Topic: Oil pressure gauge calibration

[ruppstang]

I am restoring a 67 and the oil pressure just barely makes the low end of the range on the gauge. When I ground the sender wire it pegs the gauge so the gauge appears to work. I purchased a new sender and still reads the same. Yesterday I installed a mechanical gauge to test it and it read nearly 55lbs at idle.
My question is there any way to calibrate or adjust the gauge?   

[carlite65]

is there a very small hole on the rear of the gauge? i 'think' there is an adjustment screw in a very small hole on rear of gauge.

[jwc66k]

is there a very small hole on the rear of the gauge? i 'think' there is an adjustment screw in a very small hole on rear of gauge.

There are two adjustment holes on the back, one for minimum readings, the other for maximum. The adjustment mechanism looks like a "gear", at least two teeth are visible. I'm looking at a 65-66 oil pressure gauge marked C5ZF-9B309 (that may be the face plate part number) and it's needle is reading at the minimum of the sweep range, not the "L", with no power. In the interest of science, and Mustangs I will (without witnesses) attempt to adjust the upper "gear". Zowie! The gauge now reads At the "L" bar. Applying 3 VDC to the terminals give me almost maximum deflection. Conclusion: this meter works, but I don't know what the other adjusting gear will do.
We return you to our regularly scheduled programing on CBS, the NFL - Jets at the Steelers, 24-13.
Jim

[ruppstang]

Thanks guy I will give it a try.

[Brian Conway]

Pictoral aides.  Brian

[67gta289]

I tested three 1967 instrument clusters, and all three gauges read effectively the same.  Perhaps a millifreckle difference between them.  I was pleasantly surprised at the consistency.

I used the same resistor decade box and measured the resistance with a Fluke to verify.  Rather than try to describe the results, let's go with the picture is worth a thousand words phrase.

Note that I have not compared any of the pressure transducers, but it would be interesting.  I have a hand pump and calibrated gauge, so it's possible.  I would want to check one or two readily available over the counter parts.