I have heard in the past that putting in a high volume hig pressure oil pump with the stock pan will suck all of the oil out of the pan, leaving maybe 1 quart, even with a windage tray. Is this true? Do I need to buy a higher capacity pan for the high voume pump?

 

rule of thumb is with a HV pump you need a larger pan. why do you want a HV pump?

 

I've ran a stock 4 qt pan with a high volume pump. Never ran dry on me. Guess it's possible though, but doubtful.

 

run it at or above 6000 rpm for any period of time and see how much oil stays in the pan. HV pumps are soemthing lot of people think they need when in fact they don't. standard M55 pump is all any street and most preformance engines will ever need.

 

Very interesting ede. I have always been taught that the high volume pump (with in reason) is basically a security blanket. I had never actually heard any hp gains on them, just safety. I would like to try running a high volume pump, but I would not like to have to change the pan if the stock pan was not enough.

My apologies for the misspelling in the subject.

 

Not only is it possible, it's actual. It happened to me. Spun #3 & 4 rod bearing. It pumps the oil out of the pan faster than it drains back. Not what I would call a safety blanket.

 

the only time i put a higher volume pump on a motor is when its a extreme high mile junker that im playing around with...

and even then, i cleanup the drainback holes in the heads so the oil can fall back to the pan...

 

It may actually hurt performance ...The pump will rob more power to operate itself and and extra oil pressure will put un-needed stress on parts.

 

I would also switch to a HV pump when bearing clearances are increased. Get the M55 per ede's suggestion. Then get the little $4 spring from Mr. Gasket. The m-26 or something like that. That increases the pressure of the oil, without increasing the volume itself.

 

http://www.melling.com/highvol.html

Good reading.

 

I use a high volume pump with the high pressure spring in a stock pan, and i rev to 7,000 without problems...

just my experience.

 

Where can I get the M55 or M56? Who makes them, Melling or GM? I don't plan on spinning past 6,000 so I should be OK by your oppinions.

 

The M55 is produced by Melling. Summit sells the M55. Im sure your local auto parts store probably carries them.

 

I never could understand why so many people are against HV oil pumps. I just said that I personally have not had a problem with them.

It seems others have though.....

 

think auto zone sells melling pumps. get the m55 pump, the mr gasket #26 spring, new pick up, a solid drive shaft from arp or melling, weld a brace from the pick up to the pump body and bolt it.

 

we stock the M55HV at Advance Auto parts...

 

i actually take the high perssure spring that it comes with out, and stick a stock one in..

i dont need higher pressure...just more volume.

the higher pressure wont do anything but push harder on everything... sure it makes the gauge look good, but thats about it.

 

OK. I found the M55 in some of my catalogues. They also offer a high volume M55 and a regular M55 that I could buy a diferent spring for. Mr. Dude, you said you used the high volume but not pressure, would it be good for me to do the same? I now understand more on the pressure side. As for increasing the volume it will pump, I don't know.

 

The HV version comes with two springs as I recall. One for higher pressure, the other for high volume. I used the high volume spring. But my stock oil pressure gage still pegged out when the engine was cold. (ran around 65 PSI cold).

Not sure what type of application that you'd want to use the high pressure spring for, like Dude says...

 

This is the honest truth...the only real reason to use a HV pump is if you have a bleed off, such as a turbo or supercharger that has oil running thru it and back to the pan. In normal situations all it does is put wear and stress on the timing chain, dist. gear and related parts, besides loss of power. And the above mentioned pitfalls.

 

PRESSURE and VOLUME are NOT the same thing.


the pressure is determined by the spring. when the pressure is high enough, a piston pushes on the spring, and the extra oil goes back into the pan.


the VOLUME is determined by the gear height. the oil pump is a simple pump.. two gears mesh to pump the oil.. by making the gears taller, they displace more... and that means more volume.


you cannot change the volume of the pump. you can easily change the spring pressure.

 

<b>standard M55 pump is all any street and most preformance engines will ever need.</b>

I thought the Melling 55 WAS a high volume oil pump? thats why it came with the stock spring in case you didnt want it to be?

I put an M55 with my stock pan, it pushes 80+PSI when cold at idle, and 15-20PSI when hot at idle (900 rpm idle) at 600 rpms hot I get 12PSI (yes mechanical guage). during daily driving it rarelly goes over 45PSI when hot, but during WOT i see 60+ PSI.

But just for your "information", This exact same pump, before I rebuilt my motor (overheated) was putting out 5-8 LESS PSI at all times, I assume it was because of excessive main / rod bearing clearances. So that goes to show you that a M55 may push 50PSI on one motor but only 40PSI on another, etc etc...

 

m55 is standard pump. think the HV pump is m55HV BBC pump is m77 i think

 

i just swiped it off summits website:

 

Ok, so what is different about the M55A?? Does it come with the different pressure spring?

 

LOL -

What?? You don't think I know that? Of course they're not.

One spring is obviously a lower tension spring, and the higher tension spring is for higher pressure.

The pump itself has a set max volume per revolution. Your just adjusting bleedoff. I thought that was a given.....