11/9/04

Hi guys, What’s up with my small block Chevy rear main cap? When I install a bearing insert into the cap I noticed it didn’t fit snugly in the cap. I pushed the bearing all the way to one side and could get a .10 thousandth's feeler gauge between the thrust and the main cap; is this normal? It is a 400 small block with a 4-bolt main that I believe has never been line bored. I just got the motor back from the machine shop and am ready to build. I showed the machinist this and he suggested using some shim stock and make a shim that I could cutout to fit between the cap and bearing thrust and pin it in place with some brass pins. He said the only other solution was to put another rear main cap on the block, which would require a lot of work. Have you ever heard of a problem like this before? Thank You Malcolm Tanner

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Malcolm,

Thanks for writing. Here is the bad news. I have seen this before and honestly the only way I would fix it is to get another cap that fits the bearing better and have it line bored. I just don’t like inserting shims anywhere in an engine and worrying if they will stay put. Also, I'm assuming you had a misprint on the clearance and you meant .010" instead of .10". The possible, but not likely, good news would be that the bearing is at fault. Have you tried a different set just to make sure? That would be too easy! Hope this helps.

Jay

 

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