CMP GM Dash Oil Pressure thread size?

[Bruce Parker (RIP)]

Originally Posted by Phil Waterman

Hi All

I'm using 1/8 inch copper and plastic on 235 and 261 engines which run 42+PSI on the pressure to the gauge with no problems. With the non 216 engines 5-20 PSI 1/8 copper works fine on the 235 & 261 engines with higher oil pressure I've installed a T and a second gauge with higher range to monitor oil pressure.

The original gauges, early design, just hit the pin at 30PSI while the second gauge reads around 42 PSI, the original oil gauge has been being over pressured with no ill effects for years.

Cheers Phil

Interesting. If you look carefully at my pic of the Chev gauge below you'll see "0" on the left and "30" on the right, perfect range for a splash 216. Yet painted on the glass dash panel for a GMC 270 (the panel was Fox) the range is "0" to "80" and the 0/30 would be completely covered. But pressure is pressure so how would the gauge figure out which scale to use?

[rob love]

Is the part number for the Fox gauge the same as for the trucks with the 216? If so, the only way I can think of that you could make the gauge read properly for 80 vice 30 would be to re calibrate the spring tension on the gauge itself.

[Jordan Baker]

Originally Posted by Bruce Parker

Interesting. If you look carefully at my pic of the Chev gauge below you'll see "0" on the left and "30" on the right, perfect range for a splash 216. Yet painted on the glass dash panel for a GMC 270 (the panel was Fox) the range is "0" to "80" and the 0/30 would be completely covered. But pressure is pressure so how would the gauge figure out which scale to use?

This is why I’m thinking there might be an error in the parts books for the Fox and Otter. I’ll have a go through the GM service bulletins for the Fox and Otter and see if anything mentions that oil gauge.