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Hi there. I'm planning to replace my balancer, and while I'm at it, add a new bump stick into my LS1. Its has nearly 175,000 miles, and I can only assume all original behind the balancer. So I will replace the timing cover seal, timing chain, but that leaves me with question of the oil pump. They seem simple in design, and I've see rebuild kits for them, should I rebuild or replace, or just reinstall the original? If I replace I was eyeballing the Melling 10295 for the slightly higher pressure, as I will be adding an external oil cooler as well. This car will see some HPDE events this year, and more and more track duty as the years go by.
I anticipate most will tell me to replace haha, but I'm curious to hear from the experienced.
What year is the car? The early pumps were hit and miss. If the stocker looks good I'd just port it and reinstall if it's the later "LS6" pump. Don't forget to shim any pump when it comes time to install. The idea is to ensure there's a gap between the rotor and housing. I've got an LM4 on the stand, likely 175k like yours, looks excellent inside so I'm porting the stock pump and it goes right back on. Supposed to be the foundation for my LS swap in my Camaro but been dragging my feet. There was a graph posted eons ago by Pumba that showed flow vs RPM. I seem to recall the GM pumps cavitated north of 6000 or so and the Mellings did not, but that chart did not include ported pumps.
Melling recommends the M295 pump as the standard replacement pump for Gen III engines. The 10295 is the high performance version of the M295 pump, with a hard anodized housing for wear resistance.
For older engines, engines with increased clearances, or for remote oil cooler installations, they recommend the M295HV. This pump provides +/-18% more flow volume and it comes with a couple different bypass spring options for pressure regulation. The 10296 is the high performance version of the M295HV. It has a hard anodized housing for wear resistance.
Thanks Tron Z, as always you are a wealth of knowledge. Last night I was getting ready to order a pump from Improved Racing, when their product description gave me pause. They recommend the 10295 for remote oil cooler setups, and do NOT recommend the 10296 for road race setups. Lovely, just adds to my confusion. I shot them an email and will get their recommendation directly.
Nephew went the standard volume high pressure on his LS1 GTO with miles around the same as your car. It worked great and another friend did the same with a motor over 150k miles which had a cam and run HPDEs. I would not go high volume on a LS1.
2 years ago replaced my oil-pump (2001 base) with the melling pump and if I remember right,,,more pressure is good, but not to increase the volume. I'm sure there are some folks
that know more about why. ?????? Bill Curlee maybe?
mike venth
Thanks Tron Z, as always you are a wealth of knowledge. Last night I was getting ready to order a pump from Improved Racing, when their product description gave me pause. They recommend the 10295 for remote oil cooler setups, and do NOT recommend the 10296 for road race setups. Lovely, just adds to my confusion. I shot them an email and will get their recommendation directly.
My information comes from a combination of the Melling reference information on their web site and a vid on Melling's youtube site. Note that some of this information IMHO seemed to be a wee bit contradictory. Additionally, there is always the chance that I got something the wrong way around, so please do your own research.
The LS platform does not drain oil back to the pan well, under sustained RPM the LS can pump the pan dry and fill the top of the heads with oil.
This is, indeed, a concern. But from my research it is only a serious concern if fitting a Gen IV pump, which is intended for AFM and VVT engines, onto a Gen III engine.These pumps provide more than 50% additional oil flow which is not needed, unless you have a truly exotic external oil cooling system. And even then, this type of pump would still likely be massive overkill. The pump would be in perpetual bypass mode, shearing the oil (decreasing its life), heating the oil and significantly increasing the parasitic power loss.
Therefore, it is important to make an informed and realistic decision when it comes to selecting an oil pump for your LS engine.
I used the $81 standard pressure and volume Summit pump on mine 8500 miles ago. If you look at the pictures on the Summit site it has the Melling 295 casting number on it. They gotta purchase it from someone...
So far so good. Oil temp 216°F, 1950 rpm and 42 psi cruising back from the airport this evening. I've never seen anything lower than 30 psi.
YMMV
Edit: Summit LS2 chains are $30 (were $18 last year). LS2 on the right
Last edited by Prop Joe; Mar 10, 2024 at 10:40 PM.
Bearing clearance determines you flow needs, not the presence of a cooler. If the bottom end hasn't been opened up, a HV pump is not the right decision.
Hi there. I'm planning to replace my balancer, and while I'm at it, add a new bump stick into my LS1. Its has nearly 175,000 miles, and I can only assume all original behind the balancer. So I will replace the timing cover seal, timing chain, but that leaves me with question of the oil pump. They seem simple in design, and I've see rebuild kits for them, should I rebuild or replace, or just reinstall the original? If I replace I was eyeballing the Melling 10295 for the slightly higher pressure, as I will be adding an external oil cooler as well. This car will see some HPDE events this year, and more and more track duty as the years go by.
I anticipate most will tell me to replace haha, but I'm curious to hear from the experienced.
Thanks
Not sure if you already spoke with someone here, but I would definitely replace an oil pump with 175k miles on it. It's going to have some wear. It's worth replacing if you have the pump off, and it's worth just buying a new pump considering the relatively low cost.
The features and advantages mentioned in the Melling video someone posted make it worth using one of the Melling performance pumps, unless you are on a very tight budget. The 10295 would be the right choice for your application. If you're running an oil cooler, it's a good idea to use the higher pressure spring, as this will increase the peak oil pressure and compensate for the slight pressure drop across the oil cooling circuit.
We could go into this in a whole lot more detail if you like, but let us know if you have any other questions!
Thank you so much for the prompt reply via the forum and a reply via e-mail from Jerry Epperly which echoed the same advice! I'll be purchasing the 10295 in short order. I'm a big fan of your products, and if I ever upgrade my one piece oil pan to a 2-piece, I'll be adding your trap door baffles as well.
Just to be clear, the high pressure spring is the one that is pre-installed in the pump?
Thanks!
Last edited by Markolc1981; Mar 11, 2024 at 10:44 PM.
Thank you so much for the prompt reply via the forum and a reply via e-mail from Jerry Epperly which echoed the same advice! I'll be purchasing the 10295 in short order. I'm a big fan of your products, and if I ever upgrade my one piece oil pan to a 2-piece, I'll be adding your trap door baffles as well.
Just to be clear, the high pressure spring is the one that is pre-installed in the pump?
Thanks!
You're welcome!
Yes, they should come from Melling with the high-pressure spring preinstalled, but it's a good idea to double check.
I have been following this thread. Watch the Melling video, around 8:20 they mention the use of countersunk fasteners on the cover to allow for the use of a double roller timing chain which I imagine is ever wider than an LS2 chain.
Edit: Summit LS2 chains are $30 (were $18 last year). LS2 on the right
I use the Summit brand LS2 chain on mine too. My stock LS6 with a ported stock oil pump and $30 chain runs to 7400rpm without issue. I also have a DRM race oil cooler. I would just get a stock Melling replacement and use the high pressure spring if you want. No need for extra volume.
Watkins Glen is almost all 3rd gear in my car and Im at or close to the limiter alot through the boot.
Replace Oil pump, or rebuild?
