Ive been getting conflicting opinions on this topic. I read in carcraft to get a HV pump for the rebuild but I have read on this board to get a standard volume with the mr.gasket high pressure spring. In carcraft, it specificly says 'volume is what you want, not pressure.' What do you guys think?

 

What engine is this going into, stock, rebuilt? Powerband? What do you plan to do with the car? How tight are the bearings, or how tight will the bearings be(if you are rebuilding). A stock pump is plenty in most HP street applications. The better spring is a little extra insurance. High pressure pump isn't normally needed.

 

Have you modified the lubrication system? Modifications that would require more volume would be adding timing chain oil nozzles, priority main oiling with gundrilled galleries in the crank and case, valve spring cooler manifolds/nozzles, etc.

For most stock-like rebuilds, where the lubrication system is not altered significantly, a high volume pump is unnecessary and will only create more load on the cam gear and distributor. New bearing shells and proper tolerances will provide more than adequate oil pressure at a flow that the stock pump can easily deliver. Chevy didn't skimp on the pump capacity when the original SBC was designed, and has really only been cutting it a little too close in later years, since fuel mileage has been a prime concern. Late engines have pump gears that may actually be sized a little too small for my comfort on some engines, while others control (reduce) the oil pressure at idle by controlled bleeding.

 

No mods to the lube system. It will basicly be a stock rebuild with a little umph as a daily driver, 10:1, ported heads, mild cam, and HSR. I put the crank in yesterday and all the main bearings clearances were at .002 and I was gunna do the pistons tonite but my ring compressor broke.(DAMN YOU EBAY!) So should I just get the standard volume melling and forget the spring?

 

Use the standard Mellind pump, and also the spring. The spring raises the pressure but not the volume; if you get the regular cheap Melling M55 pump, it will have a spring that regulates it to around 35-40 psi; the Mr G spring sets it to about 55-60, which is what the expensive Melling pump (M55A) would also put out. For that matter, the M55HV or the M99HVS would also produce about 55-60 psi.

Like Vader said, if you haven't modified the stock oil flow system, and you're running stock bearing clearances as you are, the HV pumps will do no good for you and will be a net loss. But upping the pressure would be a good thing.

 

A high volume pump can, under certain conditions, suck a stock 5 quart oil pan dry. Stick with the standard pump, it's all you'll even need.

 

don't believe everything you read. lot of them guys talk a lot and don't do much, and if they break something it usually doesn't cost them much if anything to fix it again

 

I guess I'm missing something here?!? Are you referring to the advice given in the above posts?


Anyway...

I'll have to pretty much agree with the other posts. If the engine will be built close to stock, ( RPM range etc ) I'd go with a stock type pump. Me personally, I've built more than few small block chevy's over the last 15 years or so, and I've never had trouble using a stock type replacement pump. I used to use the GM "Z28" pressure spring, but have since just started using a regular plain jane Melling replacement.

The BIGGEST thing you can do to help extend the life of your engine and increase durability is probably one of the cheapest if you do it yourself. All it takes is some time, a few tools and attention to detail. Triple-checking all the clearances in the engine, especially main and rod bearing clearance will greatly approve engine durability, as will spending the extra $ to have the rotating assembly balanced.

Get just about any Vizard book about Blueprinting the SBC, the only added expense is sometimes having to buy individual bearings to get the desired clearance, but most of this depends on how good your core is and how good the machine work done on it was.

The stock SBC oiling system was designed to support the engine up to 6000 RPM. So it's safe to say that there's a good bit of cushion there. And besides, if it's primarily a street driven engine, you better build it to make it's power peak alot lower than that, or it will be a dog to drive on the street ....

I think the single best thing you can do for the SBC oiling system is simply smoothing any and all casting flash or protusions in the block itself, and after a good cleaning(s) of the block, paint the lifter valley with a Glyptol (sp?) type paint, it greatly helps the oil flow back down to the pan to start it's cycle all over again.

READ THIS

It will answer most if not all of your questions on this subject, and is very informative.


HTH

 

i meant all you read in the hot rod mags, sorry guess i could of been a little clearer, i knew exactily what i was trying to say.

 

go with the standard pump..no need for the high volume or high pressure..waste of money.

 

http://www.melling.com/support/bulletins/default.asp

Never happen.
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.


http://www.melling.com/support/bulletins/view.asp?id=12

 

dear friend...DO YOU NEED IT???
if you are going no more than 5000 rpm, then you dont.
if your going up to 8000 rpm then yes, you do big time
i've just read it at "chevy high performance"
one of the reasons also being that a takes more power to move a high volume pump than a stock one.
good luck.
Fernando.

 

I have another question and I figured I ask it here since most of you will get an email message. Is there a gasket that needs to go between the oil pump and main bearing cap? Thanks
BTW, I went with a standard volume with the high pressure spring.

 

no gasket on a SBC, or a lot of other if not all GM engines.