from the inside of the cylinder walls. Fig. 675 shows the type of blowpipe used for this work. 1, Remove a spark plug or a port plug from the engine cylinder. 2. Put the piston in the cylinder being worked on, on T. D. C. compres- sion stroke. Fig. 077. Oxygen and Acetylene Lead Burnin- Enuipment (Oxweld). Garage Shop Repair Methods 581 3. Light a match and permit it to burn until the match stick is well afire. 4. Having the oxygen regulator valve and blowpipe set for a light pressure and ready to operate, the lighted match is dropped into the cylinder. 5. Immediately the long flexible tube of the blowpipe is inserted and the combustion of the oxygen takes place. This is evidenced by brilliant white Oxweld Lead Burning Torch. Sparks coming from the cylinder and a roaring sound. Sometimes in cases of cylinders very badly carbonized the combustion is accompanied with loud explosion-like reports. Keep the tip of the blowpipe moving about in the cylinder until all recesses have been reached. When no more carbon is present the combustion can no longer be maintained. Test the cylinder after the flame goes out by dropping in another burning match and attempting to start combustion. 6. Treat each cylinder in turn. LEAD BURNING. Storage battery work requires a knowledge of lead burning or lead welding. Whenever two pieces of the same metal are joined together by fusion they are said to be welded together. Fusion means that they are heated to such a Fig. 679. Oxweld lead-burning equipment using oxygen and city gas- battery terminal straps. -welding 582 Automotive Trade Training point that they melt and are thus joined in one piece. In welding lead the filler rod used is lead. The groups of plates are burned together. This work is done in the factory. Where a single plate is joined to an old group it must be burned in, as lead welding is called in the repair shop. The lead connector straps are burned to the group posts. Lead burning, has been found to be the most satisfactory means of joining the battery parts together. Any other method is very likely to cause trouble due to the corrosive effects of acid. Figs. 676 to 678 show lead burning equipment. Fig. 677 shows the oxygen- acetylene outfit as made by the Oxweld Acetylene Co. In this instance an acetylene gas tank similar to that used for automobile lighting is used to supply the acetylene gas. The oxygen is supplied from the taller of the two tanks. Oxygen is a commercial product and may be secured in any of the larger cities. The same blowpipe shown in Fig. 676 may be used with oxygen and natural or artificial gas. Certain companies make torches suitable for oxygen and hydrogen. In actual lead burning the greatest difBculty is to bring the parts to the fusing point without having the walls break down and run away. Lead will retain its shape until the melting point is reached over a considerable area. When it starts to collapse the action is very sudden. In burning lead straps onto the storage battery care must be used to prevent the entire end of the strap reaching the melting point. Too large a flame will result in this trouble. The lead burning operation may also be used about the battery shop to burn leaden vessels together. These vessels are used as acid containers. The small flame of the lead burning outfit is of service in welding thin sheet metal, or in brazing small parts. Fig. 680. Oxweld burning on battery connecting straps. Garage Shop Repair Methods 583 JOB 239. BURNING CONNECTOR STRAPS ON BATTERIES. In dismantling a battery the lead connector straps are removed by drilling. Assemble these in place and proceed to burn them onto the posts as indicated in Fig. 680 and the steps outlined below. 1. Have the terminal post extending into the strap end about one-third of the way. 2. Place the flame into the hole until it is almost against the top of the post. 3. The top of the post and the bottom of the link or strap should be melted together as rapidly as possible. 4. Fill the hole with the welding rod seeing that the portions filled in actually fuse with the walls of the hole. 5. It is sometimes advisable to only partially burn in the one end before giving it a chance to cool, thus preventing it breaking down. 6. After the link is welded, the top is leveled ofif with the blowpipe. Use a wire brush to remove any oxide or scum tending to collect on the top of the finished weld. OXY-ACETYLENE WELDING. Oxy-acetylene welding consists of melting the edges of two pieces of metal so that they run together and become solid when cold. In order to do this a very hot flame is used. This flame is produced by burning together two gases, acetylene and oxygen. The equipment required consists of a cylinder or tank of oxygen, a tank of acetylene, two regulators or reducing valves — one for the acetylene tank and the other for the oxygen tank — a welding blowpipe, and two pieces of hose to connect the welding blowpipe to the regulators. Oxygen. — Oxygen is a gas that is used to help burn the acetylene. If it were not for this gas, the high temperature of the flame could not be secured. Oxygen does not burn itself. It merely helps the other gas to burn. It has no odor and is invisible. It is usually supplied in steel cylinders or tanks. The standard cylinders hold 200 cubic feet of oxygen. The oxygen is pumped into these cylinders at 1800 lbs. pressure. The amount of oxygen in a cylinder can be determined by looking at the high pressure gauge of the regulator. We know that when the cylinder is filled — when the high pressure gauge shows 1800 lbs. — there are 200 cubic feet of oxygen in the.cylinder. If the pressure is 900 lbs., which is one-half of the pressure when filled, there will be just half as much oxygen in the cylinder, or 100 cubic feet. Likewise, if pressure on the big gauge should show 450 lbs. in the cylinder, there would be one-quarter as much, or 50 cubic feet. In general, for every 9 lbs. pressure below the filling pressure of 1800 lbs., there will be 1 cu. ft. less of oxygen in the cylinder. A mixture of oxygen and gas, being explosive, should be avoided in the presence of a flame. Oxygen also will combine with grease, oil, or other inflammable materials with explosive violence. The oxygen regulator and the valve of the oxygen cylinder should therefore not be greased or oiled at any time. Care must be taken that the gauges on the regulator have no oil or grease on them. An oxygen cylinder, when filled, should be handled carefully, because there is such a high pressure within it. Do not knock it over or drop it. When the cylinder is not in service, the valve should be protected by means of a cap, which comes with it. Before attaching a regulator to the cylinder valve, always first 'crack" the valve (open the valve slightly) both to clean out the valve and to see that it is operating properly. Acetylene. — Acetylene is the gas that burns in the oxy-acetylene flame. When it is burned alone, without any previous mixture of oxygen, it produces a yellowish, smoky flame. When mixed with oxygen, it produces a bluish white flame. It is an invisible gas, but has a distinct odor. 584 Automotive Trade Training Acetylene is made by dropping a grayish, stone-like substance, called calcium carbide, into water. The acetylene bubbles up through the water, leaving a white sludge at the bottom of the vessel. This sludge is slaked lime. The machine in which acetylene is made is called an acetylene generator. Oxweld Welding Unit Fig. 681. Acetylene Tanks. — It is not possible to compress acetylene at a high pressure into an empty tank, as is done with oxygen. This is because acetylene at a high pressure will explode. For this reason a dififerent style of tank is used. Inside the tank is placed a material that is porous. This material is soaked in a liquid called acetone. Acetylene will be dissolved in this liquid just like sugar is dissolved in water. When acetylene is pumped into a tank of this kind, it is safe. It is never pumped up to a pressure above 250 lbs. The usual tank of acetylene contains 300 cubic feet of gas. No blowpipe that will empty it in less than seven hours should be used on Garage Shop Repair Methods 585 any acetylene tank. If the tank is emptied in a shorter time than this, the liquid will be drawn out of the tank. Do not drop or jar an acetylene cylinder. Handle it carefully. Always keep an acetylene cylinder in as cool a place as possible. Do not stand it near a fire. If possible, it should be kept out of the hot sun. Before connecting an acetylene regulator to a tank, be sure that the cylinder valve is operating properly and that there is no leakage around the nut of the stem. Because acetylene is inflammable, all leaks in the cylinder MGM PRBSSURt CALVE DfAPHRAGM HANDLE COflNECTtNC NUT DOST PLUG y/ALV E NOZZLE OUTLET CONJ^ECTION Fig. 682. Regulator. valve, hose, and connections should be avoided. If there is a cap supplied for the tank valve, always see that this is in place before moving the cylinder. Do not transfer actylene from the cylinder to an empty tank. Avoid large volumes ol acetylene under pressure. Acetylene will act on pure copper so that it will produce an explosive compound. Because of this, never use copper in acetylene equipment. Brass or bronze, however, can be safely used. Never use acetylene at any time at a pressure above 15 lbs. Beyond this it is dangerous. Do not attempt to locate a leak in the acetylene connections with an open flame. To locate a leak use soap and water with a brush. When the leak is located, bubbles will appear. Because acetylene is not compressed in an empty tank like oxygen, but is dissolved m a liquid, it is not possible to determine the amount of acetylene being used by the gauge readings. This may be determined, however, by O m^N VALVE , CXYCEN C/^AMBFR _ /NJECTOR Fig. 683. Blowpipe. 586 Automotive Trade Training weighing the tank before and after the job. There are 14J/^ cu. ft. of acetylene to a pound. Regulator or Reducing Valve. — A regulator or reducing valve is used in an oxy-acetylene unit to reduce the pressure of the gas and to keep this pressure constant or even. Fig. 682 shows a section of one type of regulator. The regulator is a delicate device, very sensitive, and must be handled very carefully. Never drop or jar it. Do not use oil, grease, or such material for lubrication in connection with the oxygen regulator. Keep as much dust and dirt out of it as possible, by inserting the dust plug when the regulator is not in service. Do not change the regulator from one cylinder to another without taking the pressure off the diaphragm, which can be done by turnmg the handle to the left. A regulator should not be repaired by any but skilled workmen. Do not replace diaphragms, valve seats, springs, or other wearing parts, except with those actually manufactured for the regulator. Welding Blowpipe. — Fig. 683 represents a welding blowpipe. The blow- pipe is the instrument which is used for welding It is designed to be easy of control and manipulation. It consists of a tubular handle, in one end of which is a valve body carrying both the oxygen and acetylene valves. On the other end is a head into which are inserted welding heads or tips of different sizes. The mixture of gases occurs in these tips. If the blowpipe is handled properly, it should not require a great amount of attention. It should only be necessary to clean the removable and working parts and occasionally the tips and WELDING TABLE Size Per Hour Per Linear Foot Thickness of Metal of Welding Head Oxygen Pressure Speed Gas Consumption Gas Consumption Iron or Best Shop Filling Tip Lb. Per Condition Practice uxygen Acetylene Oxygen Acetylene Wire In. Sq. In. Lm. Ft. Lin. Ft Cu Ft Cu. Ft. Cu. Ft Cu. Ft Lb. W-3 W-1 W-3 W-] A=No. 28 1 4 30 26 3.5 3.S 0.14 0.13 A=No. 22 1 2 6 9 26 22 4.5 4.2 0.20 0.19 0.005 A=No. 18 2 8 23 19 5.5 5.2 29 0.27 0.007 ,^=No. 16 3 3 10 10 21 17 6.6 6.2 0.39 0.37 0.01 A=No. 13 4 4 11 11 17 14 8.7 8.3 0.62 0.59 0.02 K=No. 11 5 5 12 12 14 ny2 10.8 10.2 0.94 0.89 0.04 6 14 11 9 15.0 14.2 1.67 1 58 0.08 7 16 9 7 19.2 18.3 2.74 2.62 0.15 U 8 19 6M 4K 27.6 26.3 6.13 5.85 0.3 10 21 43/2 3 36.0 34.3 12.0 11.4 0.6 M 12 25 2H I'A 52.8 50.4 35.2 33.6 1.4 1 and Over 15 30 2 1 69 7 66.3 69.7 66.3 2 4 Fi£ eS4, Blowpipe. Garage Shop Repair Methods 687 passages of the welding heads. The tips should never be cleaned out with anything but a soft copper or brass wire. If something harder is used, the hole will become larger and the head will not work so well. Occasionally dirt can be blown out of the head by means of high oxygen pressure. If the flame is not properly adjusted, or the tip becomes clogged, the blowpipe may backfire. When this occurs, close the acetylene valve for a few seconds. Then open this valve fully and re-light the blowpipe. If the backfire continues, close both the acetylene and oxygen valves, then relight the blowpipe. If the blowpipe becomes heated, it may be cooled by plunging it into a bucket of water. When this is done, be sure that the acetylene has been shut off and a small quantity of oxygen is passing through the blowpipe. The blowpipe may be cleaned by removing both the acetylene and the oxygen hose and then connecting the tip of the head to the oxygen hose. Then turn on about 30 lbs. oxygen pressure. The acetylene valve must be opened Fig. 685. Oxweld welding heads. and the oxygen valve closed. This will drive any dirt or carbon through the larger acetylene passages. After this is done, the acetylene valve should be closed and the oxygen valve opened. This will clean out the oxygen passages. Hose. — Two colors of hose are used, black tor acetylene and red for oxygen. This is to prevent interchanging when connecting the apparatus. All hose connections must be tight. A good hose clamp should be used. Both acetylene and oxygen hose should be blown out occasionally so that dirt and dust will not be carried into the blowpipe. Welding Heads. — There are ten sizes of welding heads supplied with a blowpipe. Each of these heads gives a certain size flame. Each of these flames is to be used on different thicknesses of metal, as is shown by the table on page 586. The acetylene pressure tor all the heads is the same — namely, 1 lb. The oxygen pressure varies, ranging trom 9 to 30 lbs., according to the size of the head. Oxy-Acetylene Flame. — When the oxy-acetylene flame has just the right proportion of each gas, it is called neutral. This is shown by a clearly defined central cone, bright bluish green in color, surrounded by a bushy, weak flame, 588 Automotive irade Training purplish yellow in color. When too much oxygen is used, this central