^ FWIW the LS4 has a larger gerotor which flows more oil w/ each stroke. You can use a high volume pump w/ a lower relief spring.

For me... when oil is hot on track (270ish) running through an oil cooler on a hot day end of a 30 min session. My oil pressure was in the high 30's at times.

I'm fine w/ my added pressure and not looking back.

 

If I recall higher volume does mean higher pressure. Assuming that the oil passages are the same the only way you can flow higher volume is if you have higher pressure. If you are going to put more fluid through a same sized orifice you will generate higher pressure with the extra flow.

It is not as I recall an exactly proportional relationship. I kinda recall there is a square of something involved, but directionally higher pressure gives more flow (volume).

My engine builder has the new pump and it will go in.

Perry

 

My main reason for installing the LS4 pump is that I'm adding a oil fed blower soon, and wanted some additional volume to offset that. I'll post any changes in oil pressure that I observe after the install.

 

This scares me lol. Ive put 5 grand in parts for this new motor so far and dont want this 70$ oil pump I bought to be its downfall. Anyone have any theories on how well the ls4 pump will run in a truck? Keep in mind the different pan. I'd hate to have to buy another pump, but I would hate to kill the motor because im cheap as well! Anyone got ideas/theories?

-Lurius

 

I just installed the ls4 pump on my car. When I ordered it this information was not yet out. Do any of you think if putting the spring from the stock oil pump in the ls4 pump will reduce the risk of sucking the pan dry? It's just an idea???

 

I put a LS4 pump in my C5 last summer and am very pleased with it. Great pressure, and have never noticed it losing pressure from pumping the pan dry. But maybe it has to do with how you use the car. For general street and some time at the strip, it seems to be working great.
Would this cause the balancer to stick out a little bit? I have noticed that my pulleys are off about a .060"-.070" and had to space them out. But I am running a aftermarket balancer too. Plus a aftermarket 8-rib belt drive.

 

3000 miles w/o any issues... lots of WOT to 7000 rpms.

 

I just read through this entire thread hoping to see someone running this pump who is having the same problem as me. I am seeing over 120psi with this pump and it is causing me all sorts of problems. The main one is that once the oil pressure gets high enough, it pumps up the lifters all the way by over powering the valve springs and starts to float the valves at higher RPM. I have not charted the pressure with RPM but after a WOT pull on the dyno the oil pressure gauge was pegged at 150psi. Could it be that I just got really lucky and got a defective pump or could something else be wrong.

The motor was bought used so I never saw it running before we went through it. I changed the rod bolts, put the LS4 pump and LS2 timing chain. I have a comp 232/236 cam, cnc'd 243 heads, and Jesel rockers. I am running the Caddy lifters and sized the pushrods to give me right at .060 preload. I have a Defi pressure gauge monted behind the intake in the stock location. I am running a purolator pure one filter.

Mike

 

^^^ Sorry you are having problems with it. I decided not to use it with my build and went with LS6 instead at the last minute. I am glad I did it.

 

It sounds like the relief valve in your pump is stuck! Is your replacement oil pressure gauge accurate? You might check the pressure with a known to be good mechanical gauge just to verify. You can balloon the oil filter, releasing contaminants into your engine with that much pressure. If you actually have that much pressure, I would suggest replacing your pump with pump #12612289.

I personally don't see why the newer version of the high volume pump wouldn't be great for any performance or heavy duty application. The higher volume pump will tend to maintain normal oil pressure at low rpm and during times when the oil is thinned out by extreme heat.

It has already been mentioned in this thread that the only way to increase the flow of oil through the system is to increase the pressure. GM has already fixed the problem of too much pressure with their latest pump #12612289 which has a lower 42psi relief valve. Oil pumps have a fixed output per revolution. High volume pumps simply make more oil available to the oiling system. Regardless of the type of pump (standard or high volume), the excess oil is returned directly to the pan by the relief valve. More oil is not pushed through the engine by a high volume pump. When a high volume pump is used, any unnecessary additional oil is simply returned to the pan by the relief valve. When comparing a high volume or standard volume pump, if the output pressure of both pumps is the same, the same amount of oil should remain in the pan.

For anyone who is really concerned about the issue of 42 psi sucking the pan dry, you could use the high volume pump and cut a coil off the spring to reduce the pressure down to the 32 psi stock rating. The spring from the stock pump in the high volume pump may or may not work, depending on the preload and diameter of the relief valves etc. Some experimentation would be needed to see how that would work. Some of the old Melling high volume pumps for small blocks used to come with two relief springs, one for stock pressure and one for 60 psi.

