<VV> Rebuild II

[Tony Underwood]

At 03:03 hours 11/13/2005, Stephen Upham wrote:
>
>
>Here are some things he said to me which I would love to hear opinions on:
>
>Don't reuse the cylinder head studs.


??


>They deteriorate with age and reuse.  Install new ones and use "head 
>savers" which he described as an insert in the heads in which the 
>new studs would be secured to, or "you'll be sorry".


Humm... if this were the case (no pun) my ragtop's crankcase would be 
a wasted mess... must have had the heads on and off that engine a 
half-dozen times at least over the duration.    It still has all its 
original studs.

Floor that matter, I have NEVER had a stud just "fail".   The ends 
may rust to Hell and back, sticking the head nut to the end, or they 
may get broken from nitwits picking up a longblock by snatching the 
ends of the studs to lift it and bending them (when then are further 
damaged when they get bent back), but I've never seen a stud break 
from "reuse".    I have seen them back out of the crankcase after 
getting stuck to the head nuts etc which usually takes metal from the 
crankcase with the stud threads, but that's about it.   I've also 
seen them pull out of the crankcase, likely aggravated by overheating 
and swelling of the heads and putting stress on the crankcase threads etc.

In fact, I think you'll find the consensus to be along the lines of 
leaving those studs alone and NOT replacing them unless they're 
obviously damaged, or the crankcase threads are damaged, or the nut 
threads are shot.


>He tapped with his finger on the studs of the side that does not 
>have the head attached, listening to the sound like a tuning 
>fork.  He said he could tell the condition of the stud by the 
>resonance, or lack thereof, of the stud.  He said that the Porche 
>mechanics would never reuse a stud after a tear-down.


They must have wanted to sell a lot of studs.   I've always gone by 
the adage of "never replace a Vair stud unless absolutely 
necessary".    He *was* right about listening to plucked studs... 
loose studs won't ring like the tight ones.


>He stated that GM licensed the design of the Corvair engine from Porche.


Balderdash.   The Vair boxer-6 predates the Porsche boxer-6 by 
several years.   The Vair engine owes more of its legacy to boxer-6 
aero engines than anything Porsche may have contributed, although the 
VW automobile no doubt was in the thoughts of the engineers cooking 
up the Vair... but not because of the VW engine which was rather 
anemic and inadequate when compared to the proposed Vair 
engine.    For that matter, I'd be willing to wager that the Tucker 
(and possibly even Fiat) offered up more inspiration for the layout 
of the Corvair than either Porsche or VW.


>( The only reference to this in Tony's book is on page 13 "But the 
>test cars on the road in early 1958 were mostly Porsches with 
>prototype drive trains.  'Mostly Porsches' may be just a euphemism 
>since they only looked like Porsches to the casual observer.

Early on, GM used some 356s to serve as test beds for the early Vair 
drivelines, transaxles and all.    It was the only vehicle available 
that would readily accept the driveline and still look 
"innocent".   GM also used modified Aussie Holdens for driveline 
testing, disguised to resemble standard Holdens but running Vair 
drivetrains.   So, the "mostly Porsches" comment was just 
that.   Mostly Porsches.

GM wasn't keen on outside observers getting much of a close look at 
what they were up to.


>The wheels and tread widths were not Porsche, and the whole rear end 
>was not Porsche.  Nor, for that matter was the front suspension a 
>Porsche suspension.")

These were probably the Holdens...  the Porsche will accept a Vair 
driveline without serious mods to the vehicle and in fact can be 
converted back without much trouble.

>P.S. What is the best method to separate fins on the heads that have 
>been mashed together.


#2m flatblade scruedriver.   Or maybe a HD 
putty  knife.    ...whatever is within reach and handy.



tony..