Instructions for the installation, inspection and maintenance of the Wright Whirlwind Aviation Engine
Models J-5A J-5C
Wright Aeronautical Corporation - Paterson, NJ
January, 1927
WRIGHT WHIRLWIND ENGINES
CHAPTER V.
Inspection Routine
In order to obtain maximum reliability and service from Whirlwind engines a regular schedule of inspections and overhauls should be maintained. Serious failures very often arise from minor causes which a few minutes inspection could have averted. The following schedule is suggested.
Every Flying Day:
7. Are spark plugs tight?
8. Grease rocker shaft with Alemite gun using automobile transmission oil.
10. Are ignition terminals secure to wires and plugs and is insulation on wires intact?
11. Is compression normal?
Check all- cylinders, one at a time in firing order (1, 3, 5, 7, 9, 2, 4, 6, 8)
After all cylinders have been checked proceed as follows :
12. Are carburetor and carburetor manifold tight at securing flanges?
13. Are fuel tanks filled ?
14. Is oil tank filled?
15. Are magneto ground wires secure?
16. Are throttle, mixture and magneto controls free throughout their range?
17. What is full throttle R.P.M.?
18. Is engine operation good on either magneto?
19. What are oil pressure and temperature? Compare with values given on page 25.
20. What is gasoline pressure? (Should be 2-4 lb per sq. in.)
Model J-5
The daily inspection of the Model J-5 engine should include items 7, 8 and 10 to 20 inclusive.
Twenty Hours:
After every twenty hours of flight the valve gear should be disassembled and inspected as follows:
1. Remove the rocker box covers and make a check of the amount of motion of the various parts. If the tappet clearance seems normal it should not be disturbed. If any part seems to have too much motion, or if the tappet clearance is excessive, the rocker arm and push rod should be removed and the cause determined. Check the offending part against the maximum allowable clearance as indicated in the charts on pages 136 to 144 and replace if this is exceeded or if in the opinion of the operator it seems advisable.
Wright Aeronautical Corporation
Service Instruction No. 35.
Subject: Setting Valve Tappet Clearances.
Models: All "Whirlwind" Engines.
Reference: Page 68 Paragraph 11 in Instruction Book for Wright 'Whirlwind" Engines.
In setting the tappet clearance it is essential that the piston of the cylinder in question be at top center on the firing stroke. Unless this is done, it is quite possible for one of the tappets to be riding unnoticed on the rising part of a cam, causing an error in the tappet setting.
To avoid the possibility of making this error proceed as follows: Turn the crankshaft until the valves of the No. 1 cylinder indicate that the piston is on top center at the beginning of the suction stroke. At this point both the valves will be open and the keyway in the shaft will be facing the No. 1 cylinder. If the propeller is mounted on the shaft one of the blades will be in the line of the keyway. Then turn the shaft through one complete revolution and set the clearances on the No. 1 cylinder in the manner prescribed on page 68. Having done this turn the crankshaft in the direction of rotation until the keyway or propeller blade is facing the No. 3 cylinder and set the clearances. Repeat on the rest of the cylinders, taking them in the firing order (1, 3, 5, 7, 9, 2, 4, 6, 8).
5-1-27
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Service Instruction No. 36
Subject: Valve Operating Mechanism Adjustments
Models: "Whirlwind" J-5 Series
References: Instruction Book for "Whirlwind" Engines pages 62 and 63, page 34 paragraph 19.
Reports from the field seem to indicate that the operation and maintenance of the valve gear on the J-5 Series "Whirlwind" engines is not thoroughly understood. Furthermore, since a number of engines of this series have been in service for a considerable time, additional points of interest relative to upkeep have been brought out. Consequently it has been found advisable to issue this service instruction to bring up to date information for maintenance found in the manual.
The following routine is suggested for checking the valve gear. This should be done on one cylinder at a time following the method outlined in Service Instruction No. 35.
1. After the engine has been in service for 20 hours loosen the push rod housing clamping screw And back off on the adjusting nut until the push rod housing is free. With a set of thickness gages check the clearance under rear end of the rocker box. To this value add .005" and tighten up on the adjusting nut until the increased clearance is obtained. Then tighten up on the clamping screw. It is essential that this be done when both the valves are closed to prevent errors caused by the forces set up when the valve is opening or closing.