cone or jet becomes bluer in color, and loses the greenish tinge; it is not so clearly defined. When too much acetylene is used, the jet becomes bluish white and is streaky. The neutral flame should always be used. The student should test his flame from time to time as he is welding. This is done by turning on a slight excess of acetylene, by means of the acetylene valve, and then trimming it down so that a neutral flame is produced. CONNECTING AND STARTING THE WELDING UNIT. Attaching Regulator That Controls Flow of Oxygen. — The oxygen tank is the taller, with the flat bottom and the bullet shaped head, covered with a metal cap. This cap must be unscrewed. Under the cap is a valve. Slightly open this valve to allow the oxygen to escape in order to remove the particles of dust or dirt which may have collected. The tank is usually painted gray and green, red, yellow, or dark green. With each outfit is furnished a two- gauge regulator painted red. Remove the dust plug from the regulator union nut. Attach this regulator to the oxygen cylinder valve by means of the union nut in the back of the regulator. Be sure that this nut is pulled up tight so that no oxygen will leak. With each regulator is furnished a piece of red hose. This hose must be connected with the outlet connection of the regulator. Be sure that this connection is tight. Attaching Regulator That Controls Flow of Acetylene. — The acetylene tank is the shorter and stouter of the two tanks, and has a depression at both ends. In one of these depressions is fixed a valve of the same type as the' valve in the oxygen tank. These tanks are always painted black and have a name plate on them giving the quantity of gas that the tank contains. Open the valve very slightly to blow out any dirt that may have accu- mulated. With each outfit is furnished an adapter, which is a small curved brass connection that connects the tank and regulator. This adapter must be fitted to the valve. Most acetylene cylinder valves have left-handed threads, and for this reason the adapter is- left-handed. When the adapter hks heen attached to the cylinder by means of the male connecting nut and stud, the regulator is fastened to the other end of the adapter by means of a connecting nut similar to the nut of the oxygen regulator, but threaded left-handed. The acetylene regulator is usually the same in design as the oxygen regulator, except that it is painted black and the gauges on it are for low pressure. When the acetylene regulator is tightly connected, the acetylene hose is attached to the outlet of the regulator. This hose is usually black in color. Blowing Out Hose to Clean. — Before going any farther, it is necessary that we blow the hose out to remove dirt and dust. This is done as follows: Slowly turn on the oxygen valve. This valve should be turned to the left by means of the hand wheel on it until the valve is open as far as it will go. The pressure of the oxygen in the cylinder will show on the big gauge. If the cylinder is full this big gauge will read 100 per cent at 1800 lbs. Then turn the handscrew of the regulator to the right until oxygen passes through the hose. Keep turning the handle until a pressure of about 5 lbs. shows on the small or low pressure gauge. Let the oxygen pass through this hose for a few seconds, and then turn the handle of the regulator to the left until the flow of oxygen stops. Now slowly open the valve on the head of the acetylene tank by means of the wrench supplied. This valve should never be opened more than two full turns. The pressure in the acetylene tank will then be shown on the big gauge. This pressure will be about 250 lbs. when the tank is full. The handscrew of the regulator should then be turned to the right until a small amount of acetylene passes through the hose. Care must be taken that no fires or flames Garage Shop Repair Methods 589 are near at the time, otherwise the acetylene will become lighted. The gas is allowed to flow through the hose until all dirt is removed. This should not take more than five seconds. When the hose is clean, the handle of the regulator should be turned to the left until the flow of gas is stopped. Connecting Blowpipe. — We are now ready to connect the blowpipe to the hose. First, connect the oxygen hose from the oxygen regulator to the hose connection on the blowpipe marked oxygen. Likewise connect the acetylene hose to the blowpipe valve marked acetylene. Then select the proper welding head or tip that is to be used according to the chart or table furnished you, and screw it carefully into the blowpipe. Turn on the oxygen by means of the handscrew of the oxygen regulator until the pressure on the small gauge is as given on the chart. Be sure that when this is done the oxygen valve on the blowpipe is open. Then close this valve, and open the acetylene valve on the blowpipe. Now turn the handscrew on the acetylene regulator to the right until acetylene is passing through the blowpipe, and close the acetylene valve on the blowpipe. OXYGEN REGULATOR CONNECTING NUT^ CYLINDER VALVE> ACETYLENE REGULATOR PRESSURE GAUGE HANOLR. OUST PLUG> CYLINDER VALVE^ ..«— "HIGH PRESSURE GAUGE ^^OW PRESSURE GAUGE HANDLE -HOSE CONNECTtON -DUST PLUG -OXYGEN HOSE ^CUTTING NOZZLE CUTTING BLOWPIPE ,_^CUTTINO y^OXYGEN VfkLVE riir^ PRE-HE ATINO VJ. oxygen VALVE -ACETYLENE VALVE Fig. GS6. Oxy-Acetylene welding unit. 590 Automotive Trade Training Lighting Blowpipe. — The apparatus is now ready for use, and the gases are further regulated when necessary by adjusting the valves on the blowpipe itself. Open the acetylene valve entirely. Open the oxygen valve slightly. Then light the gases. After lighting the gases, open the oxygen valve wide; adjust the flame by turning the acetylene valve to the right until a neutral flame is produced. To Shut Off Blowpipe. — When the job is finished and you want to shut off the blowpipe for a short time, release or turn the handscrew on both oxygen and acetylene regulators to the left until the flame on the blowpipe goes out, after which close the blowpipe valves. When work is completed for the day and the apparatus is to be put away, first close the acetylene valve, and the oxygen valve of the blowpipe and turn off the valves on both cylinders. Then open the valves on the blowpipes until all the gas in the regulators and hose passes, out of the blowpipe into the air, and turn the handscrew of both regu- lators to the left until loose. Then disconnect the oxygen and acetylene regulators from the cylinders. Each regulator has a dust plug which is to be put on its cylinder connection during all time the regulators are not connected to the cylinders. Place the regulators and blowpipes with wrenches, goggles, heads, and tips in their proper place so that they will be safe and protected from dust, dirt, and rough handling. Roll up the hose and put it i i the case or tool box where it belongs. PROPERTIES OF METALS. In order that a welder may intelligently handle the work placed before him he must be able to immediately establish the identity of the metal, recog- nize its properties, have a complete knowledge of its behavior under the welding flame, and know exactly what treatment to give it. This necessary knowledge cannot be acquired within a short time. It will result only from experience, careful observation, and close examination of the work during welding. Melting Point. — The first property to be considered, common to all metals, is the melting point. Autogenous welding is the joining together of two metals by uniform fusion at the line of contact. In other words, in order to secure a perfect weld it is necessary that each part be melted, and the molten metal allowed to flow together and harden in this state of mixture. The melting point of any metal is a definite quantity. If the temperature is raised to a certain point, fusion or liquefaction of the metal occurs. The melting points of the principal metals and alloys are given in the accompanying table. Expansion and Contraction. — When metallic bodies are subjected to an increase in temperature they expand, the rate of this expansion being definitely known for each degree of rise in temperature. When the temperature is lowered a reverse action takes place, the bodies contract and the volume and linear dimensions decrease. Metals are very susceptible to this change in volume, each metal having its own coefficient of expansion, which varies materially from other metals. As seen from the table given here, of the metals most commonly welded aluminum expands the most, bronze and brass next, then copper, steel, and iron. It will be seen that aluminum expands almost twice as much as iron or steel. The effect of this expansion and contraction is of great importance to the welder. The expansion and contraction of the welded piece cannot be controlled mechanically, because these forces are irresistible. In malleable or ductile pietals the expansion is liable to produce warping or deformation of the piece, while in materials that are not of this nature— Garage Shop Repair Methods 591 1 .^ JO ; Latent Heat ol Fusion B. T. U' per Lb. •o • •OS • rJ^fM-^ ^ ""^ .<:o •00 • !(X) • i-H • •t- • OOTtOS OS CO •d •CO ; •IT- • 1—1 CO • ^ rj< • ^ : UO •(M • CD 1 ■^ CO • a- • Relati Hea Conduct Copp Wl.O O • o CO •T-i ■ •lO • lO 1—1 o • o: • • US • c^ t- • 1—1 1-1 CO CO • • s ; ! bp^pH* o U5 •CO •00 1—1 11^ lO • o • t- •O^ '• O • t- as 1—1 UO CO t> •o 1—1 Ti« • tH •00 • C^] •(M (M (M '* 00 •t- (M • t- • o •as • 1 • 1 1 CO CO t- •CO S^l 1—1 • tH • •tH . ?^ ■■^ CO CO ;C0 CO as •(M t- ^ 1-1 •CO C o o o ^ o o o o o o o o ^ o o o o o o o o § T}< iO ^ oo o ^ O (M as o lO ^ • o I^ IlO CJ CO ! CO Q T— f CO : CO Us ^ j^ o ■ o .?£> ; o • as 00 as as 00 c^ ^O ■^ 1— ( •00 • t> o tr- t- as Oi o^ f • 1 • 1— 1 00 t- 1—1 ■^ uo las o o c • c ;CO • gsj (M ""^ CO ^ CO N : o • o '■ CD ■ ? 3 • :3 u : O d 2 1 g 1 — , < 1 1 d Q SI § PQ IS d Q 1 o 1 o O o 1 Q < Q 1— 1 ;z: 1 "Z }— SI 1 S s «1 592 Automotive Trade Training brittle materials such as cast iron — the result of the expansion or contraction, unless properly cared for, is breakage. Conductivity. — The conductivity of a metal is its property of transmitting heat throughout its mass. This property is not the same for all metals, and varies within wide limits. It is commonly called thermal conductivity. It can be seen that if one metal conducts or transmits the heat from the welding blowpipe throughout its mass more rapidly than another, it is neces- sary that allowance be made as to the method of handling the job, the size of the blowpipe, and the nature of the preheating equipment used. In welding metals of high thermal conductivity it is necessary to use oversize blowpipes — as in the case of copper. While the melting point of copper is low, yet the conductivity is high, and consequently a blowpipe head of larger size than would be used on a similar thickness of steel must be employed. The conductivity of a metal will have a great bearing on the correct way of considering the problem of expansion and contraction. If one metal absorbs or leads the heat away from the welding blowpipe more rapidly than another, the heated area will become very much larger; and consequently the expansion and contraction strains are affected proportionately. Oxidation. — Oxidation is the reaction produced by the combination of ctxygen with a metal. The weld may become oxidized by contact with the oxygen in the air and by the presence of excess oxygen in the welding flame. An oxide has none of the metallic properties of the metal from which it is formed. When present in a weld it is an impurity, and it is therefore very necessary that it be avoided as far as possible. Some oxides are lighter than the metal itself, while others are heavier. Consequently, when a metal is reduced to a molten condition the oxide will either float on the surface of the liquid metal or sink to the bottom of the weld. It can be seen that the sinking is the least desirable, as the presence of the oxide in the weld itself is extremely bad. The melting point of oxides is in some cases higher, and in others lower, than that of the original metals. This point must be considered in attempfjn.^ to eliminate oxide from the weld. Certain metals when molten also have the property of dissolving a portion of the oxide, the extent of this solution being dependent upon the metal itself. When this is the case the oxide is retained in solution until the metal hardens, in some cases separating and producing a weakened weld, in others being retained permanently in solution as an alloy. Oxide may be dealt with in two ways. First, by taking such means as possible to prevent its formation, by the use of a neutral or reducing flame in the blowpipe as required, or by the uses of various cleaning fluxes, etc. Second, by eliminating the oxide after its formation with suitable fluxes, which either dissolve or float it off, or by mechanically removing it by the manipula- tion of the welding rod or a paddle made for this purpose. The subject of oxidation is one of vital importance to the welder, one that he should study thoroughly in order to become familiar with all its forms. It is due to oxidation that the great majority of defective welds are faulty. PREHEATING. In autogenous welding it is essential that the welding be preceded by some preliminary heating operation, as there are many advantages to be gained by this treatment. Preheating is employed for two reasons: first, to prevent the effect of expansion and contraction; second, to decrease the cost of welding by supply- ing from a cheaper source a considerable volume of the heat required. Garage Shop Repair Methods 593 When a weld is being done on a large casting, it is entirely too expensive to supply the total amount of required heat from the blowpipe alone. To offset this, preheating by some cheaper method is used; and the result is usually a saving of from 25 to 60 per cent of the cost of welding. Not only is a great saving in gases effected, but it is possible to accomplish the welding ivith greater speed, due to the casting being at a higher temperature when ivelding is started. There are various means of carrying out this preliminary heating. The simplest, and one of the most used on light objects, is that of utilizing the secondary or envelope flame of the welding blowpipe. In welding thin castings and thin sheet metal work, the secondary flame of the blowpipe needs to be playe.d upon the parts at the line of the weld for only a few seconds in order that the pieces attain a red heat. If the article to be welded is of fairly large size the use of a gas or