main bearing oil hole aligment

[mcjweller]

Hello...building my first VW motor (type 1). Done some building before (some, as in I'm not a professional builder) but not a VW motor. New Autolina AS41 case.

I test fit the bearings (silverlines, great fit), and noticed the oiling depends on grooves cut on the backside of the bearings as an oil channel, where it is let out elsewhere from the bearings.

I noticed that the "channel" and the oil holes don't entirely line up. Half of each hole in the case is covered, the other half is open to the channel on each bearing.

I checked the old 1970 VW case that this new case is replacing. Same deal. Exactly. Thought it seemed odd, but its not the first odd thing I've seen with VW so I moved on.

Now that the case halves are assembled (glued), I'm starting to second guess and over-think it.

Is the oil pressure sufficient to not be an issue (as in is this some sort of built-in restrictor) or should I rip it all apart and start over with some Dremel work either on the bearings or the case to get a better "overlap"?

Its worth noting that by design, the width of the oil channel is less than the oil hole...meaning some degree over overlap would always be there, even if the main oiling holes were not off a little to the center of the groove (assuming they are off, as I said both the old VW case and VW bearings were exactly the same in fitment...) I have seen many posts about people modifying for racing, this motor will never be run hard. Thoughts?

[oprn]

Yes I have noticed that too on all the stock cases. In all the years I have street driven air cooled VWs (from about 1967) it has never been a problem. Making them match most certainly will not hurt anything.
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Our cars get old, we get old but driving an old VW never gets old!

[Brian_e]

You do need make sure they match up, otherwise you will be restricting about half of the oil flowing to the bearings. This is most important on the center main, as that one is trying to supply oil to 2 rod bearings, and well as the center main bearing.

It only takes a few minutes to do with a dremel tool.

More importantly... you should not have sealed up the case until you have your rocker geometry already figured out, especially if this is your first engine build. All that really important cam break-in lube will be wiped off when you have to spin the engine over 50-100 times getting the geometry straightened out.

Brian
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[mcjweller]

Thanks

I should clarify, the cam is already broken in and mated to the lifters...it has less than 500 miles on it. This build, is essentially replacing a crappy case with a new one. That being said, I have built engines before, just not a VW...but that's not to say I'm a pro who does it every day...

When I've built non-vw motors, (flat tappets...all of them) I've degreed the cams, measured lift, checked geometry checked rotational drag, likely spinning them over 100 times or more by hand by the time I'm done...and the assembly lube survives on the cam beyond that and onto 1st startup. (I know this because on my very first build, I was paranoid and used a borescope to go in and look!)

Nonetheless, I made the decision tonight to pull it all apart. The bearings concern me, plus I didn't like how the autolina oil pickup prevents installation of any oil screen, so to put a stock VW pickup in it had to come apart again.

I used some die to make witness marks on the bearings, actually all have the channel centred on the oil holes except one, which is the split bearing so I will modify. That hole is off centre by about 1/16". Probably ok for a stock gently driven build, but hey, nows the time to fix it.