Inliners International Forums General Discussion Engines chevy 250 lower oil pressure

I have a low milage rebuild 250. Running straight 30. In
Los Angeles heat. My pressure at start is 16 to 18 cold at idle. revs up to 40.
My pressure at operating temp is 8 to 10 at 750rpm. No noise runs fine. Is this low.
should I put 20x50 in or a High volume pump and a bronze distributor gear? Please give me some feed back thanks.

How quickly does pressure rise with RPM?

you should have close to 30 at idle at temp. (well any motor I have ever had 20-30 Hot) But it could just the fact your running straight 30. AND YOU don't need a high volume or high pressure Pump it's not good for the dist. gear. I run a stock pump even in my race motor. idles at 30psi hot and will go 60 under rpm load.

I’m using stock pump. My pressure goes up to 42 when rpm goes up. But when warm it’s 8 to 10. I ran 10/30 oil and was told to run straight 30 and when it’s cold I’m getting 18 or more at idle. As soon as normal operating temp hits oil pressure goes down to 8 to 10 at 700rpm . Low mileage rebuild . Should I run 20 50 to increase pressure?oil pressure rises with rpm revs.

You should be running 10w30 all the time. Los Angeles doesn't get very cold or very hot, as compared to other areas in the state. I run 10w30 in areas that get down below freezing and into the triple digits most of the summer.

When you change your oil, is there any shiny specs? It sounds like your bearing clearances are a little wide, or you may need a new oil pump. I bought a 292 with 155k on it, and it has 30psi while cranking. I haven't ran the engine yet, still getting parts to finish it, but you should have at least 30 psi at idle on your engine.

It might be worth the effort to drop the pan and check things out on the bottom end.

Heck, my 4.0 in my Jeep Cherokee with 207k on it idles at 30 psi and 60 psi above 1,000 rpm

Edit: I was wrong, the 4.0 idles at 60 psi when cold, and will drop to 30 psi when hot, and that is using 10w30.