Pumba

Gentlemen,

Over the past few days I have had an opportunity to discuss LS gerotor oil pumps with an engineer who designs and tests such pumps.

Before I go any further, I need to warn that some of the data I am going to present will confound and upset some of you. So, if you decide to read on, don't throw darts.

• All three of the Detroit OEMs are working on improving their crank mounted gerotor pumps.

• Ford is having problems with their supercharged modular engines and gerotor oil pumps. It seems that the belt load of their supercharger is deflecting the snout of the crankshaft and putting a high load on the inner gear of the oil pump. So, if you have or are looking at putting a supercharger on you LS engine, be certain that you have a good fully counterweighted, internally balanced forged crankshaft, with the appropriate ATI damper on the snout to minimize the deflection of the crankshaft and its snout.

• Chrylser is also looking at the design of their gerotor oil pumps on their HEMI engines for improved output.

• GM is looking at improving the output of the gerotor oil pump for the LS7, LSA, and LS9 engines.

The following chart gives a comparison of oil pumps that are available for the LS engine:


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It is obvious from the data that the Melling M10355 or M365 pumps are a major improvement over the original and even the improved LS7 and LS9 oil pumps. They are available from JEGS and Summit.

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If you are having an engine built that will use a gerotor pump have your engine builder install either the M10355 or M365 pump. For less than $150, it's a great engine life improvement.


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davidfarmer

actual data above 6200rpm would be nice....just because the slop is negative does not mean it doesn't provide adequate pressure. I doesn't necessarily take much pressure to keep and engine safe.

Are those parts completely interchangeable???? I've always just shimmed the bypass spring in my LS1/LS6 builds, but would be nice to know what pumps can interchange.

travisnd

FWIW I've run the GM LS4 pump on 2 different cars now... the first one was the original LS4 pump with the higher pressure 52 psi relief spring. For my current setup I selected the newer LS4 pump with the 42 psi relief spring.

Running Amsoil 10w40 with a K&N filter and a DRM oil cooler kit with the larger Setrab 625 cooler My oil pressure stays above 50 psi even in the hottest conditions. In the cooler months It stays around 70 at WOT.

I went with the lower psi relief this time because I was tired of looking down and seeing 55lbs oil pressure at idle on my old car. That just seemed a bit too high.... 38-42ish hot idle "feels" better :p

EDIT - the engine is a nearly stock LS6 wet sump.

Pumba

Dave,

These pumps ARE intechangeable.


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67Ranger

Just out of curiousity, do you know if Moroso makes their own pump, or if its just a rebranded melling?

Pumba

I do not know if Moroso makes their own pumps.


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Pumba

Some have asked for a graphical representation of the data for the four types of pumps:

aggie_corvette

Pumba

Below are pictures of the Melling 10355 pump:


Front-View






Rear-View






All you have to do after you purchase it is take it apart, cleanup any sharp edges on the inlet and outlet port for smoother flow, reassembly it, fill it will a heavy weight oil to prime the system, and install it.

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C5ZEE06

Installing a crate LS6 this week in the HPDE car and considering the M365. Keeping it stock otherwise. The car has an integral oil cooler and accusump.

Ive been using a shimmed LS6 pump, but thats not helping to increase flow any.

Anyone using the M365 ?

btw..i assume the multiple references herein to the 10335 are a typo...for the 10355 pump - correct ?

Pumba

Congratulations on your new and improved oil pump. I have corrected the parts numbers on the post. 10355 is correct.

C5ZEE06

figured that.
btw..missed one lol.

btw again..Melling says the M10355 is not available - and there is currently no schedule for manufacturing more.

Pumba

I found the last one and corrected it.

I will see if I can check with Melling and find out when or if they will be making more 10355 pumps.

JVetthead

One more time for your viewing pleasure...

travisnd

If you want to save a few bucks the GM LS4 pump is a high volume pump and it's only around $80. I got the 2nd version on my current car that has the 42lb relief spring.

I had one of the original LS4 pumps on my old Z06 with the 52lb spring and it had a bit more oil pressure than I was comfortable with.

The pump in the car now is perfect.

RX-Ben

Would the frown-shaped graph for a stock LS1/6 pump lead to elevated oil temps (even with a cooler) and low oil paressure (~35psi) at higher rpm (6500+)?
I ran into an issue at Pocono - oil temps are at 280F after 3 laps (never saw above 250F previously), though pressure is low throughout the rev range once hot (including around 35 psi at 6500rpm, 280 oil temp). Car feels fine, numbers are scary. Had 0W-30 Mobil 1 on Fri/Sat, car behaved the same on Sunday with Motul 5W-40. Previously ran Mobil 1 10W-40.
Just bought a oil filter cutter to take a look inside, but the engine is a lower mileage swap and may have had a latent problem that would only be exposed at a place like Pocono (extensive high rpm WOT running due to gearing).

Thinking there is bearing damage...

Also - anyone running the higher volume pumps (the Melling or the LS4) - any worries about the increased volume removing too much oil from the pan?

Pumba

Certainly many things could cause the low oil pressure and high temperature you were seeing.

I would not advise using Mobil 1 0W30 for a track car. I would suggest Redline or AMSOIL in a 0W40 or 10W40, along with one of the good Melling pumps.

sebdavid

I have the stock oil pump on my LS6, which has head and cams & about 500 engine hp. I also have an Accusump. Am I in any danger and should I change the oil pump just to be safe? I would think the Accusump would supplement the pressure if it drops, and it wouldn't last long since I barely spend any time above 6,200rpm.

0Anthony @ LGMotorsports

You guys should be cautious as to how much oil these pumps move. Just because they flow more, isnt necessarily a good thing. Draining the pan has been a problem in the past because the flow rate of the pumps, exceeds the drainback volume of the engine itself, thus leaving more oil in the top end of the engine, as opposed to the pan.

The LS6 pumps have worked great for many many years, and thats what we continue to use with good success.

Fwiw, the LS engines float the crank at idle, with 4 psi.

trackboss

I'd have to agree. High oil pressure is completely unecessary.