2. Check the valve tappet clearances in the manner prescribed in Service Instruction No. 35. Just before checking the clearance, the push rod end of each rocker arm should be tapped sharply with a hammer handle to make sure the roller is riding on the cam. The cam followers are fitted with very little clearance and are sometimes too tight to be moved easily with the fingers, necessitating this operation. It has been noted that many operators make curved feelers .040" thick for setting the tappet clearance. This type gage is very handy for checking the clearance but for resetting it is recommended that the method described on page 68 be followed.
3. Every twenty hours the cotter pins should be removed and the rocker arm pin nuts (Part No. 19415) checked for tightness. This is very important'as any looseness on the part of this nut permits the rocker arm pin, sleeve and thrust washers to turn and is apt to cause serious wear in these parts.
4. It is most important to use the correct type of grease in the rocker arms of the "Whirlwind" as many types will become hard and carbonize at the temperature to which they are subjected. Grease containing soap and graphite are most objectionable in this respect and should never be used. Automobile transmission oil has been found satisfactory for rocker arms but care should be exercised not to over-grease these parts as the lubricant may get on to the hot valve stems and stick the valves by the carbon formation. When Uniflow lubricators are used for long endurance flights, vasoline is found satisfactory as it flows at the proper rate to give lubrication for a number of hours.
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WRIGHT WHIRLWIND ENGINES
11—Tappet Clearance
The adjustment on the Model J-5 is quite different, the clearance for both tappets being .040. Loosen the clamping screw on the push rod end of the rocker arm and with a large screw driver turn down on the adjusting screw until the rocker roller touches the valve plug. Then back off on the adjusting screw until the arrow on top has passed eight divisions of the scale on the rocker arm (each division is equivalent to .005" clearance on the valve stem). Lock in place by tightening the clamping screw.
After the valve gear has been inspected, repaired and reassembled the following items should be checked (all "J" series models except as noted) :
1.
2. Are spark plug points clean and are gaps set at proper clearance (.020" to .025" for A. C. Plugs ; .015" for B. G. Plugs).
3. Are nuts on inlet pipe upper flanges tight?
4. Are inlet pipe packing nuts tight?
5. Are cylinder hold down nuts tight?
6. Are fuel strainers clean ?
7. Are fuel lines and connections secure and free from leaks?
8. Is lock on gasoline pump pressure adjusting screw secure?
9. Are oil strainers clean ?
10. Drain the old oil from the tanks and lines and flush with kerosene until perfectly clean. (Do not use kerosene inside the engine.) Replace the lines and put two gallons of clean oil in the tank. Run the engine for twenty minutes and then drain out all the oil again. Replace the lines and fill the tank with clean oil, (Great care should he taken to see that all the oil lines are replaced properly and there are no air leaksl Small air leaks are apt to interfere seriously with the proper functioning of the lubricating system.
11. Oil tanks should be drained and filled with fresh oil.
12. See that hand turning gear is well lubricated.
13. Are engine mounting bolts tight?
14. Does each magneto get full advance when operated from cockpit?
15. Are magneto breaker points clean and gaps set at .012"?
16. Are magneto couplings in good condition?
17. Put four drops of medium machine oil in rear magneto oil holes. Fill front holes.
18. Are propeller hub lock nuts and propeller hub bolts tight ?
19. Check the clearance between the rear of the rocker boxes and the cylinder heads and make sure it is .031" (Engine cold ). While this dimension should not vary it is extremely important and should be checked carefully. Incorrect clearance is very apt to result in failure of the rocker box studs.
When not flying:
It is advisable to run the engine at part throttle for at least 1/4 or 1/2 hour twice a week in order to keep interior parts flushed with oil. This will prevent the vapor due to condensation in the crankcase from rusting steel parts.
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Complete Overhaul
It is suggested that the compression, as noted in Item 11 of the daily inspection, be checked very carefully on each cylinder. As soon as one is found to be low it should be removed, the valves tested for leakage and the piston rings checked for tension. The valves should be ground and the piston rings replaced when necessary. ( See page 50.) In this manner the engine can be kept up to power and speed. It is sometimes very difficult to distinguish between a valve which is leaking and one which is being held open by a bit of dirt or carbon on the seat. The only way to check this out is to run the engine for several minutes and then try the compression again.
