Lads,
With all due respect, I am a MG Midget owner who monitors this list
for my dad (who needs to restore his 1500). I have had problems with
the Midget overheating.
Is the problem "thermomechanical"? Heat expands a metal which in turn
push/pulls a spring on the temp gauge.
(1)Is the thermostat working?
(2)Is the temp sending unit working?
Heat a pan (glass or steel) with water (in the garage). You can use a
blowtorch. Place the thermostat in the pan (heat the pan evenly). The
thermostat (for the Midget) opens at 180 degrees F. What is the
"opening" temperature for the 1500?
I'm not sure what kind of sending unit is found on the 1500. I would
guess that it is "thermomechanical" rather than "thermoelectrical".
So check the sending unit. Once at the opening temperature of the
thermostat (now you'll know how your gauge correlates to when the
thermostat is open).
You can also determine where the gauge would read at the "boil over"
point. Heat the water to boiling and read what the gauge reads. It
should be hot. Obviously. There is a slight difference in actual
versus observed at the high end of the calibration. This would be due
to the fact that during operation the cooling system is a "closed
system". No water can escape.
The pan of boiliing water is an "open system". The water can boil
away. Remember that boiling water cannot exceed 212 degrees F (under
any circumstances).
Cheers - And Good Luck,
Jeff Mathys
1976 Midget (powered by a Triumph 1500 cc motor stock)
Art Mathys
1964 SPL-310 (powered by a Datsun 1500 cc motor stock)
---"HUBBARD, Charles E." <chubbard@shl.com> wrote:
>
> Greg,
>
> I have the same problem with my 64 1500. Running down the highway,
the
> gauge just kept climbing. Slow down below 2900 RPM and the temp
would go
> down. I'm getting ready to replace my radiator core but will
remember to
> test the gauge first. If the gauge is sending bad information, does
anyone
> have any ideas on how to calibrate the gauges to read correctly?
>
> Charlie Hubbard
>
> > -----Original Message-----
> > From: greg mitchell [SMTP:gregm@gippstafe.vic.edu.au]
> > Sent: Monday, February 08, 1999 6:25 PM
> > To: datsun-roadsters@autox.team.net
> > Subject: datsun sp310
> >
> > i`ve just joined this list server and are trying it out.
> > i have got a sp310 1965 1500 eng.and are restoring it.the car is
> > 100%original with a 61,000 gen mileage.i am currently cutting the
rust
> > out and welding in new sections ready for painting the under body
i have
> > painted and rustproofed.
> > a quick note on overheating,my car was recording upwards of 210` i
> > replaced the radiator with a new 3 core unit instead of the old 2
core
> > drove the car , guess what the tems still similiar.mmmm
> > i borrowed a laser guided temperature gun from work
> > results as follows.
> > engine running at 170 deg--------- gun result-157deg top of radiator
> > tank
> > engine running at 190 deg--------- gun result-158 deg
> > aiming gun on head also recorded 158 deg
> > moral check out the gauge
> > more stories soon
> > greg
>
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