Hi volume oil pump vs standard volume pump

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moparmat2000

moparmat2000

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I got a few pump questions for y'all. I understand that all things being equal on an engine a high volume oil pump will produce a higher pump pressure as well.

On a rebuilt engine with a mild hop up with stock bearing clearances and maybe a 5,500 rpm rev limit is a high volume pump necessary? Does a high volume pump and higher pressure it produces actually hurt horsepower with its associated drag on an engine like this?

I can see a higher volume oil pump being used on a higher revving higher HP engine to protect its bearings, or in one thats got enlarged bearing clearances because its worn out and the high volume pump is being used to somewhat extend its life a bit.

Anybody else have any other facts on this? Am i off base with my thoughts on this?

Thanks
Matt
 
The pressure is controlled by the bypass valve spring regardless of pump volume. Pump output is linear with RPM so as the pump spins faster, it pumps more oil. As the pump tries to stuff more oil through the engine, the pressure will rise as the engine can only consume so much oil. Once the pressure rises to the point the bypass opens, any additional oil is just returned to the pan. A bigger pump will just cause the bypass valve to open at a lower RPM and then just pump more oil back to the pan. If the bearing clearances are within factory specs, a standard volume pump will open the bypass well before 3000 RPM. The larger pump offers no real advantage. If you use a stronger spring in the bypass valve, the oil pressure will be higher before it begins to dump back into the pan. Higher pressure does not mean more oil is going anywhere, sometimes the opposite. Higher pressure WILL increase the load on the intermediate shaft, cam and timing chain as well as requiring more power to operate.

The short answer is the stock oil pump is just fine for most applications with normal bearing clearances.

The old warning about a high volume pump sucking the pan dry at high RPM is not typically the case. Too much oil to the valvetrain is what causes that.
 
The 72 and the 72hv use the same pressure relief spring.
A standard pump with a larger pickup tube will out flow a hv pump with a stock pickup.
If you use a hv pump or install a high pressure spring I would use the intermediate shaft with the hardened tip.
So using a hv pump with a standard pickup tube is not going to do anymore than a standard pump but maybe twist off the end of the drive.
When the bypass kicks in the oil just circulates within the pump it does not go back to the oil pan.
 
The pressure is controlled by the spring, yes, but a high volume pump most certainly WILL make more pressure than a standard pump because it is pumping more oil into the same space, so pressure will certainly increase in comparison to the stock pump. Been there, done that.
 
70psi is 70psi. If you have a differant spring or the plug is pushed in farther on 1 pump you will have differant pressures.
 
Ok thanks. I am taking it from reading this is what i already surmized. That on a rebuilt stock or mildly hopped up engine with stock clearances that a standard volume oil pump will be just fine, and a high volume pump will offer no real additional benefit, and may in fact actually hurt performance. Rounding up parts for a mild 318 to build up with my kid as he gets older. Figured a stock volume pump would be just fine for what we will be doing, but wanted to verify what i knew.
 
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IDK how it works, and don't care.
On my streeter, I put one on,(HV) with a 7qt pan, so I could engineer more oil to the top end to protect my expensive valve gear, and to cool my valve springs at 7200rpm. It seems to have worked cuz the engine has accumulated over 100,000 miles on it since year 1999 with no top-end failures.
I have no clue about my oil-pressure, cuz I run the slow-to-respond stock 1969 factory un-calibrated gauge, which I never look at anyhow. The way I see it, if something happens at 7200, that's 120 revolutions per second, so even if I had the oilpressure gauge wired to my brain, and even if I could respond instantly, the engine would be cooked before it stopped spinning of it's own inertia. So I hardly ever almost never look at that gauge.

But one thing I can tell you is this;
the first time I revved it up, this engine blew oil out onto the passenger side header, which I traced to the oilfilter plate. This, after I ported the internal oil-passages and enlarged the oilfeeds to all the bearings, and supplied extra oil to the top-end, and with the same 15W40 oil, that I had always used, with never before having this issue. I doubled up that plate,drilled 4 more holes in it, and enlarged the hole up the center of the filter retainer, and switched to 10W30,and that was that.
How many stock engines have ever had this problem.

