List,
I too have installed an electric fan on my TR4A as a replacement for the crank
driven fan. Initially I used one of the thermo switches that has a capillary
tube inserted into the top hose. While that worked OK and was adjustable it
was not a very neat installation and in my case the tube eventually cracked
due to my attempt at a cleaner installation. Incidentally, I would strongly
recommend against monitoring the temperature via any kind of device in the
lower hose or pipe between lower hoses unless your setting is much lower than
your desired running temperature. Reason; the hottest water is coming off the
head and needs to be monitored there in order to keep the engine running in an
acceptable temperature range. It is after all where the temperature gauge is
sensing the engine temperature.
Here is my solution, I soldered a copper fitting into the top tank of the
radiator and installed a thermo switch kit from Summit racing that had a
preset on and off temperature. I used their kit with the lowest settings for
switching on. While that was OK I felt that it switched on too late and
subsequently allowed the engine and the engine compartment to get too hot
before cooling started. Understand, it was only needed in slow traffic or at a
stop light at idle. The problem then was that the gas started to boil and
often would result in considerable stumble upon starting from a stop. The
crank driven fan in addition to cooling the radiator at idle provides air
circulation under hood and cooling therefore of other components, namely the
carburetors and fuel bowls.
I subsequently found a thermo switch sourced from one of the Street Rod
providers that turns on and off at lower temperatures, I believe I now come on
at about 190 and off at 175. It works well, but I still had the problem with
gas boiling, remember that stock fan does keep air moving all of the time. I
then wrapped my stock TR4A exhaust manifold with the racers fiberglass heat
tape and that seems to have cured the gas boiling problem.
Wiring is a matter of personal choice, however, the thermo switch must be used
with a relay as it can not handle the high current draw of the fan and will
fail immediately if subjected to the fan draw. I have included a manual
override as well as a warning light to advise when the fan is running.
If anyone has specific questions I'd be happy to answer them.
Jerry Van Vlack
----- Original Message -----
From: Mike Kitchener
To: triumphs@autox.team.net
Sent: Saturday, April 05, 2003 3:10 AM
Subject: Re: Electric Fan Control
Bill Stagg wrote :
> For those who have installed electric fans, do you use a thermostatic
> switch to control the fan, or did you hook up a manual on/off switch?
> Or both? If you used a thermo, what type of sensor and location on
> the radiator did you select?
Bill ,
I use a thermo switch ( adjustable Jumo ) and a manual over-ride switch .
The sensor is fitted in the steel pipe between the water pump and the bottom
radiator
outlet and is set to about 1700F .
Cheers
Mike
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