BUT it just went lower and lower when getting warm. Lowest i have seen is like 7 and thats on idle. the engine is reabuilt by my uncle and he know what he's doin so. But he told me that he didnt change the oilpump so i might me doin this.
First, I would NOT trust the gauge you have, until you check it. You can do that, by installing a mechanical oil pressure gauge, and compare the readings. It's either right, or wrong. Need to know!
Oil pump. Okay, he didn't change it. What did he do with it???
Stock oil pump on my 69 440...simply cleaned it (like all the other engine parts). But, they need all the clearances checked, to be sure their still good, and the pump itself is still in good shape. NO...the pumps don't need to be replaced, at every overhaul.
Besides the pump, two other things affect oil pressure. One, is the oil pressure relief spring, that's inside the pump, including the seat/valve, the spring pushes against.
Those springs, over time, can weaken, and need to be replaced. The mentioned seat/valve, needs to be in good shape.
Second is, the overall engine clearances. Was it built tight, loose, what? What oil weight are you using, though that won't affect things that much.
If the oil pressure readings are right, something is wrong!
