Calculating oil pump requirements

[FED 387]

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

[buzzinhalfdozen]

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

[FED 387]

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)