Originally Posted by jarrodlaforce
My and my dad bought an s10 with a "rebuilt" 350 bored .60 over flat top pistons mild cam eldebrock intake etc. I was driving it for quite a while.. almost a year and on my way home one day I noticed very low pressure than normal (normal was 60 psi) its was running maybe around 30 psi and by the time I got home I had no pressure. I tried using a drill to spin the shaft through the distributor.. no pressure. took the valve covers off to make sure it wasnt sending unit.. no oil. When I did all of this I had a full pan of oil. Ive been told it could be a plug in the cam galley? Im not sure if its a high volume pump unfourtunatly. And I was also told that it could be a pressure relief valve in the oil pump.. Im not sure what it is yet but Im going to be pulling the motor to take a look at the cam.. then the pump. Thank you for your help!
The oil pickup tube on most SBC oil pumps are only pressed into place, they can- and DO- fall off.
If you want to check this w/o pulling the pan off, add a few more quarts of oil so the pump will be submerged even w/o the pickup attached. Don't try to start the engine- the crank will be in the oil and you'll froth the oil badly. Use the drill to spin the pump and check for pressure. If it comes up- it's the pickup.
If it were my truck and I had done the checks you already have, I would be planning on pulling the engine to take the pan off to get to the bottom of it (no pun intended).
If it's the pickup, you can reattach it (get it brazed or welded into place this time) or get a new pickup and press it into place correctly.
You might want to inspect the bearings to be sure that no damage was done to them or the journals by running w/low oil pressure. If there was any pressure to speak of and the engine wasn't beat on, the bearings, etc. will probably be OK- but you should check them anyway.
If the pickup is still in place, you'll need to look further. The oil pump bypass rarely will get blown out, because of how its retained, but it can stick open. There's another pressure bypass located in the oil filter mount of older (large filter) SBC engines. Check to see that it's still there and nor held open by a broken spring or whatever. Then there are the various oil gallery plugs. The front ones are usually cup plugs staked in position. The rear plugs are threaded.