[Healeys] Temp Gauge

[Bob Spidell]

re: " I believe the factory used 
these calibration points with specific input voltages in order to make the 
gauge reasonably accurate over its full range" 

AFAIK, the gauge is entirely 'mechanical,' driven by expanding ether moving a Bourdon tube. Thanks for the tip on the needle, I think if I can get 180 when running stable I'd be happy. 

I know the speedos have a 'calibration' point--a small white dot at about (negative) 5MPH--but I don't see any dots on the temp gauge. Mine used to read 212 exactly when I shut the engine down, so it was probably accurate before. 

Bob 


-------------------------------- 
Bob Spidell - San Jose, CA 

----- Original Message -----


Bob, I'm assuming you are referring to your BJ8. The needle can be pulled 
off and reset wherever you want it, but there are two real calibration 
points as indicated by two small dots on the face of the gauge between 120 - 
160 and at about 212. Although I have no proof, I believe the factory used 
these calibration points with specific input voltages in order to make the 
gauge reasonably accurate over its full range. If you pull off the needle 
and put it on 180 (if you know for sure the sensor is sensing 180), then the 
gauge might be inaccurate everywhere else. 
The best way to check calibration, although a real pain, is to remove the 
gauge from the dash and check the gauge reading while the sensor is in 
boiling water at sea level. I did this with my gauge and found it reading 
about 10 deg. high. After pulling the needle off and repositioning it 
between the two dots at 212, the gauge was accurate enough for me through 
its range. 

Steve Byers 
HBJ8L/36666 
BJ8 Registry 
Havelock, NC USA