Modifying Engine Oil Relief Valve

[LBZ]

Has anyone ever or can you even modify the OPRV to raise the pressure on it? Kinda like how we do with the FPRV? My hot oil pressure is right on the line for minimum spec and I'm getting a little nervous with it there. Trying to avoid dropping my front member to upgrade my pump. The valve is much easier to get at.

Years ago Simon modified one to flow more in Abby's first engine due to too high pressure but not sure what he did.

 

[Chevy1925]

Modifying the valve won't change idle pressure, only the blow off pressure when it gets to that point. Can't remember what that is but I want to say around 70-80psi before it opens

 

[moparkxracer]

Be careful what pump you use if you go aftermarket. I'd like to know what people say on modifying the relief valve as well.

 

[LBZ]

Before I get carried away though I think I'm dicked before I start. Isn't the relief opening pressure around 65psi? I only see about 75psi at cold idle.
And nowhere near that on the highway.
Edit: you guys beat me to my own thinking. I forgot it's a relief, not a regulator.

 

[LBZ]

So who makes/sells a good higher flow pump? Are there different flow rating options?
I know whichever one Simon put in was ridiculous high.

 

[Chevy1925]

Be careful what pump you use if you go aftermarket. I'd like to know what people say on modifying the relief valve as well.

Mopar, would you mind pm'ing on what pump you had issues with and what it did?

 

[gmc502]

I had a couple of mellings that would lock up as you tightened them down,,that was a couple of years ago.

 

[Burn Down]

So who makes/sells a good higher flow pump? Are there different flow rating options?
I know whichever one Simon put in was ridiculous high.

Simon had a DPR pump I'm pretty sure. I know the Socal one has an external regulator you can add to bring the pressure down out of the stratosphere.

 

[moparkxracer]

Be careful what aftermarket pump you put in there. One of the ones mentioned above didn't last 1k miles.

 

[S Phinney]

Socals pump is not intended for daily driving. He will not sell them for that purpose anymore. If you want better oil pressure there are two options. Use a Melling high volume pump or convert over to the LML oil pump. That requires buying a few extra pieces like front cover ,upper pan and pickup. The Melling way is cheaper but it's not that bad ok converting over. I think around 600 bucks to do that. Less than half to do a Melling pump.


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[Cknight199]

I had a similar issue with low oil pressure when the engine would get HOT, due to my clearances. Ended up switching to a Melling pump and it helped quite a bit.


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[LBZ]

Well the lml option would have been an option a month ago but not now that the engine is in the truck.

Who sells melling pumps?

Also does that socal valve go in place of the stock relief or is it something different?

 

[LBZ]

Didn't see a Duramax listing on Melling's site.

 

[WVRigrat05]

Sub'd. Mine is low as well. Has been since it was unloaded off the delivery truck. I haven't seen any ill affects but I don't like it knowing my LLY held 45+ loaded with 12k wfo.

This truck barely breaks 35-40 unloaded when hot.

 

[S Phinney]

SoCal sells the Melling pump. Their relief valve is specific for their pump. It is a pressure relief that is plumbed into the filter housing and return oil regulate pressures. Basically a blow off valve by Peterson made for oil systems.


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[x MadMAX DIESEL]

The basic melling? Or some crazy high dollar melling? If it's just the normal replacement summit is about the cheapest price


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[S Phinney]

They usually are running around mid 200s I believe. I know SoCal will key theirs if you ask.


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[Burn Down]

Anyone swapped to a LML setup or a Melling know what you picked up for pressure?

 

[Chevy1925]

Anyone swapped to a LML setup or a Melling know what you picked up for pressure?

last melling i installed with .0025-.0027 main clearance and .0022-.0023 rod clearance, i saw about 10 psi increase at idle and up the RPM range. 15w40 oil and around 90* outside temp. never saw under 28psi at idle and hot after running it hard.

it will be hard to say the actual PSI increase you will see because most are building an engine at this point and clearances in mains/rods/ect can open up more for higher performance.

 

[Burn Down]

last melling i installed with .0025-.0027 main clearance and .0022-.0023 rod clearance, i saw about 10 psi increase at idle and up the RPM range. 15w40 oil and around 90* outside temp. never saw under 28psi at idle and hot after running it hard.

it will be hard to say the actual PSI increase you will see because most are building an engine at this point and clearances in mains/rods/ect can open up more for higher performance.

Thanks James:thumb: Those are the numbers I was looking for.