high voume vs. factory spec oil pump

Attempting to look at this logically (bear with me), your bearing clearances and lifter orifices provide the resistance against flow, while your oil pump can deliver a predetermined amount of flow and pressure. The ONLY way you can flow TOO MUCH oil, and drain the pan, is if

A: the pump provides extremely high PRESSURE AND VOLUME, and pushes way too much oil through the bearings and to the topside of the engine through the lifters, or

B: The pump supplies a normal amount of pressure, but the bearings and/or lifters allow an excessive amount of flow.

In case A, it is clearly the fault of the oil pump, as the bearings and clearances were set up correctly, but excess pressure caused an abnormally high amount of flow. In this case, if a stock type pump, or a HIGH VOLUME (normal pressure) pump were used instead, the pan wouldn't get sucked dry and everyone would be happy

In case B, the pump CAN be a high volume pump, but as long as it has the correct pressure rating on the relief valve, that extra volume should just return right back to the oil pan. However, since there is inadequate oil restriction in the bearings and lifters, they allow that excess flow from the pump, and the pump is happy to oblige. In this case, if a stock type oil pump were used, you wouldn't suck the pan dry, but you would see a definite loss of oil pressure vs. the high volume pump, even though they were both rated at the same pressure.

In both cases, I think you are probably best off with the high volume, standard pressure, oil pump. If you have normal oil pressure (40-60psi) and are able to suck the pan dry, that is caused by other issues, not the pump, and the only way to lower the volume is to also lower the oil pressure which is generally not good a good thing.

Here's the link to the melling site's discussion on HV oil pumps

http://data.melling.com/Tech%20pdfs/HIGHVOLUMEPUMPS.pdf

To the original poster. FE engines like lots of oil pressure and flow. Do what you can to get both.

the myth is still out there. The pump is not the cause of a dry oil pan. Nor have I ever seen it happen in the 20+ years of being around race cars. Both circle and drag. The Melling site explains this myth in quite detail under the heading "This is what a high volume oil pump will NOT do "

I too have been using HV oil pumps for more than 25 years with NO problem. That is till my 460 started to lose oil pressure at 4600 rpm. see other post.

The point I want to make is if it was never pumped dry with a HV pump on a 6 quart pan the same pump sure isn't pumping this 10 quart pan dry now is it? But I'm loosing pressure.... windage!

I agree with the guys with the windage theory. I've had so much input while trying to figure out this problem of mine that I have to agree it's the pan, windage tray combo not the pump.

Does anyone know of this trick you can do to your oil pump (either stock pump or HV pump) to give it more oil psi readings both idle and WOT driving??

You don't necessarily have to change springs. Whatever spring a guy has can be shimmed up. In other words, what your pump is doing tells you what to do. Shimming the spring can boost the pressure as the system is configured now.

I hear this is a good trick that gives you more oil psi for those who have lower readings than they would like.

Yup, works. It's the poor mans bearing extender, lifter quieter ))

I knew a kid when we were back in high school that did that so he could take his worn out Mustang to the prom...

It took the tick out of it for a while.

So if what some of you state about HV pumps is true then you should not see any increase in oil pressure on the gage with a HV normal pressure pump verses a standard pump.

gotta be careful doing the shims tho because i have seen a few filters blown off because of it lol/.

Originally Posted by retyler

So if what some of you state about HV pumps is true then you should not see any increase in oil pressure on the gage with a HV normal pressure pump verses a standard pump.

Right.


About any pump can make an engine live while idling. Super low pressure super low volume. What happens when you rev it up? Needs more volume and needs more pressure. A HV pump is nothing special - somebody already posted that if the bearings are tight the extra flow just goes back to the pan. But, at high rpm's the extra flow may just save your engine when it gets into a marginal situation.

Cheap insurance. Some buy it, some don't.

In the '80's low volume low pressure pumps were on all engines from the factory. Many (many!!) engines died as a result of that decision to save 0.0001 mpg. My (ahem) Chevy Duramax runs 90 psi and is expected to go 250,000 to 500,000 miles (with a few already over 500k on original rings and bearings). I wonder why they are now using higher volume and higher pressure oil pumps? Could it be we expect engines to last 200-400K miles?

jb

jb

yeah what he said !