Expert: Brad Sears - 2/3/2011

Question
QUESTION: Putting in a new late model Chevy 350 stroker motor - (377 ci) with a B.W. T5 tranny. I bought new pilot bearing, but it goes almost all the way in without any pressure. I am told it should mic out at 1.94 o.d , but every one I check is 1.92 ( if my mic is right)It will push in to about 1/8 th from flush before it snugs up - is this normal, and how far in should it go. Maybe I just need to tap it in, but how far ?

ANSWER: I assume that this is a bronze/brass bushing and not a ball bearing. If it is a bushing I have run into this in the past. The fix that I have used is to take the pilot bearing and place it on the transmission output shaft. Then with a center punch I make a mark using a small hammer on the outside of the bearing. this will raise the metal a small amount. Do this around the bushing every quarter of an inch or so. Then drive the bushing in using the transmission input shaft or a pilot shaft to keep the bushing from collapsing. Then check the fit between the bushing and the transmission input shaft to make sure that it is not binding.It should go into the pocket in the end of the crankshaft until it is flush with the edge of the bore. This is all providing that the aftermarket supplier of the crankshaft has machined it to factory specs in this area.

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QUESTION: It is a bearing, not a bushing. Is this procedure ok with a needle bearing type - not going to damage bearings, etc. Also, I was told to
nipple the hole in the crank vs the bearing itself. A re-measurement of
of bearing came out 1.092. Is the crank hole too big ?

Answer
I would use this only on bushings, not needle bearing. The problem with dimpling the hole is that the needle bearing shell is light weight material and if the hole that it is going into is not smooth, and it won't be when dimpled, early wear can occur. Back in the day every shop had a supply of brass shim stock. Very thin material that we used to wrap things like this to take up space.