"LS4" Oil Pump Information!
Joined: Nov 2001
Posts: 3,043
Likes: 0
From: Texas and Qatar
The mellings and "LS4" pump are almost identical in gearing dimensions and design, other than the regulator spring. I've used a few of both with expected results.
Staging Lane
Joined: Dec 2006
Posts: 55
Likes: 0
Doe the Melling flow more oil than the LQ4?
Reason I am asking is that I recently put a 416 in my car with the supplied GM High volume low pressure spring pump. Cold idle oil pressure with 20/50 oil is right at 50. 200 degree idle is 31-32 and cruise is 40psi. It will go up to 50 or so at higher rpm. This weekend at the track (road course) I shifted at 4500-5000 because my oil pressure under load at 260 degree oil temps was 35 psi. The pressure would not go up with the RPMs. I only did one session because I was worried that I would be ventilating the block. If I let off the throttle the pressure would build about 3 psi at the same RPM
Main Brg Clear
1 - .0029
2 - .0027
3 - .0028
4 - .0028
5 - .0027
Rod bearing are all .0026
These are the measurements supplied by the builder. When I asked them about minimum pressure they sent me a new high volume pump saying that they may have shipped me the wrong one. They didn't but it got me off the phone I guess.
I am running a oil cooler and accusump.
Do I even need more oil pressure? I am going to switch to synthetic oil. Hopefully it won't break down as much with the heat.
Thanks for the help.
Reason I am asking is that I recently put a 416 in my car with the supplied GM High volume low pressure spring pump. Cold idle oil pressure with 20/50 oil is right at 50. 200 degree idle is 31-32 and cruise is 40psi. It will go up to 50 or so at higher rpm. This weekend at the track (road course) I shifted at 4500-5000 because my oil pressure under load at 260 degree oil temps was 35 psi. The pressure would not go up with the RPMs. I only did one session because I was worried that I would be ventilating the block. If I let off the throttle the pressure would build about 3 psi at the same RPM
Main Brg Clear
1 - .0029
2 - .0027
3 - .0028
4 - .0028
5 - .0027
Rod bearing are all .0026
These are the measurements supplied by the builder. When I asked them about minimum pressure they sent me a new high volume pump saying that they may have shipped me the wrong one. They didn't but it got me off the phone I guess.
I am running a oil cooler and accusump.
Do I even need more oil pressure? I am going to switch to synthetic oil. Hopefully it won't break down as much with the heat.
Thanks for the help.
Last edited by Rob 's 73; Apr 27, 2009 at 08:33 PM.
TECH Resident
Joined: Jun 2007
Posts: 952
Likes: 0
i got a couple of questions-
i got a customer who bought me this pump- for me to put on his ls3 engine..
part number on the box is 17801830
also does anyone have info on this pump http://leperformance.com/mellinglepb...s6oilpump.aspx
i got a customer who bought me this pump- for me to put on his ls3 engine..
part number on the box is 17801830
also does anyone have info on this pump http://leperformance.com/mellinglepb...s6oilpump.aspx
So do you people do anything to try and enhance the
drain-back? Like when I have ported my own heads,
I've radiused the drain hole entries, hogged back some
rocker bosses and casting flash to make the oil return
as smooth as possible. From what I've seen of the
innards on my motor, it looks like drain-back is way
better than old SBCs.
If pump outruns drainback it doesn't matter how much
capacity you start with, empty is only a matter of
time.
drain-back? Like when I have ported my own heads,
I've radiused the drain hole entries, hogged back some
rocker bosses and casting flash to make the oil return
as smooth as possible. From what I've seen of the
innards on my motor, it looks like drain-back is way
better than old SBCs.
If pump outruns drainback it doesn't matter how much
capacity you start with, empty is only a matter of
time.
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17801830 is GMPP's "hi volume" pump. 12586665 is GM's "LS6" pump.
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Largest Stocking Distributor of LS-x Engines / CHECK OUT OUR NEW WEBSITE!
COMP - FAST - PACESETTER - DIAMOND RACING - EAGLE SPECIALTY PRODUCTS - CALLIES - COMETIC GASKETS
RAM CLUTCHES - MOSER ENGINEERING - KOOK'S HEADERS - ARP - GM BOLTS AND GASKETS - MSD - NGK
POWERBOND - ASP - AND MORE!
On The Tree
Joined: Sep 2005
Posts: 162
Likes: 0
From: bay area
so my tuner recommended the ls4 oil pump in my 01z06 when im doing my cam install whats the opinion on that? can anyone shed some light. my car will be for street/strip use but mostly a weekend car. thanks
Last edited by 85firebird; Apr 30, 2009 at 08:00 PM.
Alot of people keep getting confused with the part #s. Part #17801830 is the oil pump kit that includes the o-ring (part #12557752) and the oil pump (part #1258665). If you just order the oil pump (#1258665) you won't get an o-ring.
http://www.sdparts.com/product/17801...esEngines.aspx
http://www.sdparts.com/product/17801...esEngines.aspx
