Melling Oil Pump Question
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From: SoCal CA
Melling Oil Pump Question
I may have to replace my oil pump soon and Ive read mixed reviews on the Melling oil pump #10296. The pump is advertised as having 18% additional volume of flow and comes with an optional high pressure spring. Thing is Ive read some say that having a high volume pump can pump the pan dry on wot and hard maintained acceleration. Since the car sees the drag strip and road courses, I wonder if the Melliing is a good option. The motor makes almost 500rwhp and redlines at 7200rpm. Anyone here use H/V Melling pump, and if you do, do you run the high pressure spring or keep it at stock pressure? Looks like if you run that pump those are the two configurations, 1)high volume with stock pressure, or 2)high volume and high pressure. Any input is appreciated. Thanks.
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Safety Car
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From: SoCal CA
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Mine sees the track ( drag strip that is) I run the HV pump and it comes with the high pressure spring pre installed and I went with that. Ive had no issues 
. As far as starvation at the drag strip, i shift at around 7500, with the juice hehe and it still hasn't had any starvation issues. I talked to the shop prior to purchasing it and they told me unless i was gonna be pulling 1g or over for a long long long time WHILE at 6500 rpm or above.
Just my two sense, get the HV and leave the HP spring in the bad boy.
. As far as starvation at the drag strip, i shift at around 7500, with the juice hehe and it still hasn't had any starvation issues. I talked to the shop prior to purchasing it and they told me unless i was gonna be pulling 1g or over for a long long long time WHILE at 6500 rpm or above. Just my two sense, get the HV and leave the HP spring in the bad boy.
Thread Starter
Safety Car
Joined: Apr 2007
Posts: 3,582
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From: SoCal CA
Mine sees the track ( drag strip that is) I run the HV pump and it comes with the high pressure spring pre installed and I went with that. Ive had no issues . As far as starvation at the drag strip, i shift at around 7500, with the juice hehe and it still hasn't had any starvation issues. I talked to the shop prior to purchasing it and they told me unless i was gonna be pulling 1g or over for a long long long time WHILE at 6500 rpm or above.
Just my two sense, get the HV and leave the HP spring in the bad boy.
. As far as starvation at the drag strip, i shift at around 7500, with the juice hehe and it still hasn't had any starvation issues. I talked to the shop prior to purchasing it and they told me unless i was gonna be pulling 1g or over for a long long long time WHILE at 6500 rpm or above. Just my two sense, get the HV and leave the HP spring in the bad boy.
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Safety Car
Joined: Apr 2007
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From: SoCal CA
Started to get low pressure readings at the road course at idle. It idled first at 15psi then it would cool and go normal. After I noticed it was reading a bit lower on the track, in the 30s mid rpms and 38-40 wot. Then cruising home it was at 20psi on the fwy and got as low as 8psi at hot idle when i shut her off. Next morning cold start was normal but itll go low, 15-20psi idle, when hot. Oil temps at the track were 257*. Theyre checking a few thing such as the osu and are gonna hook up a mechanical gauge as well. One funny thing I noticed was the pressure would slightly go up when the nose of the car pointed down, downhill. It dropped a bit going up hill. Could be a bad o ring where the pump may be sucking up air. First oil sample showed no metal in it but they have yet to open up the filter. Idk if the press relied vlv got stuck as well. Pressure never went to 0 though. It is a stock LS1 pump, or whatever came in a 2002 coupe. Oil was pennzoil 10w30 with an extra quart for the track. Motor sounds healthy, at least nothing obvious, even if you rev it up. Press does increase with rpms so theres always the chance of a bad osu.
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Started to get low pressure readings at the road course at idle. It idled first at 15psi then it would cool and go normal. After I noticed it was reading a bit lower on the track, in the 30s mid rpms and 38-40 wot. Then cruising home it was at 20psi on the fwy and got as low as 8psi at hot idle when i shut her off. Next morning cold start was normal but itll go low, 15-20psi idle, when hot. Oil temps at the track were 257*. Theyre checking a few thing such as the osu and are gonna hook up a mechanical gauge as well. One funny thing I noticed was the pressure would slightly go up when the nose of the car pointed down, downhill. It dropped a bit going up hill. Could be a bad o ring where the pump may be sucking up air. First oil sample showed no metal in it but they have yet to open up the filter. Idk if the press relied vlv got stuck as well. Pressure never went to 0 though. It is a stock LS1 pump, or whatever came in a 2002 coupe. Oil was pennzoil 10w30 with an extra quart for the track. Motor sounds healthy, at least nothing obvious, even if you rev it up. Press does increase with rpms so theres always the chance of a bad osu.
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From: SoCal CA
^^
Did it make noise at idle or with rpms? I ask because I couldnt hear any unusual valvetrain nouse at all. What repairs did you end up doing, rebuild or new cam and cam bearings?
Did it make noise at idle or with rpms? I ask because I couldnt hear any unusual valvetrain nouse at all. What repairs did you end up doing, rebuild or new cam and cam bearings?
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I went with a new LS6 block, forged crank, Wiseco pistons..ARP studs...C5R timing chain, melling oil pump....clevite bearings, new blower cam
the cylinder walls were scored and could have been honed but it wasn't worth it...the crank and cam were toast. I always said if the SHTF I am going forged internals only problem was it was sooner rather than later but then again it never happens on your schedule
got the car back putting down 490/490 with room to grow...I need a 2 bar map and smaller pulley to crank up the boost but for now I am just happy I have it back
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Thing is my motor is already forged and built so Im really hoping my bearings are still ok. The pressure never went to 0 so I hope I caught the issue in time. Im also at 490+rwhp at 12:1cr.
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for ya...only one way to find out....either way oil starvation is no way to go....I see 80PSI+ on start up and 40+ at temp
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From: SoCal CA
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From: SoCal CA
Forgot to mention on the day before the hpde, i had the valve covers off to inspect the valvetrain. All was in oreder, nothing was loose or had play. Not long ago i found a lifter on the passenger side that had a bad roller bearing. I replaced all the lifters on that side and made sure the cam had not been damaged. The car sounded good but i noticed a rocker arm had play and thats how i found the bad lifter. The roller still rolled so i caught it before it did any damage. The last two months since, the car has ran perfect. Not until last week that i noticed my oil pressure was at 25* hot idle but every told me it was fine and i forgot about it. Last week a started getting some false knock at really low load or even idle. I use e85 so i figured maybe i got a batch of winter blend which is actually e70. So i added some octane booster and it got better, i had 0 knock retard at the track and wot. Not until sunday morning, the day after my oil issues, that i started seeing a lot more kr at idle but it would go away as you revved up the motor to about 1500-2000rpm. So we are looking into that too. Got a bad gut feeling about it tho.
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Well, a mechanical gauge confirmed the low pressures though the dash gauge reads about 3-4psi lower than the mexhanical gauge. The oil was drained and they said there were no obvious signs of metal or metal shavings in it. With fresh oil the pressures improved, 40psi warm startup idle and 23-25 hot idle. By monday the pan will be off and they will take a look at the whole bottom end and oil pump. Also there was no knock retard on the data logger at idle leading me to believe what I saw last time was false knock from the lifters that had bled off oil from the low pressure and were pumping up again. My builder doesnt think there was any real damage done to the bottom end and feels it was a combo of high heat, oil breakdown and possibly a pump issue, such as a bypass valve or o ring issue. Guess I'll find out on monday.