oil burning preheating torch is economical. These preheating torches, however, limit the area of the surface covered. They are consequently used more successfully on that work which requires localized preheating. The flames produced are of sufficient temperature, but not the necessary volume to evenly heat the entire casting of any great size. Then, too, the heating zones of these burners vary because they are operated with an air blast which, unless unusually well controlled, fluctuates in pressure. A common method of preheating is by means of a charcoal or coke fire built around the article to be welded. The usual procedure is to build a small temporary fire brick furnace around the piece and then fill in with coke or BUTT WELD FLANGED WELD EDGE WELD Fig. 687. charcoal loosely set up. Occasionally coke and charcoal are mixed. This is ignited by means of kerosene. As the combustion of the charcoal or coke is rather slow, the preheating is carried out gradually and evenly. An air blast should not be used. In welding large castings of a complicated nature it is necessary that they be preheated evenly throughout, and that the welding be carried on while the casting is at a dull red temperature. It is impossible to do this while gas or oil burners are playing on the casting, as the blast of these blowpipes is such 594 Automotive Trade Training that it would seriously interfere with the working of the oxy-acetylene flame. Therefore, the most satisfactory way to accomplish this is to partly bury the casting in charcoal or coke and carry on the work while it is buried in the hot coals. The cost of this method is less than that of any other, and because of its ease of application it is used more generally by welders. Where it is necessary to preheat many castings of a similar nature, such as gas engine cylinders, furnace sections, etc., it is best that a permanent preheating oven or furnace be installed. These furnaces may be designed particularly for the work they are to receive, and the fuel used can be coaf, coke, charcoal, gas, or oil. In some cases the furnaces are muffled — that is, the flame is not allowed to play directly on the casting; in others the casting is laid directly in the flame. With suitable draft controlling arrangements it is possible to establish a fairly constant temperature in these furnaces, the advan- tages of which can be readily seen. PREPARATION OF WELDS. The success of oxy-acetylene welding depends, to a very great extent, upon the proper preparation of the parts to be welded. While the preparation of a weld depends very much upon the particular location and condition of the parts to be welded, there are nevertheless certain general rules that must be followed. The preparation should be given as much consideration by the welder as are the proper selection of welding rods, fluxes, and size of blowpipe head. The weld that is not prepared properly will usually offset any skill that the welder may have. Careless preparation has caused many failures. Bevelling. — In making an autogenous weld, it is necessary that fusion penetrate entirely through the metal. In order to aid this the -pieces are usually champfered or beveled with an air hammer, a grinder, or cold chisel. By bevelling is meant the grooving or champfering of the metal at the line of the weld, the depth of this groove or V being equivalent to the thickness of the metal. x Bevelling is not required on castings or plates lighter than %" in thickness From ys" to -h" in thickness a narrow champfer only is necessary; one in which the angle opening is 90° is sufficient. From fg" up to the maximum thickness weldable by the oxy-acetylene blowpipe, an angle opening of from 60° to 90° is sufficient, the angle being dependent somewhat upon the nature of the material and the location of the weld. It is not sufficient to merely separate the edges, because in this case the upper corners will be melted down and will flow into the space between the pieces, adhering to the sides rather than fusing intimately. This does not produce a weld in any sense, as experience speedily shows. Under certain conditions it is possible to use an oxygen cutting blowpipe for bevelling. In case this is done, care must be taken that all the oxide produced on the surfaces cut by the blowpipe be removed before welding. Setting Up Work. — Before starting to weld, it is necessary to adjust or arrange the parts to be welded, so that during the operation they remain in relatively the same position. It is a common fault of inexperienced welders to overlook this important item, and consequently the strength of the weld, as well as the progress of the work, will be seriously affected. In lining up a piece it is essential that the deviation from the original lines, caused by expansion and contraction, must be thoroughly understood and cared for. In repairing castings of nonmalleable nature, the adjustment before welding should be very carefully done. This adjusting is usually carried out by means of straight edges, jig clamps, keys, wedges, and other devices. Garage Shop Repair Methods 595 CHARACTER OF FLAME. The combustion of acetylene in oxygen produces a two-phase flame. The luminus cone or jet indicates the following re-action: C2H.+ 0. = 2C0 + H. The oxygen in this reaction is supplied from the cylinder. It is at this point that the endothermic energy of acetylene is released. The bushy non-luminous envelope shows this combination: 2H.+02=2H20 The oxygen in this phase is supplied by the atmosphere. The character of the oxy-acetylene flame depends upon the proportion of oxygen and acetylene contained in the mixed gas as it issues from the tip of the blowpipe. This proportion is controlled to some extent by regulators or other devices installed with the equipment. The final adjustment, however, should be with the needle valves of the blowpipe. The proportion of oxygen is approximately regulated by adjusting the oxygen regulator to the proper pressure as shown in the table on page 586. The acetylene is also regulated when using a medium pressure generator, or dissolved acetylene from tanks, by means of various regulators and regulating devices. In the use of low pressure and acetylene generators it is not necessary to use devices such as this, since the correct amount of acetylene is drawn into the blowpipe by means of an injector in the welding head or blowpipe. The proportion of the gases may produce three divisions in the character of the flame — called reducing or carbonizing, neutral, and oxidizing. The welder should at all times observe carefully the type of flame produced, and any divergence from the type desired should be instantly detected and corrected. Reducing or Carbonizing Flame. — When the blowpipe is first lighted the acetylene is greatly in excess. The flame produced is of abnormal volume, a dirty yellow color, and of uniform consistency. This is the reducing type in an exaggerated degree. By increasing the oxygen pressure the size of the Fig, Welding position. flame is lessened, and gradually a white zone of greater luminosity appears near the blowpipe tip. This luminous zone is not clearly defined. The flame is still of abnormal size, is streaky in appearance, and a brilliant white. The 596 Automotive Trade Training extent of the reducing or carbonizing action of the flame is judged practical. y by the size and definition of the luminous zone. When the luminous zone becomes more clearly defined and takes the form and color of a bluish white incandescent cone or pencil, the streakiness is diminished and the flame approaches neutral. The reducing flame is used to some extent on certain alloy steels, aluminum, and non-ferrous alloys. Neutral or Normal Flame. — When acetylene and oxygen are ignited in the correct proportions a neutral flame is produced. The appearance of this flame is characteristic. It is made up of a distinct and clearly defined incandescent pencil or cone of bluish green in color, surrounded by a faint purplish yellow secondary flame or envelope of bushy appearance. The incandescent pencil or cone may be from J4 " to 5^" in length, and is usually rounded or tapered at the ends. The maximum temperature of the oxy-acetylene flame is %" to ^g" beyond the extremity of this jet. In establishing a neutral flame the jet should be of the maximum size for the particular blowpipe head in use. This flame is established by gradually increasing the oxygen supply until the point at which the incandescent jet is of the greatest clearness is just passed, and then f nally adjusting by decreasing the oxygen supply until the desired condition is obtained. This type of flame is the one most extensively used, and no welder is proficient until he is thoroughly familiar with its appearance and distinguishing characteristics. Oxidizing Flame. — When an excess of oxygen exists in the welding flame it is called oxidizing. The effect of too much oxygen is to diminish the size of the flame*, blunt or blur the incandescent cone, and produce a weak, streaky or scattering flame. The oxidizing flame has neither the size nor the illumin- ating qualities of the reducing flame, but" the incandescent flame is slightly more pronounced. It is a pale violet color. In some blowpipes the incandescent cone is not only diminished in size, but is slightly bulged at its extremity as compared to the normal flame. It is rare that a welder has occasion to use this type of flame, and hence he should be particularly careful regarding its use. MANIPULATION OF BLOWPIPE. The blowpipe must be grasped firmly in the hand. It is not good practice to hold it in the fingers, because it is impossible to manipulate the flame with as great regularity and control, nor will it be possible to do as heavy work without tiring. Occasionally the hose is thrown over the man's shoulder. In this case the weight of the blowpipe is suspended and held by the tubing, so that it is only necessary to impart the typical welding motion to the blowpipe, which can usually be done by the fingers. The movement of the welding flame is hindered, however; and this method is therefore not recommended, and should be used only as a relief when the work is of long duration and the operator's wrist and forearm become tired. The head of the blowpipe should be inclined at an angle of about 60° ta the plane of the weld, as in Fig. 688. The inclination of the head should not be too great, because the molten metal will be blown ahead of the welding zone and will adhere to the comparatively cold sides of the weld. On- the other hand, the welding head should not be inclined too near the vertical, because the preheating effect of the secondary flame will not be efficiently applied. There are certain cases, however, where the conductivity of the metal is such that it is not necessary to utilize this preheating. Also certain metals have the property of absorbing the gases of this flame. Consequently, in these Garage Shop Repair Methods 597 cases it is best that the flame impingement be concentrated to as small an area as possible. The motion of the blowpipe should be away from the welder and not toward him, as closer observation of the work can be obtained and greater facility in making the weld will be experienced. Where thin sheet material is being welded and it is not necessary to use a welding rod or wire, a weld may be produced by moving the blowpipe in a straight line. It can readily be seen that this does not apply to welds which have been bevelled, and which require the use of filling material, for in this case a swinging motion must be imparted to the blowpipe to take in both edges of the weld and the welding wire at practically the same time. In comparatively light work a motion is imparted to the blowpipe which Fig. 689. Blowpipe motion. will cause the incandescent cone to describe a series of overlapping circles, the overlapping extending in the direction of the welding. In order that the weld be of good appearance this must be constant and regular in its advance. The width of this motion is dependent upon the size of the material being welded and varies accordingly with the nature of the work. In heavier work, if the above system were used, a great deal of the motion would be superfluous. Consequently either an oscillating movement, or one in which the jet of the blowpipe will describe semi-circles, should be used (Fig. 689.) This confines the welding zone; and while the progress is not so fast, it is more thorough than the other system for thisclass of work. To the average beginner the regular control of these motions is difficult, and considerable practice is required to become skilled. It is the regularity of these motions that produces the characteristic even-rippled surface of good autogenous welding. The progress of a welder and the quality of his work can be determined to some extent by the skill with which he produces this effect. After the swinging motions of the blowpipe have been mastered, the next step will be to introduce the welding rod into the weld in such a manner that the regular advance of the blowpipe will not be hindered nor retarded. It can be seen that there is quite a little attention needed to secure perfect cooperation between the two hands, one controlling the blowpipe and the other adding the welding rod. The welding rod should be held and inclined as shown in Fig. 690. In this position sufficient quantity of metal may be added at the right time. With the weldmg rod held m a vertical position or horizontal, the possibility of the addition ot an excess of metal, part of which is not fused, is great. In adding this metal, care must be exercised that the edges of the weld are in the proper state of fusion to receive it. If the metal is not sufficiently hot, the added material will merely stick to the sides and fusion will not exist. It is therefore 598 Automotive Trade Training necessary that, by the motion of the blowpipe, fusion be produced at the edges of the weld equal with that of the welding rod. The usual faults of the beginner are failure to introduce the welding rod at the proper time into the welding zone, to hold the rod at the wrong angle, or to fuse either too little or too much of the rod. The filling material when melted should never be allowed to fall into the weld in drops or globules. When the proper time arrives to add it, the welding rod is lowered into the weld until it is in contact with the molten metal of the edges. When in this position the flame of the blowpipe is directed around it, and thus fusion is produced. It is customary to add metal in excess to that of the original section. There are