Thoughts on high volume oil pumps?

[dailydriver]

Originally Posted By: GMBoy
Leave it alone. The powertrain engineers have ceritfied the stock oil pump to be more than enough under all conditions the truck may encounter including max towing.


Ok, but about a well (ab)used (150K+ miles), stock LS1 pump??

Would it be worth it to replace that to stave off future; wear/failure/problems just due to mileage while one was already in there replacing the timing set anyway with a 'low cost factory upgrade' LS2 single roller timing set??

I was looking at the Scoggins-Dickey graphite coated deal, the Katech one (pretty much the GM factory racing builder), and the Schumann Motorsports Sportsman unit with the ballcheck valve, ALL stock oil pressure, but supposedly slightly higher volume.

 

[dailydriver]

Originally Posted By: dailydriver
Originally Posted By: GMBoy
Leave it alone. The powertrain engineers have ceritfied the stock oil pump to be more than enough under all conditions the truck may encounter including max towing.


Ok, but about a well (ab)used (150K+ miles), stock LS1 pump??


The above should be "but WHAT about ....."

 

[440Magnum]

Originally Posted By: dailydriver
Originally Posted By: GMBoy
Leave it alone. The powertrain engineers have ceritfied the stock oil pump to be more than enough under all conditions the truck may encounter including max towing.


Ok, but about a well (ab)used (150K+ miles), stock LS1 pump??

Would it be worth it to replace that to stave off future; wear/failure/problems just due to mileage while one was already in there replacing the timing set anyway with a 'low cost factory upgrade' LS2 single roller timing set??


How is the oil pressure NOW? If its in spec at hot idle without going to thicker-than-recommended oil, then the pump is just fine. Now if its BARELY in spec by 1 psi or something, then it might be worth it depending on how much further in you have to go (I'm not intimately familiar with the LSx engines).

 

[rslifkin]

Originally Posted By: 440Magnum
How is the oil pressure NOW? If its in spec at hot idle without going to thicker-than-recommended oil, then the pump is just fine. Now if its BARELY in spec by 1 psi or something, then it might be worth it depending on how much further in you have to go (I'm not intimately familiar with the LSx engines).


Exactly. If a standard volume pump can produce enough pressure, there's no reason to go to the high volume. Now, if you're bleeding off some oil for a bypass filter, etc. that will cause a pressure drop, then sure, go for the high volume pump.

 

[3311]

A Melling 10296 with the stock spring installed and be done with it!!!!!! I will install one on my 06 below as a preventive measure soon and whatever I do with the 04 below it will have one as well. If you ever need the volume it's there and if not it just bypassed internally within the pump. No reason not to run one, especially on a higher mileage engine. I doubt if any power loss would be measurable.

These pumps use an aluminum housing, not cast iron like the old in pan pumps and turn at twice the rpm. That is one of the benefits of the front crank mounted oil pumps, it helps with cavitation. But twice the rpm = much more wear especially when considering the aluminum housing and bypass valve bore.

 

[440Magnum]

Originally Posted By: 3311
If you ever need the volume it's there and if not it just bypassed internally within the pump. No reason not to run one, especially on a higher mileage engine. I doubt if any power loss would be measurable.


I actually disagree there. When the oil is bypassed in the pump, its squeezed up to the relief pressure and then blasted through a small opening back into the pump inlet at low pressure, where the cycle repeats. So the oil is both sheared and heated significantly during pressure relief events. And the power loss may not show up *much*, but its there. The power it takes to run a pump is proportional to the product of the volume pumped across a pressure differential times the pressure differential. For the same pressure setting (the pressure differential), a high-volume pump always moves a higher volume across that pressure differential than a stock pump, and whether that oil is then dumped through the bypass or not doesn't matter because its still discharged back to the lower pressure side. If its 2x the volume, then it takes 2x the power.

I say this having installed HV pumps on my two 440s. For the new build engine (in the '66) its one of the things I'd do differently if I were building the engine again. And in fact, I may change the pump to a stocker this summer- its relatively easy on a 440 since the pump bolts to the outside of the block.

 

[3311]

Originally Posted By: 440Magnum
Originally Posted By: 3311
If you ever need the volume it's there and if not it just bypassed internally within the pump. No reason not to run one, especially on a higher mileage engine. I doubt if any power loss would be measurable.


I actually disagree there. When the oil is bypassed in the pump, its squeezed up to the relief pressure and then blasted through a small opening back into the pump inlet at low pressure, where the cycle repeats. So the oil is both sheared and heated significantly during pressure relief events. And the power loss may not show up *much*, but its there. The power it takes to run a pump is proportional to the product of the volume pumped across a pressure differential times the pressure differential. For the same pressure setting (the pressure differential), a high-volume pump always moves a higher volume across that pressure differential than a stock pump, and whether that oil is then dumped through the bypass or not doesn't matter because its still discharged back to the lower pressure side. If its 2x the volume, then it takes 2x the power.

I say this having installed HV pumps on my two 440s. For the new build engine (in the '66) its one of the things I'd do differently if I were building the engine again. And in fact, I may change the pump to a stocker this summer- its relatively easy on a 440 since the pump bolts to the outside of the block.

