V 
 
 INSTRUCTIONS FOR THE 
 
 OPERATION, CARE, AND REPAIR 
 
 > 
 
 OF 
 
 MAIN PROPELLING 
 
 MACHINERY 
 
 
 
 SECTION IV 
 
 DIESEL ENGINES 
 
 ( Reprint of Section IV, Chapter 7, of the Manual of Engineering Instructions ) 
 
 NAVY DEPARTMENT 
 BUREAU OF ENGINEERING 
 
 ftif Hi : 
 
 OCT 3 0 
 
 N-'VEfis.ry ot tLLmm 
 
 WASHINGTON 
 
 GOVERNMENT PRINTING OFFICE 
 
 1924 
 
“Sc <fe. 
 
 Gai.4-34 
 
 ~UNr\ "3 <- 
 
 MANUAL OF ENGINEERING INSTRUCTIONS. 
 
 CHAPTER 7 
 
 SECTION IV.—DIESEL ENGINES. 
 
 (Articles 7-800 to 7-910.) 
 
 Part 1. General. Articles 7-800 to 7-801, inclusive. 
 
 Part 2. Operating instructions. Articles 7-810 to 7-846, inclusive. 
 
 A. Starting. Articles 7-810 to 7-813, inclusive. 
 
 B. Operation under way. Articles 7-820 to 7-838, inclusive. 
 
 C. Stopping and securing. Articles 7-845 to 7-846, inclusive. 
 Part 3. Care and repair. Articles 7-854 to 7-884. 
 
 Part 4. Tests and inspections. Article 7-895. 
 
 Part 5. Safety precautions. Article 7-900. 
 
 Part 6. Repair guide list. Article 7-910. 
 
 CT7> 
 
 PART 1.—GENERAL. 
 
 7-800. Due to the high speeds of rotating apd reciprocating ^^etVi^' ^ y 
 parts, high pressures, high temperatures, and complicated fuel, 
 lubricating, and cooling systems inherent in engines working on 
 the Diesel principle, it is absolutely necessary, in order to insure 
 successful operation, that all commissioned and enlisted per¬ 
 sonnel assigned duties in connection with operation and repairs 
 to Diesel engines he thoroughly familiar with the details of the 
 principle of construction, operation, adjustments, and repairs in¬ 
 volved. Due to the limited use of Diesel engines in the naval 
 service at present and to the rapid development now being made 
 in this method of power development, both in the naval service 
 and commercially, the courses at the Naval Academy and at the 
 trade schools for enlisted men must be followed up by careful 
 and constant training and educating of the personnel afloat. 
 
 7-801. (1) All commanding and engineer officers of submarines, Instructions to 
 and other commissioned and enlisted personnel having duties in be stud,,>d * 
 connection with operation and maintenance of Diesel engines, be¬ 
 fore being considered qualified for this duty, should first be 
 thoroughly familiar with the following bureau instructions: 
 
 (a) Descriptive pamphlets and instructions for the care and 
 operation of Diesel engines, prepared by the builders of the en¬ 
 gines and issued to the commanding officers by the Bureau of 
 Engineering. The instructions contained in these pamphlets are 
 to be followed. In case of discrepancy between the general 
 'instructions and safety precautions given in the Manual of Engi¬ 
 neering Instructions and the descriptive pamphlets mentioned 
 above, the bureau shall be informed, and instructions requested 
 as to which procedure is to be followed. 
 
 (ft) Bureau orders and circular letters. 
 
 70182°—24 
 
 7-401 
 
7-402 
 
 CHAPTER 7, SECTION IV. 
 
 Textbooks and (2) In addition to the above, the following subjects should be 
 studied™ 1 * t0 mastered from study of such reference and text books and current 
 periodicals as the department may furnish to libraries of sub¬ 
 marines, tenders, and bases from time to time: 
 
 (a) Theory of the Diesel cycle. 
 
 (5) Difference between two and four cycle Diesel engines. 
 
 (c) Advantages and disadvantages of two and four cycle en¬ 
 gines. 
 
 ( d) What takes place during each portion of the Diesel cycle, 
 two and four cycle, and reasons therefor. 
 
 (e) Thorough understanding of how to take and analyze in¬ 
 dicator diagrams on Diesel engines and to locate faults therefrom. 
 
 (f) Practical calculations for mechanical efficiency, B. H. P., 
 I. H. P., mean effective pressure (indicated and brake), piston 
 speeds, and electric H. P. delivered by a Diesel eugine generator. 
 
 (</) Fuel and lubricating oils, composition and methods of re¬ 
 fining. Advantages and disadvantages of the various qualities. 
 Methods of testing for viscosity, flash point, fire point, calorific 
 value, specific gravity, and tests for presence of both fresh and 
 salt water in oil. 
 
 PART 2.—OPERATING INSTRUCTIONS. 
 
 Valves In cyl 
 inder bead. 
 
 A.-STARTING. 
 
 Preparation 7-810. Many of the inspections itemized below may not be nec- 
 for starting en¬ 
 gines not in use essary during preparation for starting when engines have not 
 
 for some time. p een use f or some time. The engineer officer must decide 
 
 which are necessary, keeping in view the condition of the engine, 
 
 the time it has been idle, and the attention given during the 
 
 idle period: 
 
 (a) Examine all working parts of the engine and see that they 
 are clear for running and in good condition. Go carefully over 
 all nuts, bolts, and locking devices. 
 
 (7;) Test spray valves. Lubricate valve spindle and test for 
 freedom of motion. Grind in or replace if necessary. See that 
 nozzle holes are clear and of proper size. 
 
 (c) Test by hand exhaust, intake, and starting valves for free 
 movement. If stiff, lubricate with mixture of lubricating and 
 fuel oil; if this is unsuccessful, dismount and clean. See that all 
 valve springs are properly in place and working. 
 
 ( d ) Check up clearances of all valve rollers; clearances to be 
 measured between roller and concentric part of cam. Check spray 
 valve lift. 
 
 (e) Take out, clean, and reinstall air compressor valves, 
 
 sys- ( f ) Clear fuel oil gravity tank of w r ater and sediment. See 
 
 that all valves are in proper position. Clean filters and suction 
 strainers. 
 
 ( g ) Check suction valves of fuel measuring pump, and pump 
 lines full to each check valve body. Test for the amount of flow 
 to each valve. 
 
 Lubricating (ft) Clean out crank case and all filters. Pump water or sedi- 
 aad cooling oil. m ent from sump tanks, then run oil purifier until oil is pure. Re¬ 
 plenish oil in sump tanks if necessary. See that the gauge cock 
 is clear and fastened in open position, and that all valves and 
 
 Fuel 
 
 tern. 
 
 oil 
 
DIESEL ENGINES. 
 
 7-403 
 
 cocks are in running position. Start independent driven lubricat¬ 
 ing oil pumps and force oil through the system. Inspect for leaks 
 inside and outside of crank case. Fill up grease cups and screw 
 them down tight. Lubricate by hand all rubbing parts that are 
 not lubricated by pressure. Fill mechanical oilers and turn them 
 by hand until oil comes out of overflow valves. Jack engine over 
 several times by hand with independent lubricating oil pump run¬ 
 ning. See that the mechanical oilers for the working and air 
 compressor cylinders are functioning properly. 
 
 (0 Clean cooling water filters and blow out the sea valve. 
 Set all cocks and valves in running position. See that the 
 gauge cocks are clear and secured in the open position. Start the 
 independent driven circulating water pump. Verify the flow of 
 water through each individual part of the engine. Inspect for 
 leaks, especially in packing glands on cylinder liners inside of 
 crank case, when installed. Renew zincs where necessary. 
 
 (;) Open the air compressor throttle. Close drains and vents, 
 except drain from flasks. Open valves to spray air flasks. See 
 that all gauge cocks are clear, and secured in open position. 
 Blow through spray air line. Test spray air relief valves. 
 Fill spray air flasks to about 900 lbs. Test the tightness of 
 the spray air valves by opening the indicator cocks with the 
 starting lever on the stop position. If the exhaust and inlet air 
 valves have not been tested recently they may be tested by means 
 of spray air pressure, taking care not to admit sufficient air to 
 turn the engine over. 
 
