<VV> Cam bearing, lifter galley wear

[Roger Gault]

Hi, Chuck,
Of the vast number of blocks I've measured recently (2), exactly 50% had
clearances on the order of .006".  The "rest" ran about .002"-.003".  ;-)
I needed a prototype for trying out some design ideas, so I sacrificed the
loose one.

Granted, .004" off the mating surfaces would have made the plastigage
readings look good, but that would have only solved "half" the problem,
since the wear would still be there parallel to the part line.

It seems to me all this talk of case machining or line boring and bushings,
etc. is the hard solution.  Metal spraying and chroming of cam journals is
really common and is probably just as cheap (and a lot less risky) than
taking your block to the local machine for a shave.  I haven't priced it,
but I suspect that any number of cam grinders would do it for $100.  I bet
Ray Sedman (or one of his competitors) could point the way to getting that
work done reasonably.

Of course, as long as blocks are available for $50....

Roger

----- Original Message ----- 
From: "Chuck Kubin" <dreamwoodck at yahoo.com>
To: <virtualvairs at corvair.org>
Sent: Tuesday, February 07, 2006 12:55 PM
Subject: <VV> Cam bearing, lifter galley wear


> Hey gang,
>   Assuming any one engine hasn't been run without oil, how much wear would
you anticipate there would be to the lifter galleys and cam bearings?  These
parts are always at least partially submerged, are they not? I know
lubricated parts wear, but to what extent?
>   Someone who is always inside engines might see a lot of wear, but HOW
often? The lifters especially would seem to have a significantly-large
bearing surface considering how little they move. Is this a common problem,
or are we killing a fly with a cannon?
>   I agree with the philosophy that a couple of thou out of round is easier
to live with than the cost and brain damage of trying to correct it. Also,
how significant would the wear have to be for the experts among us to
consider addressing the issue or trashing the block?
>   The solution of shaving a couple thou off the block to get the lands
back into tolerance seems like a good solution to me. Like Tony, I don't
believe any of the bolt-ons are machined close enough to make a difference.
Also, how much closer CAN you move the piston to the head without getting
into trouble?
>
>   Chuck Kubin
>
>
>
>
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