Mechanical Oil Pressure Gauge

A mechanical gauge might fluctuate at idle or low rpm, but it shouldn't "shake". Does this only happen at low rpm? Is your gauge mounted to the engine? Does your engine have a rough idle due to a cam? An electric gauge is slow to react to the resistance changes in the sender.

If this is going to be a permanent installation, don't use compression connectors on the copper tubing. The compression ferule will cut into the copper (over time) and cause the tubing to break. Use flare fittings or a stainless braided line.

JB's suggestions are good. You may be expecting too much here. Any gauge that has a fast response time will have needle-shake. Ones with an electrical delay-loop won't, but you also won't see oil pressure fluctuations, either. A glycerin-filled mechanical gauge will damp the needle-shake at low rpms to some extent, but remember, the gauge is at the far end of a long, convoluted oil passage full of openings- like 16 lifters and the rod/main/cam bearing passages all opening and closing! An accurate gauge WILL fluctuate until the rpms come up. FWIW, my non-glycerin-filled mechanical gauge is mounted directly to the tee fitting on the rear of the block & the needle has vibrated since I mounted it.... in 1992. No problems yet.

Thanks JB and Boss,

I have it plumbed off of a tee and soildered the ends. I do have a mild roller cam but the engine is rock solid at idle and the gauge is mounted to the intake. The needle-shake does get a bit smoother when the idle goes up. I just bought a cheep gauge to just test if the one currently on it might be bad. It's a 70.00 equus which should be good. I guess as long as it's moving up and down with idle I know that I at least have pressure so I could just live with it like the BOSS has. But, you know cat owners we just can't just leave things alone.
Thanks

A few things we do in the HVAC Business to get accurate readings on guages is :

1. the mounting should have a isolator between the intake and the bracket .. like a rubber gromit between the inate and bracket.
2. As Boss said A glycerin-filled mechanical gauge will damp the needle-shake .. which I have seen in automotive guages.
3. We use a device called a snubber. They suppress pressure pulses and pressure peaks ..They make them in 1/4" so you caould put it on the back of the guage and then attach the tubing.
4. Last but not least on guages we mount with capilary tubes ..we usually leave a nice coil of 4 loops ...this acts as a suppressor ... but mostly in high pressure applications.


My opinion ...buy a 1/4" snubber and be done with it.

Ron

Your dealing with the cycles of your Oil Pump,
New part, new problem.
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Mark

I put the less expensive gauge on and the the needle was still. I put the expensive one on and wow it was still also. I thought I was done with it. I have had a small coolant leak at the thermostat pipe so I thought that i would replace the gasket. I actually doubled the gasket because it seems that the new coolant pipe flange may not be exactly flat. After messing with refilling the coolant and making sure that the thermostat opened up I happened to look at the oil gauge and yep it's bouncing again. I let the engine idle for about a half hr to make sure the coolant level was right and the gauge never settled down. I try the snubber. I thought that the way mu luck was going I was going to have a leak a theermostat but it seems ok. Thanks all