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Bearings Measurements

4.9K views 6 replies 3 participants last post by  Everett#2390  
#1 ·
I need to buy some bearings for my 327. We took the engine apart and I thought I would be able to get he measurements for the main bearings and rod bearings from the markings on the old bearings.

Here are what

Rod Bearing 12020-HD
Main Bearings 12556-HDA

The thing is I wont have the engine with me or a micrometer to actually measure the bearings. Is there any way I can get the measurements for the bearings from the markings on the old bearings?
I have a 327 that has been board .06 over.
 
#2 ·
Re: Bearings Measurments

Generally, the bearing oversize is stamped on the back, ie, '010 OS'.
I suggest to invest $10 in a Harbor Freight 0-6 inch caliper, better than nothing.
You might take the shells to a NAPA store and ask them to look in their catalog for matching.
 
#3 ·
Re: Bearings Measurments

Measuring the crank journals is the only correct way the determine what bearins you need. As Everett said the bearngs are usually marked, I don't know f I have ever seen an after market bearing that wasn't marked. You wouid be wasting time and most likely shipping the bearings back if you don't have the journals measured.
 
#7 ·
With a rod journal diameter of 1.990, you have a small journal crankshft undersized by 0.010", ie, 2.000" - 0.010" = 1.990".
Mains are also undersize by 0.020", ie, 2.299" - 0.020" = 2.280".
So you would need a 010 oversize rod kit and a 020 oversize main kit.
It is imperative to have the journals miked to get the third decimal place figure to be sure, unless you are positive on the measuring performed.