Calculating oil pump requirements
 

I'm pretty sure I've got too much oil pump on my engine (dry sump) is there a way of figuring out exactly how much pump you need? Would you use total bearing area or another method? Or am I simply trying to find an answer that doesn't exist? Thanks Joe

Re: Calculating oil pump requirements
 

Joe--- I was told by a friend who is a mechanical engineer that the way an engineer calculates an engines requirements is to find the total surface area in the engine that needs to be lubricated , the thickness of the film you want, the replenishing rate you will need to maintain a cool steady supply of lubricant usually measured in GPM(gallons per minute)-- you then need to calculate the space need for the pump and the area ofthe pan. Its a complex set of calcu;ations--- quite simply I would call Tech @ Serdi/Peterson/Weaver see what these guys say--- Generally the amount of pressure in a hot engine with hot oil at idle should be sufficient to lubricate a drag engine at speeds less than about 8500 rpm----FED 387

Re: Calculating oil pump requirements
 

Thanks for the reply, yeah I figured there was more to it than I thought. I did speak to Peterson about a pump a couple years ago but he asked what my GPH requirement was you can guess my reply. Being as most of my oil is contained in the tank I thought maybe that would make it simpler. I suppose another call can't hurt, maybe it's not even worth the effort but it seems like it would be considering the load that seems to be on the pump when I oil prime it. Thanks again Joe

Re: Calculating oil pump requirements
 

Joe--- pump gear ratio determines how fast the pump is turning you don't need crazy RPMS I think the absolute pump max should turn like 57% of engine speed usually lots lower than that probably like 1/3 of engine speed and usually there is an adjustment on the pump to increase or decrease the pressure--- you only need so much to make it work and since the pump is belt driven we are talking HORSEPOWER here maybe as much as 15HP if ya got it all wrong. You definitely need to talk around see what these pump guys recommend. Just remember that the oil gets sucked out of the pan into the tank and then along with the help of gravity feed gets sucked out of the tank thru a little bitty hose to the pump to be dispersed thru out the engine ---That sucking/pumping takes a lot of power (horsepower) to run the pump. I'll bet you could get away with maybe around 30 pounds pressure to lube your engine ya really don't need 70-100 pounds. It'll be high when the oil is cold but as it warms up it'll come down to where you want it.---Just remember pressure and volume are not the same thing you can have lots pressure and very little oil actually moving thru the system conversely you can have lots volume and very little pressure. You need to have everything sized correctly( Hoses/ fittings/Bends in the hose etc)

Re: Calculating oil pump requirements
 

Could you elaborate what do you mean by too much oil?

Re: Calculating oil pump requirements
 

Too much oil 'pressure' would force the pressure release valve open . Too much oil would be excessive clearances. I remember running a circle track motor I couldn't keep oil pressure, switched to a dry sump problem solved. ---Trevor

Re: Calculating oil pump requirements
 

SSDiv6 Too much oil pump, Pumps more oil GPH than engine requirements. FED 387, I'm running the pump @ 45% engine speed, yes I'm aware of the adjustable pressure regulator, set @ 50 PSI cold, really never loses any pressure. Problem with (in my mind) slowing the pump more is I'm also slowing the scavenge stages, maybe it's not an issue I don't know or maybe I need a smaller pump section and keep the current scavenge, I'm certainly no expert on this hence the questions. Thanks for all the replies. Joe

Re: Calculating oil pump requirements
 

Joe,
If you are still running the V-6 engine, like you stated, you may need a smaller pump.

Re: Calculating oil pump requirements
 

Yeah still trying with the V6 stuff, agreed I believe my pump is too large. Think I'll try on of the pump companies again and see what they'll recommend. Thanks Joe

Re: Calculating oil pump requirements
 

It would be slick if you could run a factory pump at a constant speed with n electric motor to measure how long it takes to pump a quart, or whatever. Do they rate them in gallon an hour, like a fuel pump? (I'm thinking not) Then do the same with your dry sump pump. Might be a trick to get an electric motor to run at a constant RPM with both pumps. May be easier to do it off a gasoline engine. It would be interesting to know if shortening the housing and impeller 10% would get a 10% drop in volume pumped.

During the 1980s I ran an "outlaw" sprint car on dirt, (didn't drive it, you can hire crazy people for that) with a Peterson dry sump set up. I felt like it was way more pump than I needed. Never did play with that, making enough power was never an issue. Always wondered about that pump. I'm sure it was over-kill in size to cover their tails.

Re: Calculating oil pump requirements
 

Ed,
Oil pump flow is measured in GPM. The flow will vary based on the relief settings.
Your best best is to call the tech guys at Peterson or Dailey.
This link is a good article regarding engine bearing lubrication:

http://www.epi-eng.com/piston_engine...e_bearings.htm

Re: Calculating oil pump requirements
 

suggestion ----Joe you know Brian Browell he runs a Chevy V6 call him run it by him a Ford or Chevy gotta be pretty similar I would think see what he says--or talk to Bob Huettman he could check wth some of the NASCAR guys see what they ran---FED 387

Re: Calculating oil pump requirements
 

Years ago I modified some Melling m55 oil pumps for small block chevy stock eliminator engines. I cut the gears down and cnc machined a plate to go in the bottom to take up the space I also did some other modifications. I did some 1/4 " and some 3/8" pumps. The 3/8" pumps were worth 9 horsepower more than a m55 in back to back dyno tests.I was planning to tap into the bypass circuit and plumb in a flow meter to monitor bypass flow. About that time Schumann started making pumps and I was raising my son so I didn't have time to pursue it. If you can monitor bypass flow you could find out how much oil pump you need. Derek

Re: Calculating oil pump requirements
 

I like the idea, since I've got 2 of these pumps I've wondered about cutting down the gears and putting a plate in the void. I believe it's a inch and a half pump section, which is how I believe they rate them (by body size) may be worth looking into. Maybe make it 1 inch?

Re: Calculating oil pump requirements
 

I use Larry Stewart's low volume pumps. He does the same. Shortens the gears and machines a "stuffer" plate to fill the gap. Not sure how else you would do it without shortening the shaft.

Re: Calculating oil pump requirements
 

Have run the Stewart pump in my stocker. If you like make an offer and you can have it.

The Schuman pump is a good deal. You may need to do some fabrication to make their latest model work, you will not be disappointed.