<VV> Pilot bearings

[Bob Dunahugh]

Yes. Chevy designers  meant for the crank and the trans input shaft to be perfectly aligned. U joints are used were shafts don't align. A few thousands can be tolerated. But .000 is best and correct. Bottom line is, it's best to check it, deck it, and give your clutch parts a better chance to live a long and happy life. I have a shop that has central heat, air, and a hoist next to the house. But I still don't like pulling drive trains and replacing parts. If your clutch has ever failed. This could have been part of the problem.  Fruit for thought.   Bob Dunahugh

> Date: Mon, 8 Aug 2011 20:34:58 -0700
> Subject: Re: <VV> Pilot bearings
> From: 62vair at gmail.com
> To: yenko108 at hotmail.com
> CC: bobhelt at aol.com; virtualvairs at corvair.org
> 
> A caved bell housing changes the alignment of the shaft in the pilot
> bearing, so it wears fast.. Mark Durham
> 
> On Mon, Aug 8, 2011 at 8:57 AM, Bob Dunahugh <yenko108 at hotmail.com> wrote:
> >
> > Since the engine and transaxle are only mounted at the vary front and vary rear. And both are vary ridged units.  Thus the bell housing needs to keep the center lines of both, lined up. The bell housing starts to sag due to the car hitting large dips in the roads and other abuse. The bell housing caves in above the crankshaft were it bolts to the engine. This also takes out the trans input shaft seal. Double shaft seal can't help  for long under this condition. PG bell housings cave in also. Some even more. Look at it this way. How comfortable would you feel in a dune bug by mounting the engine on a ridged mount transaxle. Then not supporting the back of the engine?  To deck the bell housing. I knock the steel alignment pins out of the way. I place the bell housing on my Bridgeport mill with the diff. side down. I then deck the engine side. If too much needs to be taken off, discard, as this can create other problems. Cheapest method to check the bell is to use a dial indicat
> >  or with a magnetic base on a steal table saw. Set the dial indicator up and move the bell around under the dial indicator. This will tell you the sag.   Bob Dunahugh.  If anyone wants to call. My cell is 319-521-4891 Any time. Iowa.
> >
> > From: BobHelt at aol.com
> > Date: Mon, 8 Aug 2011 10:21:02 -0400
> > Subject: Re: <VV> Pilot bearings
> > To: yenko108 at hotmail.com; virtualvairs at corvair.org
> >
> >
> >
> >
> > Hi Bob,
> > Maybe it is the early morning hour, or the binge last nite, but I don't see how a caved-in bell housing should limit the life of a pilot bearing. Can you please explain this further. Thanks.
> > Regards,
> > Bob Helt
> >
> >
> > In a message dated 8/7/2011 9:07:33 P.M. US Mountain Standard Time, yenko108 at hotmail.com writes:
> > This weekend I was checking out my extra bell housings. I don't know if this has been discussed in the passed years. But, 25 years ago my daughter's 66 Corsa was going threw pilot bearings every 6000 miles. I found the problem was the bell housing. Out of the 16 that I checked yesterday, 2 were caved in about .030 to .042. 6 were at around .008 and the rest were .001 to .004. I never put a bell housing in without decking the engine side. Maybe this can help someone. Bob Dunahugh.
> >
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