3.8 rod bearings, oversized, 2-3 thousandths, 96 non SG Pk Ave.

[dgroom]

Do you know of any mfg. that makes 2 - 3 thousandths over stock sized rod bearings? It's a 96 non supercharged Park Avenue.

If no mfg makes a 2-3 thousandth over standard rod bearing specifically for a 3.8, do you know of any other rod bearing that would fit?

Please advise.

Thank you.

Dale Groom

[NTX5467]

You desire a rod bearing which is .002-.003" "thicker" than the stock bearing to put the bearing clearance "right" for a crankshaft journal that is .002-.003" "undersized" due to wear?

In the world of GM parts, they many times listed a "Std, Hi-Limit" bearing. This would probably do what you desire . . . BUT I know of NO aftermarket bearing supplier that had that particular nomenclature or sizing bearings. These bearings and similar-situation pistons were designed to allow the use of cranks which had slightly-out-of-spec journals, for whatever reason, rather than put them on the scrap pile.

What you CAN do, is something out of "historic engine rebuilding". I'd purchase a rebuilt connecting rod from a supplier, which will have a new bearing in it, hopefully. Then carefully install it on the crank and plasti-gage the bearing for clearance (at the appropriate crankshaft/connecting rod position!). Then, carefully remove the rod assy and check the plasti-gage's squished-out width, to see what the bearing clearance is. Then carefully put the rod cap or rod main piece in a vice, securely, and gently file the mating surfaces and bearing ends. After a few careful strokes, then get a new string of plasti-gage and repeat the clearance check again. Yes, this can be time-consuming and laborious. Hopefully, the first or second procedure will get you where you want to be with the clearance.

The reason I recommend getting a reconditioned/reman connecting rod with bearing is that once you file the cap/rod mating surface, the only way to undo what you did is to hone "the big end" of the rod/rod cap assy with a connecting rod hone machine. Plus, when you do a full rebuild on the motor, with a "turned" crankshaft, then put the original rod back into play and eveyrthing should be fine again.

The OTHER part of "historic engine rebuilding" would be to find some shim stock, .001" thick, and place it between the existing bearing and EACH the main rod and the rod cap's bearing halves. Just as with the filing the cap/bearing ends, you'll also need to do a slight "pass" with the file over the bearing ends so they'll still seat and index in the rod AND yield the smaller effective diameter to mate with the worn journal. Be sure to plasti-gage then to verify what you've done.

Personally, I like the first "file the caps" procedure as there's nothing to potentially slide out from behind the bearing in that procedure. But I wanted to mention the "shim" method for good measure, as it was used, too.

ALSO, be sure to mark the rods and rod caps with the number of the cylinder they came out of, BEFORE you take them out of the motor!

I recommend AGAINST trying to cross-breed another manufacturer's engine bearings with your Buick!


Regards,
NTX5467

[dgroom]

NTX5467,

Thanks for your response and council. I appreciate them.

Later,
Dale Groom