 (k) Test the fuel oil pump under pressure for leaks. 
 
 ( l ) Slowly open the valve on the spray air flasks connecting 
 them to the air compressor and see that the air lines, high-pressure 
 air coolers, and separators are tight. Where suitable provisions 
 are made, the valve in the drain manifold may be cracked to 
 admit air into the air coolers and separators of low and inter¬ 
 mediate stages to test them for leaks. The corresponding gauges 
 on the gauge board must be watched so that at no time shall the 
 ordinary running pressures be exceeded. By slowly opening the 
 A-alve connecting the spray air flasks to the engine, the spray air 
 lines may be tested, and in a similar manner the starting air 
 lines may be tested by opening the valve on the starting air 
 flask. 
 
 (???) Prime the fuel lines up to the spray valves by hand. 
 
 7-811. Immediately before starting, or when starting after sur¬ 
 facing : 
 
 (a) Open the circulating water overboard discharge valve, and 
 after a few minutes close the air vents and drainage valves on 
 the mufflers if these are installed. 
 
 (&) Jack the engine over by hand at least one revolution with 
 indicator cocks open, observing closely for any indications of 
 water in the cylinders. 
 
 ( c ) Disengage hand jacking gear. 
 
 (d) To further insure there is no water in the cylinders, turn 
 the engine over a few revolutions by air with indicator cocks open 
 in the following manner: Place the starting mechanism on the 
 starting position, then crack the main valve on the starting flask 
 
 Cooling water. 
 
 Starting and 
 spray air. 
 
 Fuel oil pump. 
 
 Test of air 
 lines. 
 
 Priming lines. 
 
 Procedure im¬ 
 mediately before 
 starting. 
 
7-404 
 
 CHAPTER 7, SECTION IV. 
 
 very carefully so that the engine turns over very slowly. If there 
 is any water in the cylinders, it will show up in the form of 
 spray from the indicator cocks. To get all the water out of the 
 cylinder, place the piston on top dead center and then admit spray 
 air through the spray valve until dry air is blown out of the 
 indicator cocks. If water is present, it must be removed before 
 turning engine over by power. 
 
 (e) See that the starting levers are in the stop position. 
 
 (f) Open outboard exhaust valve. 
 
 (g) Throw in clutch. 
 
 ( h ) Close vent cocks and valves on the starting and spray air 
 leads. 
 
 Inspection of 
 pressures after 
 starting. 
 
 Starting by 
 electric motor. 
 
 (i) Close indicator cocks after engine starts to turn over. 
 
 O’) Open the fuel regulating valve and air compressor throttle. 
 Place all valves and cocks on fuel oil, lubricating oil, and cir¬ 
 culating water systems in their running positions. 
 
 (A;) Oil by hand and set up on grease cups as required. 
 
 (0 If engines are of the reversing type set the reversing gear 
 in the proper position. 
 
 (m) Start up detached oil and water pumps. Shut them 
 down after engine has started and attached pumps have taken 
 the load. 
 
 ( n ) Slowly open the valves to spray air and starting flasks. 
 The spray air pressure must be at least 650 pounds; if the flask 
 pressure is below this, build it up from the starting or ship’s 
 flasks or by turning the engine over with the main motor until 
 the necessary pressure is built up. 
 
 (o) The inboard exhaust valve should be open and drains from 
 exhaust piping and manifold should be closed as the engine starts 
 to turn over. 
 
 ( p ) The actual manipulation of the starting gear must con¬ 
 form strictly with the instructions issued to commanding officers 
 for the particular installation in question. 
 
 7-812. On starting observe the various gauges carefully. If, 
 after a few revolutions, the pressure on the lubricating oil, cir¬ 
 culating water, or intermediate stages of air compressor should 
 not commence to rise, as indicated by the needle remaining sta¬ 
 tionary, the engine shall immediately be stopped and reported 
 “ out of order ” until the cause is found and remedied. The nor¬ 
 mal pressures and temperatures to be maintained are issued with 
 the instruction for each particular installation and should be 
 carefully followed. 
 
 7-813. In many installations air starting is not provided and 
 even if it' is provided it is frequently more advisable to start 
 with the main motors, as the engine can be started more slowly 
 by the latter method and time and care can be taken to see 
 that everything is in proper working order. This method must 
 necessarily be used when starting flask pressure is low and no 
 auxiliary air is available, and is preferable where temperatures 
 are so low as to make air starting difficult. In general, the 
 procedure outlined in article 7-811 is carried out, with the fol¬ 
 lowing additional instructions; 
 
DIESEL ENGINES. 
 
 7-405 
 
 (Or) The fuel oil control must be set so that no fuel is ad¬ 
 mitted to the spray valves until the engine is up to necessary 
 speed and ready for firing. 
 
 ( b ) The starting levers must be in the stop position. 
 
 (c) The reversing gear, if provided, must be set in the same 
 direction as the motor. 
 
 (d) The indicator cocks, or hand operated relief valves, should 
 be open. 
 
 (e) The engines should be started as slowly as possible and 
 the revolutions per minute increased very slowly. 
 
 (f) The starting levers are not to be shifted to running posi¬ 
 tion until the engine is turning over at least 100 R. P. M. and 
 the spray air is up to at least 650 pounds. 
 
 (g) Fuel must be admitted gradually and when the engine 
 fires and takes the load, the main motor should be cut out. 
 
 (70 The precautions outlined in article 7-811 (b) for air start¬ 
 ing, regarding presence of water in cylinders and the provisions 
 of article 7-812 regarding gauge pressures must be adhered to. 
 
 B.-OPERATION UNDER WAY. 
 
 7-820. Engines must not be run at critical speeds. To do so 
 will result in overstressing, and eventually in breaking of shaft¬ 
 ing, heating of bearings, and other serious incidental damage. 
 When going from one speed to another the critical ranges must 
 be passed through as quickly as possible. Detailed information 
 relative to critical speeds will be issued with each installation. 
 Tachometers will be marked to show ranges of critical speeds in 
 which it is forbidden to operate except in emergency. The in¬ 
 accuracy and unreliability of tachometers is well known. They, 
 therefore, must be checked with mechanical counters at least 
 once every four hours and if found to be in error, proper cor¬ 
 rection must be made to tachometer readings to insure that the 
 engines are not operated at critical speeds as indicated on the 
 tachometers. 
 
 7-821. When starting from cold the load on engines must be 
 built up gradually. At least the following time intervals should 
 be allowed; to build up to cruising speed, 5 minutes; to full 
 speed, 15 minutes; to emergency speed, 20 minutes. Under 
 normal conditions of operation the above time intervals should 
 be doubled. 
 
 7-822. Neither-the designed limiting M. E. P. nor the limiting 
 piston speed of any installation shall ever be exceeded. In 
 order not to exceed the designed piston speed it is only neces¬ 
 sary not to exceed the maximum allowable R. P. M. 
 
 7-823. To determine the proper engine speed with maximum 
 M. E. P. in cases where the motors may be run at the full rated 
 horsepower of the engines, proceed as follows: 
 
 (a) On the latest approved standardization curves draw a line 
 of maximum M. E. P. Figure 7-41 shows an example as applied 
 to the S-1S to S-41 class of submarines. This line is determined 
 by two points, 1,200 B. H. P. at 3S0 R. P. M., and 1,200 X ff£= 
 1,105 B. PI. P. at 350 R. P. M. In a similar manner several more 
 converging straight lines corresponding to various percentages of 
 overload may be added. 
 
 Critical speeds. 
 
 Building up 
 load after cold 
 starting. 
 
 Excessire pres¬ 
 sure and piston 
 speeds. 
 
 Maxi m u in 
 M. E. r. 
 
