<VV> Thermostats

[Jim Simpson]

Every thermostat that has failed in my car has failed "open" (fully
expanded).  The bellows is designed to be at full expansion when it springs
a leak and the butyl alcohol evaporates.  That's what bugs me about this
one; if it is opening at all, it seems to opening at a higher than normal
temperature.  That's certainly NOT a normal failure mode.

But I may be over reacting and perhaps the damper door is just closing
before I get back to check on it.  That's why I wanted to see what the
"normal" opening temperature is.

I've heard that the reproduction thermostats fail more often/more quickly
than the GM originals, but I like to see some data on that.  I've certainly
had a number of GM originals fail over the last 44 years.  (And I think I'm
handling them correctly -- for instance, not putting any torque on them.)

So does anyone have a surplus of original GM thermostats that they want to
sell?

Jim Simpson
Group Corvair

On Tue, Jul 31, 2012 at 11:03 PM, J R Read <hmlinc at sbcglobal.net> wrote:

> **
> The "fail"position is open.
> Later, JR
>
> ----- Original Message -----
> *From:* Jim Simpson <simpsonj at verizon.net>
> *To:* J R Read <hmlinc at sbcglobal.net>
> *Cc:* Virtual Vairs <virtualvairs at corvair.org>
> *Sent:* Tuesday, July 31, 2012 9:50 PM
> *Subject:* Re: <VV> Thermostats
>
> I used to be able to watch the right (passenger) side damper door close
> after shutting the engine down.  Yes, it has always definitely closed
> first, but now it seems to be on the verge of never opening -- or at least
> opening at a higher temperature.
>
> Perhaps I'm over reacting; I just drove back from Sturbridge (to Maryland)
> and in the ~90 temps near home, everything was hot...  I think I'll go
> ahead and swap in one of the reproduction thermostats and see what happens.
>
> Jim Simpson
> Group Corvair
>
> On Tue, Jul 31, 2012 at 9:54 PM, J R Read <hmlinc at sbcglobal.net> wrote:
>
>> Jim,
>>
>> The left side opens first and closes last.  This is normal.
>>
>> It is probably not possible to stop the car and run to the RR fast enough
>> to see that door still open.
>>
>> Later, JR
>>
>>
>> ----- Original Message ----- From: "Jim Simpson" <simpsonj at verizon.net>
>> To: "Virtual Vairs" <virtualvairs at corvair.org>
>> Sent: Tuesday, July 31, 2012 7:10 PM
>>
>> Subject: <VV> Thermostats
>>
>>
>> Does anyone know at what temperature the stock thermostats are supposed to
>>> open?  I can't find it in any of the standard references.  (One of the
>>> damper doors on my Corvair doesn't seem to open properly.  It's free to
>>> move, but lately even when the engine is hot, it seems to stay closed.
>>> And
>>> yes, it is adjusted according to the book.)
>>>
>>> Supposedly the thermostats are filled with one of the isomers of butyl
>>> alcohol but there are four varieties, each with a different boiling
>>> point.
>>> And the fill may be a mix.  Even if I knew which one, it's still a bit
>>> more
>>> complex since bellows is designed to fail open and therefore is under a
>>> partial vacuum when cold which would affect the boiling point.
>>>
>>> I've checked several reproduction thermostats and they start to expand in
>>> boiling water but not fully.  By contrast, the one I removed from the car
>>> -- a GM original -- doesn't show any signs of expanding in boiling water.
>>>
>>> Jim Simpson
>>> Group Corvair
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>>
>