At 10:43 AM 7/18/96 -0400, David Crandall wrote:
.....
>3) Underheating (a rare problem!) - I'm curious about others
> experience running without a thermostat. My 4/4 seems quite
> happy without one although it takes a good run to get up to
> 180-190.
When I was driving my 4/4 everyday as a kid (I was 20, now I'm 40+)
I ran without a thermostat all summer. Did this for several years
without any problems.
> One of our fellows who's an engineer admonished me, saying that the
> engine is designed to be most efficient at the higher temp.
As a mechanical engineer and speaking from a therdynamic standpoint
he is correct. In fact the larger the temperature difference between
the engine and the outside air, the more work that can be extracted.
With this in mind why not let the engines run at 500+ degrees?
The answer is obvious, oil will breakdown, gas will boil and not
flow, and the metal parts will think about melting.
> My question - what am I losing/risking by running without it?
> Decresaed mileage seems nominal, I'm not sure the reading on the
> guage is anywhere near what the engine actually runs at anyway
> given the placement of the sending unit way up on the radiator, I'm
> not a 10,000 mile a year driver being a New Englander, etc. So,
> what's the big deal?
The theory is that the thermostat should be in the cooling system.
It's job is to restrict the water in 2 ways:
1. to keep the water in the engine long enough for it to pick up a
goodly amount of heat.
2. to keep the water in the radiator long enough to let the radiator
disipate the heat. Thus cooling the engine.
If you take the thermostat out, the theory is that the water will be
allowed to uncontrollably flow through the system. Thus it won't
stay in the radiator long enough to disapate the heat. So the temp.
will go up, and up, and up, and up......
In practice this depends on the engine and the cooling system. As I
said earlier, I usually ran my car all summer with out the thermostat,
and kept my eye on the temp guage. If it started to over heat, I'd
slow down, speed up, or pull over and stop. What ever it took.
> My +4 has a supplementary fan, so overheating is kept under control
> that way. Avoiding the expense of installing one on the 4/4, the
> issue of a pusher or puller fan aside, is something I like, but...
>
This is a solution that many are using. But it can present problems
of its own. Talking to "the" major radiator shop in town, they say
that the added area of the fan and motor can cause overheating
problems of its own especially at speeds.
The bottom line is, try it! If it works, who cares! Also you can
check the calibration of your temp guage, by pulling the sending
unit. Placing it in a pan of water along with a candy thermometer.
Turning on the electrical system (I suggest that you pull the low voltage
wire to the coil), and heating the pan with a propane tourch.
Check the temp guage and the thermometer.
You are correct about the temp. guage only being an indication of
the eng. temp. While not exact, we are trying to keep the water
from boiling and not cooling the eng. As long as the water is
cool (160-210) your engine should be in good shape.
John
John T. Blair WA4OHZ email: jblair@exis.net
Va. Beach, Va Phone: (757) 495-8229
48 TR1800 48 #4 Midget 65 Morgan 4/4 Series V
75 Bricklin SV1 77 Spitfire
The one with the most toys, wins!
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