Alright guys, we finally got a straight answer back from the engineers at GM on what exactly the difference is in these pumps!

We'll start off with the 12586665 OE pump that started in the GenIII motors and carried over into some GenIV. This is not the high flow pump. This pump has a thinner gear set and smaller diameter compared to the high flow pump. Also, this pressure relief valve cracks open at 32 psi.

Next the 12571885 pump. This oil pump began its life in 2005 on the W-body V8’s and the LH6 5.3L in the truck applications of the Trailblazer/SSR's. This is the high flow oil pump, but no longer in production. This was in production until July, 2006. This pump is very similar to the 12586665 pump, but has a thicker gerotor with larger OD and a stiffer relief valve spring that cracks open at 52 psi. There are some differences also in the pump housing but nothing major. It was replaced by the pump listed below, 12612289.

Finally, the 12612289. As stated above, this pump is the current high flow pump in production. It is identical to the 12571885 pump, but the relief valve isn't as stiff. This relief valve cracks open at 42 psi.

We spoke with the GM engineering team and they informed us that these high flow pumps should not be run on the LS2/3 engines with the stock pan, because they were starving the pan of oil. At first it may not make sense, but what was happening is the high flow pumps were pumping the oil out of the pan faster than it could return. So after a short period of time, the big pump had emptied the oil pan of oil. We were told the big pumps generally go on aluminum block applications with phaser and/or AFM (Active Fuel Management AKA: displacement on demand) hardware. The small pump goes on all iron block applications as well as the aluminum block applications without a phaser and/or AFM hardware.

In conclusion: These high-flow pumps are NOT for everybody. For those wanting to use them, it would be in your best interest to run an aftermarket oil cooler or remote mounted filter so that you have the extra oil capacity needed for this pump! Of course, Scoggin Dickey has options on both of those available for you as well! For the guys not looking for the added cost of such add-ons, we still offer our blueprinted and ported LS1 pumps for $149.95. They will give you the added oil pressure that most are looking for, without running the risk of sucking your pan dry.

 

^^^ So Matt I am NOT supposed to use 12612289 with my LS1 Supercharged setup?

 

Would the Melling pump have the same issue on a LSX/L92 motor if it didn't have an external/remote oil filter? I wanted to use it combined with the Moroso pan.

 

FactoryRaceCar: From everything the engineer we have been talking to has told us, I would rather see you running the SDPC pump.

Dragaholic: Melling has a high pressure pump and a high volume pump. Assuming your pan will still have the same capacity as the stocker, you'd want to go with Melling's high pressure pump, not high volume.

 

When GM found that the pumps were running the pan dry, did you by chance ask how much oil they were runing. I know most here run betwene 6-6.5 quarts, and the factory LS1 F-body pan will hold 7 quarts and still clear the crank.

 

You state not to be used on the ls2/3 engines. Does this also apply to the ls1? I am also curious as to the question about running extra oil in the pan as I do so also and have the second part number. #12571885

 

The Moroso pan has a 6 quart capacity. Not sure if its bigger or smaller than the stock one. If I had to guess, I would think it would be bigger (volume).

 

Yes, you could assume that the same would hold true for the LS1 engines as well.

 

So if I opted for the Melling high volume pump and Moroso pan, I would need to run a remote oil filter which is essentially an external/in-line filter?

 

Great info Matt. Thanks for doing the research for all of us! I'll go with your reccomendation when I am ready to order the rest of my rotating assembly from you here shortly

 

That is correct!

 

Ok guys, here is the issue.

Sure you want plenty of oil pressure and plenty of volume, but you don't want too much. Think about it. That pump creating excessively high pressure is just negative work on your motor. Super high volume will move a lot of oil, but as stated will run the pan dry on your motor.

Understand this, without proper restirction on the oiling system on many engines will pump the pan dry and leave all the oil in the top of the motor.

If your motor is fresh and tight, you don't need 75psi at idle. It's not making you more power. In fact, it consumes power. Sure, some folks who run looser tolerances may need a slightly higher volume pump or a slighly higher pressure.

I know of somoen who took a high pressure high volume pump and then they ported it extensively. It was filling the top of the heads up with oil, and pumping the pan dry. Folks need to understand that if you can't drain the oil back in the pan, then its just going to back up somewhere.

Just like everything else. Figure out what you need, and size accordingly. Like many other topics that seem to come up here, bigger is not necessarily better. If the engineers at GM are telling you something, it'd probably pay to listen to them...

 

I'll have a fresh new motor built by Erik at HKE. Not sure on the tolerances, but I'm pretty sure they're tight. That's just a guess though. I may not need a high pressure, but possibly a high volume. I certainly don't want to ruin a several thousand dollar engine and want to make sure that I plan it out right beforehand.

 

well crap I just ordered a 1885 pump from my local dealer, so I guess I better go see if it hasn't been ordered yet and hopefully beable to cancel it and stick to a ported LS6 pump.

 

Where is the engine oil collecting in when the LSx engines are equipped with these pumps? If it is up in the heads then drilling out the lifter trays might help. Am I thinking straight? I don't know where else it could collect in such vast quantities.

 

Well, this sucks. Just when we thought we had a lower-cost alternative to the LS6 pump for LS1/2 the rug gets pulled out from under us. Well, I guess it's back to the LS6.

 

I am running oil restricted push rods,drilled lifter cups and 7 quarts. Works well.

 

and mine just got delivered today from SDPC

 

I am curious as to this as well. Any info?

 

i have a 98 Camaro w/ LGM heads by CRD and a G5X2 cam. made 450rwhp/420rwtq. i open tracked the car for a few years on a road course. kept the motor over 4K for 20-30 minutes solid and frequently hit 6800 between corners. i ran a ported LS6 pump and have never had oiling issues. i ran 8 qrts in the motor = 7 for the motor and the 8th for the oil cooler and lines. these motors easily hold 7 qts.
back in 2001 on the Power Tour, i spoke w/ a few GM engineers about the C5 and F-bodies poping motors on long left hand sweeping turns. i was told the fix was adding a extra qt - put 7 qts in it. i said the book calles for 5.5, so 6.5 would be correct. he said no. 97-99 owners manuals listed 5.5 qts as the capacity. 00 and up listed 6 qts. there was a reason for this change. so adding 7 qts should be no issue on a stock pan set-up. add coolers, add more oil.
why am i posting this? its a good data point for you guys. i run a 95 Camaro in Camaro Mustang challenge now (since 2005) and in a stock LT1 w/ an oil cooler (same one from my LS1) i run 8 qts. i also have the Canton 242-T pan. no issues in 2 full years of racing. some races are 40 minutes long.