Bearing Clearances

Greg Jones

Greg Jones

Well-known member
I just finished checking bearing clearances on my main babbitted bearings in my stock Model T block. I used Herm's method using a spot of oil on the crank then plastigage. I measure the clearance at 0.0015" which I thought was ideal. Once everything is assembled and torqued down, however, I can easily spin the crank by hand. The Model T service manual implies there should be felt "increased resistance" when taking up the bearings. Should I just quit fretting and call it good? Or?
 
When I built mine the crank would initially stick, but a firm grip on a journal would send it spinning. Once up on oil it would maybe roll one full turn from a flick on that journal. I think youre good. Hows the thrust? ws
 
Thrust is about .005" and exceeds specs. I have seen worse however in the smoothest running engines. However you have to believe having all that mass ram back and forth cant be good for any part of the engine.
 
Actually I should note that this is with the bearing caps on using Lubriplate engine assembly. So it is lubricated....
 
SHHHH !!!! Dont use the "L" word around the exspurts! Lubriplate is all I ever use for assembly. "Its the film..." ws
 
Do not use Lubriplate if you do not intend to run the engine shortly after assembly. I had to tear down a rebuilt engine assembled with Lubriplate and had sat for a couple of decades with out ever running. The Lubriplate had solidified!
 
van Dyck said:
Do not use Lubriplate if you do not intend to run the engine shortly after assembly. I had to tear down a rebuilt engine assembled with Lubriplate and had sat for a couple of decades with out ever running. The Lubriplate had solidified!
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I have seen the same thing!
 
Boy I'm glad I don't use Lubriplate. I was thinking about using it but then I realized I wasn't rebuilding any engines and I use vegetable oil for cooking so it came to me that I really don't have a use for Lubriplate. And if I was rebuilding an engine I wouldn't use it on a bet because, well, it's not good stuff.
 
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