C1 Oil Pressure Too High For PV?

[Bob B.]

Hi all,

I disassembled my engine to rebuild, but when I noticed a ridge at the top of the cylinders, I took it to a machine shop to bore it 30 over and went ahead and had them reassemble it with the standard rebuild kit, including new oil pump. When at hot idle, my oil pressure is 45 and it is 60 when traveling. I want to PV the car and go for Duntov. The PV manual indicates the needle should be mid-range.

I dread the thought of replacing the oil pump, not because it is a difficult job, but because the pan doesn't leak now and I don't want it to start by taking it off. Any suggestions?

Thaks,

Bob

[Jack H.]

Re: C1 Oil Pressure Too High For PV?

There was a recent post on this subject (should now be in the archives) where the bottom line was the Melling oil pump that was used...

[Duke W.]

Re: C1 Oil Pressure Too High For PV?

AFAIK the first 55-60 psi oil pressure relief spring was late '63 mechanical lifter engines. All prior engines are 40-45 psi hot at 2000 and above. Check the AMA specs.

I constantly admonish owners to MANAGE their machine shop and "engine builders". Otherwise there's a good chance you will end up with a bunch of useless hot rod parts in the engine - weird cams, low compression, roller rockers - high volume or high pressure oil pumps - all kinds of junk.

Management starts with a written work order that specifies exact operations and parts by specifying manufacturer and part number for every new part, and it's the owner's responsibility to know that specifed parts meet OE specs. Whenever possible use GM or OE replacement brand name parts from Federal Mogul or Dana Corp., not hot rod brands. Work orders should also state that any parts or operation deviations or additions must be approved by the owner.

Duke

[Mitch S.]

Re: C1 Oil Pressure Too High For PV?

Bob, I went thru the exact same headache last year on the PV for my 67 small block roadster, oil pressure too high exactly as you stated. I had my mechanic check and change the spring to the lower tension and it works fine now, good luck

[Dave Suesz]

Hmmm...

My '55 runs on the high peg all the time except when idling hot. This is a replacement 55 engine, assembled with NOS parts. My Dad told me the original engine had the same pressure characteristics. Of course, the 55 had a unique oiling system, this may not apply to later engines.

[Joe R.]

Re: C1 Oil Pressure Too High For PV?

Hi Bob:

If, given the choice, you would rather pull the gauge than the oil pan, you might be able to alter your oil pressure gauge to meet the PV criteria. Since the utility of the oil pressure gauge provides mostly qualitative information anyway, you might be able to modify it to read artificially low so that it looks correct for PV.

[Roy B.]

Re: Hmmm...

I also have high oil pressure and it's ALL original engine over 100K miles , also the engine water temp runs below 180. Battery hardly ever move much to +, so I see now I would never pass a PV test.

[Chris Patrick]

Re: C1 Oil Pressure Too High For PV?

Yeah, that's an idea. Use a pressure regulator for the oil line.

Now if you can figure how to hide one, you might be set.

[Joe R.]

Re: C1 Oil Pressure Too High For PV?

Actually, I was thinking of something as simple as pulling the needle off and re-installing it a little bit counterclockwise of its original position, so that it reads low. There might be other issues related to where the needle ends up getting parked when the engine is off, but maybe there is a stop for the needle at the low end of the range. If not, one could probably be installed.