polo708

What is the determining factor in choosing an oil pump?

Im building a 347 stroker with AFR 185cc heads an a Comp Cam XE274HR cam. Should I go with a standard oil pump or a high volume oil pump?

standard: http://www.cjponyparts.com/oil-pump-...-1973/p/OILP2/

hi-volume: http://www.cjponyparts.com/oil-pump-...-1973/p/OILP3/

polo708

Also I see a lot about Melling oil pumps... anyone running these "sealed power" pumps?

GTnotchback

Im using high volume melling with APR rod.

tinman

Melling is a very good oil pump IMO.
I'm using a high volume onr on my 352SBF, works good......

bluebeastsrt

Same here.

Maxwelhse

Melling all the way.. Sterling reputation throughout the big 3..

Just for reference, what you generally don't want is a high PRESSURE oil pump.. High volume is the way to go.

Duncan_GT

You guys w HV pumps - does the pump suck the pan dry?

Maxwelhse

There is a reason that swinging pickups and baffled oil pans exist in the world...

YES, the pump CAN suck the pan dry given the right opportunity.

tinman

I don't know about a swinging pick-up for a small block Ford but if the tube diameter is to big you could easily suck the sump dry........

wydopnthrtl

When you have larger than stock bearing clearances and/or higher than stock rpms and/or higher piston loading... you'll want to step up to a high volume pump to cover the unstudied unknowns.

The stock oil pump is calculated, tested, and approved to be adequate for the OEM spec'ed oil viscosity, OEM regulated (max) rpms, and OEM bearing clearances.

Change any of those and you change the pressure and/or volume needs.
Since none of us have the resources to test this.. we just put in high volume pumps to cover the unknowns.

Taking the path of only higher pressure is not necessarily a bad thing if your just talking about small power & rpm increases. But the downside is that a stiffer spring in the regulating valve might not last as long. (it all depends on how much homework the oil pump maker has done. (springs have life cycles just like everything else in the world)).

Also, w/o adequate oil volume & pressure there will be a possibility of cavitating the oil at high rpms. A situation where the oil supply has inadequate pressure and/or volume to keep up with whats needed for the bearings and raceways to stay separated.

My advise is based on me building my own engines & spending over 20yrs in drivetrain engineering..... if your under a 35% power improvement, stock bearing clearances, and not going more than 200-300 high rpms higher than stock limits.... just use a stock pump and premium synthetic oil. (I generally like to use 10W-30 Mobil 1 for the typical "bolt on" engine because its fairly cheap. Costco btw..)
If your going over 35% increase in power... open up the bearing clearances by about 20%, use a high quality high volume pump, open up the puck to pan clearance by 3-6mm more than stock, use a larger oil filter, and use the least viscosity oil you can to try and achieve 10psi per 1000rpms. (once the oil is hot)