several very important reasons for doing this. First, the weld is reinforced and the strength is accordingly increased. Second, in case a finished surface is desired, a sufficient stock must remain to allow for finish. Third, small pinholes or blowholes may be found just under the sSfface of the weld, which do not extend to any depth, and may be removed by filing or machining. Fig. Welding rod position. SOURCES OF TROUBLE. The first source of trouble in making a weld is improper adjustment of the welding flame. If the flame is not adjusted properly the resultant weld will be inferior. The commonest fault is the presence of too much oxygen. In this case, unless the welder takes a great deal of care in removing the oxide by mechanical means, it will be incorporated throughout the weld. The presence of oxide prevents the thorough blending of the metal, and therefore decreases its strength. Failure to penetrate to the bottom of the weld is the cause of a great many defects. This fault is not only that of a beginner, but also the skilled operator. Very often the desire to complete a weld rapidly will cause the operator to hasten over the most important part of his work, which is to secure the absolute fusion of the edges at the bottom of the weld, before the filling rod is added. This defect not only reduces the section of the weld, but also produces a line of weakness in case the weld is submitted to bending or transverse strains. When molten metal is added to metal which is not in fusion, a weld is not Garage Shop Repair Methods 599 secured. The molten metal merely sticks to the cooler metal; this defect is common with careless operators. It may be caused by improperly bevelling the pieces to be welded, by the faulty manipulation of the blowpipe, or by improper use of the welding rod. For the beginner it is at first difficult to distinguish the proper temperature at which to add the filling material. Usually he applies the filling rod before the edges of the weld are in fusion. The adhesion in this case occurs at both edges. Occasionally one edge of the weld is in fusion, but the other is not, in which event the adhesion is restricted to one side. In some cases the edges of the weld are both at a point of fusion too soon. Under these conditions a film of oxide may exist on each edge. When a filling material is added, adhesion is produced with a film of oxide separating the edges and the added material. Quite often an operator in applying the welding rod to the weld will concentrate his flame on the welding rod and the edges of the weld. As he plays the blowpipe around the rod he will inadvertently force some of the molten metal ahead. The metal is not in the proper state of fusion, so there will consequently be a small area of adhesion. In welding cast iron, copper, and to some extent steel, a very common fault of the beginner is that of forming blowholes or porous sections in the weld. This can be overcome by close observation of the work while welding and by certain corrective means, the principal one of which is the use of proper fluxes and proper manipulation of the welding rod. It is needless to say that the existence of this defect in a weld seriously affects its ultimate strength. Occasionally welds are encountered in which dirt or some foreign material is incorporated. This will cause porosity and an inferior weld, which could readily have been avoided by removing the material either before or during the execution of the weld. STEEL. Steel is one of the purest forms of iron. It can be molded, forged, or drawn to any desired shape. It usually contains about 98 per cent or more of iron. The principal constituent of steel, after iron, is carbon. It is present from almost nothing up to 1.50 per cent. As in cast iron, the carbon plays an important role in the properties of the metal. Wrought iron is almost the same as a very low carbon steel. It is never cast, but is always forged. The process of its manufacture is different, however, in that it is finished in a pasty rather than liquid condition, and there is always 1 to 2 per cent of slag present in it. From the standpoint of welding, it can be considered as a mild steel. Carbon is dissolved in the steel. It is never free as graphite. The carbon exerts a hardening effect on the metal, which increases with the carbon content. Carbon also increases the tensile strength up to about 1.30 per cent, where it begins to lower it. The ductility decreases very rapidly from 5 per cent to 15 per cent carbon. From there on the decrease is more gradual. Silicon has very little effect on the strength of steel. Its principal property is that of producing soundness. Sulphur lowers the strength and ductility of the metal. It also produces "red-shortness," which causes checking during the working or casting of it. Phosphorus produces brittleness and weakens the metal with respect to shock or vibrating stresses. Manganese increases the tensile strength of steel when it is present above .4 per cent. Its effect is dependent upon the amount of carbon present. Oxide of iron does not have any great effect on the strength of steel, but does affect its ductile properties. Welding of Steel.— Steel melts at 2500-2700**. When molten it is not 600 Automotive Trade Training extremely fluid. At dull red heat it begins to oxidize rapidly. The oxide, which melts at a temperature of several hundred degrees below that of the metal, remains at the surface and can be easily removed. A flux is not necessary. Close attention must be paid to its removal, however, for its presence is very harmful. It is a common fault to have layers of oxide in the weld, which cause a laminated structure that weakens the weld seriously. Steel does not melt rapidly. It gradually comes to fusion, confined to small areas. Because of this, the weld is made up of small overlapping layers. The strength of the weld depends greatly on the thorough bonding of these layers to each other and to the bevelled edges of the piece being welded. It is a common fault to force the metal ahead of the welding area and allow it to adhere to the cold sides of the bevelled edges. This should be avoided, as a weld is not produced. A welding rod of pure iron wire is generally used. Occasionally a nickel steel rod is used with good results on such work as crank shafts, etc. A mild steel rod is particularly satisfactory on steel castings. Thickness of Steel Diameter of Welding Rod Vs" ^^ y4' to T^s" /s" J4" to Vs" ^s" Yz' and up %" Steel is very sensitive to the blowpipe flame. An excess of acetylene tends to carbonize the metal; an excess of oxygen tends to oxidize. Therefore a neutral flame should always be used and should be tested frequently in order that it be kept in proper adjustment. Failures due to expansion and contraction are not numerous, because of the toughness and strength of the metal. If expansion and contraction are not properly taken care of, however, warping and buckling will surely take place, and internal strains will exist in the weld. These can be avoided by properly setting up the work and with proper preheating methods. " The strength of a steel weld can be improved by mechanical treatment. Hammering is the most common method employed. After the welding has been completed, the entire weld should be heated to a bright red heat, and the hammering carried on at this temperature. If the hammering is done at a lower temperature, the weld will be. weakened instead of strengthened. CAST IRON. Cast iron is hard and brittle. It cannot be rolled. It is therefore neces- sary that it be cast into the desired shapes. There are two general classifica- tions of commercial cast iron, called grey iron and white iron. There is an inter- mediate stage known as "mottled" iron. The difference between grey and white cast is the nature or state of the carbon present. In grey iron the greater portion of the carbon precipitates as graphite. In white iron the major portion of the carbon is combined. The grey color of grey iron is due to the precipitated graphite. White iron is hard and quite brittle. Grey iron is softer and tougher. Cast iron contains other substances, such as silicon, sulphur, phosphorus, and manganese. These all have certain effects on the properties of the iron. Silicon is used to soften the iron, since its presence aids in the forming of graphitic carbon. Manganese has the reverse effect. When present in quantities of more than A per cent it causes the carbon to remain in the combined state; although below this quantity it is somewhat beneficial as it counteracts the hardening actions of sulphur. Phosphorus increases the Garage Shop Repair Methods 601 fluidity of the molten cast iron. Above one per cent it weakens the iron. Sulphur causes the carbon to combine with the iron, thus increasing the hardness and the brittleness. It also has a weakening effect. It should never be present in quantities of more than one per cent. Effect of Cooling. — When cast iron is melted and cooled quickly the carbon does not have a sufficient length of time to form as graphite. It remains in the combined state, which causes the iron to have a low tensile strength, to be hard and brittle. A fracture in cast iron is very smooth, close grained, and of a silvery lustre, hence it is known as white cast iron. When cast iron is cooled slowly, the carbon will form graphite. This produces a large open-grained iron which fractures with a rough granular surface. It is soft, can be readily machined, and is grey in color, due to the graphite present; hence it is com- mercially known as grey cast iron. Except in very rare cases where hardness is desired the aim of the welder is to produce grey iron. Preheating. — All cast iron work should be preheated to some extent. The most important factor in the success of welds on large castings is the proper treatment by preheating for expansion and contraction. In planning the method of welding a large complicated casting the pre- heating is always of primary importance. It should be carefully studied from all angles and should be thorough. There are by far more failures in the welding of this metal from haphazard methods of relieving expansion and contraction than from any other cause. Welding of Cast Iron. — When cast iron is in fusion it oxidizes very rapidly. The oxide begins to form at a bright red heat. It melts at a temperature of 2400'-2450° Fahrenheit. Since the metal itself melts at a temperature 300°-400'' F. below this, it can be seen that the oxide will not be fused at the same time as the metal. In order to break the oxide down and allow the metal to flow together a flux must be used. A properly formulated flux will dissolve the oxide and float it to the surface, so that it may be removed by scraping the molten surface with the end of the welding rod. Be sure to tap the end against something to free it from oxide before continuing to add it to the weld. Cast iron is quite fluid when melted. For this reason it offers a little difficulty where vertical or overhead welding is attempted. Also its fluidity causes it to entrap gases, dirt, and oxide. These may be removed by proper manipulation of the blowpipe and w.elding rod. The molten iron can be forced ahead of the weld very easily. Adhesion to the cold metal will result, if the welding is not watched carefully. The silicon will volatize to some extent in the molten metal. As stated above, the lowering of the amount of this constituent will seriously affect the metal. In order to compensate for this loss, a welding rod is used that contains from 2.75 per cent to 3.5 per cent silicon. The other substances such as sulphur, manganese, and phosphorus should be kept within rigid limits. The welding rod should be soundly cast, free from dirt, sand, scale, rust, etc. The welding flame should always be neutral. The flame should be applied to the weld at such an angle that the metal will not be blown ahead. Inasmuch as the metal is quite fluid when molten, the welding is carried on in a series of overlapping "pools" or puddles. The welding rod is applied by placing it in these pools and playing the blowpipe around it. The welding is aided by continually "working" the rod in the weld in order that blowholes, dirt, scale, etc., will be forced out. The central jet of the flame should never impinge on the molten metal. It should be held ys" to fg" from it. Occasionally it is necessary to remove a blowhole, in which case the hole is burnt out with the flame and then the metal is worked over with the welding rod.' The working over of a weld should be avoided unless it is absolutely necessary. If it is necessary to do this the 602 Automotive Trade Training welding rod should be used always, for otherwise a portion of the silicon will be lost. When the weld is finished and it is still hot, the accumulation of scale, dirt, flux, etc., on the surface should be removed by scraping with a coarse file or other tool. This is a superficial coating that, when cold, is very hard. As soft welds are nearly always desired, the castings should be cooled slowly and evenly. Where the work is complicated or of heavy section, it is by all means best to reheat it to a good red heat and then allow it to cool. In some cases it is sufficient to allow the casting to cool in the preheating fire, without the additional reheating. MALLEABLE IRON. Malleable iron is a form of cast iron. Its principal characteristic as compared to grey iron is its toughness and ability to resist shock. It is produced by annealing white iron castings in pots or boxes, packed with hammer and rolling mill scale, turnings, borings, etc., at a temperature of 1200°- 1300° F. for 48-96 hours. The castings are then cooled slowly. During this annealing process the material in which the castings are packed absorbs the carbon from the surface of the casting. In this way the surface becomes of steely nature, while the interior retains its cast iron properties. In small castings the decarbonization may exist throughout; in the larger, a core or heart of cast iron is always present. It can be readily seen that a fusion weld of this material is not practical, because of the variation in its composition. An attempt to weld it will produce a hard, brittle weld, full of blowholes, and of very little strength. In order to join this metal with the blowpipe, brazing is used. The metal is heated to a bright red heat, just below fusion, and Tobin or manganese bronze is added as a filling material. A brazing flux is also used. This makes a generally satisfactory joint of this material. ALUMINUM. There are two general types of this metal of interest to the welder — rolled or drawn aluminum, and cast aluminum. The commercial rolled metal varies in purity from 98 per cent to 99.75 per cent, the impurities being silicon and iron. Pure aluminum is rarely used for casting purposes, because its strength is much less than that of aluminum alloyed with other metals. Zinc is the principal alloying metal, although small percentages of copper are very frequently used with it. The amount of zinc ranges from 5 per cent to 25 per cent, according to the requirements of the casting. Aluminum has a very low melting point as compared to other metals, 1215° F. It is of high thermal conductivity and has a high specific heat. From the standpoint of welding its most important property is its combination with oxygen. Due to the action of the oxygen in the air, aluminum is always covered with a thin coating of oxide. When fused a heavy coating forms. The oxide is very refractory, melting at a temperature above 5000°. The oxide is also of a greater specific gravity than the molten metal with the result that if it is not removed it will be distributed throughout the metal. It has a short fusion range, retaining its normal properties up to a temperature near fusion, when it becomes pasty and then passes rapidly into complete fusion. Oxidation becomes severe just previous to fusion. The metal, when molten, is quite fluid. Gases such as nitrogen, carbon monoxide, hydrogen, etc., are easily absorbed in aluminum, and if not worked out will produce blowholes and porosity. Garage Shop Repair Methods 603 Because of the rapid fusion and fluidity of aluminum, welding requires a little practice in order to properly control it under the blowpipe. After this is done the welding is comparatively simple. The greatest difficulty is that of removing the oxide. On sheet aluminum work a flux should be used. The composition of this flux is usually of alkaline fluorides and chlorides. It is applied to the weld by means of the welding rod, or it is dissolved in water to either a paste or liquid and applied with a brush. This flux will react with the oxide and form a fusible compound that will float to the surface, which further serves as a protecting coating and prevents absorption of gases. The welding rod should be as pure as possible — particularly free from certain metals, such as copper, that have a tendency to set up a galvanic action in the weld. In preparing the metal for welding, the edges to be welded and the adjacent surfaces should be carefully cleaned. In heavier sheets the edges should be bevelled. In the lighter sheets the welding will be aided by flanging them about ^". mLYEJLEvm. mssLmmss mviJSQL oams exrssuysLJ Fig. 691. Section cutting torch. All aluminum articles should be preheated to some extent before welding. In certain cases the playing of the secondary flame on the object will be sufficient; in others a more thorough treatment is required, such as charcoal or coke. Aluminum castings are handled a little differently from sheets or plates. As mentioned above, castings are of different composition. Since the metal has a low melting point, high conductivity, and becomes rather fragile previous to fusion, preheating and cooling must be carried out very carefully. The average aluminum casting is somewhat complicated in its design, hence the necessity of skillfulness in carrying it through the preliminary heating period. The use of a flux on castings has been abandoned by the majority of welders. In place of it they break down and remove the oxide by means of a paddle, which is also used to smooth off the surface of the weld after it is completed When the weld is finished the casting should be allowed to cool very slowly and evenly. CUTTING OF STEEL. When a jet of oxygen strikes steel which has been previously raised to a high temperature, rapid combustion takes place at the point where the jet strikes the metal. The heat generated by the combustion and that supplied in the preliminary heating is sufficient to bring the products of the combustion (oxides of iron) to a molten condition. This slag flows out, or is blown out. 604 Automotive Trade Training of the cut. After the reaction is started it is carried on continuously by the application of the heating source and oxygen jet. Steel and wrought iron are the only metals that can be cut economically by this process. These two metals combine readily with oxygen, with the libera- tion of heat. The slag is produced at a temperature below that of the melting point of the metal, with the result that it is easily separated from it. Other metals do not produce so much heat when combining with oxygen, and the oxide formed is not reduced to a molten condition at temperatures below that of the metal, with the result that it cannot be easily separated. The combination of the oxygen with the iron is not that of complete combustion. An examination of the slag produced shows the presence of metallic iron, which leads to the belief that the oxidation follows the grain surfaces of the metal and more or less mechanically disintegrates the mass at the line of cutting. Cutting Blowpipes. — A cutting blowpipe is used for applying this method of cutting. In principle the cutting blowpipe differs from the welding. In addition to the oxy-acetylene flame which serves as a heating agent, there is a separate jet of pure oxygen for bringing about combustion. This is commonly called the cutting jet. The oxy-acetylene flame is usually made up of two or more jets, the size and position of which are regulated with different nozzles or tips for the different thicknesses of metal. The oxygen for the oxy-acety- lene flame and that for the oxygen jet is controlled by separate valves. The cutting jet valve is usually of the lever or plunger type, in order that it can be conveniently opened and closed. Fig. 691 shows a low pressure cutting blowpipe. It can be used with both low pressure or medium pressure acetylene generators or acetylene cylinders. Like the low pressure welding blowpipe, it utilizes an injector to secure the proper oxygen and acetylene mixture. Cutting is a simple operation. There are four principal factors to be considered, namely: Speed of advance; pressure; volume of oxygen; and size of preheating flame. When the cutting blowpipe is moved too fast, the oxygen does not penetrate, and the preheating flame does not have an oppor- tunity to bring the metal up to the proper temperature. If the speed is too slow, the consumption of the gases is too high and the cost is increased. The blowpipe should be held steady and advanced at a constant rate, in order that the cut may be smooth; for if it is irregular a rough cut is produced. In making a cut a definite volume of oxygen is required. The pressure of the oxygen should be such that it will reach the bottom edge of the metal. There are two ways of doing this, by using a small nozzle and a higher pressure, or by using a larger nozzle with a lower pressure. Of the two the latter gives the better results for average work. The preheating flame should be of the proper size. Too small a flame retards the speed of cutting. Too large a flame not only gives a rough cut. but in some cases hinders the combustion. JOB 240. PRACTICAL OXWELDING PROBLEMS. Object: Job 240 is to give the student practice in the melting of metal and in running it together. The student should light the blowpipe in accordance with the directions given and establish a neutral flame. He should use a No. 4 welding head, with 11 lbs. pressure. The steel should be set at an angle as shown in Fig. 692. The student should take the blowpipe in his right hand and hold the flame on the two pieces to be welded until the metal is hot enough to run together. In doing this job, the torch should be held at an angle of about 45°. The tip of the flame should be kept about^ }i'\irom the metal. Garage Shop Repair Methods 605 When the metal commences to melt, the blowpipe should be moved by a swinging motion from side to side, so as to melt both edges together. The melting of the edges of the two pieces should be carried on by means of this swinging motion until the entire length of the joint has been covered. In making this weld, you should watch carefully the following points: Do not run the hot metal on top of the cold metal. Do not leave any blow holes nor scale in the weld. Do not hold the flame on one side of the metal so long that it will burn before the other side is melted. In other words, keep the flame moving over the pieces to be welded. When the welding has once started, carry it on continuously. Do not stop and go back over your work. This problem should be practiced until there is produced a sample with a clean, smooth, finished weld. WELD HERE STEEL »/8"x 2" FLAT FINISHED WELD Fig. 692. JOB 241. The object of this job is to teach the proper method of adding the filling rod to the weld. Take two %" plates and bevel them 45°. This can be done on an emery wheel or with the cutting blowpipe. The edges to be welded must be clean and free from rust, grease, scale, etc. In setting up the two plates, butt one end of the two edges together; spread the other end 54"- Use the same size welding head and the same oxygen pressure as is used in Job 240. The filling rod is used to fill up the V made in the metal. Care must be taken to see that the rod is properly added. It is usually a rod varying in size from 3/64" to J4" in diameter, depending on the size of the work, and 30" to 36" long. For J4" plate a yi" rod should be used. The blowpipe should be held at the same angle as in Job 240. The filling rod is held in the left hand and at about 60° in front of the blowpipe. The filling rod should be held ^" or fe" in front of the blowpipe flame. After the bevel edges of the plate are brought to a welding point, the filling rod should be held down in the V in the molten metal, the flame being moved around the rod and not on it. This will melt it satisfactorily. In this manner feed in the welding rod to the joint until the V is built up i^" or ^" thicker than the original plates. Proceed in this manner until the joint is completed. Do not start to add the filling rod until the bottom of the V has been melted together. Do not place the cold welding rod into the molten metal. Always be sure that the welding rod is melted into metal that is already molten. Do not hold the end of the filling rod above the metal and allow it to drop into the weld. Do not add the metal from the filling rod to the cold metal of the weld. Do not force the molten metal ahead on the cold sides of the V. As in Job 240, both sides of the V should be brought up to melting temperature at the same time. 606 Automotive Trade Training WELD HERE STEEL '/4" PLATE FINISHED WELD Fig. 693. JOB 242. Welding Heavy Steel Plate. — Take two plates 1" in thickness and bevel one edge of each 60° on each side. These should be set up the same as in Fig. 694, that is, the bevelled edges should touch each other at one end and be %." apart at the other. The No. 15 welding head should be used with 30 lbs. oxygen pressure. Use yi" diameter welding rod. Proceed from one side, but see that the weld is re-enfdrced yi". When one side is finished, turn the piece over and finish the other. Be sure that the bottom of the V of the second side is thoroughly melted in order that it will meet the bottom of the weld of the other side. This point is very important. When the first side is completed and turned over, take the welding rod and scrape ofif any scale that has been formed during the welding. (Sec Fig. 694.) \WeLD HERE STEEL I" PLATE FINISHED WELO Fig. 094. JOB 243. To Fill up a Section of a Gear or Pinion that has had a Tooth or Teeth Stripped. — Great care should be taken, that at the beginning of the weld the metal is melted thoroughly before the welding rod is added. It is necessary that care also be taken that the shape of the tooth be followed as closely as possible, in order that the least amount of finish will be required. Refer to Fig. 695. WELD HERE CAST STEEL FINISHED WELD Fig. 695. JOB 244. Building up Lugs and Bosses. — Take a plate of heavy steel and build up a lug 1" high. This is done in exactly the same way as any other weld, except Garage Shop Repair Methods 607 that care must be taken to control the metal and not let it run over the plate. Add the metal in layers of Y^" in thickness. Then add to one corner of the plate a section of metal 2" x 3" x J^" thick. This should be done without letting the metal run over the edges. (See Fig. 696.) Be sure that a good weld is obtained at the beginning and that each layer is thoroughly welded to the next. If a good weld to the surface of the plate is not first obtained, the rest of the work is worthless. Do not hold the blowpipe too long in one place. Keep it always in motion; otherwise the metal will run down on the sides. Be sure that all scale and dirt are worked out of the metal. WELD HEPE STEEL I/2" PLATE FINISHED WELD Fig. 696. JOB 245. Welding Cast Iron. — Prepare a sample with a 45° bevel. Place the two beveled edges together. Use a No. 12 head with the proper cfxygen pressure. Use Ya" cast-iron filling rod. Cast iron is always welded with a flux, which is a chemical compound added with the filling rod to prevent oxidation and to remove impurities. But in order to show the purpose of a flux, the sample should be welded first without it. The welding flame should be pointed the same as before in welding steel; but after the metal has commenced to melt, the rod should be put in the molten metal and the blowpipe should be swung from one side of the V to the other. Cast iron cannot be welded in layers like steel. It should be carried on in molten puddles. The welding rod should be held in this molten metal and w^orked in by rubbing the rod against the sides of the V. This rubbing of the rod against the sides of the V works out to the surface any sand or impurities that may be in the metal. It will be noted that the metal is covered with a scale or coating that is difficult to remove. The use of the flux will aid in removing this coating. After this job is completed another sample should be prepared in the same way. This time the student should carry on the welding exactly as before, except that a flux or scaling powder will be used. This application is made by dipping the hot welding rod into the flux, a small quantity of which will stick to the rod. When the rod is inserted into the weld, this will melt oflF. The flux should be added to the weld whenever scale or sand or dirt appears. Too much flux should not be used as it would have a bad effect on the weld. The rod should be kept in motion