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Sat Apr 04, 2020 7:50 am

Hi
After have bored my 1600 engine case, i hve check the oversized main bearing that the guy have gived to me. It's KOLBENSCHMIDT bearings, so suppose to be good quality bearings. But the main bearing have a bizarre thing. The groove for oil passage is not center with the hole. Is-it suppose to be like that? I search in internet and don't find similar bearing...

Sat Apr 04, 2020 7:56 am

The hole in the new bearing is larger than the old bearing. It is fine. You must make sure the bearing hole lines up perfectly with the case hole.

Sat Apr 04, 2020 10:13 am

Ok but. A very good engine rebuilder here in Quebec have told-me that a have several issues with that bearing. Why this oil groove is not align with the hole? Somebody have an explication for that?

Sat Apr 04, 2020 3:30 pm

No idea why it's like that, but it happens a lot. We generally carefully grind a little on one side of the bearing hole, to make it line up with the case hole. That the two holes line up, I more important than them being off center.
Kolbenschmidt are good bearings, I'd take them over many other brands.

Sat Apr 04, 2020 5:33 pm

Lahucheapin wrote: Ok but. A very good engine rebuilder here in Quebec have told-me that a have several issues with that bearing. Why this oil groove is not align with the hole? Somebody have an explication for that?

I assure you no issues w/ the KS bearings at all. They are the very best you can get.

I modify the bearing w/ a small endmill cut to accomodate the oil hole.

like so..

Or...you can chamfer the oil hole in the case so it can line up without modifying the bearing. LInebored cases will have the oil hole move. Just be mindful of that alignment. THis is all part of good sense engine building practice. A small burr from a dremel tool can chamfer the case saddle just fine.

Sat Apr 04, 2020 8:32 pm

So, the best is made a groove from hole to the oil passage like that? (like first on left)

Sat Apr 04, 2020 8:35 pm

Either direct the oil w/ the bearing or the saddle - up to you.

the saddle is probably the easiest. Just make the bur cut to 'direct' the oil towards the best position of the groove in the bearing.

somebody can probably post a pic of what I mean. If not I can post tomorrow.

Sat Apr 04, 2020 10:54 pm

OE hole is 2x larger than needed, The new hole is 4x larger than needed.

Does not really matter, still ok to use.
The hole is not where the restriction is.

Grinding more out is just making it weaker, don't bother.

Sun Apr 05, 2020 6:20 pm

That looks like the new aluminum bearings. Check the split bearing and see if it is magnetic. It should have some heft to it as well.

Mon Apr 06, 2020 9:37 am

KS are good. Run it as-is.

Always check hole alignment in case. I prefer to modify the case so that it cannot happen ever again...

Thu Jan 21, 2021 9:41 pm

I was given a "B" case engine that had broken a valve. After removing the broken piston and cylinder, the crank rolled easily, but being an optimist (not), I continued to separate the cases only to find the fuel pump shaft had bent and was no longer touching the Distributor Drive Pinion, also a flat lobe on the offending valve. So I was right.

I am looking at the bearings and the split main has an elephant and the kb stamp, part number is 85071710 0.25, I am pretty sure it is a Kolbenschmidt.

Can any body translate this for me? VW shops are few and far between in my area.

Thanks

Fri Jan 22, 2021 12:08 am

Given the width of the groove, would there be any difference if the groove was perfectly aligned with the hole?

Fri Jan 22, 2021 12:18 am

.25 means .25mm undersize.
old KS part numbers remain a mystery in the english speaking world.

The groove in the bearings is offset towards the front, so that it clears the dowel pin. Always been that way.
I dislike large oil holes in bearings because it weakens them.
Four small holes would be superior to two big ones.