7-406 
 
 CHAPTER 7, SECTION IV. 
 
 (b) A run on motors of at least five minutes’ duration must 
 be made to determine the It. P. M. at full horsepower of the en¬ 
 gines. Point F, 1,200 B. H. P. at 375 R. P. M. may thus be ob¬ 
 tained. Another run of similar duration at a slightly smaller 
 load on the motors is made and point G, 1,100 B. H. P. at 366 
 R. P. M., plotted. Thus a straight line FG may be drawn as a 
 part of the B. H. P.-R. P. M. curve for each individual boat 
 under existing conditions of bottom and trim. 
 
 (c) Point H at the intersection of the line FG with the line 
 of maximum M. E. P. gives the R. P. M. at which the engines 
 may be run without exceeding their designed maximum M. E. P. 
 In our example point H gives 373 R. P. M. 
 
 (d) If it is desirable to carry a floating battery load on the mo¬ 
 tors, a line parallel to the line of maximum M. E. P. correspond¬ 
 ing to the deduction for float in B. H. P. may be drawn. The in¬ 
 tersection of line FG with this float allowance line at point I 
 gives the R. P. M. In our example a floating load of 25 B. H. P. 
 was allowed and the speed reduced thereby to 370 R. P. M. 
 
 (e) Attention is called to comparative results obtained from 
 two sister ships of this class. On one the trials were run with 
 clean bottom, the other Avas six weeks out of dock. The first 
 one could run the engines full speed (380 R. P. M.) and still be 
 2^ per cent below the maximum M. E. P.; the other would be 
 overloading the engines about 15 per cent if run at the same 
 R. P. M., point A. Even when developing the designed horse¬ 
 power at the slower speed of 367 R. P. M. as shown by point B, 
 the engines would be overloaded by about 4 per cent. Point C 
 shows the proper speed for the engines without overloading, 
 362 R. P. M., or if an allowance of say 35 B. H. P. be made for 
 float, the engine speed should not exceed 358 R. P. M. 
 
 indicator 7-824. In case the horsepower of the motor is not sufficient to 
 curds in deter* 
 
 mining M. E. p.permit running full engine horsepower, the only criterion of over¬ 
 loading will be the indicator card. In such cases the card must 
 be planimetered, or the area figured out in some other appropriate 
 manner. This area divided by the length of the card will express, 
 in the scale of the spring used, the indicated M. E. P., and this 
 must not exceed 110 to 120 pounds square per inch. 
 
 Causes of ex- 7-825. (1) Any of the following conditions may seriously in- 
 (.ssire M. E. p * crease |] ie yp pp p. f 0r any given horsepower, and should always 
 
 be considered and allowed for: 
 
 (a) One or more cylinders not developing proper proportion 
 of power. 
 
 (b) Increase in foulness of bottom, bent propellers, or shafting 
 out of alignment. 
 
 (c) Increase of draft, change of trim, setting of submerged 
 bow planes or stern diving rudders, condition of sea. 
 
 (d) Towing another vessel. 
 
 ( e ) Running on one engine. 
 
 (2) Under the above conditions, the revolutions per minute 
 and brake horsepower should be reduced sufficiently to bring the 
 M. E. P. within the designed limits. Always remember that de¬ 
 signed pressures on steam boilers are rarely exceeded, as injuries 
 to both personnel and material may be disastrous. In internal- 
 combustion cylinders the injuries to material are likely to be just 
 as disastrous, although the danger to personnel may not be present. 
 
3fill ON3 JO aVOUJAQjQ ofa 
 
 DIESEL ENGINES. 
 
 7-407 
 
 0 : 
 
 <$s 
 
 Fig. 7-41. 
 
 B. H. P. and R. P. M. curves for S-18 to S-41 class of submarines, showing method of 
 
 determining engine speed for maximum M. E. P. 
 
 2 
 
 76182°—24 
 
7-408 
 
 CHAPTER 7, SECTION IV. 
 
 indications of 7-826. Watch the gauges and thermometers carefully at all 
 times, and see that needles and pointers are in the proper fields 
 for the power being developed. If exhaust temperatures are high, 
 exhaust smoky, and the engine generally overheated, the engine is 
 probably overloaded and should be slowed down immediately. 
 watcr. CUlatlHS 7-827. Circulating water should be at about the same tempera¬ 
 ture from each cylinder discharge. Circulating water tempera r 
 tures should never exceed 122° F. at the overboard discharge, as 
 higher temperatures will cause deposits of salt and other solids 
 in the water in the jacket spaces. The circulating water through 
 the air coolers should be as cold as possible. 
 
 Danger of cold 7-828. Under no condition must a large amount of cold water 
 
 water in hot en¬ 
 gine. be driven suddenly into a hot engine. This causes sudden cooling, 
 
 resulting in cracked cylinder heads and cylinders, and seizing 
 
 of pistons. 
 
 Circulating 7-829. When the circulating water can not be increased and 
 water fails. ,, , , , . 7 . 
 
 the temperatures are too high stop the engine. 
 
 7-830. Keep the air compressors, starting flasks, and spray air 
 flasks drained. 
 
 inspectionano 7-831. Watch carefully all bearings and other moving parts, 
 moving ft parts . ° f and when it can be done with safety, feel them from time to 
 time. All bearings, rocker arms, links, valve guides, etc., not 
 connected to the force lubrication system must be oiled by hand 
 every hour and grease cups must be set up. 
 
 inspection of 7-832. (1) See that the mechanical oilers are feeding and that 
 they do not get air bound. Check the oil level in the sump tanks 
 from time to time and keep them approximately three-fourths 
 full. Keep the lubricating oil purifiers running at all times when 
 one or more engines are in operation, and for a sufficient length 
 of time after shutting down to keep the oil pure. 
 
 (2) Test the lubricating oil for presence of salt water before 
 getting under way and once during each watch while the engine 
 is in operation. Lack of necessity for the usual amount of make¬ 
 up oil or a rise of oil level in the sump tanks indicate oil or 
 water leakage from a source outside the system and continued 
 operation under these conditions will lead to disastrous results. 
 Keep the filters and strainers whole and clean. 
 
 Lubricating- 7-833. Where by-passes are fitted from the circulating water 
 oil tempo..iturcs. discharge £ 0 the circulating water pump suction, water through 
 the cooler should be regulated so as to give an oil discharge tem¬ 
 perature from the cooler not warmer than 95° F., or cooler than 
 78° F. The piston cooling discharge must not be warmer than 
 140° F. 
 
 Temperature of 7-834. Air discharged from an air cooler must be as cold as pos- 
 air from cooler. never higher than 140° F. When an increase of circulating 
 
 water is of no benefit the cooler tubes must be cleaned. 
 
 Rocker arm 7-835. Watch the rocker arm rollers for play. If the proper 
 rollers. x x 
 
 play is lacking the rollers will run hot. 
 
 Engine ex- 7-836. Even under full load the engine exhaust should be almost 
 
 haust. 
 
 invisible. If exhaust is dark, the engine is overloaded or not 
 properly adjusted. 
 
DIESEL ENGINES. 7-409 
 
 7-837. The engine must be kept properly cleaned at all times. Care iu clean- 
 
 lug*' 
 
 Oil from leaks may result in fire; dirt or grit may result in a hot 
 roller, cam, or other working part; a mislaid wrench may foul a 
 moving part and completely disable the engine. 
 
 7-838. Take the floor plates up as necessary for examination , inspection of 
 
 bilges and out- 
 
 underneath from time to time. Inspect the exhaust on the out- board exhaust, 
 board side of the engine at least once each watch. 
 
 C.—STOPPING AND SECURING. 
 
 7-845. To stop the engine, proceed as follows: Stopping the 
 
 engine. 
 
 (a) Place the starting levers in the stop position, or the fuel 
 handwheel in the “ fuel off ” position, according to the instal¬ 
 lation. 
 
 (&) Place the reverse gear midway between ahead and astern 
 if air reversing is installed. 
 