If I'm reading your post correctly, your saying that a hv(not high pressure) pump will have a higher flow than a standard pump at the same pressure? For example, if both pumps are at 20 psi then your saying that hv is pumping a higher volume?

This is contrary to my understanding. I thought that the bypass valve, clearances, rpm etc.. determines pressure. Within an engine, it's my understanding that the two pumps will move the same volume at the same pressure but the hv has a greater ability to maintain that pressure as demand increases, from wear, temperature etc... Isn't this correct?

 

[Shannow]

typical pumps are positive displacement...simplistically, they shift the same amount of oil from low to high pressure per revolution. A higher volume pump shifts that proportion more per revolution...every revolution.

Consider the pressure supplied, as a funnel, atop a hose and held a height above the engine (say 60 psi oil pressure, that's about 160-165 feet of hose straight up). That head pressure will force a certain amount of oil into the engine in a given period of time.

A properly size oil pump will fill the funnel at the same rate that it drains out of it, keeping a constant oil level. Too much flow will overflow the funnel.

Now take the funnel out of the equation, and have the pump feed the bearings directly.

The properly sized pump will feed the bearings exactly the right quantity of oil at 60psi to keep oil to the bearings. The pump will use the minimum power consumption that the lubrication system needs.

A high volume oil pump (that would make the funnel overflow in that analogy) is positively shifting oil every revolution, but shifting too much for the engine to swallow.

Two ways this can end is to increase the pressure until takes all of the oil (can break stuff, burst filters etc.), or flow through the bypass valve that controls the top of the oil pressure (height of the funnel).

The extra oil flowing through the bypass in the high volume example has been pumped and pressurised, and is then released through the bypass valve. That takes work,and makes heat.

A high volume pump, on a stock engine will suck more power to run it, and that extra power is converted into oil heat, which cooks the oil unnecessarily.

 

[SteveSRT8]

Originally Posted By: Shannow

A high volume pump, on a stock engine will suck more power to run it, and that extra power is converted into oil heat, which cooks the oil unnecessarily.


THIS! I have seen this countless times in many different engines. Unless you have oil squirters or some other need you likely do not need a HV or HP oil pump.

 

[3311]

I'm skeptical that parasitic losses or heating could be measured reliably. To be sure there are small parasitic losses. With respect to heating and shear, and although these crank mounted gearator pumps bypass within the pump, the oil oil doesn't stay there very long. It either leaks out of the pump housing or pumped through the circuit.

If you look at the volume that these pumps, stock as well as hv, move here in this thread a few posts down. They are moving gallons per minute relative to the housing holding probably a few ounces(~8 if I had to guess). I betting any additional oil heating would be immeasurable

http://ls1tech.com/forums/generation-iv-internal-engine/1505847-aftermarket-oil-pump-necessary.html

IMO, and I'm certainly not an engineer, there will be a point in an engines life when it will become beneficial to run a hv pump, so run one and it's there when needed. This especially holds true IMO with the aluminum housed gearator crank pumps the turn at twice the rpm of the old cast iron body cam driven pumps where only a few thousandths of pump body wear menas the pump is worn out.

 

[SteveSRT8]

While it is your truck and you get to do whatever you want, please note that my FANATICAL quality freak 3rd generation machinist disagrees with you.

And he builds them for a living!

But you are correct in the matter of it is unlikely to actually hurt anything.

I have a 6.0 in his shop right now being redone better than new. It will go in a 3500 Savana van that weighs right at 9200 pounds every single day and runs the hardest duty cycle on the planet.

It will have a brand new STOCK oil pump...

 

[Shannow]

Originally Posted By: 3311
I'm skeptical that parasitic losses or heating could be measured reliably. To be sure there are small parasitic losses. With respect to heating and shear, and although these crank mounted gearator pumps bypass within the pump, the oil oil doesn't stay there very long. It either leaks out of the pump housing or pumped through the circuit.


Laws of physics will let you calculate the heat rise directly.

If 10% of the flow is going through the bypass, then 10% of the pump power is doing absolutely nothing but adding heat to the oil.

 

[3311]

Originally Posted By: Shannow
Originally Posted By: 3311
I'm skeptical that parasitic losses or heating could be measured reliably. To be sure there are small parasitic losses. With respect to heating and shear, and although these crank mounted gearator pumps bypass within the pump, the oil oil doesn't stay there very long. It either leaks out of the pump housing or pumped through the circuit.


Laws of physics will let you calculate the heat rise directly.

If 10% of the flow is going through the bypass, then 10% of the pump power is doing absolutely nothing but adding heat to the oil.
I'm sure your correct, but how much will the oil heat up if it is there for a very short time?

 

[3311]

Originally Posted By: SteveSRT8
While it is your truck and you get to do whatever you want, please note that my FANATICAL quality freak 3rd generation machinist disagrees with you.

And he builds them for a living!

But you are correct in the matter of it is unlikely to actually hurt anything.

I have a 6.0 in his shop right now being redone better than new. It will go in a 3500 Savana van that weighs right at 9200 pounds every single day and runs the hardest duty cycle on the planet.

It will have a brand new STOCK oil pump...
I'm sure it will work well for you. I'm gonna pm you about your machinist.