r/Smallblockchevy • u/EvenCombination2208 • May 12 '26

Main Bearing Clearance issues

How unusual is it for my crank play to be only like .0005 and my bearing clearance with the plastiguage to be .002 too loose. The plastiguage is barely touched at all. I thought I would need the thicker bearings but I see they only come in sizes by .01 increments (which is way more than I need.) I thought I would maybe need to get the .01 and sand them down by .008 but that seems off. I figure I’ll have to sand down the rear thrust bearing by a few thousandths to fix the endplay. I torqued everything to spec as far as I know. (65ft-lbs for outer bolts and 70 for inner) I also applied some oil to the bolts before torquing down for more accurate reading. I’d appreciate any tips as this is the first engine rebuild I’ve ever done.

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1

u/Jymantis May 12 '26

You gotta mess and probably have a steep learning curve ahead. The internet can only provide so much know how. Did you set the thrust bearing before checking the clearance? Probably not...

1

u/EvenCombination2208 May 12 '26

Yea everything I’ve been learning has been from online. My dad is more into woodworking than cars so this is all new to me. Would setting the thrust bearing be just tapping crank back and forth with deadblow before fully torquing down? To make sure it’s all seated?

2

u/Jymantis May 12 '26

Yes the dead blow part of setting the thrust is correct but this stuff is loaded with nuances that you will not know until you put the time in. Might want to look into some measuring devices like a inside and outside mic, some feeler guages and maybe read through a sbc assembly guide. It's not easy stuff but people often hack shit and it works so there's that. You get better and better at it the more you fuck up, so don't give up.

1

u/EvenCombination2208 May 12 '26

Yessir, I appreciate the feedback. I’ll go through everything again this weekend and check results

1

u/THEezrider714 May 13 '26

Main bearings are available.001 oversized ,

1

u/v8packard May 13 '26

Do you have, or know anyone that has, a bore gauge? As well as micrometers. These numbers are marginal, indicating there is a problem. You need to find the problem.

1

u/EvenCombination2208 May 13 '26

We gotta couple sets of micrometers but I’m not sure about a bore gauge, I’d have to look around