M20 crank bearings in M42?

[Beemerdan]

I just received the crank bearing that I ordered from BMA and they sent me m20 bearings. I looked up the numbers on their website and it looks like they sell them as the same thing. I have heard of using m20 bearings in the M42, but just wanted to check with you guys to see if this is normal? Any problems with doing this?

Thanks!
Dan

[wazzu70]

You need to have the main caps machined to use the M20 bearings. You need M42/M50 bearings.

[Rocla]

You need to have the main caps machined to use the M20 bearings. You need M42/M50 bearings.

If m20 bearings are for 3/88 or newer block they are same as m42 and m50 ones.

IIRC new m20, m42 and m50 have two holding claws in bearing while older ones only have one.

[Beemerdan]

Just looked at the package again, it says they are for m20/m50/m52/m21d/m51. Also it looks like the holding claws match up right. The block and their bearings have on claw, while the main caps and their bearings both have two.

[shEck3lls0]

I used m20 bearings in my m42 rebuild.... Let me look back on exactly what I used/did.

[wazzu70]

If m20 bearings are for 3/88 or newer block they are same as m42 and m50 ones.

IIRC new m20, m42 and m50 have two holding claws in bearing while older ones only have one.

This is correct. I forgot it was only the early M20 bearings that are not compatible!