Thread: Loss in Oil Pressure

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Today I started up my 454 getting ready to break in the cam when I noticed that the oil pressure slowly dropped from 20 to 0 after it warmed up and never came back up. I am using Rotella Diesel 14w30 and pan is full. I stopped the engine and first check my oil pressure gauge line that is tapped into the oil filter housing, no kinks everything looks good, then I removed the gauge and tested it. Gauge tested OK. Then I decided to remove the distributor and everything was intact. Next thing I did was remove a valve cover and see if the pushrods were getting any oil. Once I fired up the car there was no oil coming out of the pushrods, I promptly shut the motor off and I am now stumped. The oil pump is brand new and installed correct as it was working previously and randomly quit. Only thing I can think of is that the oil pickup may have fallen off but that just seems unlikely due to the fact I tack welded it on. Any suggestions? Thank you in advance.

Watch the hole as you run the priming tool. There should be a boat load of oil gushing in the distributor bore area of the block. One possibility is the "hidden" plug was not re-installed OR the outside part of the distributor shaft is worn and bypassing. A couple of tidbits to look at.

i fired it up before to do my breakin but its timing was off, but it ran for several minutes with 10-20 psi, and oil was coming out of the pushrods, i cant figure out how it would just stop, also sometimes it would smoke slightly out of the valvecover breather

possible air bubbles in your sending unit line, bleed it....


Mike...

Definitely use a priming tool, don't start it again until you get it to make pressure. Did you change the cam bearings? If they aren't aligned right they can block pressure to the gauge port, or other places.

You have to watch out on the new oil pumps I've seen where the factory put too much cosmoline on the pumps to prevent rusting will stick the relief valve open and you have no oil pressure. So take the pump apart and clean it real good and make sure the relief valve is working freely. Then apply 50 wt oil inside the pump so it will prime up quicker.

So today I used a priming tool and noticed that I could build roughly 15psi at full drill speed which is somewhere around 2000rpm. I relocated the oil pressure tap to the oil tap towards the timing cover instead of the oil filter housing and pressure went to 19psi but the heads are still not getting any oil. We only primed for about 20 mins. Everything seems to point towards a stuck open pressure relief valve. Any other suggestions before I pull the engine again. Also the oil seems heavily saturated with molylube, could this have any correlation with my problem?

Same thing happened to my brothers 496 but it started out with 60 psi then dropped down to about 15 psi. We messed around with the fittings the gauge. Finally we just dropped the oil and put Rotella 15w-40 started it back up and back to normal. We thought we where going to pull the engine too until we did that. The oil almost looked a little milky maybe from all the assembly lube I don't know. Still good oil pressure to this day. Good luck

don't worry about the assembly lube that is just part of new engs. drop the pan and you may have a stuck relief valve. are you using a correct priming tool, old dist, or just a blade? if a blade you won't get any oil to the heads. I would not run the eng any more till you find the problem.

no oil psi past 20 psi and no oil to the top of the engine .i would say you do not have the oil plugs in the front of the engine they plug the lifter oil galleys with plugs out will just dump all of your top end oil right out them and you will never see much oil psi i did see a big block that a guy did and the oil pump was not down all the way on the main cap.it had a stud kit and used a 6 point nut that hit the the oil pump body and held it off the cap BIG OIL LEAK and did see some one try to use a small block oil pump drive in a big block that will not work

Where are all the plugs I should be looking at?

the two plugs under the top timing gear in the front timming cover what year is the big block?

i found the prob somehow my pump came loose, so i had to pull it , but its fixed now and has 60-75 psi.

yes, and i used loc-tite