Experience with "Whirlwind" engines in service has indicated that the length of the period between overhauls is limited by the tendency of the lubricating system to fill up with sludge. This is composed of gums formed in burning the lubricating oil, carbon, lint and substances taken into the engine through the carburetor or breathers. After 200 hours of service the accumulation is likely to become severe enough to plug up one of the passages resulting in the seizure of the bearing whose oil supply is cut off. It is therefore recommended that "Whirlwind" engines be given a complete overhaul after every 200 hours of service.
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Wright Aeronautical Corporation
Service Instruction No. 35.
Subject: Setting Valve Tappet Clearances.
Models: All "Whirlwind" Engines.
Reference: Page 68 Paragraph 11 in Instruction Book for Wright 'Whirlwind" Engines.
In setting the tappet clearance it is essential that the piston of the cylinder in question be at top center on the firing stroke. Unless this is done, it is quite possible for one of the tappets to be riding unnoticed on the rising part of a cam, causing an error in the tappet setting.
To avoid the possibility of making this error proceed as follows: Turn the crankshaft until the valves of the No. 1 cylinder indicate that the piston is on top center at the beginning of the suction stroke. At this point both the valves will be open and the keyway in the shaft will be facing the No. 1 cylinder. If the propeller is mounted on the shaft one of the blades will be in the line of the keyway. Then turn the shaft through one complete revolution and set the clearances on the No. 1 cylinder in the manner prescribed on page 68. Having done this turn the crankshaft in the direction of rotation until the keyway or propeller blade is facing the No. 3 cylinder and set the clearances. Repeat on the rest of the cylinders, taking them in the firing order (1, 3, 5, 7, 9, 2, 4, 6, 8).
5-1-27
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Service Instruction No. 36
Subject: Valve Operating Mechanism Adjustments
Models: "Whirlwind" J-5 Series
References: Instruction Book for "Whirlwind" Engines pages 62 and 63, page 34 paragraph 19.
Reports from the field seem to indicate that the operation and maintenance of the valve gear on the J-5 Series "Whirlwind" engines is not thoroughly understood. Furthermore, since a number of engines of this series have been in service for a considerable time, additional points of interest relative to upkeep have been brought out. Consequently it has been found advisable to issue this service instruction to bring up to date information for maintenance found in the manual.
The following routine is suggested for checking the valve gear. This should be done on one cylinder at a time following the method outlined in Service Instruction No. 35.
1. After the engine has been in service for 20 hours loosen the push rod housing clamping screw And back off on the adjusting nut until the push rod housing is free. With a set of thickness gages check the clearance under rear end of the rocker box. To this value add .005" and tighten up on the adjusting nut until the increased clearance is obtained. Then tighten up on the clamping screw. It is essential that this be done when both the valves are closed to prevent errors caused by the forces set up when the valve is opening or closing.
2. Check the valve tappet clearances in the manner prescribed in Service Instruction No. 35. Just before checking the clearance, the push rod end of each rocker arm should be tapped sharply with a hammer handle to make sure the roller is riding on the cam. The cam followers are fitted with very little clearance and are sometimes too tight to be moved easily with the fingers, necessitating this operation. It has been noted that many operators make curved feelers .040" thick for setting the tappet clearance. This type gage is very handy for checking the clearance but for resetting it is recommended that the method described on page 68 be followed.
3. Every twenty hours the cotter pins should be removed and the rocker arm pin nuts (Part No. 19415) checked for tightness. This is very important'as any looseness on the part of this nut permits the rocker arm pin, sleeve and thrust washers to turn and is apt to cause serious wear in these parts.
4. It is most important to use the correct type of grease in the rocker arms of the "Whirlwind" as many types will become hard and carbonize at the temperature to which they are subjected. Grease containing soap and graphite are most objectionable in this respect and should never be used. Automobile transmission oil has been found satisfactory for rocker arms but care should be exercised not to over-grease these parts as the lubricant may get on to the hot valve stems and stick the valves by the carbon formation. When Uniflow lubricators are used for long endurance flights, vasoline is found satisfactory as it flows at the proper rate to give lubrication for a number of hours.
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WRIGHT WHIRLWIND ENGINES
11—Tappet Clearance
The adjustment on the Model J-5 is quite different, the clearance for both tappets being .040. Loosen the clamping screw on the push rod end of the rocker arm and with a large screw driver turn down on the adjusting screw until the rocker roller touches the valve plug. Then back off on the adjusting screw until the arrow on top has passed eight divisions of the scale on the rocker arm (each division is equivalent to .005" clearance on the valve stem). Lock in place by tightening the clamping screw.
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