So, I just got done swapping cam//valvetrain/head gaskets due to a bad lifter. I had bent pushrods a few weeks ago, that cracked the lifter trays and let one lifter go sideways (I guess) and grind itself and the cam down.

Put it all back together. and it fires up and runs good, my oil pressure is 60psi cold as normal. I get out and check some things in the enginebay and go for a short drive around the block. I notice a light valvetrain tap and then notice my oil pressure is less than 40psi. By the time I get back home I have to hold the throttle at stop signs to keep the oil pressure off of zero.

I go get some oil and figure maybe my old oil was diluted. I put in 5.5 quarts of 20-50 and now I have zero pressure even if I rev it up slightly. I havent let it run more than 3-4 seconds at a time this way, and have tried several times to see if the pump will prime itself again.

When I did the cam swap I did not disturb the oil pump or pickup at all.

What the hell gives here?

I am about to drop the oilpan and pull the front cover back off again, I guess.

IF this v8 keeps treating me like **** then I might wind up with the first turbo rotary powered denali in the world, because I could have already built and put 500 miles on one of those during the time I've been screwing with this truck.

 

might check and make sure you didnt break your oil pressure sending unit..what your describing is about what happend to me..i had changed my intake and new one had a fittin and the sending unit was in the way

 

I'm very sure I didnt, because I was pretty careful reinstalling everything, and again I had great pressure upon startup. The lack of pressure and the valvetrain noise started together. IT wasnt as though I had no pressure after completing the work...it happened over the course of a few minutes, and slowly fell until it was gone.

 

Sounds kind of like the pump may have gotten clogged or maybe some clogged oil passages. Sorry to hear your having such a bastard of a time getting that thing going again. Hope you get it figured out soon.

Hopefully you didn't do like this guy did.
https://www.performancetrucks.net/fo...d.php?t=402337

 

I'm 95% sure either your oil pump failed or you blew the pickup tube oring. Have fun tearing the whole thing down again. It happened to me as well as tons of others.

 

Well, the oilpan is off. Found a few small needles from the aforementioned dead lifter, but otherwise nothing out of the ordinary. Pickup was clean and free of debris. Pickup o-ring was still in the pump and in perfect condition.

I pulled off a rod cap and the bearing looked fine and still had some oil, just not fresh oil. I was going to pull a main cap off until I read that the bolts were TTY and would have to be replaced, plus it looked a little more involved than "normal" with 6 fasteners each, all of different sizes, the 2 on the sides being hard to get to with the motor in the truck.I'll just assume that since the rod bearings/journals still had oil on them and looked okay, the mains do too.

Front cover and oil pump coming off today. I am sure the oil pump oring will be fine as it was not disturbed. I know that every single reply about oil pressure seems to be "your orings are bad!" but that is not the case here, as mine are stock and unmolested.

I did read a post that suggested that any little spec of dirt can make a relief valve stick open in the pump and dump all the pressure back into the oilpan before sending it into the engine. Since I had the entire top half of the engine off I would say this is more likely. I used a shop vac and compressed air to try and remove all contaminants from the heads and valley cover before removal but it is entirely possible that some specs of dirt fell into the oilpan regardless of how careful I was.

One would think that the oil filter would take care of this, but apparently not.

 

Did you check to make sure that the cam retaining plate was bolted up and tightened down right? Theres a rubber gasket on the backside of it that channels oil from one side of the block to the other. Make sure that's not damaged too.

 

pull the pump apart and look inside. if it picked up one of those needles it would destroy the pump. i know it seems impossible to pick up but i assure you it will.

 

Got the pump off and apart yesterday evening. Found no issues at all within it. I took the bolt/spring/piston out of it and the piston seemed to move freely and had minimal contaminants on it, so I do not beleive it was stuck open.

I cleaned it all and wiped it down, packed it with a little vaseline (a trick I sometimes use on rotaries with long pickup tubes to help the pump create suction) and put it back on. I also used a very light layer of RTV sealant on the pump case halves, and between the pump and block, after cleaning all surfaces with brake cleaner.

I put the pickup, oilpan and front cover/crank pulley back on and fired it up. I had oil pressure within 0.5-1 seconds, as is usually the case with my engine. Needless to say I am scratching my head over this, it is a real dubya tee eff experience.

I did only have about 50psi cold oil pressure which is still less than the 70 or so that I usually see. I am also running 20-50 right now, whereas I usually run 5-30 synth. I wonder if my new lifters have not filled up yet and this is why the pressure was low? I doubt it...

I guess I will throw the rest of the parts back on (waterpump stuff, front axles/diff/steering) and run it to see how it does.

Cam retaining plate was bolted down firmly and the stock gasket that was inside it was in great condition and was reused.

 

Well all I can say is good luck. I hope it's all fixed for you.