Oil Pressure Gauge Failure

Looking for theories or explanations ... we have now killed 4 of the 200 psi liquid filled oil pressure gauges on a blown alcohol hemi. They are all fine warming up at about 120 psi. On the first two gauges, after the first run they only returned to about 40 on the gauge. Then the next run it only returned to about 80. In each case, the gauge acted like it was at zero when it was at the higher number. In other words, if it was "stuck" at 40, it read 160 when warming up. If it was "stuck" at 80, it would show 200. We sent them back to the manufacturer several weeks ago and have yet to hear any answer from them. They did send us two replacements. This past weekend, the replacements acted "normal" warming the car up. After the first run, the gauge was "stuck" at about 140. When we warmed up for the next run, it again acted like that was zero and pegged the gauge when the engine fired. After the second run it was "stuck" at 180. We put the other gauge on after that and it did exactly the same thing (same progression over a couple of runs).
The data logger shows oil pressure of 80 - 100 for the first half of the run, fading a little to 55-60 the last few hundred feet, so we are not exceeding the gauges range.

Anybody ever seen anything like that or have any ideas?

Lyle Greenberg

 

Ive had the same thing happen to me.... What i found i took the gauge out and took a air gun to it, and then it worked... Give it shot it wont cost ya... I run nitro 70 oil... Never had any probs.hen i ran 50w

hope this helps

 

Oil Gauge

Do you use silicone on anything internal to the engine? All it takes is a small piece to clog up the works.

 

Tried putting the air gun to it with no success.

No silicone, but we do use peanut butter grease liberally on pushrods. We often see really small "globs" of that on the oil filter. I didn't think that this would be an issue as I assumed it would usually be caught by the filter or disappated by the time we make a run. A fresh gauge always goes back to zero after waming the car up ... only sticks at the conclusion of a run.

Lyle Greenberg

 

I have seen some dry sump systems that will spike the oil pressure, breaking a 200 psi gauge.

 

It sounds like the black pointer is turning on the shaft. This is usually caused by the sudden force on the red pointer and the viscousity of the oil in the gauge when it is hit by pressure spike. You can fix it by restricting the inlet to the gauge. Hope this helps.
Joe