Flywheel housing shims

P

PC/SR

Well-known member
After some trial and error, I got the flywheel housing within .002 all the way around. However, it took shims of .022 on one ear and .018 on the other, which is way more than the gasket on the block which was .011. Question is, how many shims are too many shims. Seems to me, and this is the question, that at some point the housing is going to be tilted relative the the crankshaft center line and hence the pilot bearing. The top of the housing at the shims is going to be farther away from the block than is the area around the gasket. Any experience, thoughts, suggestions? Thanks
 
When you put your dial gauge on the end of the crank shaft and measure the edge of the flywheel housing, you are checking that it is perpendicular to the crank shaft. With 0.002" is a good reading so your housing is pretty well square to the crank - well within limits. Well done.
I think what you have found is the most common situation with flywheel housings. I bet that at some stage, that flywheel housing was on an engine when someone lifted the front of the motor to do some job without loosening the rear engine mount bolts. That distorts the housing and may even crack it. Did you check for cracks? When a housing is distorted that way, the ears at the top are bent back and the bottom is pulled forward so you'd need more shims under them the top to bring the housing back to square. Loosening those bolts is VERY commonly overlooked.
 
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Synchro909 said:
When you put your dial gauge on the end of the crank shaft and measure the edge of the flywheel housing, you are checking that it is perpendicular to the crank shaft. With 0.002" is a good reading so your housing is pretty well square to the crank - well within limits. Well done.
I think what you have found is the most common situation with flywheel housings. I bet that at some stage, that flywheel housing was on an engine when someone lifted the front of the motor to do some job without loosening the rear engine mount bolts. That distorts the housing and may even crack it. Did you check for cracks? When a housing is distorted that way, the ears at the top are bent back and the bottom is pulled forward so you'd need more shims under them the top to bring the housing back to square. Loosening those bolts is a VERY commonly overlooked.
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Synchro, very good information... a good heads up, something to keep our eyeballs on doing a rebuild. Thanks for sharing your expertise
 
I'd take it to a machine shop and have the front face surfaced so that it's parallel to the back face. Shouldn't cost much, then put the shim stock back on the shelf.


But, that's just my approach to the problem.
 
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