Hey STINEY, you ever have this problem?

[tardis454]

I put the VW engine case together today (temporarily). I lubed & sealed it up, torqued the case, checked for free rotation just like it said in the book. After everything was torqued and done I noticed the crank had a tight spot in it, and I heard a metal squeaking noise while turning it over. Completely and utterly disgusted I took the case back apart and found the center main bearings had pretty substantial rub/wear marks on them while all other bearings were perfectly fine.

The bearings I'm using are Silverline brand made in Mexico, standard case, .020 under crank.



This is the 2nd set of new main bearings I purchased for this project. I replaced the 1st set because the cam gear puller galled up the front thrust bearing when I pulled the cam gears off. The center mains on the 1st set were also kinda buggered up right out of the box. I polished them up, they fit fine, but I figured I'd just use everything from the new set. The center mains on the 2nd set never seemed to fit or seat properly though. I pulled the dowel pins & polished the journals and they seemed to fit fine afterwards.

When I pulled the case back apart I compared each set of center mains. I zip tied the shells together tight to get a rough measurement from each set. The crank is ground to 2.144. The 1st set of bearings measures 2.147 center to center, about .003 over the crank which is fine and should crush to 2.146 -2.1465 when installed. The 2nd set measures 2.145-2.147 center to center (they're ovaled out), .0005-.001 which leaves almost no room for a crush fit and explains the rubbing/wear marks issue. I'm considering using the center mains from the 1st bearing set. I used some oil soaked scotchbrite and 400 grit paper to smooth them and ended up taking off a fair amount of plating in the process. I've done this in the past on other engine builds with no ill effects, but the plating on these particular bearings appears to be very thin. See photos:

Without flash..



With flash..



The case halves are in good shape with no big lips of ridges in the journals..

Studded side..



Non studded side..




So my question is, WTF is going on here!?!?!?!
I've read the crank might be bent, twisted.
I've read the journals may need line bored.
I've also read people have been getting shitty bearings and are having the same issues I'm having.
Have you ever had this problem Chris?
What would you do???

[Loren]

Not that I'm a VW guy, or Stiney, but a crank problem would cause scuffing all the way around the bearing as it was turned. This is a bearing or case issue. You could mic the bearing at different places to check for uneven thickness, also clamp in in under torque to inside-mic and check for that plus roundness. After that, the case needs looking at which is tougher to gauge.

An old-timer would probably just stick the individual shells from the first set that didn't have the problem and after another inspection, go with it.

Stiney?

A couple weeks ago I just bought the first inside-mic I've ever owned, after all this time. It's off .002" which is a mile for a micrometer, and jams up. Always check tools before taking them home I guess.

[STINEY]

I vote bearings. While I have not had an issue like yours personally, a good friend of mine has fought a very similar battle on his VW 82mm stroker.

Like Loren stated, a bad crank would stick all around, and a case would have to be pretty trashed also and would stick all around as well.

VW air cooled parts quality have taken a large nose dive since the China outsourcing came into vogue. Did either set of those bearings have Brazilian markings on them?

I would not be afraid to run the mixed setup you came up with. All bearings get rub marks on them after the first startup anyways. No assembly lube on them beyond that first fire. No worries.

good on you for catching that first center set was tight.

[tardis454]

I vote bearings. While I have not had an issue like yours personally, a good friend of mine has fought a very similar battle on his VW 82mm stroker.

Like Loren stated, a bad crank would stick all around, and a case would have to be pretty trashed also and would stick all around as well.

VW air cooled parts quality have taken a large nose dive since the China outsourcing came into vogue. Did either set of those bearings have Brazilian markings on them?

No Brazilian markings, just a 'made in Mexico' on the box.
What are your thoughts on using the 1st set of center mains?
The shells look OK-ish, but I polished them quite a bit to smooth them out..
Should I roll the dice and buy another set of bearings?

***Another thing I noticed, the case stud o-rings don't seem to be crushing/sealing properly.
They appear to be of Chinesium quality. Is there a particular brand of 'good' case stud o-rings out there?

[STINEY]

I would run the 1st set of center mains and never think twice about it. The norm has become to buy several sets and pick from them what clearances check out and work for each particular engine build.

On the stud o-rings, I always shuffle pin the center studs and omit the seal there. Sealant on the stud threads will suffice. Some years engines were NOT machined for the stud seals, '66-'67 I believe. Yours does appear to be machined for them though.

I have not had trouble with the center seals. They don't normally deform. As long as they are still pliable they seem to do their job.

This is the set I use. http://vwparts.aircooled.net/Gasket-...198-007afg.htm

Nothing fancy.

[tardis454]

I would run the 1st set of center mains and never think twice about it. The norm has become to buy several sets and pick from them what clearances check out and work for each particular engine build.

On the stud o-rings, I always shuffle pin the center studs and omit the seal there. Sealant on the stud threads will suffice. Some years engines were NOT machined for the stud seals, '66-'67 I believe. Yours does appear to be machined for them though.

I have not had trouble with the center seals. They don't normally deform. As long as they are still pliable they seem to do their job.

This is the set I use. http://vwparts.aircooled.net/Gasket-...198-007afg.htm

Nothing fancy.

That's pretty much where I was at, use the 1st set of bearings. This is my 1st go around with these engines so I figured I'd consult an expert.
The o-rings are new, I noticed when I split the case again the aviation sealer I used on the main studs drooled onto the o-rings and seeped into the journals.
Many curse words were spoken last night, so I called it a night and walked away. I figured this wasn't an isolated incident with the bearings though.

Thanks for the help Loren & STINEY. I know I'll have more questions regarding this build as time goes on.