I have just rebuilt a 71 351 Cleveland and need some help, I have no oil pressure on starting, I let the engine run for about 30 sec. And still no pressure, I primed the oil pump and have oil coming up from the rear oil pressure sensor area when I spun the oil pump with a drill prior to starting, but still no pressure, did I miss something, the galley plugs were removed and replaced with new plugs after having the block checked and cleaned. Any help is very appreciated.

 

When you say "coming up from the rear sensor area" it sounds like this was a visual inspection. Is that the case? If so, I would just spin the pump with the drill again until you can feel it grab the oil - it will really slow down your drill, do this while another person monitors the gauge. You could have a faulty sender or gauge. Pressure will be really low with a drill, but I think enough to register something.

 

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. Don't remember, does 351C have an oil pump driveshaft to put in before the distributor? Did you get it all together correctly?

. I wouldn't start the engine again until can get oil pressure with the drill... I think a 120 volt 2500 RPM drill can get 20 psi or so of oil pressure... battery drills may not be fast/powerful enough...

 

The oil pump drive shaft goes in from the bottom, with the oil pump. There is a circular spring clip that keeps it from being pulled out the top when removing the distributor, without it the drive shaft could possibly fall into the oil pan.

 

I forgot the oil pressure sensor when I was priming the oil galleys, installed the sensor reprimed for little over 5 min, started the engine no oil pressure, ran the engine for 30 sec. Then shut it down.

 

While you were spinning the oil pump with the drill, and the sending unit out, did you get a big puddle oil under the engine? If so, it sounds like the pump is working ok. You need to install a mechanical gauge, then spin the pump with the drill and see what happens.

 

Go buy a cheap mechanical oil gage and a grease gun flexible rubber hose they should mount together if not you may need a union. Once you have them together you should be able to screw the hose into the original oil sending units location. Then you can monitor "real time" oil pressure under the hood.
Hopefully you are spinning the pump counter clock wise. You'll be able to fill the drill when oil starts to pump.

 

A 1/2" drill should be able to produce 80psi if the pump will. Mine did.

The only way for oil to be pumping, and not pressurizing, is if you left out one of the oil rail plugs on the front of the engine. Or a lifter has come out. Or the filter is plugged up.

 

I use a 1/4"-drive handheld speed wrench for this - I can spin it fast enough to build up plenty of oil pressure + it lets me *feel* when the filter is full and oil starts pumping through the engine.





Use some duct tape to tape the socket onto the wrench for added insurance that it won't come off and fall into the engine.

 

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. Prolly won't get much oil pressure if the oil pressure sender port is open... and the gauge won't work with no sender... sounds like you discovered all that...

 

What ended up happening here?