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Well I absolutely need some help on this one. 1970 455 rod bearing as removed from the original block. Purchased new Clevite rod bearings, they do not look like the originals. No slot as in photo. Picture shows numbers on the old bearing. Whats with the spit hole, what does it do. Rods are to be reconditioned, crank ground 10 under, do I need special high dollar bearings to make all this right. School me on this, I am committed to completing this rebuild properly.
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Last edited by REO442; Dec 27, 2021 at 07:02 PM.
Reason: add pictures
I think the spit hole, theoretically, is to spurt oil onto the underside of the camshaft lobes and the piston skirts. How much oil gets spurted is anybodys guess.
The hole was to help oil the cam and pistons like ed said.. GM did away with them somewhere along the line. The later engines did not have them. Don't worry about them. Chevy and Pontiac were the same way and also done away with in later engines.
If you really wanted to I suppose you could take a small round file or die grinder and put the slot in the bearings. The later bearings did not have the long slot like the ones you show. It was only a small half round spot in each half.
Personally with modern oils I don't know if I would even want the extra oil getting thrown onto the pistons. I have never put the slots back in bearings and have never had a problem.
Everyone is correct about the spit holes providing lubrication to the cam. The rods are supposed to be oriented in the block so that the spit holes face the cam, obviously.
The purpose of the oil "spit" holes is to enhance low engine speed oiling of the cylinders not the cam. The only time the spit holes will see enough pressure to function is when the cut out in the bearing is aligned with the oil passage on the journal. This roughly occurs when it is closest and somewhat perpendicular to the opposite cylinder bore. The engine will function without them just normally. You can always have a competent machinist modify the bearing but in my opinion it's not worth it.
Spit on it!
