HELP 1950 chrysler newyorker straight 8 has high oil pressure

[Notmechanic]

So my 1950 chrysler newyorker with the straight 8 has very high oil pressure. The oil pressure relief valve has been removed and cleaned and polished. I ran it without the plunger in just to see and had no oil pressure. Is the spring too stiff? Are my oil passages clogged? Are there any tricks to remedy this? Is there anyone out there that has had this problem before?  

 

I got this car as my first project car and have made great progress on it until now. This site has already helped me alot. This site and all its members are fantastic! A friend of mine that worked in a old car shop told me about this site very glad to be a part of it. I hope my struggles eventually help some people in the future. Thanks guys! 

[TerryB]

Not sure if this is any help, note info about color of oil pressure spring.  Info is from a 1958 MOTOR’s Repair manual.

 

[TTR]

So, what is this “very high oil pressure” ?

As you can see TerryB’s posted images, a normal oil pressure should be somewhere between 45 & 60 psi.

It’s also possible your cars factory gauge could be faulty.

I would start by obtaining a good quality aftermarket mechanical gauge with wide enough range (0-100 psi) and good, clear face dial showing increments with at least every 20 psi (i.e. 0 - 20 - 40 - 60 - etc.) and connect it, using a T-connector, with the factory gauge feed line/tube on the engine.

This way you’re able get an accurate reading what the pressure actually is while comparing it with the factory unit readout scale to see if latter is close to accurate.

Also, keep in mind the “normal” pressure is usually indicated with engine fully warm at operating temperature and under moderate load conditions, i.e. while driving.

 

Basic, old school rule-of-thumb is that a reasonably good or safe oil pressure should be at least and rise 10 psi per each 1000 RPM, i.e. 5 psi at 500 RPM, 20 psi at 2000 RPM, etc…

 

Another example, I just finished a full rebuild on a ‘53 DeSoto 276” V8 about a week ago and did 100+ mile road test earlier this morning. I’m using 20W-50 oil and when cold the oil pressure goes immediately to about 42-45 psi and after the engine gets fully warm (almost 180*) stays there, whether I’m idling at signal lights or driving 60 MPH.

The oil pressure relief spring in the NOS oil pump I just installed is “standard” and while I have heavier, I’ll use this until I see a reason to change, but I don’t expect that to happen for tens of thousands of miles.

Edited August 7, 2022 by TTR (see edit history)

[Notmechanic]

The stock meter is pinned. I believe it bent the spring in the guage to where is doesnt return to 0 now. Didn't used to be like that. Also. The first in line (back to front) hydraulic lifter is not holding oil. That lifter was removed cleaned and dry tested. I believe the oil pressure is holding the ball valve open when cycling. I will get a other oil pressure guage and test that as well.