Main Bearings

chadder1313

Registered User
Im in the process of putting in main bearings and the first set i had difficulties with. I got all of them in fine except for the ones closest to the crank, but they eventueally went in but very tight. I put the caps on and torqued it down and now the motor will not turn over. Ive heard lots of storys about these clevite bearings. I know there is a bearing thats undersized but i thought it was the rear most bearing not the front most bearing. Im at a loss here. Help?? Thanks alot!!
 
Did you plasti-gauge the bearings individually all torqued together. This would have shown you which bearing is too tight. Do not turn the motor at all when using plasti-guage, but spec each bearing set, then clean that off, reassemble with some good lube, torque and then try to turn the crank. Should be effortless with no connected rods.

What do you mean by, "but they eventueally went in but very tight"

You mean they went into the journal and cap tight, or the end gap was tight making the cap sit off the journal a little before tightening, which would bind it all up.
 
if the crank won't turn now ,then the bearing are pinching on the crank

what-ever you do - do not use a breaker bar to turn it over.

bearing should not be hard to install

take the caps back off -all of them -these need to be installed back in the same location and position they came from -don't mix them

remove crank -insert the bottom-half bearing in all the journals ,make sure they are setted -lube the bottom half bearing /use the right half of the bearing
now set the crank in it's journal's - rotate the crank (-remember the lube on the bearing before putting the crank in )

rotate the crank ,should turn very easy ,now install one of the top caps -add lube to the top half with bearing half installed ,

torque it down evenly at half it's torque spec....rotate the crank...it should still turn over very easy..do this with all of them ,once they are all installed go back over all of the cap bolts and one at a time torque and rotate crank each time ,torque them to the proper value

there is nothing hard about installing bearing
if you have never done this before ,it's best to ask someone who has and how they did it and maybe what to look out for while doing such.

a shop manual isn't bad to have at hand either - know your using the right torque spec for what you are doing

ask if you don't know -get it done right the first time

good luck

cheers
steve
 
So....you are doing this in the car? Or is the front cover still attached or what? If you are scared to take it out, than this may be a bigger task than you can handle on your own. Im not sure why you would not remove the crank to do bearings. You run the risk of screwing up the bearings. Not to mention how you are getting them between the crank and the block.

Chris
 
#4 journal bearings are a different size then the rest. If you put the wrong bearings in the #4 journal you'll not be able to turn the crank when the mains are torqued down.

You really should have checked the bearings before you went too far. That's like rule #12 or #34 or #50 or something like that for rebuilding your motor.

Not to mention, how did you know which bearings to order if you didn't check your dimensions? Did you buy oversize bearings?
 
The engine is out of the car and the front cover is still attached. i just did heads and cam the prevouis year so i really did not wanna take the front cover back off. Not to mention i allready put new rod bearings in. I will take the front cover off the motor tomorrow and finish this up. My problem is im in a big rush trying to get everything done before my vacation. Which i know is a big no no.
 
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