Low oil pressure on new build using LML/L5P oiling parts

[Chilly]

Anyone having issues with low oil pressure after adding the 2020 cooler and external cooler via sand which plate on the oil filter housing?

Finished up a new build with the following:
- 2020 Oil Cooler
- External Cooler
- Bearings set at 0.0025”
- Larger LML piston cooling nozzles
- New OEM oil pump from Wagler
- Running an additional turbo
- Also running Amsoil Bypass filter set up

Running 15w-40 pressures are normal when cold.
As soon as I hit 180-190, oil pressure drops to 15PSI Idle, and maximum 39PSI around 2000RPM. Won’t budge 1 PSI even past 2000RPM.

Took out front cover relief and swapped it, no difference. Blocked off Amsoil By-pass, gained 2PSI.
By-passed front external air-oil cooler. Idle pressure seems the same, although oil pressure is upwards of 42-44PSI MAX at 1800RPM.

It’s almost like the sand which plate is leaking oil back to the pan. Is anyone running around with this low of oil pressure? My eyes are glued on the gauge and it’s very nervous driving.

I plan to remove the sandwhich plate and just run the 2020 cooler. See if I can get some pressure back up top. Also going to try some 20w-50 but that’s my last resort.

 

[rcr1978]

I would say it's your LML piston nozzles they just flow a lot more then the old ones and the old style pump just doesn't have the volume for them. Your sandwich adapter can't leak oil back to the pan and the bypasses in the cooler/filter head assembly only bypass either the cooler or the filter they don't return oil to the pan. Your pressures are not to bad would be nice if they are better but about the same as a stock motor with a 260+F oil temps, I wonder what they would be like if you worked the motor hard and put some good temp in the oil. I wen't with the LML pump/piston jets, external cooler to.

 

[Chilly]

I guess I’ll dump the 15w-40 and try some 20w-50.
The piston cooling nozzles have a 25PSI spring in them. Still doesn’t make sense why I have such low oil pressure at idle??

 

[56taskforce]

Will be watching this thread... I am in the middle of an LBZ build with a LML oil pump and piston squirters with an 2020 L5P cooler. Heating up the oil is an S-483 over a Danville BMW 3794.
When finished I should have some interesting input.

 

[Chilly]

I originally had a high volume oil pump for this reason from Curtis Halverson, but it didn’t even last 1,500km.

 

[rcr1978]

How did you measure the bearing clearance, are you checking it with something else besides the dash?

 

[2004LB7]

Maybe one of the piston oil jets fell out?

 

[DAVe3283]

I would say it's your LML piston nozzles they just flow a lot more then the old ones and the old style pump just doesn't have the volume for them.

X2, this seems to be the most likely cause.

I am hopefully putting my 2020 oil cooler on later this year, and will report if my oil pressures go down at all. I can't see how a cooler would cause lower pressure though.

 

[Chilly]

None of the jets have fallen out as I just had the pan off to replace this high volume oil pump that failed. It cracked the side of the housing.

1.) No one has answered why I have such low oil pressure at idle when the jets are closed. Ideas??

2.) Has anyone done side by side comparison of before and after install of the sand-which plate for oil pressure?

3.) Who is running 20w50 in a daily driver and to what ambient temp? Anyone run it as low as -10C?

4.) Should I still be driving the truck with 80lbs of boost at 3000RPM with only 40PSI oil pressure?

 

[juddski88]

Is the stock turbo oil feed port plugged? Did you replace the cam bearings or check clearance on them?

 

[Chilly]

Yes factory turbo pick up is capped, turbo feeds from drivers side mains. Short block was rebuilt by Wagler. Everything is new.

Autometer oil gauge is plumbed behind factory gauge port off drivers #4 I believe..

 

[Bdsankey]

What external coolers did you end up using?


Sent from my iPhone using Tapatalk

 

[juddski88]

None of the jets have fallen out as I just had the pan off to replace this high volume oil pump that failed. It cracked the side of the housing.

1.) No one has answered why I have such low oil pressure at idle when the jets are closed. Ideas??

I would be referring to Wagler's opinion here, if they built the short block, then they should be the ones to tell you what could be going on with it.

2.) Has anyone done side by side comparison of before and after install of the sand-which plate for oil pressure?

3.) Who is running 20w50 in a daily driver and to what ambient temp? Anyone run it as low as -10C?

4.) Should I still be driving the truck with 80lbs of boost at 3000RPM with only 40PSI oil pressure?

I'd also refer to Wagler's judgement here. They built the short block, and if they are aware of your oil pressure concerns, then they should make the decision to either share your concern or stand behind their build if it seizes up.

 

[juddski88]

Also, the oem pump you put in, is it an old style or new style? Is it shimmed? What is your rocker setup?

 

[Chilly]

Pump was ordered from Wagler only 2 weeks ago, so I assume new style. Yes it is shimmed and keyed. Rocker set up? My valve lash? Stock rocker arm assembly set at 12 I believe it is..

 

[56taskforce]

Do the piston coolers still have checks in them and or opened up for higher flow? I don't think you are having a pressure problem as much as a flow problem. I don't believe the oil cooler has anything to do with your problem either. Maybe an oil galley plug left out somewhere, there is too much clearance somewhere, or possibly a crack. I doubt the relief on the pump is even opening so pump shims have nothing to do with this it's a volume thing...

 

[Chilly]

Piston jets are factory LML ones WITH the 30PSI springs or whatever they pop at. What specific oil gallery plugs are there? Like internal ones? Little confused on this...
Any oil gallery plugs I found were cleaned and reinstalled with high temperature NPR dope.
I will be removing the sand which plate tomorrow and installing 20W50.

 

[56taskforce]

Are you running an LML pump? If not that in itself could be the problem. The LML pump is higher volume specifically matched to the higher LML volume piston cooling nozzles.
The downside of an LML pump in earlier motors is they don't fit. Right now there doesn't seem to be any good high volume oil pump bolt in options for Duramax out there. I am mixing and matching LBZ, LML and L5P https://www.duramaxdiesels.com/forum/threads/new-build-for-the-mistress.86618/
As far as oil plugs that could be missing although I have been a Duramax enthusiasts since 2013 this is the first I have dove in to a complete build and the platform is also quickly evolving. My last post was not from Duramax specific experience but very generalized. I am happy to share anything as I learn.

 

[Chilly]

No, pump is LBZ unfortunately. I’ve already got countless hours into this truck and just didn’t really have it in me to do a LML pump on my LBZ. From what I have read, it’s only 10% larger volume.

Sandwhich plate is coming off tomorrow and adding 20W50.Will post results.

 

[56taskforce]

But the increase in volume being released at the LML piston coolers is most likely causing lower oil pressure. The LBZ pump simply cannot keep up. People have successfully modified the earlier front covers and LML pump housing to fit them and this would probably be the easiest way for you at this point. Unfortunately I believe only options are either LML pump or back to LBZ piston coolers.
I really wish they would have designed the Duramax with a direct-drive gerotor pump like an LS motor instead of a gear pump.