 (c) If running on attached pumps, start electric driven inde¬ 
 pendent lubricating and piston cooling oil pump. 
 
 (d) If running on attached pumps, start the independent cir¬ 
 culating water pump slowly and throttle it down so as to main¬ 
 tain just enough circulation of water through the jackets to pre¬ 
 vent a rise in the jacket-water temperature sufficient to cause 
 deposits of salt and solids. If independent pump is running, 
 slow and throttle it down as above. 
 
 (e) Close the inboard exhaust valve. 
 
 if) Open the drain cocks on exhaust line and headers. 
 
 ( g ) Disengage the main engine clutch. 
 
 ( li ) If about to submerge— 
 
 (1) Shut the outboard exhaust valve. 
 
 (2) Open vent and drain valve to the muffler. 
 
 (3) Stop the circulating water pump and close the sea 
 valves. 
 
 (i) Close till valves on the starting and spray air flasks. 
 
 ( j ) Open the drain valves on all air compressor separators. 
 
 (k) Open the vent cocks and valves on spray and starting air 
 
 lines. 
 
 ( l ) Open the indicator cocks. 
 
 (w) Close the cocks and valves on the fuel-oil line. 
 
 ( n ) Fifteen minutes after stopping, if not submerging, stop 
 the lubricating oil pump and the circulating water pump, and 
 close the sea valves. 
 
 (o) Immediately after stopping, feel all bearings and parts 
 subject to overheating. Jack the engine over by hand as neces¬ 
 sary to feel the various bearings. 
 
 ( p ) See that all indicator cocks on hand-operated relief valves 
 in working cylinders and air compressors are open and that 
 pressure is off spray and starting air lines. Carefully observe all 
 gauges to make sure that pressure is off. If pressure is left on , 
 the possibility of serious accident is imminent. 
 
 (q) Clean the engine and floor plates thoroughly and see that 
 the bilges are dry. 
 
 (r) Remedy any troubles discovered, regardless of how minor 
 their character may appear. 
 
7-410 
 
 CHAPTER 7, SECTION IV. 
 
 Observations 
 while submerg¬ 
 ing. 
 
 General in¬ 
 structions re¬ 
 garding care and 
 repair. 
 
 Laying up of 
 engines tempo¬ 
 rarily. 
 
 Precautions in 
 freezingweather. 
 
 Overhaul peri¬ 
 ods. 
 
 Spray valves. 
 
 7-846. (a) While submerging, observe the drains from the ex¬ 
 haust lines to make sure that the overboard exhaust valves are 
 tight. These drains must be plainly visible. If leaks are found, 
 start the bilge pump in time to prevent water from reaching the 
 electrical machinery or wiring while on an uneven keel. 
 
 ( b ) Watch circulating water gauges to make sure that sea 
 valves are tight. 
 
 PART 3.—CARE AND REPAIR. 
 
 7-854. In order to keep the engines in reliable operating condi¬ 
 tion it is necessary to dismount the various parts at regular in¬ 
 tervals and clean them thoroughly, rather than to wait until 
 some trouble makes dismounting necessary. In this connection, 
 it is impossible to lay down hard and fast rules for the length 
 of time between inspections, as service conditions vary and foul¬ 
 ing varies with the quality of the lubricating oil and fuel. The 
 skill of the engineers is an important factor, especially their 
 ability to detect quickly any irregularity in the running of the 
 engine. The intervals of time laid down for dismounting and 
 cleaning of various parts should be changed to suit different con¬ 
 ditions, depending on the service performed and personal ex¬ 
 perience. 
 
 7-855. (a) When an engine is not to be used for a consider¬ 
 able length of time, all parts must be covered with a thick coat 
 of grease to prevent corrosion. 
 
 (b) In order to make sure that all bearing surfaces of the 
 cylinders and pistons are well oiled, after cleaning, turn the 
 engine over for 15 minutes at about 200 It. P. M. with the main 
 motor, with all oiling and lubricating systems in operation. Re¬ 
 peat this cleaning, greasing, and turning over by electric motor 
 once a month. 
 
 (c) Jack the engine over by hand daily, taking care that the 
 pistons take a different position each day. 
 
 7-856. In freezing weather, all water jackets, cooling chambers, 
 etc., must be thoroughly drained and blown out one by one, 
 using low pressure air. Proper blowmg out of the water can be 
 accomplished only by closing off all cooling spaces and emptying 
 them separately , one after the other. 
 
 7-857. In order to keep the engines in reliable running con¬ 
 dition, it is necessary to dismount certain parts periodically for 
 examination, cleaning, grinding in, etc. The interval of time for 
 this routine work is issued with the individual instructions for 
 each installation. Due to service conditions it may be impossible 
 to follow this routine exactly. In such cases the routine must be 
 carried out at the first opportunity afforded after the specified 
 interval of time lias elapsed, and responsibility rests with the 
 commanding officer to make proper requests for overhaul periods 
 as required. 
 
 7-858. {a) Before inspecting spray valves, vent the spray air 
 lines. At routine examinations lubricate the packing and guides. 
 Examine the nozzle plate holes and orifices. On long runs the 
 spray valve spindle should be given a couple of turns every 48 
 
DIESEL ENGINES. 
 
 7-411 
 
 hours where special provision is made to permit this, in order 
 to prevent sticking of the spindle. When removing spray valve 
 needles take necessary precautions to insure that fuel oil is not 
 pumped into the cylinder by the hand pump or a dangerous ex¬ 
 plosion may occur on starting. The valve needles must work 
 freely, and should fall on their seats themselves when turned 
 around two or three times. When installing the valve needle, 
 turn it back and forth; if it sticks in one place and moves 
 easily in another, the spindle is bent and must be immediately 
 replaced. 
 
 (b) A dirty atomizer will give poor combustion and cloudy ex¬ 
 haust. The atomizer holes should be cleaned periodically with 
 brass wire of suitable size. 
 
 (c) Spray valve packing must not be set up while the engine 
 is turning over. When a spray valve stuffing box leaks, new 
 packing must not be put on top of the old. The old packing 
 must be removed, the stuffing box cleaned, and new packing in¬ 
 serted. 
 
 (d) Unnecessary grinding in of spray valves is to be avoided. 
 It is necessary only when the seat has been damaged and leaks. 
 In grinding in spray valves use only the finest grinding compound. 
 To test for leaks, open the indicator cocks and admit spray air 
 up to the valves. 
 
 7-859. (a) Air intake and exhaust valves should be carefully 
 examined and ground in every two weeks if possible. If the 
 engine is running at full or overload, the duty of the exhaust 
 valves is very severe and they must be examined more often. See 
 that the cooling spaces in the exhaust valves and cages are kept 
 clear. 
 
 (b) To test the exhaust or intake valves for leaks, jack the 
 engine over until the cylinder is on top dead center; close the in¬ 
 dicator cocks and place the starting levers and reversing wheel 
 in the proper position to allow spray air to blow into the cylin¬ 
 der through the spray valve. If the valves leak, the escaping air 
 can be heard. 
 
 7-860. (a) A leaky cylinder relief valve may be detected by 
 its heating up. Relief valves must be tested every three months 
 even where there are no indications of defects. 
 
 (b) Relief valves are set slightly above the maximum cylinder 
 working pressure and are intended to call attention to, and pre¬ 
 vent, destructive pressures. Repeated lifting of relief valves while 
 the engine is running indicates either that its spring has become 
 weakened; that ignition occurs too early, i. e., before the dead 
 center; that the spray air is too high; or that the spray valve is 
 sticking and leaking. When this occurs, the engine must be 
 stopped immediately and the cause of the trouble determined and 
 remedied. If the valve lifts when starting, it may be caused either 
 by sticking or leaking of the spray or starting valve; by prema¬ 
 ture explosion of fuel oil in the cylinders; or by too heavy spray 
 air pressure. It may also be caused by admitting fuel to cylin¬ 
 ders before the engine is speeded up to sufficient R. P. M.’s to 
 ignite the incoming charge of oil. 
 
