Struggling to find the right oil pressure balance

[furious70]

Been having quite the time trying to figure out oil psi on my Fury.

Here's where I started:
The oil pump that was on the engine as I got it fired up with around 65psi cold and would be 25-30psi hot idle. Down the road at 2200rpm it would be 45-50psi. Problem was it was leaking between the pump and filter adaptor body. Location indicates it was the smaller o ring inside. I could not locate a replacement without buying a $60 rebuild kit and at that point I figured I'd just buy a new one. Plus when I pulled it apart there was some scoring on the pump body so I kept it but didn't use it.

The pump I have now (standard issue Melling - not HV or HP) has 75psi cold start up and only 12psi hot idle. It will only do 25-30psi at 2000-2200rpm. It will do 45psi at 3000 rpm. It was even a little worse than this until I took the spring out of the leaking pump and put in this one.
This is all with VR1 20-50 oil.

To me the engine itself seems healthy enough with clearances based on how the first oil pump behaved.

How do I go about giving myself more psi when hot without blowing the filter off when cold? I've never tried a 10w50 oil but it looks like they make it, not sure about the right chemistry for these engines however. Would 10w vs 20w materially reduce cold psi?
And then put a washer in with the spring? I've never needed to do that even though I've always heard people talk about it. How many washers do you need to gain 10-20psi at hot idle?


Any ideas are appreciated!

 

[turbine68rt]

Have you verified the readings with a mechanical gauge? I think the standard pressure Mellings have a 45psi relief spring. If you are getting an accurate reading of 12 psi at a hot idle, it won't be beneficial to add washers in an attempt to raise pressure, since it hasn't reached the relief psi threshold. What type of main bearings are you using, 180° half-groove or full-groove? Mobil-1 makes a synthetic 15w-50 made for flat tappet cams.

 

[RemCharger]

You need a high volume pump.
I've seen them go over 100psi ( if there's something wrong with the relief) but never seen one " blow the filter off"

Not saying it's hypothetically impossible. Get a better filter if it's interfering with your sleep.

 

[BSB67]

Is this a big block? Oil filter adaptor? What’s that?

Here is a possible scenario. Just spit balling here. First, older Mopar oil pumps have a larger relief valve, I.e will bypass more oil when open, than the newer Melling pumps. This might be the reason the cold oil pressure is higher. Second, possibly the old pump is a high volume pump, which will deliver higher pressures most notably at lower rpm.

A lot of unlikely ifs, but possible.

 

[whyjay]

Check the pickup tube screen for trash and clearance to oil pan. I chased a high cold pressure/low hot pressure issue for quite a while until checking mine.

 

[4speed68rt]

What engine? What is the condition of it? Sounds like the bearings may be worn.

 

[furious70]

This is with a autogauge pro comp gauge.
Don't know the bearing type unfortunately as I didn't build it.
HV pump giving more low rpm psi is something I didn't know. With a stock c body pan I wasn't looking to flow too much oil but that's something to consider now.

 

[furious70]

Check the pickup tube screen for trash and clearance to oil pan. I chased a high cold pressure/low hot pressure issue for quite a while until checking mine.

I had the pan off and switched all that less than 2k miles ago.

 

[furious70]

383, sorry. Rebuilt around 10k miles ago. Doesn't use any oil, 20" idle vacuum

 

[R413]

Last thing to put on with a stock pan is a hi volume pump.

just fix the leaks with the first oil pump, it was working well. Some scoring in the pump is not a deal breaker. This engine with idle vacuum at 20 has a stock type cam so it’s not going to rev very much over 5K.

 

[furious70]

Yes it's an RV type cam. Twin turbo, efi.

 

[4speed68rt]

Just a TWIN TURBO EFI? Haha. Something probably worth mentioning. Doesn't the oil go through the turbos and get real hot?

 

[BSB67]

A high volume pump at 60psi does not pump any more oil volume to the motor than a standard pump at 60 psi.

 

[furious70]

Just a TWIN TURBO EFI? Haha. Something probably worth mentioning. Doesn't the oil go through the turbos and get real hot?

The setup has been running since 2012, I did a small upgrade with this engine in 2022. Old engine was fine with the turbos.
Maybe I just need to pull the pump off the other engine, lol

 

[4speed68rt]

Show us some pictures of the twin turbo efi set-up, please.

 

[RemCharger]

The first thing you do with any BB mopar with any pan, is put on a high volume oil pump.
Add 1 quart, mainly if you're going above 6 grand, with a stock pan.
The whole, quote/unquote, " Suck The Pan Dry¡!!!!!!!!!!" Is from little old house wives, spinning tales.

 

[RemCharger]

A high volume pump at 60psi does not pump any more oil volume to the motor than a standard pump at 60 psi.

Thank you.

 

[R413]

The first thing you do with any BB mopar with any pan, is put on a high volume oil pump.
Add 1 quart, mainly if you're going above 6 grand, with a stock pan.
The whole, quote/unquote, " Suck The Pan Dry¡!!!!!!!!!!" Is from little old house wives, spinning tales.

what the heck for? Don’t need that much pressure.

high pressure is a resistance to flow.

 

[furious70]

.

 

[furious70]

A high volume pump at 60psi does not pump any more oil volume to the motor than a standard pump at 60 psi.

yes, because as it tries to pump more volume through the same orifices in the block the psi would go up, come against the relief spring, and bypass more.
What is a HV pump really used for then it makes me wonder.

And is there anything to the point raised in post #4 where HV pumps output map will deliver my psi at lower rpm? I need to look at that pump to see if there are any casting numbers on it to identify it.