 

I think you're missing some things...the pressure doesn't "suck the pan dry." The larger rotor inside the pump moved more volume and that can suck a pan dry.

Also, your statement of "the only way to increase the flow of oil through the system is to increase the pressure" is kind of misleading! Look at it like a water hose...if you put your finger over the end you have higher pressure in the hose, that's restriction. And even though the water coming out at the end looks different, you're not getting any more water out of it! You can use the basics of Ohm's law in oiling systems to a certain extent (I'm no engineer, they can chime in with the technical talk about this stuff)....

 

What GTO69 is saying is that you can not flow more oil through the system unless you increase the pressure. The system is a fixed set of passages and its resistance does not change. Anytime you flow a volume of fluid through a restiction the pressure will be determined by how much fluid you are trying to pass. This assumes that the restriction stays the same.

for example: if 10gpm through system A produces 50psi, then supplying more gpm will increase the pressure. Therefor, in order to flow more fluid you have to see a pressure increase. This assumes a positive displacement pump. The extra volume has to go through the system and has to create higher pressure. If you do not get more psi, you are not flowing any more fluid through the system. This is what we have in our oil system except we have a bypass valve. Now the extra oil gets returned to the pan once the set pressure is reached.

So, if the stock pump already flows enough oil to generate 50psi of oil pressure, and cause the bypass spring to go into effect, then putting in a higher volume pump will only get to 50 psi sooner. After generating enough volume/pressure to crack the bypass spring, all the extra oil will be just bypassed back to the pan. In order to use the extra volume you have to increase the spring pressure and allow the system to run at a higher pressure to force the extra oil through the system and not back to the pan.

So basically, if both pumps flow enough to generate the desired oil pressure, then the high volume one is just wasting the extra oil by returning it via the bypass. The only benefit to the high volume pump is if the stock pump was unable to supply enough volume to generate the required PSI. If you block off the bypass on a standard LS6 pump, I bet it moves enough oil to generate 100+psi if you wanted. At that point the max PSI would be the ultimate limit of flow against the oiling system restriction.

I think that is what I experienced with my LS4 pump. High volume and no bypass = high *** pressure.

 

I've got over 5000 miles since my cam swap w/ the 12571885 LS4 pump... no issues. However, I have a Dewitts racing radiator w/ a left side oil cooler and I run the car at max full w/ 5w40 Amsoil.

At hot cruise I'm at about 212-214 degrees oil temp I see 49 psi at idle, 54-56 psi at 1500-1700 rpms cruising(coolant actually warms the oil until the oil temp gets high and the cooling effect begins, and the higher presure may increase temp). At WOT I see 68-72 psi.

I have not run a track event this year (will in 2 weeks) so I'm not sure what the oil pressures will be when the oil gets up to the 260s on track. I'm gussing I'll still be in the 50s which is awesome.

So far the original LS4 is working great for my setup.

 

Bringing this topic back from the dead...... I'm planning on buying oil pump #12612289 for a 6.0L that currently now only has 30psi at hot idle. Has anyone here done as suggested above with swapping the stock 32PSI bypass spring out into this 12612289 pump? This was my intent. Otherwise for those running the 12612289 pump, what're you seeing for oil pressures and what kind of oils are you using?

 

stock LS6 oil pump = 40 PSI at idle and 60 + PSI at 2000 RPMs and above

 

I have been running the 2289 for a couple of years now. (only about 500 miles/year however). I added the new pump after my second spun bearing during a track day. It is giving me a hot idle psi of 27-30 and a cruise psi of 45-48.

I am also running the pan 1 qt over (using 6.5 qts of oil) as I think stock oil levels were contributing to my main bearing problems. This is with race tires on a road course so adjust your thinking by your usage pattern.

Perry

 

Put a Melling on it and be done.

 

My second oil pump was a Melling. It didn't put out any more pressure than my original ported LS6. It is possible this was a problem with rebuild no 1 not the pump.

the LS4 pump is working beautifully in the LS2 402 after rebuild no 2.

Perry

 

I talked to Lingenfelter yesterday and they recommended the LS4 pump with the 42 PSI relief sping. That's what I bought. Got it for put near half the price of the melling.

 

We run the Mellings with the low psi springs here,not one problem?