 Dirty atom¬ 
 izers. 
 
 Spray valve 
 packing. 
 
 Grinding in. 
 
 Air intake and 
 exhaust valves. 
 
 Cylinder re¬ 
 lief valves. 
 
7-412 
 
 F u ^ 1 pumps 
 Hindi ralre tim¬ 
 ing. 
 
 Governors. 
 
 Air compres¬ 
 sors and coolers. 
 
 Oil in air com¬ 
 pressor. 
 
 A i r starting 
 valve leaks. 
 
 Compressor re¬ 
 lief valves. 
 
 Air coolers 
 and separators. 
 
 CHAPTER 7, SECTION IV. 
 
 (c) Relief valves must never be locked closed , except in cases 
 of emergency. The valves must then be replaced or repaired as 
 soon as possible. 
 
 7-861. The instructions issued with each installation regarding: 
 fuel-measuring pumps and valve-timing adjustments and setting 
 must be strictly followed. 
 
 7-862. The governor and governor gear must move freely and 
 should be cleaned from time to time to prevent gumming of the 
 lubricating oil. 
 
 7-863. {a) Air-compressor pistons should be withdrawn and 
 cleaned at least once in six months. If the efficiency of the com¬ 
 pressor falls off, examine the alignment of pistons and cylinders. 
 See that the rings are free in the grooves, so that-they exert the 
 proper pressure against the cylinder walls. Give careful attention 
 to air compressor valves. They must be removed, inspected, and 
 cleaned at least every 150 service hours. Weakened springs and 
 defective valves must be replaced. Excessive fouling of valves is 
 due to too much lubricating oil, oil wiper rings not functioning 
 properly, improper cooling or cleaning of the air, or crank case 
 not properly drained. 
 
 (&) The amount of oil in the air compressor can be observed 
 while the engine is running by opening the indicator cock and 
 holding a piece of white paper in front of it, so that the air is 
 blown against the paper. 
 
 (c) Improper operation of air compressors, especially valves, is 
 recognized at once by a diminished pressure in the intermediate 
 stages. The normal pressures are furnished with the Instructions 
 for each individual installation and are practically independent 
 of the R. P. M. of the engine and of the actual pressure in the 
 spray air flasks. 
 
 (d) If the pressure on one stage is above normal, it means 
 either that the discharge valve of that stage, or the suction valve 
 of the next higher stage, is leaking, or that the piston rings above 
 this stage leak. When the suction valves leak the suction line 
 becomes hot. 
 
 7-864. Air starting valve leaks may be detected when running 
 by the heating of the air-starting line to the valve. When stopped 
 they may be detected by admitting a small air pressure to the 
 air-starting lines, opening the indicator cocks and listening for 
 escaping air. Take care that no oil gets into air-starting lines or 
 valves as explosions in the cylinders will result. 
 
 7-S65. The same precautions hold for compressor cylinder relief 
 valves as for working cylinder relief valves. 
 
 7-S66. (a) The air discharged from the air-compressor cylin¬ 
 ders is considerably heated up during the compression, and must 
 be cooled as much as possible before entering the next stage in 
 order to prevent explosions of lubricating oil vapor, and to con¬ 
 dense, separate, and drain off as much as possible the water and 
 oil vapors. To accomplish this, a combined cooler and separator 
 at each stage discharge is provided. The air must leave these 
 coolers as cold as possible, otherwise uncondensed oil and water 
 are drawn into the next stage, resulting in fouling of the valves 
 and piston rings. 
 
DIESEL ENGINES. 
 
 7-418 
 
 (b) When the coolers do not function properly, or after about 
 1,500 hours’ operation, they must be broken down and the coolers 
 and separators inspected and cleaned. The sediment deposit on 
 the tubes should be removed by boiling in soda solution. After 
 boiling, blow them out with air or steam and, if necessary, scrape 
 or brush. 
 
 (c) Small leaks around tubes interfere with proper circulation 
 of the cooling water. They may be detected by hot spots on the 
 tops of the coolers. Large leaks will burst safety washers or 
 open relief valves. 
 
 7-867. Starting and spray-air flasks must be tested hydrostati¬ 
 cally at pressures 50 per cent in excess of working pressures at 
 intervals not to exceed two years. 
 
 7-868. Exhaust mufflers and exhaust lines should be inspected 
 and cleaned every six months, both inside and through the jacket 
 spaces. 
 
 7-869. Air-intake ducts to working cylinders, scavenging pump 
 cylinders, and air-compressor cylinders are to be kept clean so 
 that air passage is not restricted and engine efficiency thereby re¬ 
 duced. Oil must not be allowed to accumulate in the scavenging- 
 receivers, as explosions, with disastrous results, are likely to 
 occur. 
 
 7-870. Fuel-oil filters must be kept clean. The period for clean¬ 
 ing will depend on the quality of the oil. Fuel-oil lines and tanks 
 should be cleaned once each six months. See Art. 38-110(q). 
 
 7-871. Once a week inspect cams and spray-valve needle for 
 freedom of movement in guide or stuffing box. Inspect the valve 
 seat. Inspect the atomizer for fouling. It may be that premature 
 or irregular combustion is being caused by an excess of lubricat¬ 
 ing oil being drawn into combustion space, due to worn or improp¬ 
 erly assembled wiper rings. 
 
 7-872. Inspect intake and exhaust valves or rotary scavenging- 
 valves for timing, fouling, and tightness every two weeks. 
 
 7-873. Zincs must be inspected from time to time, and renewed 
 when necessary. 
 
 7-874. Indicator diagrams for working cylinders show the work 
 performed in the cylinders, the sequence of events of the cycle 
 as actually taking place, and in conjunction with observations of 
 the exhaust, serve to judge the combustion. A good combustion 
 is shown by a clear exhaust, a broad diagram during combus¬ 
 tion, and a low end pressure on the expansion line. If the indi¬ 
 cator diagrams show irregularities, hit-and-miss methods to re¬ 
 move the troubles are to be strictly avoided. All parts of the 
 fuel oil delivery mechanism are to be tested out in proper 
 sequence for correct adjustment. Observe the exhaust of each 
 cylinder by opening the indicator or test cocks, allowing the 
 gases to blow on a moistened piece of white paper. Cylinders 
 firing properly will leave no carbon on the paper. Inspect fuel- 
 oil lines, spray air lines, and holes in spray valves for clogging. 
 Remember that adjusting the amount of fuel oil delivered to a 
 cylinder does not remedy irregularities or change the shape of 
 the card, but merely changes the superficial area. 
 
 Test of ila-sks. 
 
 Test of ex¬ 
 haust. lines. 
 
 Air-intake 
 
 ducts. 
 
 Cleaning fuel- 
 oil system. 
 
 Cams and spray 
 valves. 
 
 Intake and ex¬ 
 haust valves. 
 
 Zincs. 
 
 Indicator dia¬ 
 grams. 
 
7-414 
 
 CHAPTER 7, SECTION IV. 
 
 Adjustment, of 
 Indicator. 
 
 Necessity for 
 conforming with 
 specifications. 
 
 Strict compli¬ 
 ance with origi¬ 
 nal specifica¬ 
 tions. 
 
 Prospective 
 changes to be 
 referred to bu¬ 
 reau. 
 
 7-875. In taking indicator cards, care must be taken that both 
 the indicator and its drive are in proper working order. The 
 indicator piston must move freely in its cylinder without stick¬ 
 ing, and must he kept lubricated. The -stylus arm must move 
 freely and without play in its links. Closely-woven hemp twine, 
 with as little elasticity as possible, must be used for the drive, 
 and the lead of the twine must be such that it will run smoothly 
 back and forth. The indicator holes should be blown out by 
 opening the indicator cocks before attempting to take cards. See 
 Arts. 7-657 to 7-675. 
 
