jtl12419

iTrader: (13)

Hi,
I'm in the process of "collecting" parts for a 402 road racing engine. Do I need a hi pressure or hi vol oil pump- and why?

Is a 402 reasonable for this type of activity, or should I go for a smaller CID?

Thanks, Ya'LL

Castrellon

Well, you only need 10psi for every thousand RPM. If you build the clearances loose, you can go high volume pump and have it work high volume, regular pressure. If you run the clearances normal, it will run at a high pressure and suck up the oil faster than it can return to the sump. You'll need to run a bigger sump or an oil accumulator for reserve.
I work on 6V92 Detroit Diesels. We run high volume pumps with twin restrictors. Pressure at idle is about 10psi, high idle (about 900rpm) is 20psi and cruising speed is about 40psi. Redline is about 2100 rpm. I don't remember the clearances off the top of my head, but hopefully you get the idea. Only problem with running more clearance is that you wear more on start-up. But since these are city transit, they start once and run all day long, so that's negligable wear.

jtl12419

iTrader: (13)

Not sure that I get it. Which is more important? So on a road race engine, where I want to run from 2800 rpm to 6800rpm, continuously over a 30min race, and do this over and over in a day, It is better to have high volume? At a given psi of oil pressure, which will push more oil?

Does anyone make a swivel oil pickup for the LS cars?

Castrellon

Volume is more important. You need to float that crank and cam and rods.
Pressure is just a flow that gets restricted. Pressure=Restriction(Flow).
I see people set up stock clearances in thier hot rods and get 80psi at idle. Don't realize that's going to wash away the top coating of the bearing uberfast. Just as bad as not having enough oil.
If you buy a high volume pump, set up the clearances on the loose side. It's been for ever since I was in school learning this stuff. If memory serves crank clearance at the main is like .005-.010". You'd want it to be at .010-.015" for a high volume pump.
Hope that's better.
Another way to put it is, if you had an old high milage car (70K+) and didn't have the money to rebuild it, but wanted to push it for another 50-100K miles, you could just put a high volume pump to take up the slack and get your pressure back where it needed to be save wear and tear.

Teutonic Speedracer

iTrader: (20)

Volume.

Wickedone

iTrader: (12)

what pump would you guys recommend for a stock LS1 with 40K. It will be abused on the race track.

jtl12419

iTrader: (13)

There are several venders selling "blueprinted" and ported LS1 pumps. Also Melling sells a "high volume" pump too.

There are some who believe that the LS4 uses a higher volume pump, but there is no evidence that I've found to support that. I don't know if thats just hearsay.

DONAIMIAN

iTrader: (18)

Stock pump and 7qt's in the f-body pan. Remember these motors like to keep a lot of oil in the top end (poor drain back) and with a pump thats moving more oil youll be more likley to run the pan dry.

pkincy

iTrader: (1)

This is kinda like saying what is important more tq or more hp. Since they are proportional to each other.

Lets agree that the oil galleys stay the same for either a hi volume or hi pressure pump, OK.

Given the same restriction tell me how I am going to put a higher volume of oil through this fixed restriction?
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No cheating, keep thinking
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Obviously I will need higher pressure to put more volume through a constant restriction, correct?

So just like hp is tq recalculated to account for rpm, hi volume pumps will put up higher pressure.

Perry

jtl12419

iTrader: (13)

I think it gets complicated, because we are working on various assumptions. "Which hi performance pump" is useless without defining the other factors. Really the rate limiting event is the oil reservoir, and drainback downstream. Since, drainback into the reservoir is passive, it will vary with engine. The better the drainback, the bigger the tank, the less you worry about the reservoir being sucked dry, the more you can consider increasing the pump.

SO.. the pump has to be sized with the whole engine in mind. With a stock engine, it may not be good to change the oil pump.

pkincy

iTrader: (1)

Does anyone have experience with opening up the drain holes a bit to allow the high volume pump to work better with the block and oil galleys as a system?

My 402 is out right now (spun mains) so obviously I need to think about oiling issues. The crank and rods are gone so I have some time to work on the block until they get in.

I heard someone mention that we have poor drain back. Do we? Remember you want some oil in the top of the motor too, so there is such a thing as too much drain back.

Where is Lou Gigliotti when we need him?

Perry

americanmusl

XLNT point! As long as the pump has a min rating for that motor...you can only force as much liquid as the volute will allow...without going to extremes, psi would be the way to go for your objectives...KATEC has blueprinted, tested pumps that are tried and true for example...keep and extra qt over and a catch can system...should be fine!

Ed