<VV> Valve Seats

[J R Read_HML]

Hi Frank,

I think that his point was that dropped seats seem to be more common 
(frequent?) today than in the past.  I don't know if that is true or not, 
but it seems like a realistic assessment to me.

I feel (read that as opinion) that there are at least 2 factors involved (if 
it is actually true) ...  There are possible more than two.

The first would be HOW HOT the head got and this would possibly account for 
some (probably most) of those earlier failures you mentioned.

The second would be HOW MANY heat cycles the head has been through.  This 
would be a head which "looks" good (passes tests such as compression or leak 
down, etc), but STILL drops a seat (regardless of HP rating).

This many years later, who knows about the # of heat cycles?  So, the SMART 
thing to do [OPINION HERE] is to send even a head which appears to be fine 
through the machine shop.

Later, JR
CCE CORVANANTICS CORSA member
'61 Rampside Standard 4/110
'65 Monza Convertible 4/140
'66 beater 500 Coupe "icemobile" 4/140 (50%)

----- Original Message ----- 
From: "Frank DuVal" <corvairduval at cox.net>
To: "james rice" <ricebugg at mtco.com>
Cc: <virtualvairs at corvair.org>
Sent: Wednesday, November 14, 2007 11:13 PM
Subject: Re: <VV> Valve Seats


> 20 years ago I was having seats replaced on many Corvair engines. I had a 
> shop ( actually it was called "The Shop") in Hopewell, VA do many heads 
> for me. Maybe it is the humidity, and the seats were rusting out just like 
> the car bodies! ggggg
>
> Even back then although 140s were the main  culprits, turbos, 110s and 95s 
> all dropped seats. I have seen a 110 driven so long that the seat would no 
> longer touch any aluminum part of the head...... but it was still hanging 
> on the intake valve. That was about 1980. (64 Monza Conv).
>
> Frank DuVal
>
>
>
> james rice wrote:
>
>>All:  I do not remember valve seats being an issue 20 years ago, except
>>maybe on race cars.    Given Warren's observation, is there a preventive
>>solution?  Letting the engine cool down before shut off?  70 deg garages 
>>in
>>the winter time to keep everything warm?
>>
>>I do not know what the current process and procedures are for valve seat
>>replacement.
>>
>>If I remember correctly, Jim Schardt, before doing any of his head
>>modifications, use to take the seats out, heated the heads and seriously
>>cooled what I presume were oversize seats and press them in with 0.010"
>>interference.
>>
>>Jon Brakke, who was the last person to SCCA race Stingers competitively,
>>said he had his head re-heat treated before doing anything else.  I assume
>>he took the seats out first.
>>
>>Are there any shops doing this to street heads today?  At what cost?  What
>>heat treat specifications?
>>
>>Warren, Seth, Bob H and Bob C., got any info?
>>
>>
>>
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