I am wondering if anyone has any data comparing these 2 oil pumps. I'm under the understanding that the stock LD9 pump looses pressure after 5000rpm but haven't found any data that confirms this, more or less word of mouth. I am thinking about putting the melling pump in my car this winter when I rebuild it but I'm not sure if it is any better than the stock one or not. I am planning on picking up an oil pressure guage just so I can keep an eye on things. If anyone has some experience with the melling pump I would be interested to see what they have to say about it.
ok first off if you are going with the mellings, get the oil passages bored a bit to increase the flow, it does help alot, I have ran my car to 6000 rpm without any drop in pressure, of course, I may not go this route with the new block, as I am thinking of going with the 2.3 swap. Mellings is a bit stronger and better flowing. I only know this from experience
"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen
I compared the two when i tore my motor down to rebuild(#3rod),and i couldn't see any difference in size.
The only thing that stood out was the rotor? was smaller in the factory piece,but with 149000 miles i bet it was wore down pretty good.
Now that's just eye balling and comparing the pieces side by side.
But as far as oil pressure i run about 80psi cold start,50 psi hot @ 2500 rpm,30psi at idle.
Not sure how the oil pressure was before the rebuild,cause i bought a gauge to watch the oil after the fact,but i don't rev above 5500 rpms often
but i never noticed the oil pressure dropping when i did.
AJ B - how do you know it flows more? Do you have a flow bench? What volume was it flowing vs the stock volume?
Flow Bench for a Oil pump.............
That's a new one.
I, for instance, would use a Mechanical Gauge, and TEST it.
as, that's how most know that a OE pump's PSI drops above 5500...
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
I decided to run the secret cams and not the HO so I'm not too worried about it cause I'm not going to be reving any higher than I already am now (which is pretty much stock). If I was running the HO cams I would have probably been reving higher and would be more concerned then.
I am about 99% sure the melling is just a stock replacement.
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
Wade Jarvis wrote:I am about 99% sure the melling is just a stock replacement.
I think it is a stock replacement with a slightly different rotor, which would make a difference.
Pictures have been posted before. It was even said that JPB"s modified opil pumps was just a melling pump. Not sure if that part is true.
FU Tuning
yes the best way to tell is with a gauge, like I said never dropped in pressure, but then again, I wasn't running over 7000, so wouldn't know that far but 6000, I had no problems
"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen
I think you have to be running a full sweep gauge as well, which most people do not run. I have had both electrical and mechanical gauges never seen a difference, but not using full sweep.
Presure is not everything, flow is just as important, if not more.
Edited 1 time(s). Last edited Monday, December 28, 2009 6:00 AM
FU Tuning
The melling is more robust. I had both in my hands and the rotor is different. I saw an increase in pressure wiht the melling and no pressure drops all the way to redline. The average pressure increase was about 20%. I keep on saying that the bad thing about our oil system is that it does not have a way to cool and the chain that runs the pump and balance shafts needs to be service around every 50,000 miles if not the chain can vibrate and cause false knock or worse (etc.). But definetly go with the melling pump. Another thought that I wanted to try was changing the spring in the pump to increase the pressure, but when I build my engine I didnt have time. But if you are not in a hurry have a look at this option and you can increae the spring load.
Thanks for the insight...I have a month or 2 before I have all the parts gathered to do my build so I may look into it. Regardless I will definately be putting in the melling with the info you provided, thats what I was looking for. I am going to get a guage just to keep an eye on things but I'm only going to be reving to around 6600rpm (may adjust either way depending when I stop making power). I'm getting pretty pumped to see what the car will put down in the spring. Thanks for the help.
I really recommend that you put a oil cooler on the car.
Never heard of the chain causing ghost knock, but interesting none the less.
FU Tuning
Enter the Second design ( tow piece) Tensioner.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
Taetsch Z-24 wrote:Enter the Second design ( tow piece) Tensioner.
Chris
You are speaking of the timing chain tensioner correct?
He was speaking of the chain on the oil pump, not timing chain. 2 piece tensioner if FTL. All about the one peice tensioner.
FU Tuning
Yes, it was made for a knocking noise in 99.
I had a new GM one piece fale on me after 30 miles..... no thanks.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
Taetsch Z-24 wrote:Yes, it was made for a knocking noise in 99.
I had a new GM one piece fale on me after 30 miles..... no thanks.
Chris
2 piece was 97+. To get a 1 piece you have to get it for a 96. We had 6 of the 2 piece ones. 3 new 3 used. Only one (used) would work. Every 2.4 I have done timing chain work on I have installed a 1 piece. I will not work on a LD9 without having a 1 piece to install, because of all the time we have installed a one peice and then it won't hole tension.
Having it work off oil pressure is a poor design to me.
FU Tuning
