tom'sB2B Posted June 16, 2014 Report Posted June 16, 2014 Hello I've been working on cleaning up my engine and replacing gaskets. I pulled the oil pump. Cleaned it up and replaced the gasket. I put it back in, pulled the plugs and used the starter to turn the engine over to prime the oil pump. While doing so, I watched the pressure gauge for the pressure to rise. It only got up to about 10lbs of pressure. Is that enough pressure to show the pump is primed? Or should it be showing a lot more pressure? I want do this right before I try to start the engine. I also replaced all the oil lines including the oil pressure line. thanks Tom Quote
Dodgeb4ya Posted June 16, 2014 Report Posted June 16, 2014 It should go up to at least 40lbs when cranking cold. Did you pack the pump with light grease? The pressure relief valve plunger could be stuck too. Bob Quote
Don Coatney Posted June 16, 2014 Report Posted June 16, 2014 What oil pump gasket did you replace? The one on the head of the pump where the rotors are or the one where the pump bolts to the engine? When you replaced the oil pump did you index it so the distributor goes in per factory recommendations? Quote
tom'sB2B Posted June 16, 2014 Author Report Posted June 16, 2014 I replaced the gasket where the pump bolts to the engine. I'm not sure what is meant by indexing, but I rotated the engine to TDC and replaced the pump in a position to where the distributor rotor will be at "7 o'clock". Where would I pack the grease? Around the drive gear? I will check the relief valve and see if its gunked up. I was wondering if I wasn't creating enough pressure by just turning the engine over slowly with the starter. Quote
_shel_ny Posted June 16, 2014 Report Posted June 16, 2014 When I replaced the square cut o-ring in my oil pump I refilled the oil pump with oil before installing it to aid in getting oil pressure again. Quote
Don Coatney Posted June 16, 2014 Report Posted June 16, 2014 Your indexing was done correctly with the rotor pointing at 7:00 when the engine is at TDC. Grease packing would have involved disassembly of the pump to expose the internal pump rotors. By virtue of the fact that your gauge is showing pressure your pump should be primed. Forty pounds would be a good reading for a freshly rebuilt engine but you did not say your engine was fresh. Quote
tom'sB2B Posted June 16, 2014 Author Report Posted June 16, 2014 No. Its far from fresh. The engine was rebuilt in 1968. It still has good compression though.The manual says the oil pressure should be 35-40lbs above 30mph. I guess I will put the plugs back in and kick it over and cross my fingers. Quote
NiftyFifty Posted June 16, 2014 Report Posted June 16, 2014 Should have a minimum 8-10 lbs per 1000 rpm, to a max of around 40-50 psi, what oil are you running? Any dance the gauge is shot or a leak in the line, or did you use an actual gauge plumbed in? Quote
tom'sB2B Posted June 16, 2014 Author Report Posted June 16, 2014 No. The gauge is good. Was working great before I started working on it. No leaks. Running plain old 10W-30. I'm just turning the engine over with-out the plugs to prime the pump. Quote
tom'sB2B Posted June 16, 2014 Author Report Posted June 16, 2014 I think I will try starting it and see if I can get "normal" pressure. If not , then quickly shutting it down Quote
NiftyFifty Posted June 16, 2014 Report Posted June 16, 2014 Good plan, you might not be spinning fast enough to get a good reading. I would run thicker oil myself in a well "used" flathead, I actually ran a mix of 30 and 50 weight prior to rebuild, now straight 30 with zddp additive. Quote
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