CMP GM Dash Oil Pressure thread size?

[Bob Carriere]

....to the Guru!!!!!

[Jordan Baker]

Any chance it’s an SEA fitting or JIC one?

[Bruce Parker (RIP)]

Originally Posted by Jordan Baker

Any chance it’s an SEA fitting or JIC one?

Last night going with the Weatherhead tip I found a Chev restorer's website that confirms the 6100X2. It also talks about the original line being 1/8" steel but that can safely be replaced with 1/8" copper that is much easier to find today. My remaining question is whether 1/8" (primed) will carry the pressure from the engine to the gauge over ~10' or if I should step it up to 3/16" or even 1/4" tube.

[rob love]

The rule in hydraulics is that pressure is equal and undiminished in all directions. If it were a matter of flow, sure go bigger. But pressure...as long as it is not pinched closed 1/8 should work.

[Jordan Baker]

I climbed into the Otter today and took of a picture of the rear of the oil gauge. It has the larger tube size and long SAE fitting. The rest of the line is also larger then 1/8”. I’m wondering if there was a change that wasn’t reflected in the parts manual.

Some close up of the fittings from my Cab13. I realize the gauge is the later style but using to show the other type of fitting on the back side.

[Lynn Eades]

The round gauge is JIC isn't it? An American standard gauge.

[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