HV oil pump vs Stock oil pan

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512Stroker

512Stroker

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I have noticed in xtreme heat that the oil pressure on my LA 340 drops to 15-18 psi at idle while in gear. 10W-40 Dino oil, Wix filter
I am wanting to up the idle oil pressure via a high volume Melling oil pump M-72-HV.
Has anyone run a HV Melling pump with the stock 5 quart oil pan?
Ya hear the stories of "sucking the pan dry" with high volume oil pumps.
Keep in mind this engine is a street application with a rev limiter setting of 6500 rpm.
 
318/390 HV oil pump with stock oil pan. Pick up on the pan floor. About 5000 mi. No problems. Pressure in FL heat 35 psi at idle.
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what RPM do you idle at?

anything under 1000 i wouldnt bat an eye sitting at 15 PSI


as far as sucking the pan dry, what you are worried about is not how fast the pump gets rid of it, but how slow it drains back
so look up the "oil mods" sticky and make sure you're block can return the oil back to the pan
 
That combination won't be a problem at all. I run the same in my 273 Commando without issue. 65'
 
diymirage said:
what RPM do you idle at?

anything under 1000 i wouldnt bat an eye sitting at 15 PSI


as far as sucking the pan dry, what you are worried about is not how fast the pump gets rid of it, but how slow it drains back
so look up the "oil mods" sticky and make sure you're block can return the oil back to the pan
Click to expand...
850 rpm hot idle with the A/C on.
 
If you want to add more pressure, the HV pump is not the way to do it. Get the MP high pressure spring and put it in the pump you have. But 15 PSI at 800 RPM hot is plenty. If you don't think it is, unscrew the filter while it's running.
 
RustyRatRod said:
If you want to add more pressure, the HV pump is not the way to do it. Get the MP high pressure spring and put it in the pump you have. But 15 PSI at 800 RPM hot is plenty. If you don't think it is, unscrew the filter while it's running.
Click to expand...
This !
 
RustyRatRod said:
If you want to add more pressure, the HV pump is not the way to do it. Get the MP high pressure spring and put it in the pump you have. But 15 PSI at 800 RPM hot is plenty. If you don't think it is, unscrew the filter while it's running.
Click to expand...
Rusty I was advised by a Tech at Melling that the high pressure spring wont gain any more pressure at idle as the relief valve controlled by the spring is closed at idle. He recommended I install the HV oil pump to gain psi at idle.
It's the roller lifters using some extra oil causing a small pressure drop.
With flat tappet lifters this same pump produced 25 psi @ hot idle
 
You do that and you'll have the EPA knocking on your door. They'll probably try to sell you an electric car while they're there.
 
512Stroker said:
Rusty I was advised by a Tech at Melling that the high pressure spring wont gain any more pressure at idle as the relief valve controlled by the spring is closed at idle. He recommended I install the HV oil pump to gain psi at idle.
It's the roller lifters using extra oil causing a small pressure drop.
With flat tappet lifters this same pump produced 25 psi @ hot idle
Click to expand...
Here's what the HP spring in a stock pump did for my slant 6 at idle.
 
All that said, I wouldn't touch it. I don't see where you're having an issue. Honestly, if you think 15PSI is low, take my advice and unscrew the filter a thread or two at idle. You'll change your mind real quick.
 
RustyRatRod said:
All that said, I wouldn't touch it. I don't see where you're having an issue. Honestly, if you think 15PSI is low, take my advice and unscrew the filter a thread or two at idle. You'll change your mind real quick.
Click to expand...
I'll pass on your filter technique.
Those springs are dam hard to find
 
Unlikely you would run dry at that RPM, unless you're running autocross or road racing. I run a Melling high volume pump in my 360, cold start oil pressure pushes 100, hot idling 45 with 10W30 conventional oil.
 
The oil is doing what it is supposed to do with extreme heat: drop oil pressure because it thins out with the heat.
I would fix it with oil, not stronger springs or pumps.
Try 10w/50 oil. You will get the same cold weather flow with the '10', but higher viscosity at higher temps with the 50.
I live in a moderate climate [ similar to LA ] & I use 10w/60, have done for years. Not worried about the 3.768 hp I will lose....
 
512Stroker said:
I have noticed in xtreme heat that the oil pressure on my LA 340 drops to 15-18 psi at idle while in gear. 10W-40 Dino oil, Wix filter
I am wanting to up the idle oil pressure via a high volume Melling oil pump M-72-HV.
Has anyone run a HV Melling pump with the stock 5 quart oil pan?
Ya hear the stories of "sucking the pan dry" with high volume oil pumps.
Keep in mind this engine is a street application with a rev limiter setting of 6500 rpm.
Click to expand...

I ran one with the high pressure spring and windage tray in the 64 Barracuda daily driver for years. 273, spun to 3,000 rpm minimum, 6,500 rpm power shifts, sometimes past 7,000 rpm by accident or incompetence, 100,000 miles on it minimum. No problem. I always run 20w-50 or straight 30 Valvoline VR-1 since the 70's.
 
The stock pan is barely capable. If you are not going to drive it like a "normal" person. I would start there myself. The small capacity and in particular the sloshing around under acceleration or aggressive turning makes the issue worse. Tiny Bubbles are not your friend. I have the HV pump on a fresh engine and hot oil pressure at idle is around 40 psi. Also a Milodon Pan w/ baffles etc. Small investment to keep an engine alive under agressive driving.

Marion
 
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