low/no oil pressure and ticking in 390

[riderre1997]

i have a 1976 f250 with rebuilt 390 (about 5000 miles on rebuild). driving today the oil pressure dropped to nothing on the gauge and could hear lifters ticking. at higher rpm the oil pressure goes up but drops right back down at idle. also read a post about marbles in a coffee can ticking at high rpm and my engine is doing that as well. a high pitched whine at idle as well, have heard this can be an oil pump. any thoughts? Also discovered the other day that one of my spark plugs had backed out and oil was leaking out from around it, causing a ticking noise. Tightened the plug and the ticking stopped.

[Nitekruizer]

I had this happen to my engine when I rebuilt it. Check for excessive camshaft endplay. Check to see if there is a 1/4" spacer behind the camshaft timing gear. If there is, try running without the spacer. In my case, the spacer was causing the cam bearing oil holes to become exposed due to excess endplay. The oil pressure would drop to zero. The engine would also run like crap when this happened because the distributor timing was being affected when the camshaft moved back and forth. You may have bearing and cam lobe damage if this has happened several times, assuming that this is the cause of your problem.

[riderre1997]

Do you think there is any chance that it is just the oil pump screen plugged a bit and throwing some sea foam in the crankcase will clear it up? This is my daily driver and right at the moment I really don't have the time or money to tear it back apart again, and being a 2wd i can't just take the oil pan off and check as the cross member is in the way.

[tnlprt]

What brand oil filter

Take the oil filter off and cut it open and inspect it

Fix it now for a little

Fix it later for a lot

What oil are you running

Does it have enough ZDDP in it

[Gregtx]

I wouldn't necessarily assume that all of those symptoms are all related. They could be, and you could be right in that it may be a faulty oil pump, but it could simply also be a combination of different things as well.

The oil around the spark plugs is typically because the valve covers are leaking. This is extremely common on the 390. The spark plug that backed itself out would most certainly cause a ticking sound because compressed air would escape past the threads on the compression stroke. The oil pressure issue could potentially be due to a faulty oil sender unit. I'd check that first and eliminate that before you try pulling the motor.

It also sounds like you need a good motor flush. I had a bad lifter tick a while back and I fixed it right up with some motor medic. You'll need to get fresh oil and a new oil filter, but simply put the motor medic in your existing oil and let it idle for 5 minutes while warm, then drain the oil, change the oil filter and put in fresh. That may clear up your lifter tick.

Also, since it sounds like you are going to be pulling the valve covers off anyways to fix the leak, you should check the lash on the rockers (assuming that yours are adjustable).

This is less than $50 worth of stuff and some time to potentially save you from pulling the motor. I'd go through as much elimination as you can before you commit to an oil pump, because that is a FAR more involved fix.