What's a normal oil pressure

[Thor]

I am trying to learn about engines, etc as I restore my 1978 midget so please excuse my ignorance. My 1500cc has 57,000 miles on it. Seems strong, doesn't appear to burn oil, etc but I have noticed that while the oil pressure reads 60-80psi when I first start it and remians in that range for short slow speed trips around town, I see a noticable drop in pressure after high speed driving. At high speed the pressure runs 40-50 and then when I come to an idle the pressure reads 15 to 20. Can anyone tell me what this might indicate and whether I should be checking something?

If the motor is ok would the engine benefit from an oil cooler so the oil doesn't thin so much? Thanks for any suggestions.

 

[Matthew E. Herd]

sounds like you might need an oil cooler. Mine used to drop as low as 5-10 lbs after 30 min ... my 13 row cooler should be thermostatically controlled, but during the summer time, it never gets below 20 lbs at idle, even when autocrossing. With a thermostatically controlled 10-13 row cooler, you should be quite safe for driving around all year, in all weather. It may be some other problem, too, but it's my opinion that it sure can't hurt!

 

[Mike H]

The oil pressure readings you are getting are about the same as I get in my '78. When the engine gets hotter, the oil pressure will go down due to the oil being thinner.

In summer an oil cooler can help keep the engine temperature down as well as help the bottom end of the engine. If you do install one, get a cover for it if you plan to drive the car any distance in winter.

Also, be sure you are using the correct weight oil. Most of the MG owners out there use 20W50 oil.

Mike

 

[Tullamore]

I use 20W50 and also see the same pressures you are describing, I have an electric fan that run until the engine cools down so that I have a little better oil pressure when I come back out to my car if I were in a store or something.