427 LS3 - Oil pressure issues
12-07-2016, 02:51 PM
#21
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12-20-2016, 08:25 PM
#22
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I was wondering the same thing, there are 2 different size o rings or it could be damaged, I went also to the clamp with the extra bolt to hold in the pickup. I was told from one engine builder that at low rpms pressure can be good but as rpm builds its putting more pressure on the o ring causing it to leak possibly. Not sure if thats the case here but maybe?
12-20-2016, 08:52 PM
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We swapped the pump to an LS6 ported by TSP. used their oring - no change... pressure is better but still have drop at high rpm.
50PSI is the top it hits, then drops to 44~... we let of before seeing if it will continue to drop.
50PSI is the top it hits, then drops to 44~... we let of before seeing if it will continue to drop.
12-21-2016, 06:12 AM
#24
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Here's an early stock LS3 valley cover. Yes there is a rubber seal on the top.
The high RPM you speak of is while in a straight line? I.e. not under high sideways load?
The high RPM you speak of is while in a straight line? I.e. not under high sideways load?
12-23-2016, 06:22 PM
#25
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We checked the valley - the seals are preventing any leak from the oil towers.
We are revving up in neutral.
12-27-2016, 06:49 PM
#26
Did you check oil pickup to pan clearance? Perhaps you've got too much and at high rpm you are sucking it down faster than its getting back to the pan.
Other thought is a cavitation issue with the pump but you said a swap was done.
Another possibility is the oil pan relief. LS3's have an oil pressure relief built into the pan as well. The pan relief is actually for the DOD cars like the L99 but GM puts the same pan on the LS3. Perhaps it is bleeding off your pressure.
Those are areas I would focus on and then you might be to the point of disassembly and checking clearances or assembly problems.
Other thought is a cavitation issue with the pump but you said a swap was done.
Another possibility is the oil pan relief. LS3's have an oil pressure relief built into the pan as well. The pan relief is actually for the DOD cars like the L99 but GM puts the same pan on the LS3. Perhaps it is bleeding off your pressure.
Those are areas I would focus on and then you might be to the point of disassembly and checking clearances or assembly problems.
12-27-2016, 07:06 PM
#27
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I am using an LS1 Batwing pan... there is no oil relief valve on it.
I have been suggested to move to an LS2 pan, and that the car looks to be operating normally (from builder)... so... dunno, I've never seen a car drop oil pressure as the rpm goes up, only a bit of diminishing returns #psi per 1k RPM. (as relief valve opens on pump)
I have been suggested to move to an LS2 pan, and that the car looks to be operating normally (from builder)... so... dunno, I've never seen a car drop oil pressure as the rpm goes up, only a bit of diminishing returns #psi per 1k RPM. (as relief valve opens on pump)
12-27-2016, 07:21 PM
#28
I'm trying to think of some places you could be bleeding pressure. Another thought is the cam retainer plate. Some guys have had a problem with a bad seal on it allowing leak by. I'd consider that as well. You didn't mention about pickup height being verified so if that wasn't done I would also look there.
01-04-2017, 06:58 PM
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I'm trying to think of some places you could be bleeding pressure. Another thought is the cam retainer plate. Some guys have had a problem with a bad seal on it allowing leak by. I'd consider that as well. You didn't mention about pickup height being verified so if that wasn't done I would also look there.
turns out my mechanic nicked the front gasket when he changed my pump.. so we are going back in.. we will check the retainer plate/gasket at this time.
Oil pickup tube ~5/16... pretty normal?
01-05-2017, 11:43 AM
#31
01-05-2017, 01:01 PM
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Yep, issue has persisted since beginning. Pump, oring, pickup tube, valley cover tower oring s, all are good.
The gasket on front cover is leaking due to mistake but not related to pressure issue, checking cam retainer plate and gasket while we are at front cover again.
What to check after????
The gasket on front cover is leaking due to mistake but not related to pressure issue, checking cam retainer plate and gasket while we are at front cover again.
What to check after????
01-17-2017, 07:25 AM
#34
That sucks but it seems like you are at the stage of a complete tear down and inspection. Not sure how much you have into it but if it were me I would not give up finding the issue.
One thing you could try is placing pressure sending units in different places to see where pressure starts to drop off first. This way you might be able to narrow your search. For example I've got two pressure gauges on my car. One sending unit is at the oil filter/cooler and the other is the factory sending unit. They read differently as restrictions in the system gradually lower pressure. What it does show me is pressure right near the discharge of the pump and again after the oil has circulated through much of the engine and cooler. Just a thought.
One thing you could try is placing pressure sending units in different places to see where pressure starts to drop off first. This way you might be able to narrow your search. For example I've got two pressure gauges on my car. One sending unit is at the oil filter/cooler and the other is the factory sending unit. They read differently as restrictions in the system gradually lower pressure. What it does show me is pressure right near the discharge of the pump and again after the oil has circulated through much of the engine and cooler. Just a thought.
04-13-2017, 07:52 PM
#38
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Nope... I am running it... ~2k miles now
Cut filter at 1k - nothing of concern found.
burning a large amount of oil though... looking at possible vacuum issues.. unsure (tail pipes are bllaaaaaaaaaaaaaaaaaaaaack.)
Will cut next filter... going up to 20w-50 as well.
08-14-2017, 11:28 PM
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I'm having a similar issue with a newly built LS3 based 416. Oil pressure drops some when warm, but after warm up the idle pressure is around 22 psi and at 5000 I'm seeing only 47psi. Bat wing oil pan.
Builder says actual pressure with manual gauge is 3-4lbs higher then what gauge in car reads and my Dewitt's radiator with built in oil cooler and smaller lines are causing the oil pressure issue.
Only $1500-$2000 for a better external cooler...wth?
Never had an oil pressure issue with the previous 416 using same cam and heads, but this builder says he runs a larger clearance on his builds...makes no sense to me. Ideas?
Builder says actual pressure with manual gauge is 3-4lbs higher then what gauge in car reads and my Dewitt's radiator with built in oil cooler and smaller lines are causing the oil pressure issue.
Only $1500-$2000 for a better external cooler...wth?
Never had an oil pressure issue with the previous 416 using same cam and heads, but this builder says he runs a larger clearance on his builds...makes no sense to me. Ideas?