as described by rubbing it along the sides of the weld, and the weld carried on with little puddles of melted metal. Sand, scale, and blowholes should be worked out of the melted metal by means ot flux and motion of the rod. Whenever a white spot appears in the melted metal, it is either scale or sand or some other impurity. If it is allowed to remain in the weld, it will form a blowhole. When this white spot is noticed, it should be taken out with the rod and removed from it. Whenever this dirt is left on the rod it will be put back in the weld, just as soon as the rod is applied again. Cast-iron welding should be carried on continuously as fast as 608 Automotive Trade Training possible until the job Is completed. If it is absolutely necessary to go back over the weld, always add metal from the filling rod. A cast iron weld should be solid all the way through, and should be soft so that it can be machined. If a good cast iron welding rod is used, it will help the weld to be soft. All cast iron welds will be hard if they are not cooled slowly. Just after the weld has been finished and it is still at a bright-red heat, scrape off the surface to remove the flux, scale, and dirt that have been worked out of the metal. If this is not done the weld will have a very hard surface, notwithstanding the fact that it might be soft underneath. This scraping can be done by a chisel, the blunt end of a file, or a piece of flat scrap iron. WELD HEPE CAST IRON FINISHED WELD Fig. 697. JOB 246. WELDING AUTOMOBILE CYLINDERS. The object of this problem is to give practice in the welding of automobile engine cylinders. For this problem a block of two cylinders should be used. The first break to be repaired is in the water jacket, as shown at 698A. The second break is en the flange, as shown at 698B, and the third is on the water jacket, as shown at 698C. The fourth, 698D, is a crack on the head of the cylinder, extending from a spark plug thimble over the dome to the bore of the cylinder. If any WELD HEPE CAST IRON FINISHED WELOi Fig. 698A. WELD HERE CAST IRON FINISHED WELD Fig. 698B. Garage Shop Repair Methods 609 WELID HERE CAST IRON FINISHED WELD WELD HEPE Fig. 69SC. CAST IRON F'INISMED WELD Fig. 698D. of these were welded cold the casting would break from expansion, when the flame were applied to it, and from contraction after the weld had been made. In order to overcome this, it is necessary to preheat the cylinder. To do this build a little furnace around it by means of fire brick. (See Fig. 699.) In order to give this lurnace draft, the bottom row of bricks should be placed l" apart. The cylinder should be placed on this little furnace with the bore up and the head of the cylinder resting on two bricks. The furnace should be so built that there are 6" between the walls and the cylinder. There should be space enough to allow the cylinder to be turned in the fire without knocking down the walls of the furnace when it is time to weld. About three shovels of charcoal should be placed around the cylinder at first, and a little kerosene put en it before it is lighted. After the charcoal has become thoroughly lighted, and the cylinder has become slightly heated, more charcoal should be added until half the casting is covered. Then a piece of asbestos should be placed ever the top of the furnace and a few holes punched in it to allow for draft. Leave the cylinder in the furnace until it is brought up to a dark-red heat. Then turn the cylinder up so that the part to be welded can be easily reached. Then replace the asbestos sheet and cut a hole in it so that the cylinder can be CASTING ASBESTOS PAPER X^>^ AIR HOLES Fig. 699. 610 Automotive Trade Training reached by the blowpipe and rod. The crack in the cylinder should have previously been chipped out. Weld this crack exactly as described before, but use a smaller size welding head — either a No. 6 or No. 7. Never take the cylinder out of the fire to weld it. Never let the fire go out during the welding. After welding, add more charcoal to bring the cylinder up to an even heat, and leave it in the furnace to cool slowly. Care must be taken that the metal does not run through to settle in the water jacket. Be sure to work out all dirt or scale, and not leave any pinholes or blowholes. In order to prevent the bore of the cylinder from scaling, before it is placed in the preheating furnace give it a slight coat of oil and then apply a thin coating of flake graphite, which is a form of carbon. This is done by taking the graphite in the hand and throwing it against the oily side of the bore, which will cause it to stick. After welding is finished, this can be cleaned ofif by means of a piece of a rag or a piece of waste. Crack B can be welded by preheating in the same manner. It is not necessary, however, to preheat it so much. It is only necessary to heat the cylinder to a blue heat. Crack C should be welded exactly the same as Crack A. Crack D should be treated a little differently, because the crack is on the inside of the water jacket. A portion of the outer wall, over the crack, must be removed. This is done by drilling. The crack is then chipped out and placed in a preheating furnace, exactly as described in A, and the welding is carried on in the same manner. When the weld is finished, and the casting is still hot, the removed portion is placed back into the outer jacket and is welded in. In order to hold this patch in position while it is being welded, a piece of cast iron rod is welded to it, which serves as a handle. After the patch has been welded in, this rod or handle can be cut ofif. The reheating should be carried on as in Crack A and the casting also cooled slowly. After the cylinder has been welded and is cooled off, it should be tested to be sure that the weld is entirely tight. Where it is possible, this should be tested with water pressure. If it is impossible to do this, the water jacket should be filled with kerosene, because kerosene penetrates a crack or a pinhole faster than water. In case any leaks are found, the metal should be chipped out at that point, placed in the fire, and rewelded exactly as before. JOB 247. Building up of Teeth on Cast Iron Gears or Pinions. — The proper welding head and filling rod should be selected according to the chart. If the gear is a light one — that is, the face not more than three inches in width and the rim not more than one inch in thickness — the job can be done without preheating. Heavier than this the job should be preheated. WELD HERE CAST IRON FINISHED WELD Fig. 700. Garage Shop Repair Methods 611 The preheating should be done with a charcoal fire. In doing a job of this kind the greatest care should be taken to start it properly. The metal on the rim of the gear to which the tooth or teeth should be added must be first melted thoroughly. The welding rod is then added. It is necessary to control the metal so that the least amount of machining or finish is required; the tooth can be built up by using carbon blocks that have been shaped out to fit between the good teeth. If these carbon blocks are shaped and placed properly, the tooth when added with the blowpipe will require very little finish or machining. Care must be taken that the tooth is built up fully and that a little metal extends over each end. This extra metal can later be removed by filing. To add this extra metal the blowpipe flame should be held at the side of the tooth; that is, on the edge of the rim the direction of the flame should be horizontal. This is to keep the metal from running down on the side. In order that the tooth may be machined if necessary to insure a finished product that will not be brittle and crack off when used, the weld must be cooled slowly. JOB 248. Welding Cast Aluminum. — Cast aluminum is usually a little different from sheet aluminum, because it has zinc and other metals in it. A flux should not be used on cast aluminum. The oxide should be scraped out by means of a paddle as the weld progresses. A paddle such as used is made of a piece of one-fourth inch iron rod with the ends flattened down so that it is about three- eighths inch wide. This flat end should be ground smooth. WELD HERE ALUMINUM FINISHED WELO CASTING Fig. 701. In welding an aluminum casting the flame is played on it until it is melted. The metal is now brought together by use of the paddle. It is done by working the paddle in the metal similarly to the way in which the cast iron welding rod is used in working the impurities out of a cast-iron weld. The paddle breaks down the oxide which is on the melted aluminum and which would prevent it from running together. After the weld is started the paddle is laid aside and the welding rod added. The entire thickness of the plate should not be filled up by means of the welding rod at one operation. After the V has been about half filled the welding rod is laid down and the metal worked with the paddle. This is to insure a proper weld at the bottom of the V, and the sides. Then fill up the weld to the proper thickness and smooth off with the paddle. Always reinforce the weld with sufficient metal so that it can be cleaned off. Never start an aluminum weld, particularly cast alummum, unless there has been a certain amount of preheating. In some cases playing the blowpipe on both sides of the weld will be sufficient; in others the preheating must be handled more carefully. JOB 249. WELDING AN ALUMINUM CRANK CASE. The object of this problem is to give practice in the welding of aluminum castings, such as a crank case as shown. Assume that there are three breaks in this crank case — A, B, C, Fig. 702. 612 Automotive Trade Training Break A.— This is a simple break. The crank case and parts to be welded are placed in position for welding. The case and arm should be lined up with straight edges, and the arm clamped onto the body of the crank case by means of a screw clamp. The arm and case are preheated lightly either by means of a light charcoal fire or gas burner, as shown in the figure. The bearings of this crank case are usually babbitted. If the welding is not too close to a bearing, it can be pro- tected by inserting wet asbestos in it and keeping it wet throughout the weld. If the bearing or bearings are too close to the weld, they should be removed. The casting is preheated until it begins to sweat, which is shown by pimples or ■'bubbles" of metal appearing on the surface. The proper preheating tempera- ture can also be told by scraping with the paddle. When the temperature is such that the metal can be scraped off with the paddle it is ready to weld. Select a proper size welding head, which should be about one size smaller than that used lor steel. When the casting is not pr*eheated, which will rarely be the case, the same size welding head as used for steel should be used. Use a one-quarter inch drawn filling rod in order to give good alignment of the pieces. They are not beveled. It is therefore necessary to start the weld by applying the flame and scraping at a V with the paddle. The V is scraped out as the weld progresses. When an aluminum casting of this kind is heated up for welding it is not possible to turn it, and it must remain in its clamps and on straight edges. Vertical, horizontal, and in some cases overhead welding, must therefore be used. Because of the difficulty in going over a weld in cast aluminum after it has once been made, the paddle and flame are applied to the under side of the weld from time to time as welding progresses — to remove any excess metal that hangs there. The proper amount of reinforcing must be added to allow for the usual finish. In making the weld the methods o£ handling the welding rod, paddle, arid blowpipe should be employed as described in Job 248. Break B. — This break is in the rib supporting the crank shaft bearing. For this job the cr^nk case is set up and arranged as for break A. A small pre- WELD HERE ALUMINUM FINISHED WELD PQEHEAl SECTIONS WITHIN OOTTEDUNE^ 3 Fig. 702. heating fire of charcoal is built around the casting; during the preheating period the welder must watch his fire carefully to see that the casting does not become overheated. It should be brought to the same temperature as in break A. During the preheating and welding the case should be covered with asbestos paper so that it is protected from draughts. The welding should be done the same as in break A. In a break of this kind slow and even cooling is absolutely necessary and should be very carefully carried out. The casting should not be subjected to any draughts or any change in temperature. Break C. — This break represents a piece broken from the side of the crank case. The crank case and broken parts are lined up as described for A, and the Garage Shop Repair Methods 613 broken piece fitted into the hole. A preheating fire of charcoal is built and covers the area shown. The same precautions in preheating should be observed as in A and B. The v^elding and cooling is carried on in exactly the same manner. If two or more ribs in the center of the casting similar to break B were broken, it would be necessary to reheat the entire casting and carry the job on as described. JOB 250. Brazing Malleable Iron. — It is not possible to weld malleable iron, because when it is melted it loses its malleable properties. For this reason the best way to handle a job of this kind is to braze it. The parts to be joined should be beveled to 60°. Where it is possible to apply a reinforcing to the joint, it is sometimes not necessary to V it out. Bring the pieces to be welded to a cherry-red heat by means of the welding blowpipe. If the casting is large, this preheating may be helped by means of a light gas blower or flame. Use a ^" or J4" Tobin or manganese bronze welding rod; heat and dip it into the flux, then add the flux and the rod into the V as fast as it will melt in. Fill up the entire V for a short section by means of the rod, alternately dipping the rod into the flux before going ahead. In other words, do not run a thin stream of metal in the bottom of the V and go back over the weld and fill up in that manner. Always add metal so that the reinforcement of at least an eighth of an inch is secured; never less than this. When the brazing is finished it should be covered up with asbestos and allowed to cool fairly slowly. Do not heat the edges of a malleable casting to a melting heat; never get them above a cherry red. Be sure that enough flux is applied to keep the edges of the casting clean. Always use a good grade of bronze rod. Soft brass wire will not do. BRAZE HEPE^ MALLEABLE IRON BRAZING Wplate Fig. 703. FINISHED BRAZING JOB 