 7-876. In order to insure successful operation of Diesel en¬ 
 gines in service, all repairs and replacements must be in strict 
 accordance with original plans and specifications. The bureau is 
 of the opinion that many casualties to Diesel engines may be 
 traced to improper methods of making repairs, and desires to 
 emphasize the necessity of employing only accurate and correct. 
 practices in effecting repairs to engines of this type. The high 
 speeds, temperatures, and pressures, and the reciprocating motion 
 with its attendant complicated lubrication and cooling systems, 
 render repair methods, which are usually successful on other 
 types of engines, unsatisfactory with Diesel engines. The de¬ 
 signed dimensions, clearances, and lifts have been developed as 
 the result of experience, tests, and protracted periods of opera¬ 
 tion under capable supervision. In many cases slight deviation 
 from the design will cause seizures, serious overheating, burned- 
 out bearings, or failure of valves, plungers, or other parts. The 
 materials specified for use have been adopted after careful con¬ 
 sideration and study of the failures of material in service and 
 the specifications covering the manufacture of these materials 
 are based on the best available information. 
 
 7-877. To prevent casualties due to improper repair methods 
 it is directed that no deviation shall be made from the require¬ 
 ments of the original drawings and specifications covering the 
 combustion spaces and high speed reciprocating parts unless spe¬ 
 cifically authorized by the Bureau of Engineering. No welding 
 shall be done on any of the above-mentioned parts, nor shall 
 welding or patching be done on stationary or noncombustion parts 
 in any case where strength of material is one of the important 
 considerations. 
 
 7-878. All navy yards, submarine bases and tenders, and 
 crews of submarines should be impressed with the necessity of 
 accurate and correct methods of effecting repairs to Diesel en¬ 
 gines. In case there is any reason to believe that a deviation 
 from the requirements as shown on the plans and specifications 
 will give better results, it is desired that recommendation, ac¬ 
 companied by full information, be submitted to the bureau. If, 
 after review of the data available in the bureau, the suggested 
 change appears to have merit, an experimental test will be au¬ 
 thorized on an appropriate installation in the Experimental 
 Division and submarines which have been designated for experi¬ 
 mental work. The bureau will base its final decision on the 
 result of this test. It is not the bureau’s desire to discourage 
 criticisms or comments from the forces afloat or from navy yards 
 
DIESEL ENGINES. 
 
 7-415 
 
 and submarine bases concerning changes in material, dimensions, 
 clearances, tolerances, etc., or in regard to economical methods of 
 repair. However, it is of first importance that recommendations 
 be passed on by the bureau in order that a thorough and conclu¬ 
 sive test may be held by one of the vessels especially assigned 
 to this class of work before changes are undertaken on other 
 vessels. 
 
 7-879. Do not permit minor repairs to accumulate. Unexpected 
 operation orders may then require the work to be hurriedly and 
 carelessly done. 
 
 7-880. Before commencing any sort of overhaul of the engine, 
 precautions against unintentional starting of the engine must be 
 carefully carried out. The main engine clutch must be dis¬ 
 engaged. 
 
 7-881. Piston heads must be kept free from excessive carbon. 
 
 7-882. (a) Remove the working pistons periodically as neces¬ 
 sary to keep the working and wiper rings in good condition. 
 
 ( b ) In assembling pistons, when dowel pins for rings are in¬ 
 stalled, they must be in the position indicated on the plans. Clear¬ 
 ance between the top of the piston and the cylinder heads must 
 be strictly in accordance with the plans. Too much play between 
 the cylinder head and the piston in the air compressor reduces its 
 over-all efficiency. Adjustment of clearance is made in the same 
 manner as for working pistons. Ring-tip clearances must be 
 carefully checked before fitting new rings by placing the ring 
 alone, separate from the pistons, in the cylinder. 
 
 (c) In reinstalling a piston it must be carefully lubricated, 
 and dimensions, clearance, and position of rings carefully checked. 
 The ends of the rings must have the proper clearance and the ex¬ 
 act diameters of the pistons must be compared with that of the 
 cylinders. The instructions for each particular installation 
 should be referred to the proper clearances. 
 
 (d) When a new piston is installed it must be carefully lubri¬ 
 cated and after the engine is started given extra lubrication. 
 The engine should be turned over slowly, or with the main motors, 
 for 30 minutes. Full load should not be applied until after at 
 least 24 hours of operation. 
 
 7-883. Compressions, hot, should not vary more than 10 pounds 
 between cylinders. Compression is adjusted by means of shims 
 under the foot of the connecting rod. Great care must be taken 
 to use shims of uniform thickness, in order to insure that the rod 
 is properly lined up. 
 
 7-884. A loose bearing is usually detected by a slight knock. 
 When starting up after scraping in, take great care to see that it 
 does not run hot. If necessary, slacken the bearing cap nuts and 
 put in an extra shim. Take great care in installing new bearings 
 not to spring the crank shaft. Check the clearances carefully. 
 
 PART 4.—TESTS AND INSPECTIONS. 
 
 7-895. The following tests and inspections shall be made, and 
 the results logged: 
 
 (o) In order to keep engines in reliable running condition, it is 
 necessary to dismount certain parts periodically for examination, 
 
 Repairs not 
 to accumulate. 
 
 P r ec a u lions 
 before overhaul. 
 
 Carbon. 
 
 Care of pis* 
 tons. 
 
 Compressions. 
 
 Bearings aid 
 pins. 
 
7-416 
 
 CHAPTER 7, SECTION IY. 
 
 cleaning, grinding in, etc. The interval of time for this routine 
 work is issued with the individual instructions for each installa¬ 
 tion. 
 
 (b) Test lubricating oil for the presence of salt water before 
 getting under way, and once each watch. 
 
 ( c) Inspect exhaust on outboard side of engine at least once 
 each watch. 
 
 {d) Idle machinery is to be turned over daily. 
 
 (e) Spray valves are to be given a complete turn every 48 
 hours on long runs, to prevent sticking of spindle. 
 
 if) Air-compressor valves are to be removed and inspected at 
 least every 150 service hours. 
 
 (</) Atomizer holes are to be cleaned at least once a week. 
 
 ( h ) Inspect cams and spray valve needles once a week. 
 
 ( i ) Air intake and exhaust valves shall be carefully examined 
 every two weeks and ground in as necessary. 
 
 ( j ) Fuel measuring pumps and valve timing adjustments and 
 settings shall be tested once a month. 
 
 (k) Governors and governor gear shall be tested once a month. 
 
 (l) Relief valves shall be tested every three months. 
 
 ( m ) Inspect zincs quarterly. 
 
 ( n ) Air compressor pistons are to be withdrawn and cleaned at 
 least once in six months. 
 
 (o) Exhaust mufflers and exhaust lines shall be inspected and 
 cleaned every six months. 
 
 (p) Fuel oil lines and tanks shall be cleaned every six months. 
 
 {q) Starting and spray air flasks shall be tested hydrostati¬ 
 cally at pressures 50 per cent in excess of working pressure at 
 intervals not to exceed two years. 
 
 PART 5.—SAFETY PRECAUTIONS. 
 
 7-900. (a) Engines shall not be started after diving until steps 
 have been taken to insure that there is no water in the cylinders. 
 
 (b) When starting from cold, the load on the engine shall be 
 built up gradually. 
 
 (c) Engines shall not be run at critical speeds, so marked on 
 the tachometers, except in case of emergency. 
 
 ( d ) Neither the designed M. E. P. nor the limiting piston speed 
 as designed for each installation shall ever be exceeded. 
 
 (e) If, at any time, the pressure on the lubricating oil system 
 or in any stage of the air compressor falls below the normal pres¬ 
 sure, the engines shall immediately be stopped and reported “ out 
 of order” until the cause is found and remedied. The normal 
 pressures and temperatures to be maintained are laid down in the 
 operating instructions for each particular installation, and shall 
 be carefully followed. 
 
 (/) If the proper amount of circulating water, or lubricating 
 and piston cooling oil, can not be maintained and the tempera¬ 
 tures are too high., the engine shall be stopped. 
 
