End Play

[deereowner]

Does anybody know what the end play on rods measurement is on a 1949 JD A? My tractor is making a banging noise in the motor at a low idle. Oil pressure has dropped a little with new 30 weight oil.My mechanic wants to tighten the main bearings and the rod bearings.

 

[Rylee]

It is approximately 0.003 running clearance, and
use plastigauge.

 

[1949ABG]

gap should be 0.002-0.004 Use plastigage assuming the ends are nice and round.

 

[1949ABG]

LOL There was no answer until I posted mine and yours showed up at the same time!!!

 

[Rylee]

Same here. At least we agree. lol

 

[John Deere D]

Try removing one spark plug lead(at idle)at a time. Take note of any change in the engine NOISE. Take an industrial stethoscope and listen to the various sounds emitting from all parts of the engine block, head, and crankcase. Try to ascertain if the sound is originating from the head, piston, wrist pin, or the connecting rod big end. Check to see if sound varies or disappears when clutch is ingauged and or disengaged. With a timing light verify if both cylinders are firing. Place your hand on the flywheel cover (if there is a flywheel cover) and check for signs of a loose flywheel. Has there been any signs of coolant lose? If a stethoscope in not available obtain a 24" long screwdriver and a good pair of hearing protectors. Use screw driver as if it is a stethoscope, handle end against ear muff, metal end on tractor. Had a case similar to yours and the crankshaft was egged shaped! Preformed an autopsy on a
JD D....apparently there was a knocking from the top end of the cylinder....wrist pin knocked a hole in cylinder wall.....then connecting rod wrapped around crankshaft! Found a JD AR that had the piston skirt break away from foundation of piston....bad news!

 

[Mark-Ia]

Make sure the flywheel is tight...

 

[John Deere D]

Please let us know what you have discovered as the problem / repair?
Bob...

 

[deereowner]

Found the rods to be 002. Side play on crank shaft was 010. Losened flywheel, adjusted it to 006. Crank should be 005 to 010. Sounds a lot better.