<VV> Thermostats

[Jim Simpson]

Thanks for the informative response.  My experience has been just about
what you describe -- CHTs in the 325 range with sump oil temps around 240
in normal driving.  At 225, I shouldn't expect a thermostat to start
opening in boiling water (212).

What started me wondering was that I was experiencing what seemed to be
higher temps on the trip to and from Sturbridge -- in the mid-to-upper 300s
with them creeping up to around 400 while climbing long grades.  The
cruising CHT temp seemed 10 - 30 degrees higher than normal.  Plus my oil
temp stabilized at 250 or thereabouts as measured at from a temp sensor in
the back of the block near the top of the oil.  (Supposedly that's the
highest temp point.)  That's about 10 deg higher than normal.  But I rarely
drive the car more than ~50 miles one-way these days and on the trip it
seemed like temps were still creeping up for at least an hour or more into
the drive before finally stabilizing.  Plus the ambient temps were in the
upper 80s to low 90s by mid-day.

When I've put the car way in the past, I've always been able to catch the
left side damper closing a minute or so after shutting it down.  That's to
be expected with the longer exhaust manifold and oil cooler on the left.
The right side closes more quickly, but if I'm fairly quick I catch the
last movement.  After this trip the right side seemed have closed a lot
sooner.  So I thought I'd ask the question.

I think I'm just getting a bit paranoid in my old age.  After all the
discussion on VV about valve seats and then witnessing the '64 Spyder lose
a valve seat during the rally I tend to be a little concerned about temps.
(I was there when he restarted the engine after a stop on the rally; that's
a sound I don't ever want to hear from my car, a '66 Corsa turbo.  I had a
loose valve seat a long time ago; luckily it didn't drop out and break.
That was bad enough.)

Jim Simpson
Group Corvair


On Wed, Aug 1, 2012 at 10:28 AM, Mark Durham <62vair at gmail.com> wrote:

> Jim, lots of resposes but not to  your exact question. I read somewhere
> that the stats start to open at about 225 degree f, to maintain a temp of
> 250 degrees in the lower box. That gives  you cht's in the 325 degree
> range. It is difficult to catch the stats open. As soon as you pull over to
> the side of the road and go look, the air has cooled enough to allow them
> to close. I caught one one time, on the warmer side with the longer exhaust
> log, by driving down the road at 60, stopping abruptly, and dashing around
> the back. The other side had already closed and I watched th one with the
> longer exhaust log close right after I got there. As long as you have them
> adjusted properly, and they are not staying open, they should be fine.
>
> I take the lower shrouds off in the summers when I don't need heat. The
> engine temps are 20-30 degrees or more cooler and restarts are less of a
> problem. Since he cylinders are baffled, air flow does a good job of
> cooling, since there are no restrictions on where the hot air can go. This
> is really important for the oil cooler.
>
> Regards
>
>