 (g) Under no circumstances shall a large amount of cold water 
 be allowed suddenly to enter a hot engine. 
 
DIESEL ENGINES. 
 
 7-417 
 
 (ft) Engines shall be kept clean at all times, and the accumu¬ 
 lation of oil in the bilges or other pockets shall be strictly 
 guarded against. 
 
 ( i ) When the engines are stopped, all spray and starting air 
 lines must be vented. If pressure is left on, serious accident may 
 result. 
 
 ( j ) Care must be taken that water in the bilges does not reach 
 electrical machinery or wiring, particularly when on an uneven 
 keel. 
 
 (k ) In freezing weather all parts containing water and sub¬ 
 ject to freezing shall be carefully drained. 
 
 ( l ) When spray valve needles are removed, precautions shall 
 be taken to see that fuel oil is not pumped into the cylinders by 
 hand pump, or a dangerous explosion may occur on starting. 
 
 ( m) If one of the relief valves, either on the working cylinders 
 or air compressors, blows several times, the engine shall be 
 stopped immediately, and the cause of the trouble determined and 
 remedied. 
 
 (n) Relief valves shall never be locked closed, except in case 
 of emergency. 
 
 (o) To prevent casualties due to improper repair methods, no 
 deviation shall be made from the requirements of the original 
 drawings and specifications, unless specifically authorized by the 
 Bureau. 
 
 (p) The cause of any unusual noise or knocks shall be imme¬ 
 diately investigated, and steps taken to remedy the trouble. 
 
 ( q ) When the main engines are running and it is required to 
 ventilate inboard, batteries should never be charged to such a 
 state as to gas freely. It has been definitely determined that 
 under these conditions the air supplied to engines is strongly 
 contaminated with sulphuric acid vapors, which combine with the 
 iron and carbon in the form of ferrous sulphate, an extremely 
 hard and gritty substance, directly resulting in destroying lubri¬ 
 cation and scoring bearing and rubbing surfaces. In other words, 
 finishing charges and overcharges should always be made under 
 conditions permitting of outboard battery ventilation. 
 
 7-910. PART 6.—REPAIR GUIDE LIST. 
 
 Diesel engines—Two or four cycle. 
 
 _Engine. 
 
 Done. 
 
 Not 
 
 Done. 
 
 1. Refer to necessary blue prints.. 
 
 2. Refer to previous data. 
 
 3. Take cylinder compressions (hot). 
 
 ■I. Overhaul working cylinders: 
 
 (a) Remove pipe connections. 
 
 ( b) Remove rocker arms. 
 
 (c) Remove all valves and cages. 
 
 (d) Examine cam-shaft bearings. 
 
 ( e ) Remove cylinder heads. 
 
 (/) Remove pistons and connecting rods 
 
 5. Overhaul air compressors: 
 
 (а) Remove pipe connections.. 
 
 (б) Remove valves, cages.. 
 
 (c) Remove cylinders.. 
 
 (<Z) Remove pistons and connecting rods 
 
7—418 
 
 CHAPTER 7, SECTION IV. 
 
 Diesel engines — Tvx> or four cycle —Continued. 
 
 6. Overhaul scavenger pump on two-cycle engines. 
 
 (a) Remove scavenging receiver. 
 
 ( b ) Remove slide valve and piston or shutter valve. 
 
 (c) Remove cylinder head. 
 
 ( d ) Remove pistons and connecting rod. 
 
 7. Record condition of all cylinder walls, scores, and abrased surfaces_ 
 
 (a) Measure and record cylinder diameters. 
 
 Done. 
 
 Not 
 
 Done. 
 
 
 Top. 
 
 Middle. 
 
 Bottom. 
 
 Fore and aft-. 
 
 
 
 
 Athwartship. 
 
 
 
 
 Any other diameter. 
 
 
 
 
 
 
 
 
 8. Inspect for condition of liner joints, top and bottom 
 
 9. Examine, clean, and grind the following valves: 
 
 (a) Spray. 
 
 (5) Exhaust. 
 
 (c) Inlet... 
 
 ( d ) Air starting. 
 
 (e) Relief (test relief). 
 
 if) Indicator cock. 
 
 ig) Fuel oil by-pass and check. 
 
 ( h ) Spray air check. 
 
 (0 First-stage air compressor suction. 
 
 ( j) First-stage air compressor discharge. 
 
 (7c) Second-stage air compressor suction. 
 
 ( l ) Second-stage air compressor discharge. 
 
 (77i) Third-stage air compressor suction. 
 
 (n) Third-stage air compressor discharge. 
 
 (o) Fourth-stage air compressor suction. 
 
 (p) Fourth-stage air compressor discharge. 
 
 10. Remove wrist pin. 
 
 (а) Examine and take clearances. 
 
 (б) Examine bushing.: renew. 
 
 (e) Examine locking device. 
 
 11. Examine piston. 
 
 (a) Measure and record piston diameters 
 
 
 Top. 
 
 Middle. 
 
 Bottom. 
 
 Fore and aft. 
 
 
 
 
 Athwartship. 
 
 
 
 
 Anv other diameter. 
 
 
 
 
 
 
 
 
 12 . 
 
 13. 
 
 14. 
 
 15. 
 
 16. 
 17. 
 
 18 . 
 
 
 Clean. 
 
 (c) Remove splash plate and clean out piston head. 
 
 (d) Examine and clean piston cooling lines and valves.... 
 
 ( e) Clean and examine piston rings.;renew r . 
 
 Examine gaskets (cylinder heads).;renew. 
 
 Examine gears.(idler and camshaft); vertical shaft. 
 
 Remove fuel measuring pump. 
 
 (a) Disassemble ana clean. 
 
 (6) Renew parts asnecessary. 
 
 (c) Repack. 
 
 Remove and overhaul governor if necessary. 
 
 Remove exhaust elbows and renew studs. 
 
 Remove cylinders.;remove scale and mud from water jackets. 
 
 (a) Test water jackets to designed pressure. 
 
 Take out plugs in crankshaft and flush out oil passages with kerosene.. 
 
 
 fj 
 
 JP 
 
 % 
 
DIESEL ENGINES, 
 
 7-419 
 
 Diesel engines—Two or four cycle —Continued. 
 
 19. 
 
 20 . 
 
 21 . 
 
 22 . 
 
 23. 
 
 24. 
 
 25. 
 
 26. 
 
 27. 
 
 28. 
 
 29. 
 
 30. 
 
 31. 
 
 32. 
 
 33. 
 
 34. 
 
 Done. 
 
 Not 
 
 Done. 
 
 Overhaul bearings.. 
 
 (а) Take loads; adjust if necessary. 
 
 (б) Tako bridge gauge readings, compare with original for check 
 
 on alignment of shafting... 
 
 Bearing. 
 
 Condition. 
 
 Clear¬ 
 
 ance 
 
 after 
 
 fitting. 
 
 Thick¬ 
 
 ness 
 
 of 
 
 shims. 
 
 Thick¬ 
 ness 
 • of 
 leads. 
 
 Bridge 
 
 gauge. 
 
 Bear¬ 
 
 ing. 
 
 Jour¬ 
 
 nal. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 _ 
 
 _ 
 
 (c) Remove oil pipes. 
 
 ( d ) Note marks on bearing nuts. 
 
 (e ) Remove bearing nuts and cap brasses.. 
 
 Test gauges. 
 
 Examine and test air cooler.; renew tubes.; retin 
 
 Examine and test oil cooler.; renew tubes. 
 
 Examine clutch.; renew necessary parts. 
 
 (a) Check adjustment of shoes. 
 
 (&) Measure tooth clearance of jaw type clutches. 
 
 Examine holding down bolts and coupling bolts. 
 
 Replace bearing caps and shims. 
 
 Replace cylinders. 
 
 Reassemble and replace pistons and connecting rods. 
 
 Replace gaskets and cylinder heads. 
 
 Replace valves and cages. 
 
 Replace rocker arms. 
 
 Replace piping... 
 
