Stock or higher flow or pressure oil pump

i'd suggest a bigger capacity oil pan if your going to run a HV pump. a HV pump on a stock pan increases the risk of sucking the pan dry under prolonged periods of high RPM

I'm thinking it won't be necessary. The Vortech is a self contained unit that doesn't tap into your oil system right? High volume pumps are for loose (racing) bearing clearances.

Thanks to Stangnet member bubba-dough for helping to educate all of us...

http://data.melling.com/Tech pdfs/HIGHVOLUMEPUMPS.pdf
You will need the Adobe Acrobat viewer which is also a free download – http://www.adobe.com/products/acrobat/readstep2.html

From the Melling site, for those who didn't follow the link & read the tech note...



High Volume Pumps: Advantages, Myths & Fables

Most of the stock automobile engines are designed to operate from idle to 4500 RPM. The original volume and pressure oil pump will work fine in this type of application. As the demands on the engine increase so does the demands on the oiling system and pump.

The oil pump's most difficult task is to supply oil to the connecting rod bearing that is the farthest from the pump. To reach this bearing, the oil travels from three to four feet, turns numerous square corners thru small holes in the crankshaft to the rod bearing. The rod bearing doesn't help matters. It is traveling in a circle which means centrifugal force is pulling the oil out of the bearing.

A 350 Chevy has a 3.4811 stroke and a 2.111 rod journal. The outer edge of the journal travels 17.5311 every revolution. At 1000 RPM, the outer edge is traveling at 16.6 MPH and 74.7 MPH at 4500 RPM. If we take this engine to 6500 the outer edge is up to 107.9 and at 8500 it is 141.1 MPH. Now imagine driving a car around a curve at those speeds and you can feel the centrifugal force. Now imagine doing it around a circle with a 5.581, diameter.

The size of the gears or rotors determines the amount of oil a pump can move at any given RPM. Resistance to this movement creates the pressure. If a pump is not large enough to meet the demands of the engine, there will not be any pressure. Or if the demands of the engine are increased beyond the pumps capabilities there will be a loss of oil pressure. This is where high volume pumps come in; they take care of any increased demands of the engine.

Increases in the engine's oil requirements come from higher RPM, being able to rev faster, increased bearing clearances, remote oil cooler and/or filter and any combination of these. Most high volume pumps also have a increase in pressure to help get the oil out to the bearings faster.

That is what a high volume pump will do. Now let Is consider what it will not do.


It will not replace a rebuild in a worn-out engine. It may increase pressure but the engine is still worn-out.

It will not pump the oil pan dry. Both solid and hydraulic lifters have metering valves to limit flow of the oil to the top of the engine. If a pan is pumped dry, it is because the holes that drain oil back to the pan are plugged. If the high volume pump is also higher pressure, there will be a slight increase in flow to the top.

It will not wear out distributor gears. The load on the gear is directly related to the resistance to flow. Oil pressure is the measure of resistance to flow. The Ford 427 FE "side oiler" used a pump with relief valve set at 125 psi and it used a standard distributor gear. Distributor gear failures are usually caused by a worn gear on a new cam gear and/or worn bearings allowing misalignment.

It will not cause foaming of the oil. With any oil pump, the excess oil not needed by the engine is recirculated within the pump. Any additional foaming is usually created by revving the engine higher. The oil thrown from the rod bearings is going faster and causes the foaming. This is why high performance engines use a windage tray.

It will not cause spark scatter. Because of the pump pressure there is a load on the distributor gear. The number of teeth on the oil pump gears determine the number of impulses per revolution of the pump. In a SB Chevy there are seven teeth on each gear giving 14 impulses per revolution. At 6000 RPM the oil pump is turning 3000 RPM or 50 revolutions per second. To have an effect on the distributor, these impulses would have to vibrate the distributor gear through an intermediate shaft that has loose connections at both ends. Spark scatter is usually caused by weak springs in the points or dust inside the distributor cap.

High volume pumps can be a big advantage if used where needed. If installed in an engine that does not need the additional volume, they will not create a problem. The additional flow will be recirculated within the pump.

jrichker said:

High volume pumps can be a big advantage if used where needed. If installed in an engine that does not need the additional volume, they will not create a problem. The additional flow will be recirculated within the pump.

Click to expand...

I don't think that article is very good. The sentence in the quote gives it away.

How many people have twisted their stock oil pump drive shafts into twizzlers? What the heck does it mean that the additional volume will not create a problem? Sure, it won't create a problem if you are aware of the oil pump driveshaft issue and make changes to accomodate it.

Secondly, there was a lot of talk in there about uncommon or drastically varying situations. Such as the 427 side oiler with 125psi of oil pressure. How many people have those, and how many engines run that kind of psi? Definitely not our 5.0's. Then you have the talk about the chevy 350, which is widely known as having serious oiling problems. Adding a high volume pump to a SBC is just giving it normal oiling. SBF engines have never had any oiling problems with stock pumps, even when serious modifications have been made.

I am really surprised Melling produced that article, they make great pumps, but I think that article is

It totally is dependent on the bearings clearances, othewise you will not see the benefits of the higher flowing pump.

I find most aftermarket stroker cranks allow for a large rod side clearance .020"+, this will allow the oil to escape and you will not see the pressure people normally associate when using a HP pumps.

I'd suggest a Melling 10833, this is a High Peformance series pump that has a larger body with a adjustable relief spring that features 25% more volume. I'd run this with a nice 7qt pan of your choice.

Black1987Stang said:

Nah Vortechs aren't self-contained, they need oil pressure fed to them and a oil return back to the pan....I'll be using a stock pan so I'll probably go for the stock volume, if a high volume is for loose clearances, what's high pressure made for?

Click to expand...

High pressure pumps are for engines with loose bearing clearances.
High volume pumps are for engines built to spin at higher rpm than stock and also increase oil pressure in loose clearance engines.

Sounds like you need a high volume pump and a bigger capacity oil pan to feed your engine's higher rpm and feed the Vortech. If you do get the HV pump, make sure you also get a hardened oil pump shaft. The stock shaft is too weak for a HV pump and could twist itself into looking like a drill bit or break altogether.

i installed a melling during my vortech install. heel, i think the pump was like 40 bucks at the local speed shop