Mismatched Main caps

Looking for some sage advice.
I have a bare BHW block here that picked up and I was planning to use, however it appears the main caps are mismatched to the block (they came loose in a box, not mounted to block, which made me suspicious). #1 lines up nicely, but then they get progressively more misaligned to #5. It looks like #5 is offset by about 0.010".

Are there any clever tricks I can use to make this useable ? If I get it line bored, I will need main bearings with oversized OD, which don't appear to exist. I have only found "0.25mm and 0.5mm oversized" mains with smaller ID, to allow crank regrind.
any tricks ? or is it really useless ?

thx

Instead of using larger OD bearings, most manufacturers recommend removing material from the mating surface of the caps, bolting them in place and align boring to the original ID. If the caps are mismatched I don't think it will work out though because as you say the bores do not line up at the block to cap mating area.

I would suggest bringing everything to your favorite local machinist and see what they say.. Some engine machinist seem like magicians LOL..

If the misalignment is not much more than 0,25mm it should not be any problem to fix that with line boring/honing

The machine shop grind down the caps and bore the caps up to OEM size (like explained in above post)

Thx, sounds good but I am having a hard time visualising it when the offset is side to side. You would need to grind the cap down a lot to get a side-side reduction of 0.25mm as the bore sides are almost vertical.
We will see what the machinist thinks. I guess I may end up with new custom main caps to match the girdle, save playing around with spacers. Sounds like $$$$ to me !

I'd see if the person you got the block from has the proper caps or have billet ones made.

Scott_DeWitt said:

I'd see if the person you got the block from has the proper caps or have billet ones made.

Click to expand...

Thx, tried that. He doesn't. The ones I have are supposed to match, but they don't (and yes I made sure they are the right way around).

Sounds like billet caps, more $$$$$

Most of the billett main caps i have seen (atleast those from USA)
Has been very badly made,and more than 0,25mm off for sure
But somehow the machine shop i am using were able to fit them anyway
So 0,25mm is absolutely possible

Most reputable machine shops will be able to get replacement bearing caps if yours aren't serviceable..

I bought a head with mismatched cam caps, didn't realise til I'd spent £400 having it ported....
They didn't line up at all. Tried caps off another head and they looked more or less perfect. So been running with these for 30k miles no issues
I had no other choice at the time. Lesson I'll know for next time: always check caps match before buying an engine.