Can somebody explain to me what is the purpose of a high volume/pressure oil pump and what are their pros and cons. My '88 GTA 350 has a high pressure pump(already installed when I bought the car) and at warm up it soars to 70 psi until normal temp and then seems to act normal. Should I counter the high pressure with synthetic oil or just remove it completely?Does it benefit our cars or a waste off money.

 

Zim,

A high pressure oil pump can be desireable if the engine load is going to be excessive. Higher rod and crankshaft loads will tend to shear the oil film in the bearings more easily, and the additional pressure from a higher pressure pump can offset the initial loading to a higher pressure, presumably maintaining the oil film to a greater load point.

A high volume pump is usually not necessary, and can be a waste of energy. High volume pumps can be necessary if changes are made to the lubrication system when the engine is built. Timing chain oil nozzles, priority main oiling, valve spring cooling lines, and other modifications can result in a higher demand for oil flow to maintain an adequate pressure. This is where a higher volume pump is necessary.

For most (99%) of the applications, the volume of a standard oil pump is more than adequate. Even the addition of an oil cooler doesn't increase the demand for oil flow, so they usually aren't necessary.

Incidentally, changing to synthetic lubricants won't necessarily lower the oil pressure. Since synthetics have much greater thermal stability, the oil pressure would be about the same at cold start, but would tend to remain higher as the engine warms compared to regular mineral oils. Changing to a lower viscosity oil may lower the pressure, but be careful to maintain adequate pressure when the engine is fully warmed. I'm using 20W50 Mobil 1 in my TA, and the starting oil pressure often exceeds 70 PSI on cold starts. Since I allow my engine to warm before driving it, and only use the car in the summer, it isn't a major issue. Pressure generally drops to 45-50 at hot idle once the temperature reaches normal.

 

i use a standard melling m55 with a mr gasket #26 spring. works great for street and strip. only time i'd use high volumn is with a larger pan and high preasure with wider bearing clearances

 

Thanks guys for the info.

 

I've got a high flow/high volume oil pump and was wondering would i have any type of problems with it. It's going in a mostly street driven car that will see high rpms 4000+rpm, use a oil cooler and i'm going to use the stock pan. Supposely the pumps going to have about 70psi.

 

the big draw back to a HV pump is it'll pump all the oil to the top end at upper rpm range. most likely not a problem on the street and normal driving. like i said i like a standard melling m55, it's cheap and it works

 

I use 15w-50 moble1, it holds 60 PSI or so at 180* over that it drops off to about 45.

 

If it has 5 bolts on the cover its a BB pump and will take more hp to turn than its worth. Get a dynagear HV pump. It has larger internal passages. And make sure your have a larger pan and good oil drainback.

 

Say i just bought a high volume oil pump for my 7200 RPM blown 355 block thinking it was conducive to long bearing life. it will be a mostly drag car, seeing the high rpms for a few seconds (10 or less hopefully) then going back to idle. also streetable, i hope...
But anyways it comes with a spring to make it a regular volume pump, what do YOU think i should do? Im a firm beleiver in oil pressure, even if it costs me a few horsepower, but i dont want "all the oil to sit at the top of the engine" i know how that goes. should i Widen the oil return holes in the lifter valley or around the rockers or somthin?

<b>"At first i thought i was out of Gravy. the light came on and i see this gravy boat thing. then i realized i was getting a wish. my wish was for a new engine. it came true, cost me a fortune"</b>

 

I like the Seven/Seven rule of thumbfor the stock SBC pump. 7000 rpm/700 hp... Whichever comes first: then you need another one. They do excessively load the engine and well as hurt roller cam lifters, if their hydraulic.

 

start with the things that control pressure in the block. Like main bearing and rod side clearance. Keep mains to .0025 max (really .0022 is better but tough to obtain) and side clearance to .016".

don't use a torch to braze the pickup (your dink up the spring). Get a bolton pickup.

 

Im sorry excuse my ignorance but...
What do you mean? need a new what? 7000 RPMS then what happens to what? what excessively loads the engine and hurts the roller cams?

 

i weld a brace on the pick up and bolt it to the pump body, i wouldn't put heat on the pump cover even if a lot of people do.