I'm using this downtime to resume the build of a 1979 om617.952a which was
started in 2013.

None of a*******az, p*****n, f*p euro stock anything other than standard size bearing
shells.

The details below might help describe the state of this project. We have caught
quite a few errors already, always open to flagging more!

The block, crank, rods etc are at a machine shop at this writing. We re-measured
and discovered some mistakes from the first go-round.

The mains measure 2.7451" to 2.7458", in between 0 and 1, so we're going to
grind them into 1 territory.

The con rod journals measure 2.036X", slightly fatter than 1. Not sure we'll touch them.

Piston to cylinder wall diff is 0.0025"-.003". I will leave this. Also, the old machinist
neglected to chamfer the tops of the new liners.

I'm a little bummed by these mistakes, but am glad we caught them. I have tubs
of new parts to complete the build, likely am missing something.
The whole thing is sunken costs now and I'm taking it philosophically. Our world
has bigger problems.

Also seeking a machinist/builder with om617 experience local to SF bay (palo alto)


thanks and wash your hands,

Stuart

sk:

Your thread heading:
"Seeking 1st oversize main and rod bearings"

You may be on firmer ground in seeking undersizes.

Frank Reiner is right. Oversized (that would be the outside diameter) would be used if your enlarged the bearing journal area of the Block.

As an example if a Main Bearing spun messing up the bearing journal area. If there was oversized bearings for that Engine you could install the bearing caps and have the bearing journals bored to the next over sized.

At one time they used to do the same with connecting Rods.

Kind of old school stuff.

__________________
84 300D, 82 Volvo 244Gl Diesel

I can't comment on the undersized over sized availability but I have seen bearing sets on ebay made by federal mogal which used to be a US based Company.

__________________
84 300D, 82 Volvo 244Gl Diesel

Ok, thanks, yeah, I mistook piston/ring oversize for bearing undersize.

Now that I've been corrected, can anyone respond to the original question?

Try this for the rods, they may be able to supply the fifth:


https://www.ebay.com/itm/CB1026P-25MM-Clevite77-Rod-Bearings-4-Pr-Mercedes/131839190079?epid=1630569783&hash=item1eb23a643f:g:bBgAAOSwQupXVIAL

First repair bearing shell sets for your engine is 6170300640 from what I saw.

Pelican appears to have KS Automotive (Kolbenshmidt) and Mercedes OE available.

https://www.pelicanparts.com/More_Info/6170300640.htm?pn=617-030-06-40-INT&KeepHeader=Y