Help figuring out which main/rod bearings I need for my 2 bolt GTO

Hi all.

So I have taken the engine out after having suspect rod knock.

Seems my mains are well and truly knackard, so I am going to replace my mains and rod bearings, however I seem to be reading a lot of information that these engines don’t just use a “standard” bearing and will need to be “sized” for my particular engine.

Since mine is an early 2 bolt (early 1992) could anyone help with how I would go about this process please?

The gen of the engine has nothing to due with bearing size. You’re going to need to either have the crank machined, or better yet replaced. The bearing size is figured out after the machine shop is done with their work.

You could also use platigage. People have used it successfully, however it is not as accurate.

I am trying to determine if it needs a grind at all - I seem to get varying answers but when I tried to buy bearings (from here in the UK) there seems to be 4 “standard” sizes not accounting for the +.25 and +.50 for regrinds?

If your mains are trashed you may as well plan on a regrind/replacement.

1 Like

My specialty area so decided to join in this thread. So my question to you is: considering you have taken the the entire engine out and hopefully with the transaxle, are you moving into the direction of a complete overhaul and rebuild or just want to change out bearings? the reason i ask is that most people do not contemplate in complete engine removal unless they are contemplating on a complete build starting out from a bare block and heads.