dewchugr

Getting rid of the AFM in my LH6. For a stock oil pump is the Melling M295 a good choice? Also, 1281 springs, LS7 lifters, small turbo and hopefully ls1 pan fits.

Also, why do these kits have what appears to be two sets of water pump gaskets?

clinebarger

Early LS engines used paper WP gaskets ('97/'98) I believe. Later ones used the Aluminum/Silicone gaskets & have issues with leaking after a lot of miles. I use the paper ones most of the time.

I like the GM LS6/LS3 oil pump part#12586665.....Around $115. I'm not a big Melling fan for things not related to LS engines.

LS1 pans fit all Gen III & IV engines., LS7 lifters are good if you don't get to crazy with Spring Rates/RPM/Cam Profile.

G Atsma

Clinebarger- Quick hijack- what do you not like about Melling pumps?

dewchugr

Thanks clinebarger, I'm going with the LS6 pump.

I'd emailed someone at Melling about it and they told me to use the M365 pump which is the stock pump, even after I told him I was getting rid of all of the DOD stuff. That didn't make much sense since I am replacing it to get rid of the high pressure.

dewchugr

Also, searching for part number 12586665 a lot of places show it out of stock or unavailable. gmpartsdirect shows part number 12678151 as a replacement. Cheaper than rockauto

pantera_efi

iTrader: (1)

Hi Chuger, my "second" for a vote to use the 12678151.

This is a common choice by most who assembly the LS engine/stock Oil Pan/Holley pan.

GM parts direct "list" is $65.60.
I do Shim the relief spring .030".

Lance

dewchugr

Can you explain what this does and how to do this? I'm not a mechanic.

Thanks

G Atsma

It raises the peak pressure of the pump. Shimming the spring raises the pressure of the relief spring which is inside the pump.

dewchugr

Thank you

pantera_efi

iTrader: (1)

Hi Chuger, Greg is correct with a SMALL pressure increase caused by a Shim fitment.
This helps the engine with a RPM increase by increasing the HYD lifter internal pressure.
The LS engine lifters ARE KNOWN to "bleed down" causing Valve Lash with increased Cam Lobe Acceleration Rates.
Many increase Valve Spring Pressure which as the SAME EFFECT. (your 1281)

I use a Allen Socket to open the Port Plug on the Oil Pump, then place the shim into that plug.

Lance

dewchugr