Connecting Rod Bearings

[Tin Medic]

What is the difference between standard and .010 under? Put new rings on the AMC 258 i6 / 4.2l and found the bearings to be hurting.

 

[73CJ]

.010 under are meant to be used after the crank is ground to clean up wear grooves.

Plastic gage is what you need to do to verify clearances. Then see what you got

Cranks usually end up more like .020 or .030 under after clean up.

If you have excess clearance, your oil pressure can be real low. .

 

[Tin Medic]

The bearings I removed are .010 and the local parts store wants to sell me standard bearings.


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[jasonmark1993]

no go. Your crank was probably already turned at some point. Standard bearings wont work.

When the crank is machined/turned the journals get smaller, so the .010 bearings are thicker to take up the gap.

Are you just doing a rebuild or did you have a failure of some sort?

If the crank looks good and the bearings look good, I would find the .010 and buy the plasti gauge like 73 said.

Or just have the crank turned again and buy the correct bearings.

 

[Tin Medic]

No failure just some rebuilding and upgrading. New rings, bearings and head work.


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[CJ]

Then new you definately need .010 under bearings and as has been stated, plasti gage all crank and rod brearings.

 

[Tin Medic]

Dropped the head off today for cleaning & valve job, new valves, seals and guides.