 Replace scavenger pump. 
 
 Test all nut keepers, split pins, keys, etc., for tightness. 
 
 Set valves and take clearances between cams and rollers. 
 
 (a) Take cylinder compressions (hot). 
 
 Valve. 
 
 Opens. 
 
 Closes. 
 
 Opens. 
 
 Closes. 
 
 Clear¬ 
 
 ance. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 35. Take air compressor axial clearance. 
 
 (a) First stage. 
 
 ( b ) Second stage. 
 
 (c) Third stage. 
 
 ( d ) Fourth stage. 
 
 (e) See that top ring overrides top of cylinder. 
 
 36. Examine thrust bearing. 
 
 37. Examine motor bearings. 
 
 38. Examine steady bearings... 
 
 39. Examine stern tube bearing. Take clearance in dry dock. 
 
 40. Examine brake... 
 
 41. Cleanlubrication system and test on assembly to designed pressure_ 
 
 42. Overhaulcirculating water pumps. 
 
 43. Overhaullubricating oilpumps. 
 
 44. Overhaulfuel oilsupply system and sump tanks and test on assembly 
 
 to designed pressure. 
 
 45. Blow out all oil, air, and water piping w r ith steam or air. 
 
 46. Clean exhaust pipes, mufflers and connections. 
 
 47. Examine and regrind, if necessary, inside and outside exhaust valves. 
 
 (a) Overhaul pneumatic gear if fitted. 
 
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INDEX 
 
 A. 
 
 Article. 
 
 Adjustment of indicators...7-875 
 
 Air compressors and coolers, overhaul... 7-863 
 
 Air coolers and separators.... 7-866 
 
 Air intake and exhaust valves, overhaul.7-859 
 
 Air intake ducts....7-869 
 
 Air lines, test of..7-810 (l) 
 
 Air starting valve leaks.....7-864 
 
 Atomizers, dirty.. 7-858 ( b ) 
 
 B. 
 
 Bearings and pins, clearances_ 7-884 
 
 Bilges, inspection of..._ 7-838 
 
 Building up load after cold starting.... 7-821 
 
 C. 
 
 Cams and spray valves.7-871 
 
 Carbon.. 7-881 
 
 Care in cleaning. 7-837 
 
 Care of pistons... 7-882 
 
 Causes of excessive M. E. P.. 7-825 
 
 Circulating water.. 7-827 to 7-829 
 
 Cleaning, care in.. 7-837 
 
 Cleaning fuel-oil system. 7-870 
 
 Clearance of bearings and pins__7-884 
 
 Compliance with specifications_ 7-876 to 7-878 
 
 Compressions. 7-883 
 
 Compressors, draining of. 7-830 
 
 relief valves. 7-865 
 
 Cooling water.7-810 (i) 
 
 Critical speeds.. 7-820 
 
 Cylinder relief valves... 7-860 
 
 D. 
 
 Danger of cold water in a hot engine..7-828 
 
 Descriptive pamphlets.. 7-801 
 
 Determination of maximum M. E. P.7-823 
 
 Deviation from specifications to be reported 
 
 to bureau. 7-878 
 
 Draining of flasks and compressors.7-830 
 
 Ducts, air intake. 7-869 
 
 E. 
 
 Electric motor, starting by... 7-813 
 
 Engine exhaust.7-836 
 
 Excessive M. E. P., causes.. 7-825 
 
 Exhaust from engine.7-836 
 
 Exhaust lines, test of...7-868 
 
 Exhaust, outboard, inspection of.7-838 
 
 F. 
 
 Failure of circulating water.. 7-829 
 
 Familiarity with details_ 7-800 
 
 Flasks, draining of__ 7-830 
 
 test of. 7-867 
 
 Freezing weather, precautions during....7-856 
 
 Fuel-oil pump___ 7-810 ( k ) 
 
 Fuel-oil system, cleaning. 7-870 
 
 inspection__7-810 (/) ( g) 
 
 Fuel pumps and valve timing.7-S61 
 
 a. 
 
 Article. 
 
 Governors.. 7-862 
 
 Guide list, repair.....7-910 
 
 I. 
 
 Indications of overload....... 7-826 
 
 Indicator cards in determining M. E. P_7-824 
 
 diagrams... 7—874; 7-875 
 
 Inspection and lubrication of moving parts.. 7-831 
 of bilges and outboard exhaust... 7-838 
 
 of cams and spray valves...7-871 
 
 of intake and,exhaust valves_7-872 
 
 of oiling system.... 7-832 
 
 of pressure after starting. 7-812 
 
 of zincs.7-873 
 
 Inspections and tests.. 7-895 
 
 before starting.7-810 
 
 Instructions regarding care and repair, gen¬ 
 eral. 7-854 
 
 to be studied.7-801 
 
 Intake and exhaust valves.7-872 
 
 J. 
 
 Jacking of engine... 7-855 (c) 
 
 L. 
 
 Laying up of engines temporarily.7-855 
 
 Leaks in air starting valves..7-864 
 
 Limiting M. E. P. and piston speed.7-822 
 
 Lubricating and cooling oil.7-810 (A) 
 
 Lubrication...7-831 to 7-833 
 
 M. 
 
 Maximum M. E. P., determination of...7-823 
 
 Mean effective pressure. 7-823 to 7-826 
 
 O. 
 
 Observations while submerging...7-846 
 
 Overhaul of air compressors and coolers_7-863 
 
 Overhaul of air intake and exhaust valves_7-859 
 
 cylinder relief valves.7-860 
 
 spray valves.. 7-858 
 
 Overhaul periods.... 7-857 
 
 precautions before...7-880 
 
 Overload, indications of..7-826 
 
 P. 
 
 Pamphlets, descriptive..7-801 
 
 Periods of overhaul.. 7-857 
 
 Pistons, care of.. 7-822 
 
 Precautions before overhaul.7-880 
 
 Precautions in freezing weather. 7-856 
 
 Precautions, safety..7-900 
 
 Pressure, excessive, prohibited...7-822 
 
 inspection of after starting_7-812 
 
 Priming fuel lines___7-810 (m) 
 
 Procedure immediately before starting.7-811 
 
 7-421 
 
7-422 
 
 INDEX 
 
 3 0112 062295586 
 
 R. Article. 
 
 Relief valves, compressor.7-865 
 
 cylinder...___7-860 
 
 Repair guide list. 7-910 
 
 Repairs, compliance with specifications. 7-876, 
 
 to 7-878 
 
 not to accumulate. 7-879 
 
 Rocker arm rollers.. 7-835 
 
 Routine tests and inspections. 7-895 
 
 S. 
 
 Safety precautions.7-900 
 
 Separators.7-866 
 
 Specifications, compliance with. 7-876 to 7-878 
 
 Speed, excessive, prohibited.7-822 
 
 Speeds, critical. _■. 7-820 
 
 Spray air...7-810 (j) 
 
 Spray valves and cams.7-871 
 
 overhaul.7-858 
 
 Starting and spray air....7-810 (j) 
 
 Starting by electric motor.7-813 
 
 cold, building up load.7-821 
 
 Article 
 
 Starting inspections before.7-811 
 
 procedure immediately before.7-81 
 
 Stopping the engine.....7-84. 
 
 Submerging, observations while.7-84i 
 
 T. 
 
 
 I 
 
 Temperature of air from air cooler.7-83j 
 
 of circulating water..7-8: 
 
 of lubricating oil..7-: 
 
 Test of air lines....7-810 
 
 exhaust lines.7-1 
 
 flasks.7-86' 
 
 Tests and inspections.....7-89. : 
 
 Textbooks and periodicals__7-801 (2 
 
 Valves, air intake and exhaust, overhaul.7-85! 
 
 in cylinder head.7-810 ( b ) (c) (d) (e 
 
 timing.7-86 
 
 Z. 
 
 Zincs, inspection of. r 7-875 
 
 
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 UBR3RT nr 
 
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 3 0 
 
 192 
 
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