Hi all,
TR4-A's were built with altered 'waterpump manifolds' where the bypasss port
hole was cast a little smaller than for earlier TRs. The late ones I have seen
have a hole opening about 3/8" as compared to earlier about 1/2".
This is the time the Triumph factory substituted thermostat specs from sleeved
to non-sleeved.
I do have an original skirted (sleeved) thermostat, and one of the
aftermarket ones (from Jags Unlimited) in a photo line-up with the thermostat
housing showing their orientation. Note that the aftermarket sleeved
thermostat is an off-the-shelf brass Robert Shaw unit with a custom die-cut
brass sleeve silver-soldered into place.
It's well done. I paid $45.00 for 10 years ago, which now are perhaps the
$100.00 versions mentioned.
There is a difference in how the original and aftermarket thermostats operate
- the original sleeve slides toward the radiator when activated. The
aftermarket sleeve slides back toward block when activated. The bypass port in
the housing is situated such that it gets blocked properly with either
thermostat. (as proven in my stove top exercises)
If you want a photo of line-up, I can send either a jpg or pdf photo or post
it somewhere.
Regards,
Carl
'63 TR4 since '74
ps; One could save costs by simply retrofitting their pre-TR4A bypass
configuration by inserting a bypass hose restrictor inside either end of the
bypass hose as described at Terriann's website - if a previous owner hasn't
already done it.
Randall, is the skirt not some sort of tubular shroud that moves in
and out as the therm. opens across that slotted by-pass hole? In
that case it would have to be a very loose fit, (probably non
contact) to prevent potential sticking of the thermostat, thus being
quite incapable of fully blocking the bypass.
Besides, I doubt that the thermostat works in a snap on-off fashion
and that there is a range were it actually regulates an varies the
flow distribution.
triumphs@autox.team.net
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