<VV> VirtualVairs Digest, Vol 235, Issue 3

[Jim Simpson]

Re/ Dropped Valve

I'm going to assume it's a dropped valve seat, the most common problem.  In
that case, there's nothing else to do but pull the head and have it
repaired.  Hopefully the valve seat hasn't shattered and damaged the piston
& cylinder.  If there is no other damage, then having the head repaired and
an appropriate valve job done will take care of the problem.  (Think hard
about taking the other head off and having it reworked as well.)  You will
need to find a person who understands air-cooled Corvair heads to do the
job right.

If the valve seat has broken up, there's a fair chance of damage to at
least that one cylinder & piston.  And a possibility that pieces managed to
migrate to the surrounding cylinders and damaged them as well.  If so, you
are looking at replacing the damaged parts as well.  (I dropped a valve
seat on my '66 Corsa turbo a long time ago.  I was lucky -- the seat stayed
intact so the damage was confined just to the cylinder head.)

Valve seats are probably the most serious weakness in the Corvair engine
design.  I doubt that any of the designers contemplated that Corvair
engines were still going to be used 50 or 60 years after it was built, so
after who knows how many thousands of heat cycles, valve seats are coming
loose.  140's are the worst followed by turbos.

Good luck!  (I hope someone else chimes in with recommendations for good
head repair shops.)

Jim Simpson
Group Corvair

On Mon, Aug 19, 2024 at 12:00 PM <virtualvairs-request at corvair.org> wrote:

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>    1. Dropped valve (Jeffrey Hennessey)
>
>
>
> ---------- Forwarded message ----------
> From: Jeffrey Hennessey <jeffreyhennessey at verizon.net>
> To: "virtualvairs at corvair.org" <virtualvairs at corvair.org>
> Cc:
> Bcc:
> Date: Mon, 19 Aug 2024 09:30:34 -0400
> Subject: <VV> Dropped valve
> Folks…
>
> I am despondent. My 1963 Spyder Coupe, that I have owned for 24 years is
> currently a static display in my garage. My local guy did the
> troubleshooting. He has determined that I have a dropped exhaust valve. The
> problem is in the middle cylinder passenger side. Compression zero. All
> others 150. I’m in Massachusetts. I am at a loss as to how to tackle this.
> I’m looking for some guidance. Have any of my fellow Corvair people dealt
> with this?
> Jeff
> Sent from my iPad
>
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