Message text written by INTERNET:triumphs-owner@autox.team.net
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Date: Sun, 30 May 1999 04:04:30 -0700
From: Randall <randallyoung@earthlink.net>
Subject: Re: Skirted thermostat
IMO heating the operating element, or capsule, will ruin it. I've had
them fail from overheating in an engine that still had water in the
block (and wasn't otherwise harmed).
The Robertshaw 330 looks like a good candidate, in part because it has a
wide outer ring that can probably be spot welded, or even soldered to,
without overheating the capsule. Another possibility is the 337, which
has a separate spring loaded plate on the block end. (I believe it fits
VW Rabbit/Golf.)
Tony's choice of .400" for the skirt looks like a good compromise. It
will block the bypass port slightly when cold, but allow the limited
stroke (~.240" on a 330) to completely block the port when hot, at least
on a TR4 housing. (As I recall, the TR3 housing had a larger bypass
opening than the TR4.)
The TR4 housing I have isn't perfectly round, but 1.950 - 1.960" looks
like the right OD for the skirt.
When cold, the .400" skirt should rest against the sealing plate.
<
Randall,
Yes, I had suspected that even brief heat on the "capsule" would cause
significant damage. Welding to the moving "diaphragm" (sorry, don't
know the correct name) would be effective, but difficult due to tight
space. It may be the only alternative.
I see you have given careful thought to the measurements (as have I)
and found that the skirt would have to seat against the flange when cold,
and then move from there. I am away from home, so I don't have my measurements,
but your 1.950-1.960 inner diameter sounds corret to me. I also
found that the inner diameter is not perfectly round as well, but it is
pretty close. The skirt would have to have some leeway built in. I don't
have access to a small spot wleder, so I could not cheaply do the spot welding.
Maybe we have a volunteer here???
-Tony
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