Main bearings specs

[hippiepilot]

I tried the search but only got 2 results none of which had any numbers. Then I looked in the Bentley and found nothing.

I'm in the process of rebuilding my 2.0 air cooled and I'm having the machine shop do some of the engine assemble and he wants to know what the spec is for the main bearings. I used the std/std and currently from front to back they are .0045 .004 .0045 .0042. Is this in spec?

Thanks
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83 air-cooled Westy
91 Carat (daily driver)
http://www.changeisland.com

[MarkWard]

.004" is a little loose, but I believe is at the outer end of the spec. I am surprised the Bentley does not have the specs. Most machine shops have a book of clearances. If the 2.0 vanagon is not coming up. Check a Bus/Bay from 72-79. The only way to tighten the specs at this point would be to have the crank ground and go to the first oversize, which would be. .010". The aircooled VW engines had oversized bearings for both the inner diameter for crank machining, and oversized outer diameter for cases that are alignbored. Make sure to get the correct ones.

Personally, if the crank polishes up nice, I'd be inclined to not machine the crank. There is a hardness that gets removed in the grinding process. If you stick with these dimensions, maybe a high volume oil pump would help. This will bump your thread and you might want to repost in the bay forum for the exact specs.
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[hippiepilot]

I went to the shop yesterday after I posted this and for the vans you mentioned were .0036. The shop is a high performance engine/head place that uses bearings with a coating on the inside to get a precise fit. He told me I could have the bearings sent off for 50-60 bucks and have the same thing done to them and all would be good. He also mentioned bumping up the oil pump and just leaving them as they are or buying another set of bearings. He told me that in the past he has had to buy 4 or 5 sets to get the clearance to spec and this was normal when trying to use std/std bearings for a rebuild. He hasn't charge me a dime and knows I get my own parts so I feel he isn't trying to take me for a ride.

I think I'm going to go ahead and just have them coated. I never really wanted to rebuild the 2.0, but I was I lucky enough to get all my parts at cost from a deal I made with another garage for a golf-cart trade. I only have about 500 bucks into parts and I plan on doing the build myself once I get the block back. I really wanted to do a subie or tdi but don't have the funds or time to deal with that kind of engine swap.

Thanks for your technical input, I just want the darn engine back in the van so I can camp a couple of times before it gets too hot. When is the next FL meetup? I forget the name of the group but I need to join so I can hang with some other van enthusiasts here in FL.
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83 air-cooled Westy
91 Carat (daily driver)
http://www.changeisland.com