<VV> Indented Head Sealing Step

[Roger Gault]

I don't know what heads Ron is running, but if they're 140s, I would not
recommend two gaskets.  In my experience, increasing the chamber volume that
way on the 140 will result in increased tendancy to knock, not decreased.
The squish area is already too thick on that head, increasing it is the
wrong thing to do.  The crushed gasket surface is actually an improvement.
Better to cut the step away completely.  Since Ron only has one head off,
that's probably not a good plan.

I'm currently running a .040 over 140 with the steps removed, flat pistons,
and stock gaskets in Texas heat (lower shrouds removed in summer).  I have
no knocking unless I lug it bad on an uphill start.

Roger


----- Original Message ----- 
From: "N. Joseph Potts" <pottsf at msn.com>
To: "Ron" <ronh at owt.com>; <virtualvairs at corvair.org>
Sent: Sunday, July 03, 2005 1:40 PM
Subject: RE: <VV> Indented Head Sealing Step


> I have not seen this condition and have no good ideas on how it comes
about,
> but I can report that using two head gaskets is common practice (I always
do
> it) and it does not cause any problems I've ever observed at the seal. I
> would expect it to be effective in your situation, assuming that the
grooves
> you report are fairly regular and free of nicks, etc.
>     It does have another effect, which is the reason I do it. It enlarges
> the combustion chamber slightly, and accordingly, slightly reduces your
> engine's compression ratio. It should reduce your engine's susceptibility
to
> knock, and may reduce the compression you observe when you measure that.
>      I've found a peculiar situation on a head I'm refurbishing: the
bosses
> that the six (upper) head nuts bear on are INDENTED by the head nuts. I
> SUPPOSE that's from overtorquing, but I would have thought that head studs
> would either stretch or pull out of the block before this condition
> developed. Never seen it on another head.
>
> Joe Potts
> Miami, Florida USA
> 1966 Corsa coupe 140hp 4-speed with A/C
>
> -----Original Message-----
> From: virtualvairs-bounces at corvair.org
> [mailto:virtualvairs-bounces at corvair.org]On Behalf Of Ron
> Sent: Sunday, July 03, 2005 12:11 PM
> To: BobHelt at aol.com; virtualvairs at corvair.org
> Subject: Re: <VV> Loud noise when hot
>
>
> An anomaly that I noticed last night is that the head "lands" where the
head
> gasket seats are grooves and are at least half as deep as the thickness of
> the seal rings.  I assume that it's something that happened over the last
> forty years but it doesn't look good.  What causes that?  I'm inclined to
> double gasket and reinstall it.  Any comments on that?
>
> Thanks,
> RonH
>
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