Ok so, at that time, I was running a Hughes HE2430AL, and somebody is gonna ask why I would spin that 360 all the way to 7200, when clearly the power of that cam peaks around 5200. And the answer is; cuz I can. It's a streeter. And I like the sound of twin 3" full-length trumpets screaming like banshees, drowning out the screaming tires; from zero to 60, for 5 to 6 seconds atta time. If your engine could do this, you would wind her up too. It's extremely addictive. Well to me anyway.

So for me, the HV pump is really cheap insurance.
 
You would never be able to feel the "hurt performance".
 
AJ/FormS said:
IDK how it works, and don't care.
On my streeter, I put one on,(HV) with a 7qt pan, so I could engineer more oil to the top end to protect my expensive valve gear, and to cool my valve springs at 7200rpm. It seems to have worked cuz the engine has accumulated over 100,000 miles on it since year 1999 with no top-end failures.
I have no clue about my oil-pressure, cuz I run the slow-to-respond stock 1969 factory un-calibrated gauge, which I never look at anyhow. The way I see it, if something happens at 7200, that's 120 revolutions per second, so even if I had the oilpressure gauge wired to my brain, and even if I could respond instantly, the engine would be cooked before it stopped spinning of it's own inertia. So I hardly ever almost never look at that gauge.

But one thing I can tell you is this;
the first time I revved it up, this engine blew oil out onto the passenger side header, which I traced to the oilfilter plate. This, after I ported the internal oil-passages and enlarged the oilfeeds to all the bearings, and supplied extra oil to the top-end, and with the same 15W40 oil, that I had always used, with never before having this issue. I doubled up that plate,drilled 4 more holes in it, and enlarged the hole up the center of the filter retainer, and switched to 10W30,and that was that.
How many stock engines have ever had this problem.

Ok so, at that time, I was running a Hughes HE2430AL, and somebody is gonna ask why I would spin that 360 all the way to 7200, when clearly the power of that cam peaks around 5200. And the answer is; cuz I can. It's a streeter. And I like the sound of twin 3" full-length trumpets screaming like banshees, drowning out the screaming tires; from zero to 60, for 5 to 6 seconds atta time. If your engine could do this, you would wind her up too. It's extremely addictive. Well to me anyway.

So for me, the HV pump is really cheap insurance.
Click to expand...
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Yours is a far cry from a stock 318 and you have modiflied your passages.

I like the sound at 7500 even more.
 
Jadaharabi said:
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you have modiflied your passages...........
Click to expand...
As everyone should. With the stock system, all it takes is one little mistake.

I have always run manual transmissions, and it's all too easy to make one little mistake, and lose an engine. I made that mistake twice, and I wasn't gonna let it happen again.
And sure enough I made the mistake again. This time I saw the tach needle crossing the 8000line, on it's way back down! Daymn!!. But this time the engine lived.
So I fixed that stinking shifter and haven't missed a shift since 2004.
My engine is very plain. It's just a zero-deck 360 with Eddies and bolt-ons. I did however, have it externally balanced, and told the machine shop I intended to spin it excessively. Whatever they did, they done good. That combo hit 60 at the top of first gear,with 3.55s.
 
Due to the 20% taller gears on the HV pump, the pressure will rise more quickly are the RPM's below where the relief valve opens. So at low RPM's and hot temps, an HV pump will maintain better pressure into the engine.

Just to clarify, when the pump's relief spring opens it does not return oil to the pan. It just allows some of the output oil to recirculate to the input side of the pump.

And, the torque and HP required to drive the pump only varies that same 20% when going from a standard pump to an HV pump. Any change in HP required is down in a fraction of an HP; the concept of 'power-robbing' with this is nonsense.

For Matt, IMHO it more depends on the temps and oil selection. In hot Texas, it might be better to have the extra hot temp pressure capability afforded by the HV pump. But if it is just a throw-together engine, then OK on the STD pump. Having good tight tolerances is more important.
 
