Oil pressure

[Ralph]

I have a 1971 challenger with 383 mostly stock and I have about 70 to 80 psi at idle and it basically stays there through out the rpm range. This is for a weekend cruiser - never goes over 4000 rpm mostly.
Could this be the reason why I have so many leaks that are so hard to fix ? Oil pan, valve covers etc.
The dodge manual says it should be around 40 to 50 psi.
Should this be changed back to a oem type replacement oil pump. Or is this a issue with clearances in the valvetrain etc - maybe that's why previous owner installed it which was installed when the engine was rebuilt and painted.

Thanks

 

[Chryco Psycho]

Oil pressure is not responsible for leaks , Most Mopar engine using a HP oil pump with run about 80 PSI .
Is the PCV system working correctly ?

 

[Ralph]

Yep, looked good. checked it to make sure.

Are others getting this type of psi with a stock rebuild.

Thanks for your comments Chryco Psycho

 

[DetMatt1]

I’ve never had 80 psi at idle on a warm, mostly stock engine.

 

[Chryco Psycho]

I have had 100 PSI + cold & 75-80 warm with no leaks .
I used an Alcohol Hemi pump on my on my 440 it was over 200 psi cold , damaged my 200 psi gauge , it was around 180 psi warm , I changed the bypass spring immediately !!

 

[moparleo]

That much pressure is not typical. It would peg a standard oil gauge. Remember that this is pressure measured in the oiling system. Volume is not measured but is more important than pressure. Think of a firehose as opposed to a garden hose at the same water pressure. Has nothing to do with atmospheric pressure(air /vacuum in the crankcase for example) This is why Chryco asked if the pcv is working properly. The pcv valve is calibrated differently for different engine types, sizes etc...It regulates/vents the vacuum/pressure in the crankcase system. Excessive pressure could contribute to oil consumption and external gasket seal leaks. Try this. With the engine running remove the oil filler cap and place the palm of your hand to seal over the opening. Do you feel suction, pressure or nothing with the engine running ? What is the typical RPM range that this car sees in normal driving ? Race parts ar for race cars. An all out 1/4 mile car only has to last a little more than a quarter mile. Street cars are intended to last 10's of thousands of miles before teardowns. Think simple. Of course when you design an oiling system you must take into account many things like clearances, temperature, how much volume you need and how much space/capacity you have to store oil. You always hear about "sucking the pan dry". That just says how little thought went into that cars lubrication system. More fluid capacity is always prefered if practical, whether it be the coolant, the trans fluid, oil etc... more capacity keeps things COOLER, that is it. HEAT is always the enemy to longevity. Long distance designed high performance vehicles have fluid coolers everywhere. Differential, brakes, transmission, steering, coolant, oil sump systems and on and on. The more complex you make your car, the less fun you will have with it unless you like to do constant maintenance on it.
K.I.S.S is a montra to live by.

 

[Chryco Psycho]

Actually with a Melling High Pressure pump 70 -80 PSI warm is normal , it is fine to run that much pressure but Never put a high volume pump on an engine with a stock oil pan , it can empty the pan & cause oil starvation damaging rod brgs typically .
A proper PCV system is far more important , if there is pressure in the crankcase as mentioned above that is a far more likely cause for leaks , for proper operation you should have a breather on one valve cover & a PCV valve connected to the base of the carb to draw out & burn off extra pressure & fumes .

 

[fasjac]

Here’s where my 440 (500 stroker) is just before operating temp. The pump is a MP high volume BB/Hemi. Now, I did purchase a M/E Wagner pvc adjustable valve. I haven’t installed it yet but, it got my interest when researching it. I don’t have anything leaking. I do more cruising than WOT.
Check it out online if you want to. They say it can help leaks ??

 

[fasjac]

And a pc after cruising

 

[Ralph]

Thanks for all of you chiming in.
This is what I found out.
First of all using the technique of the palm over the oil filler cap opening - there was nothing. Checking the pcv valve it - had a good pull and was operating properly. I also have breather on that side of the oil filler cap that goes to my shaker.
Oil pressure at startup and after fast idle it was 76 and then as I increased to 3000 rpm it stayed at 80 psi. At operating temp it pretty much stayed the same.
I have a stock 402 oil pan installed.
Let me know what you think.
R

 

[Chryco Psycho]

sounds Ok , the valve cover gaskets can be tough to seal as the rail is not machined flat .

 

[moparleo]

If the PCV was opening with the engine rpm up, there should have been some vacuum in the valve cover. PCV opens at specific pressures. Just because the valve is rattling does not mean that it is functioning properly. The above post mentions an adjustable PCV valve. That is so the amount of vacuum required to open the valve can be adjusted. They look the same but believe it or not you can put a PCV valve that was designed for a Chevy engine and put it on a Chrysler engine and it will not work properly.
Bad PCV Valve Symptoms and How to Test the PCV Valve Yourself

 

[fasjac]

sounds Ok , the valve cover gaskets can be tough to seal as the rail is not machined flat .

I prefer rubber gaskets on the valve covers. Just snug em down. No over torque. Seems to work fine on mine.

 

[fasjac]

Anything other than valve covers leaking?

 

[Ralph]

Thanks guys for all your comments. Moparleo, will confirm pvc valve is good and for my application.
The car has leaks from the oil pan and timing cover.
Had a mechanic install a new windage tray and gasket set and its leaking again. Valve covers are worn so maybe i need new ones.
Car has about 5,000 miles since total restoration from previous owner.

What do you guys think should I change the oil pump to stock since i am using the standard 402 oil pan ?

Ralph

 

[Robert Franke]

Ralph, you didnt say if the guage was mechanical or electric...I would install a quality mechanical oil pressure guage to properly diagnose. And yes, put a stock pump on it...it will also give you some fuel milage..bigger isnt always better.

 

[chargerdon]

you do NOT have to change out your pump!! On a big block oil pump the maximum pressure is regulated by a spring... I think the standard oil pump spring is set to 65 psi max... Easy to change...simply unscrew the big ( i think 1" bolt head) at the back of the pump and pull out the spring and put in a lighter one. I believe all of the brands of oil pumps are like that... I believe you can even pull out that spring and cut off a small section of an end to test it...

I once had a long discussion with a Melling customer service technician. Melling sells TWO different pumps. Standard and high volume. They also sell the High Pressure pump, but melling tech told me the only difference between std and high pressure is the strength of the relief spring....the two pumps ....std and high pressure are otherwise identical.

 

[Ralph]

Thanks guys, yes, ordered a melling spring kit with the standard spring and will try that.
I have a mechanical pump that was painted with the rebuild and looks factory. Bet he put a high pressure spring on it.
Ralph