Crank and rist pin play on 35 hp

[fucawi]

I have a 35HD which I am restoring from previos moron owner...Starts and idles well but its 40 years old....a static timing check led me to check the TDC marks as the timing looked way too retarded....with screwdriver down the plug hole and piston at TDC how much rock ( flywheel movement ) would you expect before the piston moves ? Clearly if it was new very little or non but with wear in the crank and rist pin after 40 years use whats reasonable?

Addition ...with piston at mid stroke there is virtually no play /rock in the flywheel to move the piston..I think thats a good sign

 

[Frank Acampora]

Re: Crank and rist pin play on 35 hp

Because of the time the piston spends at TDC and the amount of movement is so small compared to crank rotation, Most larger Chrysler engines determine TDC by setting the flywheel to 36 degrees BTDC then measuring with a gauge to determine actual TDC. This operation is described in the Clymers manual. Since your 35 has a shorter stroke that 2.80 inches, the number will be different.

Practically speaking, when I do it by your method, I typically get about 2-4 degrees on either side of TDC before I feel movement, then estimate the center.

 

[fucawi]

Re: Crank and rist pin play on 35 hp

Thanks for that ..I found a better way ..push one piston to the bottom of the stroke...easier to tell if its moving up and pushing the screwdriver....got 2 teeth on the ring so thats 8.7 deg total ..why the original timing marks are so far out I dont know ...so what was retard is now advance !!!

Thanks for that Admiral