The 2's, 3's and 4's used a "skirted" thermostat to cut off the by-pass, after
the engine had warmed. Aftermarket thermostats do not have the skirt and the
system loses about 30% of the cooling capacity with the bypass open. Not a
problem on a 65 degree fall day... but get caught in traffic on the road to the
beach on a 90 degree Sunday... well, it ain't pretty.
Don S.
----------
> From: James Charles Ruwaldt <jruwaldt@indiana.edu>
> To:
> Cc: Triumph <triumphs@autox.team.net>
> Subject: Re: Skirted thermostats - Newly manufactured
> Date: August 4, 1997 3:30 PM
>
> Is there something unique about TR4's? My TR6 has been running just fine
> for the last three years with a standard thermostat that cost under two
> bucks. Now, if you're looking for originality, I can understand why
> you'd pay twenty-five bucks for one. I just find that unusual.
> Jim Ruwaldt
> '72 TR6 CC79338U(being restored)
> Bloomington, IN
>
>
> On Mon, 4 Aug 1997, Don Sforza wrote:
>
> > Hey Jack:
> >
> > $26.95 is NOT a lot of money, when you consider the other cash we've blown
on
> > our cars. I've been fortunate to land two original Smith's thermostats for
my
> > '4 at about $25.00 each. For the guy who's stuck with an aftermarket piece
of
> > junk, the money should be a non-issue.
> >
> > BTW, thanks sharing the info... it has already been entered in the "parts"
> > archive.
> >
> > "And to think, it all started with a tractor!"
> >
> > Don Sforza dsforza@megahits.com KA1WV
> > 1963 TR4 Connecticut Triumph Register CT16707L
> > Southington, Connecticut
> >
> > ----------
> > > From: Jack I. Brooks <brooks@belcotech.com>
> > > To: Triumphs@autox.team.net
> > > Cc: TRFmail@aol.com; moss@mossmotors.com
> > > Subject: Skirted thermostats - Newly manufactured
> > > Date: August 4, 1997 12:50 PM
> > >
> > > Recently a New Jersey Triumph Association club (& list) member, Bruce
Hoppe,
> > > discovered that a Jaguar restoration shop was producing a modern skirted
> > > thermostat, which he thought was similar in size to those use in the
> > > TR2/3/4's. This restorer commissioned a machine shop to produce these
> > > thermostats for them. I saw Bruce's thermostat at a club meeting and was
> > > satisfied with the quality. I purchased one, measured, tested and
installed
> > it.
> > >
> > > The Jaguar thermostat is working well in my TR3A. It is a modern 160F
> > > thermostat, which has been modified to include a skirt. The skirt is
brazed
> > > onto the thermostat in a very neat and clean manner. There is no
> > > "bleed/vent" hole at the top of the thermostat flange.
> > >
> > > This thermostat operates slightly different than the skirted thermostats
we
> > > are used to. The OEM thermostat has a skirt which is starts out behind
the
> > > bypass hole and moves forward, to block the bypass hole as the water
> > > temperature rises. The Jaguar reproduction is just the opposite. The
skirt
> > > sits against the thermostat flange, in front of the bypass hole when it
it
> > > cold and moves backward, to block the bypass hole, as the water
temperature
> > > rises.
> > >
> > > The dimensions I measured on the thermostat and my TR3A housing are shown
> > below:
> > >
> > > Dimension Thermostat My TR3A thermostat housing
> > >
> > > Skirt Diameter 1.930 inch 1.967 inch
> > > Skirt length 0.400 inch
> > > Skirt movement @ 180F 0.320 inch
> > > Bypass hole (from Flange) 0.375 inch
> > > Bypass hole (diameter) 0.430 inch
> > >
> > > If you "stack up" the skirt length and movement dimensions you will find
> > > that the skirt moves almost exactly enough to cover the bypass hole.
> > >
> > > On top of my stove, the 160F thermostat begins to open at 160-165,
achieving
> > > full open by 180F. It might have gone to full open at a lower
temperature,
> > > with more time, but I didn't realize this inadequacy in my test
procedures
> > > until after the thermostat was installed in my car.
> > >
> > > I didn't measure the percent "open area" for water flow, but it was at
least
> > > as good as most thermostats I have seen.
> > >
> > > Two downsides:
> > >
> > > 1. The thermostat costs $26.95 plus shipping.
> > >
> > > 2. The opening temperature is approx 160F, but full open does not occur
> > > right away, so the normal operational temperature is somewhat above 160F,
> > > more like 165F (electronic thermometer), but only extended idling (15+
> > > minutes) will drive it above 180-190F.
> > >
> > > As as aside, my cooling system (I think) was in pretty good condition
before
> > > I installed this thermostat. I use 70/30 water/antifreeze mix, w/water
> > > wetter. Keep in mind, that no thermostat will cure cooling system
> > > deficiencies and YMMV.
> > >
> > > The source is XK's Unlimited, 800-444-5247. They are a reputable shop and
> > > advertise in British car magazine. They have a site at www.xks.com
> > > Tell them what car the thermostat is for, your TR, but the bottom line is
> > > that their thermostat is designed for a XK120/140 Jaguar.
> > >
> > > (TRF, Moss, Vicki Brit & others - did you catch the name of that source?)
> > >
> > > I have no financial or other interest in XK's, although I wouldn't mind
one
> > > of their XK140 restored race cars (check out their site). I told them,
if
> > > it worked for me I'd be telling a few hundred of my closest friends, but
> > > still couldn't get a freebie. (I'm only kidding, I didn't ask)
> > >
> > > Also, From the SAAB list I learned about Mercedes-Benz anti-freeze. M-B
> > > created it because they were experiencing a significant number of head
> > > gasket and cooling system related failures. I have heard that it is
double
> > > buffered (against acid and base build ups). This is reputed to eliminate
> > > the salt (white chalky deposits) and goop buildups some of us find in our
> > > radiators and engine water passages. I have not yet tried this stuff
> > > ($10/gallon) but will by the end of the summer. Just another thought....
> > >
> > > BTW - After replacing your thermostat let the system get hot
(pressurized)
> > > and check for leaks. A cold (unpressurized) coolant system test, done
the
> > > night before, may not reveal the substantial leak that a three mile jaunt
> > > into town for bagels on a Sunday morning at 6AM will. You may not have
> > > enough coolant left to make it home, unless you keep a gallon of water in
> > > the boot. You may not have to put up with the smirk of a Porche Targa
> > > driver as you run through a red light and begin coasting down the last
hill
> > > on the way to your home with the engine off. To quote others on this
list
> > > "How do I know this?" ;-)
> > >
> > > Jack Brooks
> > >
> >
> >
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