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Old 05-01-2018, 08:57 PM   #1
Hyper
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2.34 LR destroker

Default My oil pressure is nervous

I don't know how else to explain this phenomena


basically you can see it in the video, the pressure fluctuates at a constant RPM/load range (most visible @ 3500 while cruising)

I have tried:

1. changed oil pump
2. swapped oil pressure sensors
3. swapped oil sensor locations (both from and rear galleys)
4. avcs is not changing rapid values

any ideas?
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Old 05-01-2018, 10:29 PM   #2
turboL
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Have you monitored supply voltage to the sensor while itís happening?
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Old 05-02-2018, 09:37 AM   #3
Samurai Jack
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Have you checked your grounds and connections?
Have you pulled your oil pan, or looked with a scope, to check you oil pick-up for any damage?
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Old 05-02-2018, 12:42 PM   #4
Hyper
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its not electrical, I confirmed that with a mechanical gauge

I am running killer b pickup, so it it failed the issue would be constant

the plunger valve is fine too in the oil pump, I made sure before installing it
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Old 05-02-2018, 03:37 PM   #5
Delphi
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My only guess then is it has to be some sort of resonance in the oiling system at that certain load and rpm with the avcs even though the advance isn't changing. Possibly the plunger is opening and closing at that rpm as well. Right on the limit of full open and closing. Just shooting in the dark with that. A shim in the pressure relief valve may fix that.
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Old 05-02-2018, 05:44 PM   #6
Hyper
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its already shimmed, max oil pressure is ~8bar
it has done it with 2 (!) different oil pumps, 12 and 11
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Old 05-02-2018, 06:34 PM   #7
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Default

Oh boy, this is an odd one. If I recall, weren't your bearings in this build on the looser side too?

My thoughts are tracking similarly to was Delphi said, seeing as you said you validated this is a second mechanical gauge. I'm wanting if it's more of a resonance of pressure from the pump talking back to the plunger. I had a similar issue that I chased down when I was at Volvo Powertrain. It turned out to be out of spec (soft side) springs for the regulator in the system.

When you ran the 12 and the 11mm pumps, did you run the same shim stack on the springs? Did you use the springs that came with each pump or did you swap the springs?

Part of me wants to say to pull the shims out and soften your preload on the plunger and see bouncing either reduces, shifts RPM, or goes away.

Did the 11mm pump have the same behavior at the same RPM?
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Old 05-02-2018, 06:59 PM   #8
Hyper
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funny thing - yes
I always shim my pumps, so when I swapped the 12mm for 11mm I shimmed it too with new washers, and ported the pump while I was at it
and yet, the odd behavior remained

the mains are loose, you are right
0.0015
0.0015
0.0015
0.0019
0.0019

however why is it doing it at certain RPM
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Old 05-02-2018, 07:08 PM   #9
Delphi
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Quote:
Originally Posted by Hyper View Post
funny thing - yes
I always shim my pumps, so when I swapped the 12mm for 11mm I shimmed it too with new washers, and ported the pump while I was at it
and yet, the odd behavior remained

the mains are loose, you are right
0.0015
0.0015
0.0015
0.0019
0.0019

however why is it doing it at certain RPM

Disable AVCS (unplug solenoids) and see if it does it?
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Old 05-03-2018, 04:50 PM   #10
Hyper
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too late, spun a bearing
game over
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Old 05-03-2018, 05:15 PM   #11
Bansheeboy11
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Thats what oil pressure looks like when the relief valve starts sticking, which usually leads to pressure/flow problems which will kill your bearings.
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Old 05-03-2018, 06:47 PM   #12
Delphi
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Quote:
Originally Posted by Hyper View Post
too late, spun a bearing
game over
Holy crap really?
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Old 05-04-2018, 04:06 PM   #13
subaru_gc8
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Quote:
Originally Posted by Hyper View Post
too late, spun a bearing
game over
thats what i was thinking
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Old 05-04-2018, 11:05 PM   #14
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Default

Quote:
Originally Posted by Delphi View Post
Holy crap really?
Yeah, he messaged me about on google. It's crappy. I hope it was minor enough to not have destroyed the rods. Those aren't cheap.
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Old 05-05-2018, 07:08 AM   #15
Hyper
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has anyone bent ARP 625 headstud before? noticed it was crooked while taking it out of the block

it looks like I lifted a head, water mixed with oil, lost pressure
however something scuffed the cylinders

there is no metal shavings, I even opened up the filter








Micah, sent you pics, looks like the crank and rods didn't take any damage

Last edited by Hyper; 05-05-2018 at 12:21 PM.
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Old 05-05-2018, 04:03 PM   #16
Delphi
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Glad the parts are okay man.

Can you catch your nail on those scuffs at the top of the bore? Lower ones look pretty normal.
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Old 05-05-2018, 04:15 PM   #17
Hyper
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lower ones are normal, but top one pictures I can feel even wearing a glove
that cylinder also got the lowest compression when I tested
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Old 06-18-2018, 07:46 PM   #18
TurboQueef
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Did you delete photos? They aren't showing up anymore... I would like to see the spun bearing and other parts.
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Old 06-28-2018, 01:59 AM   #19
kobi sti
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Default

Me too😬
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