Rex-A-CO Oil Pressure Gauge

[Paul from Maine]

Just installed a reproduction Rex-a-co oil pressure Gauge this afternoon. How accurate are they? It seemed to respond to changing engine rpms very slowly. It would show 4 lbs when cruising and then at a stop sign continue to show 4 lbs while idling. Then when I accelerateded away from the stop, it would drop to zero, even though the engine rpm had increased significantly. Then suddeny, when I had been cruising for a minute or two, it would jump back up to 4 lbs. Is this normal? Could it be my oil pump or just a sticky gauge?

 

[Gerard]

What first came to my mind is

Bleed your pressure line.

And I think you know that there is almost no oil pressure at all . the oil is pumped into the valve chamber and from there it flows to main bearings and the surplus is going over the whole in the valve chamber and the return pipe.

All this assuming that you have a stock engine with no pressurised bearings

 

[James Rogers]

In a stock system the pump supplies FLOW not pressure so you probably wont see much more than 4# at any time. I got scared once when mine dropped to zero running at 40 MPH but once I understood the system I never worry about it. I only use the gauge to make sure the pump is working not for a pressure reading.

 

[Jerry Parr WI]

The best Model A oil pressure gauge I've seen has a window with a flag that changes from "off" to "on" with about 1 lb of pressure. Tells you what you need to know.

 

[Chris Haynes]

My eBay find.