<VV> Re: corvair case line boring

[djtcz@comcast.net]

yep, OS main bearings was how it was intended.  I vaguely recall there MAY have been O/S cam bearings available from TRW if cam bores needed repair.

If the cases faces were machined (like the mating faces on rods and blocks of most engines) in order to allow boring the main line standard, then the cam bores and probably some other features would have to be restored too.  The doweled rear cover would have to be relocated on center somehow too, to keep the distributor gear from meshing too deep.

Air-cooled VWs and real (flat motor) Porschae actually have to endure case line boring for rebuilds.  There are features (like seal bores) that need to be rebored on those engines too.

These guys will do all that on a Porsche 911 case for 700 euro dollars, about 400 more than just doing the mains.
http://www.ahnendorp.com/porsche2.html

Gene Berg has been a VW High Performance hero for decades years.
He is kind of a prickly curmudgeon, but actually kind and fair.
He holds line bored VW cases in very low regard. 
http://www.geneberg.com/casepg22.htm

VW aircooled 4s use curious thick 1 piece main bearings at a few locations that I think aggrevates their main bore problems, by having 2 "captains."  Our nice thin wall steel backed inserts are a great design.

> Message: 6 
> From: BobHelt@aol.com 
> Date: Sat, 18 Dec 2004 13:09:18 EST 
> To: virtualvairs@corvair.org 
> CC: fastvair@yahoogroups.com 
> Subject: main bearing question 
> 
> Hi everybody, 
> Well this is a new one on me. Has anybody ever heard of Corvair main bearings 
> being made/sold that had a 0.020 inch versize OD to compensate for line 
> boring? I always thought line boring included removal of material at the case 
> halves mating surfact to compensate. 
> Amybody got any experience with this larger OD, or is this a mistake? 
> Regards, 
> Bob Helt