251. Brazing a Heavy Steel Part to a Light Steel Part. — A thin tube and a half-inch flange is a representative problem. A good braze will not only give a fillet at the joint of the flange to the tube, but the brazing will extend down the tube and give contact between it and the flange. To do this it must be heated properly. The flange should be brought to a red heat by means of the blowpipe. The blowpipe should be applied to the flange only during this operation. It is not necessary to direct it to the tube. After the flange has reached a good red heat, add flux and brazing wire. Always be sure to use plenty of flux, as it is necessary that both parts must be kept clean during the brazing. BRAZE HERE STEEL BRAZING 5T. TUBING Fig. 704. FINISHED BRAZING 614 Automotive Trade Training OXY-ACETYLENE CUTTING. Connecting the Cutting Blowpipe. — The cutting blowpipe is connected exactly the same as the welding blowpipe^ the only difference in the apparatus being that a heavier regulator for the oxygen cylinder is used and the hose from this regulator to the blowpipe is heavier. This is because a heavier pressure is usually employed in cutting. This refers only to the oxygen pressure, however, because the acetylene pressure is never higher than in welding. After the apparatus is connected exactly in the same method and in the same order as the welding blowpipe, the oxygen cylinder valve and the acety- lene cylinder valve are opened. Refer to the table on this page for the proper oxygen pressure to be used for the particular thickness of steel to be cut. Then establish this pressure with the cutting valve open. Be sure not to adjust this pressure with the cutting valve closed. The cutting blowpipe is made a little different from the welding blowpipe, there being several holes surrounding a larger central hole in the nozzle. From the smaller holes issues an oxy-acetylene flame that is used for preheat- ing. From the central hole issues a jet of pure oxygen for cutting. There are three valves on the blowpipe; one valve controls the acetylene, another valve controls the oxygen for the heating flame and the third valve is used to control the cutting oxygen. The first two valves are regulated exactly as welding blowpipe valves, because they must produce a neutral flame in the preheating jets. These jets are used to heat the steer so that the central jet of oxygen will burn through the steel. After the heating flames have been adjusted with the cutting oxygen valve wide open, the cutting oxygen valve is closed, leaving the heating flames only burning. The student is now ready to begin cutting. CUTTING TABLE Size of Nozzle Oxygen Pressure Per Hour Per Linear Foot Thickness of Speed Gas Consumption Gas Consumption Metal Lb. Per Machine Hand Oxygen Acetylene Oxygen Acetylene In Sq. In. Lin. Ft. Lin. Ft. Cu. Ft. Cu. Ft. Cu. Ft. Cu. Ft. ^ 1 10 120 90 28 7.8 0.31 0.09 No. 1 15 93 74 37 11.3 0.50 0.15 20 81 62 48 14.2 0.67 0.23 iz 25 73 55 58 16.3 1.05 0.30 H. 25 63 46 80 19.7 1.74 0.43 1 30 57 40 100 22.0 2.50 0.55 No. 2 35 53 36 120 23.6 3.33 0.66 1 V^ 40 50 33 141 25.3 4.27 0.77 2 50 46 29 184 27.7 6.34 0.96 3 1 55 41 24 268 31.9 11.2 1.33 4 No. 3 65 36 20 352 35.6 17.6 1.78 5 75 32 17 436 38.8 25.7 2.28 6 85 29 15 522 41.5 34.8 2.76 8 95 23 11 698 46.2 63.4 4.2 10 115 18 8 880 50.3 110.0 6.3 12 No. 4 135 15 6 1080 53.9 180.0 9.0 14 155 12 4H 1290 57.3 287. 12.7 16 Rivet Nozzle 175 40 10 3M 1520 240 60.4 25.0 434. 17.3 JOB 252. PRACTICAL CUTTING PROBLEMS. The object of this problem is to give practice in cutting J^" steel plate. Take a piece of plate and draw a line on it, which is to be followed in cutting. This line should be made with chalk, soapstone, or center punched marks, so that it will not burn off. Garage Shop Repair Methods 615 Place the preheating flames of the blowpipe, which has been lighted in accordance with the instructions previously given, to the upper edge of the plate, at the point where the cut is to be started. The preheating flame should be so placed that about %" of the metal from the edge is heated. This should be brought to a bright-red heat. When this temperature is reached, the cutting jet is turned on by means of the cutting valve. It will immediately burn out Figure 705. Cutting blowpipe. the steel, which will be shown by a great number of sparks and melted slag dropping from the plate. The blowpipe is then moved along the line previously marked out, at a speed which will allow the oxygen to burn the steel out clear through along this line. This speed will come by practice. If the blowpipe travels too fast, the metal will not be heated fast enough, and therefore the oxygen will not cut it. If the blowpipe travels too slowly, the benefit of the heat from the burning metal will be lost. After the cut has been started, the preheating flame should be carried so that the tips of the flame will just reach the plate. After skill has been acquired, it will be possible to carry the flame ^" or ^" from the plate. The student should practice on the plate until he has mastered the fundamental principles of cutting. After he has succeeded in making a cut, he should try to produce as smooth and as fast a cut as possible. For smooth cutting, there are three points to be watched. First, the preheating flame should be kept as small as possible. Second, the oxygen pressure should be kept such that it will blow the slag clear through, but will not be excessive. The speed of cutting should be constant and regular and should be as fast as is possible for the oxygen to burrr the metal out. If too large a preheating flame is used the top edges of the plate will be melted down. Do not use an oxidizing preheating flame; this will also cause the edges to oxidize and melt. Do not hold the preheating flame too far from the cut, because the cut will not be continuous and the efficiency CUTTING Fig. 706. 616 Automotive Trade Training will be lowered. If the preheating flame is held too close to the plate, the edges will be burnt. Where smoothness is necessary, the preheating flame should be held so that it is almost vertical. Where speed is required, the blowpipe should be held so that the preheating flame will travel ahead. This angle should be 60° on light plate. In cutting a plate, the left hand should grasp the blowpipe about 6" from the head. Because of the heat that will be reflected, the student should wear an asbestos glove on this hand. The right hand should grasp the handle on the blowpipe so that the thumb or finger will be in contact with the cutting valve. In order to make a smooth cut, it is necessary that the hand be steadied. This is done by resting the left hand on the plate. The smoothness of the cut depends on the steadiness with which it is carried on. When it is necessary to make a bevel cut, the same method is used as described above, except that the blowpipe is held so that a cut is made on an angle to the surface of the plate. INDEX Abbreviations or symbols, 268 Acetylene, 583; tanks, 584 Acid curing solution, 541 Adjusting clutch on Ford car, 81 Air, auxiliary, 245 ; bags, sectional, 527 ; air-bled jets, 231 ; gap, 327 ; primary. 245 ; sleeve, 243 ; sleeve adjustments, 243 ; sleeve, slow speed adjustments, 244 ; valve adjusting, 229 ; valve, automatic, 235 ; valve, auxiliary, 233 Aluminum welding. 602 ; crank case, weld- ing, 611 Ammeter, 471, 500 ; installing and wiring, 512 Ampere, 266 Angle of drive. 97 Applying new lining to cone type clutch, 92 Armatures, 276, 366, 384, 414 Attaching cables to brush holders, 400 ; wires to lamp sockets, 512 Automatic leaning device, 245 Automobile cylinders, welding, 608 Axle, full floating, 43; live. 40; plain live, 40 ; repair work, 26 ; semi-floating, 42 ; three-quarter floating, 43 >attery, 404 ; box, 288 ; care, 286, 293 ; case, judging value of, 299 ; caring for on charge. 323, in storage, 324 ; charging. 319-321; charging while in service, 296; construction, 288 ; current units, 401 ; discharging. 324 ; faults, 297 ; freezing, 294 ; grounded, 314 ; ignition, 325 ; open- ing for inspection and repair, 300 ; opera- tion of, 406; primary, 265; rating, 286; reassembling, 306 ; secondary, 265 ; shop repair methods, 310 ; system faults, de- tecting, 405 ; terminal, high resistance, 476 ; tests which indicate need of open- ing, 297 ; testing, 295 ; trickle charge in storage, 321 ; wear, 288 Bearings, burned, 129 ; main engine, 128 ; scraping in main, 131 ; taking up main, 130 Bevel gear and pinion, 45 Blowpipes, connecting, 589; cutting, 604; lighting, 590; manipulation of, 596; shutting off, 590 Borg and Beck type clutch, adjusting, 94 Brake, adjusting Packard Twin Six foot, 62 ; Packard Twin Six hand, 63 ; equal- izers. 56 ; names, 56 ; relining, 60 ; remov- ing grease and oil, 59 ; shoes, 55 ; squeak- ing, 61 ; transmission, 55 ; types of, 54 Braking surface, 54 Breaker box and distributor head assembly, 343 ; contacts, 343 ; contacts, replace- ment of, 344 ; points, 356, 367 ; width of, 558 Brazing heavy to light steel parts, 613 Brushes, 372 ; four slipring, 398 ; fitting, and sanding commutator, 487 Buick Delco ignition, 348 Bulbs and sockets, 502 Burning connector straps on batteries, 583 Cables, 390 Cadmium test, 313 Camel l)ack, 522 Cam shafts, 135; drive, 137 Carbon, removing by burning, 579 ; scrap- ing out, 173 Carbonizing or reducing flame, 595 Carburetion, principles of, 220 Carburetor, action, 249 ; adjusting Buick marvel, 237 ; adjustment. 247, 250, 257 ; air inlet, 251 ; Ball and Ball on King cars, 251 ; Buick, 236 ; Cadillac, 245 ; care of, 239, 245 ; care and maintenance, 258 ; design, 222 ; dismantling for clean- ing and repairing, 248 ; Dodge, 249 ; draining and cleaning, 251 ; float solder- ing. 578 ; Hudson supersix, 254 ; jobs, 260; Kingston models, E. & L., 237; Maxwell, 231; Packard twin six, 233; pick up device, 252 ; Pierce Arrow, 256 ; plain tube or compound nozzle type, 231 ; primary, 251 ; Rayfleld, model LL — 3P, 240 ; Schebler dash pot air valve type, 258 ; second stage, 252 ; Stromberg type M plain tube, 246; Tillotson, 234; U. S. A. Standard. 245 ; warm air, 236 Car frame, straightening, 18 Cast iron, 600 ; cooling effect of, 601 ; pre- heating, 601 ; welding of, 601, 607 Cell covers, 292 Cell jars, 289 Cement, vulcanizing, 525 Cereal preparations, use of, 208 Charging batteries and battery charging equipment, 319 ; conditions, 463 Cincinnati batteries, opening 316 Circuits, internal, 276 ; primary or low tension, 388, 395 ; secondary or high ten- sion, 388 ; 397 Cleaning hose, 588 ; and oiling exposed cone clutch, 92 ; parts of compound, 303 Jlutches. 85 ; collar care, 94 ; cone, 88 ; disk, 90 ; grabbing, 82 ; grease and oil soaked, 91 ; plate, 88 ; slipping, 92 ; transmissions and universals, 73 ; types of, 87 ; wet, 92 Coil, 338, 348, 357, 419; Bosch synchron- ous, 401 ; care and adjustment, 411 ; failure to vibrate, 411 ; operation, prin- ciple of, 408 ; troubles, cause and remedy, 411 ; vibrating and plain coil combined, 404. Commutator, 278 Condenser, 285, 332, 408, 415 ; grounded, 363; short circuited, 363 Conductors, 268 Connecticut ignition system. 354 Connecting rod bearings, fitting or taking up, 147 ; scraping, 148 ; on Ford engine, adjusting, 154 ; straps and terminals, re- moving, 300 Contact breaker, 384, 386, 415 Contacts, fitting new, 358 ; maker, 337 ; platinum interrupter, 391 Contact points, 352, 422 ; adjusting, 339 ; (relay), care of, 470; in series, 368 Cooling, fans, 200; solutions, 203 Cooling systems, 193 ; care, 195 ; direct air, 193 ; forced and pump circulation, 195 ; indirect air, 193 ; water, 194 Cord, patch, 525; tire, full section, 553, 556 ; tires, repairing, 551 ; tires, retread- ing, 568 Coupling, removing, 387 Cover sealing, 303 Cranking failures, 458 ; operation of, 443 Crank case, 114 Crank shafts, 123 ; polishing, 152 ; right and left-hand, 127 ; troubles, 128 ; types of, 126 ; V type engines, 126 Current, alternating, 276; control, 279; control and output regulator, 444; di- rect, 277; generation, 275, 387, 414; measuring, taken by lights, 517 Cushion and tube repair gum, 522 Cut-out, relay, 440, 467 Cutting, blowpipe, connecting, 614 ; prob- lems, 614 Cycles, completed per minute, 112 Cylinder, blocks, 117 ; care and repair, 120 ; heads, 120 ; heads, frozen, 123 ; head, re- moving, 166 ; head, replacing, 167 ; head, shellacing, 168 ; scored, 121 Dash pot, 230 ash and tail lamps, 495 Dead axle drive, 46 Degrees converted to inches, 145 Dies, using, 573 Differential compound wound or bucking series field, 435 617 INDEX— Continued. Disk or plate clutch, rellning, 94 Distributor, 389, 416; board, 386; head, 358 ; revolving, 357 ; timing, 346 Double distributor, care and maintenance, 350 ; Pierce Arrow, 350 Double wire or insulated return, 490 Drag link, overhauling, 38 Draining oil from, Hudson engine, 191 ; Packard engine, 190 Driving member, adjustable, 413 Drum, double width, 55 Dual, coil care and use, 403 ; ignition, Eise- mann, 419 ; system troubles, 421 ; sys- tem, wiring the, 402 Duplex coil construction, vibrating, 408 Dynamo, generator, 452 ; operation, 455 ; speed and output, 453 Dyneto system, construction and care, 451 ; Franklin car, 450 ; operation, 450 Economizer, action of, 249 ; Stromberg, 248 Electrolyte, adjusting, 318 ; determining strength of, 318 ; filling battery with, 318 ; making, 318 ; making and using, 317 Element, 289 ; and electrolyte, care of, 303 ; repair and inspection, 309 ; rotating, 424 Engine, without coil, operating 423 ; crank case, draining, flushing and refilling, 190 ; Knight type, 141 ; operation, 106 ; parts, functions of, 114 ; parts, names and loca- tion of, 105 ; power generation, 102 ; removing from Ford car, 154 ; speed gov- ernors, 259 ; starting, 390, timing, 160, 352 ; troubles and repairs, 114 ; types of, 119 Evaporating, liquids, 220 Excessive backlash, taking out, 69 Exhaust, gas jackets, 227 ; heater, 236 Exide single cover type covers, removing and re-sealing, 314 Explosive mixture, 224 External, brake bands, adjusting, 56 ; cir- cuit on Ford ignition. 375 Fabric, breaks, 520 ; tires, preparation of, 543 Fan belts, 200 ; adjusting, 201 ; care, 200 Faultfinder, description of, 471 ; testing electric systems, 471 Field, 278 Firing, irregular, 391 Flame, character of, 595 ; neutral or nor- mal, 596 ; oxidizing, 596 Float, chamber, 256 ; needle valve, 226 ; needle valve, regrinding, 260 ; troubles, 226; valve levels. 