I don't know the formula off the top of my head but a 20% in pump capacity is not equal to a 20% increase in flow. The flow is greater than 20%. So since the hole it is going thru is not increased it backs up and the bypasses kicks in.
 
Jadaharabi said:
The 72 and the 72hv use the same pressure relief spring.
A standard pump with a larger pickup tube will out flow a hv pump with a stock pickup.
If you use a hv pump or install a high pressure spring I would use the intermediate shaft with the hardened tip.
So using a hv pump with a standard pickup tube is not going to do anymore than a standard pump but maybe twist off the end of the drive.
When the bypass kicks in the oil just circulates within the pump it does not go back to the oil pan.
Click to expand...
You are correct about the relief circulating oil back within the pump.
Here is a picture of a small block pump that I had with a stuck open relief valve. The discharge side of the pump is at the top. The red arrow shows the relief valve partly stuck in the open position allowing some discharge oil to return back to the suction side of the pump.

100_4218.JPG
 
IMO I would not use a hv oil pump with a stock oil pan . Due to the risk of pumping the pan dry at upper rpm's . A standard pressure pump is o.k. with a deep pan , however . If you have fully grooved main bearings , you need extra volume , though .
 
I had an issue with a high volume oil pump that make me keep a better eye on things. I’m bad at looking at gauges on 8-9 seconds passes down the track. Luckily I have a RacePak in my Duster and while looking at data apparently my bypass spring was sticking and my oil pressure was jumping up to 130 of pressure. Again lucky my Wix oil filter was up to the task of not blowing apart.
 
Only need to use a HV pump if you move significantly more oil than oem design. High bearing clearances aren’t enough. A HV pump is reserved for large bearing clearances with ported oil galleys with an oil cooler, a turbo, etc.
 
I use hv oil pumps on the bracket cars and my street driven duster with a stock oil pan....and it has seen a few trips down the track....and it does not pump the pan dry..LOL....old wives tales never stop....

so use what you want and makes you sleep at night....
 
in a 1/4 mile a H.V. pump will not suck a 5 quart pan dry . but in a mile I have been there, zero pressure on the gauge-my friends 327 with 4.88 gears on a street blast. Smokey tested pickups-the screen type is much better-90% open, 10% metal. the bunch of drilled round holes is 50% open
 
pittsburghracer said:
I had an issue with a high volume oil pump that make me keep a better eye on things. I’m bad at looking at gauges on 8-9 seconds passes down the track. Luckily I have a RacePak in my Duster and while looking at data apparently my bypass spring was sticking and my oil pressure was jumping up to 130 of pressure. Again lucky my Wix oil filter was up to the task of not blowing apart.
Click to expand...
Not an issue with the HV pump per se.... that's an issue with the relief valve sticking which is identical in both types. Impressive on he WIX filter! I can see not looking at gauges for 8-9 seconds of fast action.....
383Scampman said:
IMO I would not use a hv oil pump with a stock oil pan . Due to the risk of pumping the pan dry at upper rpm's .
Click to expand...
Misconception due to the term 'high volume'.... The oil flow is set by the pressure into the engine, the restrictions in the engine's oil system, and the viscosity of the oil. Since both the standard and HV pumps can have the same pressure relief springs in them, they will pump identical amounts of oil at high RPM's where both will be pushing pressure up to either of the relief spring settings.
 
Early this year when I built my daily driven 360 I put a stock oil pump in it thinking everything would be all right.
Well, it wasn't.
Whenever the oil got warms up, the oilpressure at idle drops considerably to well below 20psi.
This was with 10w30 oil, to which I switched to 10w40 oil, which still has this issue.
I'm thinking the hydrualic lifters' oil bands are very close to the top of the lifter bores, causing them to bleed a lot more oil at low rpm and warm/thinner oil.

Short of changing the lifters (to solids) I plan to install a HV pump very soon first to see if this helps the situation.
 
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