Thread: Lubrication problem

Tweet

Originally Posted by swcash

Well, I pulled the on the rocker shaft and blew compressed air down through the oil passages. I then hooked up a 0-100 psi gauge at the oil filter adapter. Zero psi at idle. Changed out the gauge to verify. Zero psi at idle. I do get oil pressure as I increase the rpm. It goes as high as 80 psi and I eventually get oil from the rockers and the engine smooths out and the lifters quiet down. As soon as I let her idle the lifters get noisy and back to zero oil pressure. Next move is to drop the pan and see what is going on with the screen and the pump. Are there end clearances I can check on the pump gears? When I do get a new pump should I consider a high volume or a high pressure pump? I've seen them advertised high volume, and I've seen them high pressure, whats the difference. It seems like a high volume would have the potential of high pressure. I read that the 427 has a bypass spring set at 100 psi. Does anyone know what the normal setting is on the 390? I was surprised to see the pressure go as high as 80 today. Could that be my spring pressure?

With those miles, best thing to do is just replace the pump with and OEM rated volume and pressure pump. In an old engine, a hi volume pump will put too much oil in the top of the engine and too slow to drain back without some rework on the oil returns. Hi pressure isn't necessary on a stock engine, would do more harm then good. Pull the pump, take the pickup tube off and clean it thoroughly, reinstall it on the new pump.

Dave is right, just pick up a good quality stock oil pump and use that. Anything we say now is pure conjecture, you won't know what you really have til you pull the pan and look inside. You say the valve covers are clean, but the pan is the lowest point in the motor and sludge and crud always accumulate there.

Unless you have already done damage, I'm betting you find a clogged pickup and a weak pump and changing/ fixing those items helps. Post some pictures of the inside of the pan and all when you pull it down. We are curious.

Don

My Ford 400 lost it's oil pressure yrs ago. It turned out to be a lifter issue.
Some Fords feed the lifters first and will lose pressure from that point.
Ron

All good advice above. Before you get to far along however, give some serious consideration to pulling the front cover and replacing the timing set. If it still has the stock phenolic cam gear and it's worn enough that the fibers have plugged the pick up screen then it's done. There a couple of ways to verify a worn cam gear. Remove the fuel pump, turn the crank counter clockwise and reach in through the pump arm hole and check for chain tension. Another way is to use your timing light and check for smooth mechanical advance from about 10 to 12 degrees initial up to about 30 degrees total advance. If the timing advance is irratic the cam gear is worn or the mech. advance is worn or dirty. The bottom line is that in an engine that old the factory cam gear is almost certainly worn out. Steel replacement timing sets are quite reasonable and cheap insurance. Don't forget a new front crank seal.