259 Flux, 275, 577 ; magnetic, 424 Ford axle differential, disassembling, 71 ; inspection and reassembly, 71 Ford clutch, adjusting, 81 Ford rear axle, disassembling, 70 ; remov- ing, 70 Ford transmission bands, relining, 81 ; over- hauling, 83 Forced feed, 176 Forge fire, building, 574 Forging, 573 Ford front axle, overhauling and rebush- ing, 32 ; front radius rod, overhaul, 30 ; front wheels and bearings, overhaul, 32 ; steering gear, tightening, 32 ; steering wheel inspection and lubrication, 34 Four stroke cycle, 107 Frames and springs, 9 Friction disk drive, 73 Front axle, 25 ; castering effect, 29 ; cam- ber, 28 ; design, 27 ; straightening, 35 ; toe-in, 28 Front wheel, spindle cones or races, replac- ing. 35 ; testing and realigning, 30 Fuel systems, 213 ; gravity, 213 ; pressure feed, 213 ; vacuum, 124 ; vacuum tank, 215 Fundamental electrical data, 262 : princi- ples, 264 Fuses, 281 Garage press, use of, 570 Garage shop repair methods, 569 Gasoline, level. 226; nozzle, adjusting, 229; systems, 213 Gear, pump, 179 ; differential construction, 48; double reduction, 48; ratio, 73; section filling, 606 General information on the Rayfield, 242 Generating, characteristics, 446 ; method of, 373 ; operation, 443 Generation and power plants, 102 Generator and cut-out, Gray and Davis, 452 ; lubrication, 452 Generator, generating, 479 ; care, 470 ; motoring, 443 ; output, regulating, 431, 461, 465 ; Wagner, 470 Governor, oiling, 260 ; speed, regulating, 260 Ground, 282; armature on generator, 485; between primary and secondary wind- ings, 363 ; brush holders, 479 ; connection, high resistance, 475 ; in motor armature, 479 ; wiring to motor, 479 Half section, building up, 547 ; tearing down, 546 Hand tools, forging, 575 Head lights, 495 Heat, 222 High speed, 78, 80 ; adjusting. 241 High tension current distributing from a low tension magneto, 370 Hood and radiator covers, 202 Hot air, regulation, 242 ; stove, 227 Hot spot manifold, 227 Hot water heat, 227 Hotchkiss drive, 11 Housing, 416 Hudson Delco ignition, 347 Hydrometer reading, 295 Idling device, 242 Igniter, 354 Ignition coil, 325 ; assembly, 343 ; open cir- cuit in the primary of, 360, in the second- ary, 361, with connected windings, 361 ; short circuit in the primary, 362 ; in the secondary winding, 362 "■ Ignition, Atwater Kent, type CC, 337, type K-2, 339 ; battery, operation of, 410 ; cutting out, 389 ; dual, 371 ; fails sud- denly, 391 ; Bosch dual, 400, duplex, 406, vibrating duplex, 407 ; contact points, 341 ; detecting general trouble in, 404 ; independence of, 402 ; North East for Dodge cars, Model O, 342 ; oiling, 341 ; operation, principles of, 339 ; setting, 358, and timing, 342 ; switch, dual, 371 ; timing, 350 ; troubles, 390 ; summary of, 392 ; Wagner, 357 Impeller troubles, 199 Impulse, member, 413 ; indicating devices, 179 ; operation of, 413 ; starter, the Split- dorf, 426 ; starter care, 427 Induced current, direction of, 282 Induction, 276; coil, principle of, 325; rotors and pole shoes, 382 Injuries and blow-outs, repairing, 538 Inner tubes, splicing, 539 Insulating parts, damaged, 391 Internal, expanding brakes, adjusting, 58 ; gear drive, 47 Interrupter, removing, 391 Inside section, 551 Jars and jar covers, judging the value of, 300 Junction and fuse boxes, 501 Lamp, bulb to check timing, 346 ; for mag- neto lighting systems, 506 ; refiectors. polishing, 513 ; for service, 502 ; with bat- tery, 506 ; with dry cells, 504 ; with stor- age batteries, 502 618 INDEX— Continued. Lead burning, 581 Lean mixture, 224 Lifting engine from car, 569 Light, projection, fundamentals of, 507 ; not operating, 513; spot and search, 500 Lighting, cables, splicing, 509 ; switches, 495 Liquid preparations, use of, 208 Live axle, types of drive, 45 Low speed, adjusting, 241 Low tension magnetos, timing spark on, 370 Lubrication, exposed cone clutch, 92 ; Ford steering wheel, 34 ; generator and cut-out, 452 ; governor, 260 ; pump, 177 ; spring shackles, 36; starting motor, 457: steer- ing gear, 36; Timken front wheel bear- ings, 34 ; troubles, 187 ; universal joint, 101 Lugs and bosses, building up, 606 Magnetic, lines of force, 265 ; needle, 271 ; poles, 270 Magnetism, 269 ; producing, 270 ; residual, 270 Magnetizing steel for permanency, 273 Magnets, 365 ; electro, 270 ; permanent, 272 Magneto, 408, 419 ; armature type, high tension, 376, low tension circuit in, 377 ; Bosch duplex, 406, D. U. types, 387, high tension, 393, 395, 397; care, 424, 426; coupling, Splitdorf, adjustable, 428; Dixie, Aero models, 423, 425 ; driving, 385 ; G-4 Eisemann high tension, 414 ; Generator, K-W low tension, 379 ; H or shuttle type, low tension, 365 ; high fre- quency inductor type, 373 ; high tension, 376 ; ignition, 364 ; inductor or station- ary coil type, 365 ; inductor type, high tension, 378 ; K-W high tension, 380 ; low frequency inductor type, 371 ; low ten- sion, 364; oiling, 386, 390, 424; opera- tion on, 406 ; operation, principle of, 380, 423; setting the DU dual, 403; setting the ZR dual, 403 ; Simms high tension, 383; switch, Dixie, 426; testing, 423; timing, 385 ; to engine, 425 ; timing to motor, 417 ; trouble, detecting dual, 405 Main engine bearings, fitting or taking up, 149; scraping, 150; or crank shaft bear- ing fitting on Ford engine, 153 Malleable iron. 602 ; brazing, 613 Material and construction, 131 Maxwell Simms system, 462 Metal, bevelling, 594 ; conductivity, 592 ; expansion and contraction, 590 ; non- magnetic, 366 ; preheating, 592 ; proper- ties of, 590 Melting point, 590 Mica, undercutting, 488 Mixture of gasoline, correct, 225 ; explosive, 224 ; lean, 225 ; rich, 224 Molecular theory, 273 Motometer, Boyce, 206 Motors, overheated, 206 ; armature, open circuit or high resistance, 473, field, 473 ; cranking operation, 458 ; generator, Buick Delco, 443 ; charging equipment, 321 ; Dodge Northeast, 446 ; operation, 443 ; single unit, Hudson Delco, 458 Neatsfoot Oil, 91 Non-conductors or insulators, 269 Non-freezing solutions, 203 Non-leak solutions, 208 Nozzle, 226 Ohm, 266 Oil, draining, 187 ; pan, cleaning, 191 ; pumps, 177 ; wears out, 185 Oiling systems, 175 ; caring for, 185 ; full splash, 175 ; splash and circulating, 175 Open circuit in armature of generator, 483 ; in series coil of relay, 487 ; in shunt field of generator, 483 ; in voltage coil of relay, 486 Operating as generator, 459 Overcharge, correcting, 446 Overhauling, drag link, 38 ; Ford front radius rod, 30, front wheels and bearings, 32, transmission, 83 ; rear axles of sin- gle piece housing construction, 65 ; and rebushing Ford front axle, 32 ; split housing type rear axle, 63 ; springs, 18 ; standard selective type transmission, 83 ; universal joints, 101 ; water pump, 211 Overheated engine, cooling, 207 ; causes of, 207 ; filling, 207 ; recognizing, 206 Oxidization, 592 Oxwelding problems, 604 Oxy-Acetylene, cutting, 614 ; • flame, 587 ; welding, 583 Oxygen, 583 Packard Twin Six, foot brakes, adjusting, 62 ; hand brakes, adjusting, 63 Patches, valve, 526 Patching, cold, 542 Pierce governor, installing, 260 Pin holes and small punctures, repairing, 528 Pins, metering, 230 Pinion gears, adjusting, 67 Pipe threads, 571 Piston pins, 133; bearing, 134; bushing, removing from piston, 153 ; clamp type, removing, 153; fit, 133 fitting new, 172; securing, 133; where bushing is in rod,, removing, 153 Piston clearance allowance, 132 Piston rings, 132 ; fitting new, 169 Planetary, principle explained, 79 ; type transmission, 77 Plates, forming, 290 ; frozen, 299 ; judging the value of negative, 299 ; of positive, 299; overheated, 298 Plug gap, too wide, 290 ; short circuited, 290 Plunger pump, 179, 246 Pole shoes, 365, 383 Power, 102, 225 Pressure gauge, 179 Priming for starting, 241 Progressive drive, 73 Pump, drive, 199; gear, 179; oil, 177; packing, 211; plunger type, 179; troubles, 199; types of, 199; vane, 178 Push button, starting, 371 Quarter section, building up and tearing down, 544 Radiator, care, 209 ; cleaning, 208 ; honey- comb or cellular type, 198 ; hose, 196 ; hose care, 208 ; leak repairing with liquid compound, 210; mountings, 197; remov- ing, 209; repairing, 210; steaming, 197; testing, 209 ; troubles, 199 ; types of, 197; tubular, 198. Radius rods, 11 Rating electrical power, 268 Rear axle, bevel and pinion gears, adjust- ing, 67 ; and brakes, 40 ; single piece housing construction, overhauling, 65 ; trouble, 52 Rear wheels, pulling, 66 Regulator, controlling flow of acetylene, 588, of oxygen, 588 ; external field, defec- tive, 481 ; mercury tube, 481 ; vibrating, 482 Relay cut-out, 471 Relay trouble tests, 485 Removing, transmission bands, 81 ; noise and proper meshing of teeth, 69 Remy, ignition, 352 ; Oldsmobile, 465 Repair, fabrics, 523 ; materials, handling of, 529 ; outer casing, 543 Repaired battery charging, 318 Repairing, cord tires ; 551 ; large injuries and blow-outs, 538 ; pin holes and small punctures, 538 ; scraped side walls, 560 ; tread cuts, 558 619 INDEX— Concluded Resistance unit, 280, 350 Retread, bands, semi-cured, 527 ; building up, 563 ; curing, 564 Reverse, 78, 80 ; gear, 76 Rich mixture, 224 Rings, leaic proof, 132 Rocicer arms, 141 Rod bearings, 134 Rubber liose troubles, 196 Safety spark gap, 387, 389, 396, 417 Sanding, bruslies, 488; commutator, 487 Saturation, 274 Sealing compound, 292 ; softening, around the covers, 301 ; softening method, gas, flame, 302, hot water, 301, steam, 302 Sediment, removing, 303 Selective drive, 73 Separators, 291 ; damaged, 298 Series field regulator, 481 Setting and timing the type CC system, 338 Shackle bolts, adjusting, 15 Short circuit, in armature of generator, 484 ; between generator and battery, 485 ; in shunt field of generator, 484 ; in lighting circuit, 516 ; in motor, 476 Shunt current interruption induction, 368 Sight feed, 179 Silent chain care, 164 Single chain drive, 46 Single jet, 233 Single wire or grounded system, 490 Six cylinder firing order, 128 Slip, joint, 98 ; unnecessary, 100 ; rings, 367 Slow speed, 78, 80 Soapstone, 527 Solenoid, 285 Soldering, 577 Soldering iron, tinning, 578 Spark, advance, automatic, 345, 417 ; caused at two plugs, simultaneously, 398 ; con- trol, 331, 350, 416 ; control, manual, 346 ; plugs, 387, wiring, 393; timing, 334, 337, 351 ; unidirectional, 423 Special transmission types, 76 Split housing type rear axle overhaul, 63 ; Spraying, 222 Springs, cantilever, full elliptic, quarter elliptic, semi-elliptic, three-quarter ellip- tic, 12 ; clips, tightening, 14 ; overhaul, 18 ; leaves, graphiting, 17 ; shackles, lubricating, 16 Standard selective type, transmission over- haul, 83 Start, refusal to, 387 Starter, coupling, Bosch adjustable impulse, 412 ; construction and design, 413 ; care and maintenance, 414 ; generator output, method of readjusting, 446 Starting, 246 ; characteristics, 446 ; condi- tions, 463 ; engine with Rayfield car- buretor, 241 ; duties, division of, 429 ; failure to operate, 472 ; feature, push button, 402 ; lubrication, 457 ; motor, 470 ; motors and generators, 429 ; motor, two unit system. Gray and Davis, 456 ; motor, Wagner, 441 ; switch, 442 ; switch, open circuit or high resistance, 473 Steel, 599; cutting, 603; steel plates, weld- ing, 606 Steering gears, adjusting, 38 ; and front axles, 20 ; lubrication, 36 ; pinion and sector, 25 ; planetary, 20 ; screw and nut, 23 ; worm and gear, 22 ; worm and sec- tor, 23 Steering knuckle, arm design, 29 ; body, re- placing, 36 Storage battery, test to determine the con- dition of, 310; dry, 324; wet, 324 Stove bolt threads, 571 Sulphation, 297 Supplementary springs and needle valve, 256 Switches, 332, 402 ; and core, 407 ; feature, automatic, 356 Taps, using, 572 ; and dies, 570 Teeth on cast iron gears or pinions, build- ing up, 610 Temperature, changes of, 201 Tempering chart, 577 Terminals, and poles, 282 ; positive and negative, 269; and straps, 292; sweating or burning on. 511 Test outfit for reading voltage, 312 Thermosiphon, 194 Thermostat control. 202, 465 Third brush, adjusting, 456; control, 436, 466; regulation, 483 Third circle, retreading, 564 Thread, depth of. 571 Throttle, 230, 234, 246 ; and controls, 251 ; needle and reed valves, 256 Timer, 335 ; distributor, 329 Timing, and ignition, 347 ; contacts, ad- justing, 350 ; magneto to engine, 399, dual, 403, DU, 392 ; range, 389, 396 Timken front wheel bearings, adjusting and lubricating, 34 Tires, care, 519 ; construction, principles of, 51S; cord, 518; cures, 536; fabric, 518; full section, building up, 549, tearing down, 547 ; inflation, 520 ; repair ma- terials, 520 ; reliners, 526 ; retreading, 561 ; vulcanizing, 518 Tool steel, hardening and tempering, 576 Transformer or step-up coils, 368 Transmission, care, standard selective type, 85, overhaul, 83 ; troubles, 77 ; units, 73 Tread, cuts, 520 ; repairing, 558 ; gums, 521 ; preserving, 559 Troubles, due to loss of lubricating qualit- ies, 187 Tube repairs, 536 Tube splice, vulcanized, 541 Tungar rectifier, 323 Two valves per cylinder, 136 Undercharge, correcting, 446 Universal, fabric, 99 ; joints, 95 ; joint lub- rication, 101 ; joints, mechanical princi- ple of, 95 ; joint overhaul, 101 ; removing from axle, 70 ; type of, 97 ; use of fault- finder for testing electric systems, 471 Vacuum, 222; tank parts, Stewart, 217 .. Valves, 140 ; air, 228 ; choke, 228 ; cleaning, 158 ; grinding, 158, 140 ; lap, 144 ; lifters, 140 ; method of removing, 158 ; patches or pads, applying, 543 ; regulator or re- ducing, 586 ; reseating, 160 ; stems, guides, piston rings, cleaning of, 189 ; stems, replacing, 543 ; tappets, adjusting, 155, timing, 142 Vane pump, centrifugal or rotating, 178 Vaporization and carburetion, 222 Venturi tube, 225 Vibration coil ignition, 334 Vibrator, principle of, 334 Volatile, liquids, 220 Voltmeter, 471, 501 Volts, 266 Vulcanization, 535 Vulcanizing hints, 531 Water, distilled, 293 ; pump, overhauling, 211 Welds, preparation of, 594 Welding, blowpipe, 586; cast aluminum, 611 ; heads, 587 ; trouble, sources of, 598 ; unit, connecting and starting the, 588 Wheel bearing cups, replacing, 35 Wheels, truing up, 519 Willard battery, opening, 304 Winding, secondary, 395 Wiring, 421, 495 ; diagram, 360, 471 ; direc- tions, 409 ; and lighting, 490 ; to motor, open circuit, 478 ; to starting motor, short circuited, 477 Work, setting up, 594 Worm and gear, 46 Zenith model L plain tube compound nozzle, 242 620 T HUQS THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW RENEWED BOOKS ARE SUBJECT TO IMMEDIATE RECALL MAR i 6 1S68 UCD L( ,'RARY DUE APR 1 6 1970 APR 1 3 REC'D APR 2 3 1992 FEB 02 1995 REC'D FEB - 5 199f RECBVED FEB 6 «9S inWSKIAL8CS.LIBRABY LIBRARY, UNIVERSITY OF CALIFORNIA, DAVIS Book Slip-14,S00-8,'66(G5531s4)45{ UNIVERSITY OF CALIFORNIA, DAVI! 3 1175 01909 3023 383 ( PL145 trA Kuna ro Automotlv 9 trade train Lng. Cf. ■<- _ . .%% aj.n,^/'/ rm'« ^' r • — /' '■ """ yil^^~ :\^ .;.^>r; UNIVERSITY OF CAUFOIWIA LIBRARY