<VV> Re: Porsche Babble

[mmcguire at hiwaay.net]

To: virtualvairs at corvair.org
Message-ID: <1a4.4410d73b.30a9fba3 at aol.com>
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I have both and yes Porsche mechanics would never rebuild an engine without 
replacing the head studs and timeserting the case. They have, over the years, 
had real trouble with head studs.The 2.7l common in the 70's were notoriuos. 
They used different alloys and such (alloy, steel, dilavar?) and even putting a

Dave Fierek


Yea, they are big on "dilavar" or what ever?  What in the crap is it anyhow?  
There is no trademarked metal with that name.  Looking at all metals, expansion 
is porportional (maybe inversely) with density.  The only metal I see which 
sticks out as being different would be A-286.   They want something with a 
higher expansion coefficent to go with the AL jugs.  The stud length is much 
shorter in 911 engines, hence more of a problem than a corvair.
Maybe they make them out of A-286 barstock, but want to be able to charge $$ 
for them.   2.7 liter engines ran hot with the 70's emission stuff which 
probably agrevated the situation.
I thought Porsche had the patent on aluminum casting technology and that was 
where the Porsche/GM connection rummors of it being a Porsche design started.

Michael