moparspares
Well-Known Member
Has anyone run tighter clearances on their Rod Bearings. Of course I would like it a touch bigger but thats what I got on a couple of the rods. The others are .002
I hope that you are off a decimal...
Those clearances are waaaay too big....
Oops .0015 and .002. Not enough zeros
This is with plastiguage and it is honestly a flyshit bigger than .0015. I thought I would run a thinner Full syn oil and that would help. This already has the X bearings for extra clearance. Krazycuda you are right on the standard specs. My "How to modify your Mopar Magnum V8" and "How to build big inch Mopar Smallblock" books states rod bearing tolerance as between .0005 -.0022. The lower number being very tight and puts my .0015 just about in the middle.
My brother ran close to .003 on his 451 and he now has low oil pressure on idle. He said if he did it again he would run tighter tolerances. I am leaning towards leaving it as is.
.0005-.0015 is fine for a factory built stock engine that's built for longevity but for something that's built to make big power .0015 is the very bottom of the scale of what I like to see. Have you tried swapping around bearing shells to see if you might be able to split the difference? There shouldn't be much difference between them but even if you can get another .0001-.0003 out of it it'd help