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I know this has been done to death in a less scientific way - with the "Where do you run your engine on the tempertaure gauge" type threads, but I was tinkering this weekend, and came up with some interesting readings.

I have a GM temperature thermistor in the bottom of the radiator - the kind that varies the resistance according to the coolant temperature - hooked up to an ecu that is calibrated to give me a readout of the current coolant temperature value while the engine is running. It's set so that my (electric) fan comes on at or over 165 and off at 160 or less.

What I found interesting was the reading on the gauge when this happens - midway between 1/2 and 3/4. Making the gross assumption that my gauge is working the same as everyone elses (since I 2ble checked radiator temps with an IR thermometer and they are pretty close to the ecu reading), this would seem to indicate that those of you who are running with cars that don't go past halfway may be running them too cold.

Just a thought.
You can tell it's a slow week...
 
Alan,

If your voltage stabilizer is not functioning your temp and gas gauges will read high. The gauges are 10 volt. The stabilized is supposed to maintain 10 volts. If they receive higher than 10 they will read high. The original voltage stabilizer is grounded through its casing when it is mounted to one of the studs holding the speedo or tach.

Years ago the stabilizer in my TVR died while I was driving on the DC beltway. I was zipping along in the fast lane when I suddenly ran out of gas. Even though the gas gauge showed around 1/4 tank. The temp gauge was also reading high.
On our drive back from Seattle I was taking a snooze when the TR6 started sputtering. I asked my brother how many miles he'd driven on this tank. It was more than we had put on any of the previous tanks. He forgot the gauges were reading high. He volunteered to walk to find gas since he made the mistake. The real problem was that a PO had installed an after market teak dash. In doing so he had not grounded the voltage stabilizer. It was a quick fix once we got home and I had a chance to read up on the stabilizer.
 
bobh said:
The stabilized is supposed to maintain 10 volts.
Click to expand...
Just to be clear, the original voltage stabilizer only maintains an average of 10 volts. It does this by switching between full battery voltage and nothing, slow enough that you can see a test lamp flash.

Also, IMO, the gauges themselves vary widely from car to car. I have a collection of them for the Stag, and no two of them read the same even when tested on the bench. The senders vary too.
 
Too right. Comparing 2 gauges is like looking at 2 clocks.

If you have just one clock you can feel like you know exactly what time it is. If you have 2 clocks you're never really sure.

I just check the temp in key locations with an IR thermometer to get a feel for what is normal for the gauge in the car then don't get too concerned unless something changes. Guess the same is basically true for oil pressure.

Sure glad the TRs don't have clocks in them.
 
Geo Hahn said:
Sure glad the TRs don't have clocks in them.
Click to expand...
Stags do !

And mine is right twice a day /bcforum/images/%%GRAEMLIN_URL%%/jester.gif
 
Sure, just set it for 10:10 and it will be exactly right then.

How will you know when it is 10:10? Easy, just look at your clock.
 
bobh said:
Alan,

The real problem was that a PO had installed an after market teak dash. In doing so he had not grounded the voltage stabilizer.
Click to expand...

Isn't it automatically grounded by being attached to a gauge that is grounded?
 
Right; but at on at least some Triumphs, the gauge is grounded through the metal part of the dash.
 
Correct.

I installed a solid teak dash and I had to solder
ground wires to a few of the gauges and run the new
wires into grounding blocks.

d
 
Now it all makes more sence. I have two Voltage Stabalizers from TR4s, and thought they were both acting weird -or maybe they were actually flasher units. I watched my digital voltmeter wobble all over the place between 12 and 0 -no matter what type of power-supply (including a car battery) I used. And for some strange reason, the guages I had hooked to it, functioned normally. -This was all done on a bench. -And they read significantly higher when wired without the stabilizer unit.

-Still haven't checked the accuracy of the temp sending unit with guage and stabilizer.
 
My point was only that all my kit was attached and working but yet my temp gauge was higher than many were comfortable with.

All my gauges were reading ok(ish). I wondered how many (if any) people had actually calibrated their cars to see what temperature their cars were really running at.

No biggie. Like I said, it was a slow week.
 
TexasKnucklehead said:
Now it all makes more sence. I have two Voltage Stabalizers from TR4s, and thought they were both acting weird -or maybe they were actually flasher units. I watched my digital voltmeter wobble all over the place between 12 and 0 -no matter what type of power-supply (including a car battery) I used. And for some strange reason, the guages I had hooked to it, functioned normally. -This was all done on a bench. -And they read significantly higher when wired without the stabilizer unit.

-Still haven't checked the accuracy of the temp sending unit with guage and stabilizer.
Click to expand...
That is how the "stabilizer" works it doesn't actually stabilize the voltage. it cuts it off for a percentage of time. If you had looked at it on a slow moving analog meter, it would have produced an average of about 10 volts. It is basically a thermostat with a small heating element on it. As the voltage goes up, the heater becomes hotter, and shuts the thermostat and current flow off for a greater percentage of the time. The gauges read correctly since they move very slowly.
 
DNK,
"Isn't it automatically grounded by being attached to a gauge that is grounded?"

Yes
"The original voltage stabilizer is grounded through its casing when it is mounted to one of the studs holding the speedo or tach."

However, The PO did not mount the stabilizer on a stud. It was supported only by the wires.
 
alana said:
My point was only that all my kit was attached and working but yet my temp gauge was higher than may were comfortable with.

All my gauges were reading ok(ish). I wondered how many (if any) people had actually calibrated their cars to see what temperature their cars were really running at.
Click to expand...

I guess this thread got a bit sidetracked on the possibility that your voltage stabilzer was faulty, etc.

I check the temp at the tstat housing at the side with the temp sensor (right by the sensor in fact). Do this after a long run and the housing should be pretty close to the temp of the coolant inside.

Ideally the needle should be mid-range when this temp is normal with normal being something like 185* depending on the thermostat being used.

TR3s & TR4s actually have numbers on the gauge but their accuracy (or lack thereof) is probably one reason why later gauges do not have numbers.
 
I have helped restore my sons TR6 and and this was an issue we beat to death. I now understand that bastard of an unit we call a voltage stabilizer becuase of this thread. After cussing, discussing, and fooling around with everything for a long time, we finally installed an electronic ignition in the dizzy which a friend who is a better mechanic than I timed. The heating issue was gone. Thank the good Lord for good friends!
 
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