Engine Burning Oil

[Captain Obvious]

Oh, I'm sorry... I saw VR and I interpreted as "Variable Reluctance". Since you were talking about distributors, I was thinking you had put in a later model distributor from a 280 and the VR (variable reluctance) distributor was causing the condenser to burn up. I completely glazed over the sentence before that when you mentioned the voltage regulator.

I don't know if you would see changes in the oil pressure gauge tracking with system voltage. I doubt it, but in any event: 

In my best Emily Litella voice.... "Nevermind."   

[Dave WM]

the oil pressure gauge itself has some kind of voltage regulation going on IIRC to deal with voltage fluctuation. Its pretty crude I think but it was something Nissan addressed.

Edited August 23, 2019 by Dave WM

[Captain Obvious]

That regulator is to deal with ambient temperature variations, not system voltage. Since the needle deflection is based on temperature of the bimetallic strip, ambient temp is an issue. So they address that in the gauge.

I'd have to go back over my notes to figure out if system voltage would be a factor as well. It's a voltage divider, so system voltage variations may come out in the wash.

[240dkw]

The temperature of the bimetallic strip is a function of the current flow. The oil sensor varies the resistance which changes the current flow. Pressure up- resistance down-current higher-temperature higher. I am saying that if the pressure-resistance stays the same and the voltage goes higher the current will go higher and heat up the strip more. If the voltage regulator does not control the output of the alternator then what does?

[Captain Obvious]

Sorry, we're using too many vague references here to "regulators"...

There is a "main" voltage regulator on the alternator output that controls the whole car's system voltage. It's job is to maintain the alternator output voltage relatively constant under all conditions.

Then in addition to that "main" voltage regulator, there are also other regulators built into each of the bimetallic dash gauge that compensate for changes in ambient temperature. And it was those "secondary" regulators that Dave was talking about.

The regulators built into the gauges pulse width modulate the current to the sensor(s) by opening and closing a (second) bimetallic strip driven switch inside the gauge. It's job is to switch the current to the gauge sensor on-and-off at whatever pulse width duty cycle is necessary to keep it's "regulator" strip at a constant temperature. My supposition is that since it's more of a "power" device designed to keep the temperature of it's strip at a constant temperature, it may account for both ambient temperature AND system voltage.

If the system voltage is lower, it takes longer for the strip to warm up.
If the system voltage is higher, the strip heats up faster.

Same with changes in ambient temperature.

I haven't thought it all through thoroughly with my notes in front of me, but that's my theory. Which is mine.

[Dave WM]

That's how I assumed it worked as well CO, high voltage, high current, more heat open longer. did not think of if as a ambient temp sensor as well.

[240dkw]

Sorry, yes I have been talking about the main voltage regulator, that is what failed on my car. I still say that if my system voltage was moving up and down with the engine speed the gauge would move too. But I am the guy who pulled the head of my motor when I had an electrical problem. 

[Zed Head]

Compensator would be a better word for it.