What can I say? This is from personal experience with my '75 that I bought
new. I live in Ga, and have traveled extensively throughout the S.E.,
including all the way to Miami in late July / early August.
I experimented running with and without a thermostat in my first car, an
Austin Healey. It ran hotter without one. The motor, as measured with a
pyrometer, not the water temp. The water temp gauge may say the water's
cool, but it's no longer an accurate reflection of motor temp.
My first lesson in cooling was that the high water velocity can cause the
pump to cavitate, further increasing heat buildup. Another downside is that
it can damage the water pump by overheating the bearing or damaging the
impellers. I had to replace it. After this, I made it a point to learn more
about how cooling systems worked.
At idle, with no restrictions, heat transfer is probably acceptable in warm
weather, maybe even better than with a thermostat, but once off idle, pump
water speed and air flow over the cooling coils is up, reducing efficient
heat transfer. A thermostat, OTOH, causes a significant restriction, even
wide open.
Another reason to run a thermostat is that the motor will take much longer
to get up to temperature. This means oil doesn't flow and lubricate as well.
Excessive condensation can occur, possibly causing some bearing lubricant
stripping and subsequent galling.
Since most engine wear occurs during this time, you want it to be as short
as possible.
Fortunately, the motors used in Bricklin's are understressed and farm
implement rugged, so they stand up to incredible abuse
Even new, I've seen motors have blockage from poor casting and cleaning.
Since it doesn't take much blockage to cut water flow in half, possibly this
may be one reason why the differences in some of our experiences.
I agree that 250deg is the thermal limit with current anti-freeze and oils.
BTW, if any of you have to meet emissions, water temp needs to be between
190-210deg, minimum for the test. At any rate, the temp should be at least
180deg at idle for minimal thermal efficiency.
Concerning The Brick's tendency to overheat; it's essential that the rubber
molding that runs across the top of the firewall be deleted. The
aerodynamics of the engine bay is such that this is the only decent exhaust
vent at speed. Another is that early cars have too small a front dam, and
the revised bigger dam folds under at speed. A 2 x 2 strip of wood covered
with neoprene, to get proper spacing, attached to the lower radiator cowl
solves this problem.
Kim's post listed some other considerations.
Something I haven't tried is using a smaller pulley, if such exists, or
removing every other impeller blade on the pump rotor to further slow down
the water flow as is done for racing. It has the side benefit of gaining
additional HP.
My post wasn't as complete as it probably should have been; I'm notorious
for only responding to what's asked without elaborating. What I did write
though was fact, based on research and experience, not opinion.
I'll stick with my original recommendations, plus those listed here.
GM
----- Original Message -----
> This is not my experience. From new, my car would run 210 to 240.
> Bricklins have a reputation for running hot. They will overheat when
stuck
> in traffic on the interstate in summer. I removed my thermostat and
solved
> the overheating, but it never would run less than 190 (in Florida). In
> North Carolina, I had to run a thermostat in winter.
> Mike
> In my experience, without a thermostat the engine runs too cold -- there
is
> not an issue with water running through the radiator so fast that it
doesn't
> cool it (this is just an opinion). The thermostat opens further and
further
> the hotter and hotter it gets. I think that 220 degrees is getting on the
> hairy edge, especially considering that without the thermostat in there,
> there is no way for it to cool any more.
<SNIP>
> Of course, if overheating turn the ac off and the heater on to try to cool
> the car down. Tanner has a saying that 240 is hot and 250 is park and
walk.
> Kim
>
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