Oil pressure too high?

[John Pasinski]

I'll try and be brief (which is pretty much impossible for me). I had an experienced mechanic (not me of course) overhaul my 402. When I bought the truck, it sat for 8 years with a disintegrating piston, and clogged oil pump sump (piston pieces). Well, a new crank & bearings, replacement piston, new rings, new oil pump, new lifters later, and now the oil pressure guage is almost pegged over to the high side when running under a load, and just below that at an idle. I was told that's way too high for a chevy, and there must be a blockage somewhere. Well I asked him how he cleaned the engine. I was told he put the block in a hot tank for two separate 2 hour cleanings. After that he used air to clean out every passage, and bolt hole. My questions: Is my pressure too high? If it is, can I find the blockage and open it up w/o pulling the engine and disassembling it? BTW; when it idles, all the valve rockers are getting oil except two of them. The #5 exhaust, and the #1 intake. I'm hoping that's caused by the cam which I may have ruined cause I didn't break it in properly. So I bought a new RV cam & lifters. But I'm waiting to install till I hear from you guys. Any suggestions?

[JMac11]

You have got a mess. Back off the rockers not oiling, sometimes that will let the oil "burp" out. It will not run long without oil coming out of eah rocker. You may have a clogged pushrod or the end of the rocker may be clogged. Fix that before you do anything else.

[John Pasinski]

Yeah I figured I'm in trouble. The first thing I checked were the push rods, rockers, & rocker swivels for blockages. All are clean as a whistle. I forgot to mention, I originally suspected the (2) lifters were defective. NAPA swapped 'em out for me. Still no oil on those same lifters, & high pressure.

[toddtheodd]

What weight oil are you running?
Get an engine oil primer, and use it to push the oil around to figure out the lifter problem instead of running the motor and potentially creating a bigger problem.
I just finished building a 355, and my #2 exhaust rocker wasn't getting any oil. I pulled the rocker back off, and pulled the push rod out to make sure there wasn't a blockage. Then I put the push rod back in without the rocker, and using the primer, made sure oil was at least coming out of the push rod. After that, I put the rocker back on, and made sure oil was coming out of it. So that is something you can try. The Oil Primer thingy is only like $15 at Summit, and should be in everybody's toolbox that is really digging into their motors.

[1968SWBBigBlock]

when using an oil primer on a big block you will need to run the primer for a bit - if you do not have oil at all rockers turn the crank and continue the process, it may take a couple of full rotations to get the oil to push out.
What makes you think you wiped the cam shaft?

[John Pasinski]

When I pulled the lifter (that wasn't pumping), it was cupped out about 3/16"!
So I pulled the cam, and lo & behold the 2 or 3 lobes were obviously really bad, and others questionable. Several of the other lifters wre cupped also. I'm going to try and get a hold of a priming tool, and see how the pump is working w/o the cam installed. Then I guess I'll have to install the new cam & lifters and again try the priming tool to see if all rockers are getting oil.

[LONGHAIR]

Originally Posted by John Pasinski

When I pulled the lifter it was cupped about 3/16"! I'm going to try and get a hold of a priming tool, and see how the pump is working w/o the cam installed.

If you have one cupped that badly and visible damage to the cam.....it needs to be pulled out and completely disassembled again. There has been enough trash go through the motor to have coated everything in a fine metalic film.
It may or may not have been the cleaning process. It could have come from the initial start-up. If it didn't start quickly (a lot of cranking) you may have wiped the cam right then.

BTW, you are never going to get oil pressure with the cam out of the block. The cam's bearings are pressure oiled through passages in the block as are the lifters. If those parts are not there, you have a huge internal "leak".

It is very possible that your high pressure problems stem from the cam bearings. The holes in the bearings need to be aligned with the ones in the block. There could also be some piece of junk floating around in there from something else.

As far as "too much" oil pressure....sure. There is a point at which "more" doesn't help anything, and it becomes a liability. Not only does this extra pressure add to the load on the distributor, cam, and timing chain, it is just more for the seals to have to contain. Beyond about 10PSI per 1000 RPM you have overkill.

[John Pasinski]

Thank you sir! You have been the biggest help so far. Your advice makes a lot of sense. BTW....I attempted to put a wire through the cam bearing oil ports. It felt like it was hitting the block. To which "clock position" should those ports be alligned? They are at the 6:00 position now.

[John Pasinski]

OK......Here's the next butterfly I'm chasing. I got a suggestion that this distributor may not be the correct unit for my 402. If not, then it may cause the oil pressure to by-pass the distributor bushings, and not reach the top of the engine. Does anyone know what part number should be stamped on the distrib? The numbers on mine are: 1112064 2C7

[too much stuff]

Your dist. is correct for a 71-72 402. truck.
Eric

[John Pasinski]

Thank you sir.............back to the drawing board.

[1970 Bowtie]

John,If you dont mind me asking,who in orlando overhauled your engine?

[John Pasinski]

I'll send a P/M if you don't mind....

[1970 Bowtie]

I dont mind,send away.

[brad_man_72]

one time i had high oil pressure, aparently it was a spun main bearing. the crankshaft soon came out in 3 pieces. time for a teardown.