Low oil pressure

[Shawn MacAnanny]

Where you take pressure readings off the turbo supply line is what the mains are seeing. That line to the turbo is the same pressure as is the rest of the block. As for the 1/8 or 1/4 supply ports. They will both supply the same amount of oil to the turbo. The bearings in the turbo are a sleeve bushing type bearing. We do not have the needle or roller bearing type shaft. Banks found the 1/8 supply line gives plenty of oil to the turbo. Otherwise they would get plenty of warranty work... And they did not. So it works fine.
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I disagree with this. This would only be true if the turbo bearing needed less than 1/3 the flow in the 1/8 supply line. While it will provide adequate flow for the turbo bearing being it's the last lubricated part and drains to a non pressured vessel there will be a pressure drop. If supplied with a 1/4" line, 4 times the volume, the bearing would have adequate flow plus extra oil flow to maintain that pressure. If you have a pressure gauge on a garden hose and a valve at the end, with the valve closed you'd see 50psi, open the valve slightly and you'll see it drop to maybe 48, open it all the way and it drops to zero because the supply flow can't keep up. The same pressure drop would be in the turbo oil supply block being retrictect by the 1/8 hole taking the oil pressure downstream of that reatriction.

 

[AcIdBuRn02ZTS]

I would take pressure readings from the top/rear of the block... highest point last to receive pressure/flow. If you are getting good pressure at this point, you know everything else is as well.

As far as turbo oiling goes... the restriction there will be the bearing tolerance. That tolerance is tighter then the 1/8" or 1/4" feed.

 

[Shawn MacAnanny]

Well I have a new oil line olive leaking, I'm done messing with them, so once I change my oil, get some consistent numbers with the 15w40 with consistent outdoor temps I'll have esco make me a braided stainless turbo oil line with jic 5 connections and connect to the 1/4" side of my turbo block, which I'll tee the factory pressure sensor into, then thread my 1/8" seding unit pressure sensor currently adapted to the 1/4" tee into the 1/8" feed side and see if running a larger orifice feed line has any affect on oil pressure read at the turbo block

 

[AcIdBuRn02ZTS]

I'll say this much... We fed my buddy's 093 with 1/4" hydraulic hose. He saw a 2psi drop from being NA

 

[Shawn MacAnanny]

With the pressure sensor where? In the turbo block it's after the 1/8" orifice restriction so leaking through the bearing will cause a pressure drop if there isnt adequate flow since it's the end line restriction. If there isn't much flow then why would the ats instructions say to puncture the baffle plate below the na cdr drain on the valley pan to prevent oil from backing up?

 

[icanfixall]

 

[AcIdBuRn02ZTS]

His is "T"d at the back of the block... 1/4" oil feed goes up... mechanical gauge goes to the side. Factory gauge sender is in the turbo oil block.

However, his is an NA block with 1/8" npt port on the block... steps up to 1/4" to a 1/4" T... 1/4" feed... so if there was a chance to drop pressure, it would show on the gauge. His runs 16-18psi hot idle with 5w40

 

[Shawn MacAnanny]

His is "T"d at the back of the block... 1/4" oil feed goes up... mechanical gauge goes to the side. Factory gauge sender is in the turbo oil block.

However, his is an NA block with 1/8" npt port on the block... steps up to 1/4" to a 1/4" T... 1/4" feed... so if there was a chance to drop pressure, it would show on the gauge. His runs 16-18psi hot idle with 5w40

Right, my truck is a factory turbo and i believe the back of my block is 1/4" npt, i know my oil inlet at the turbo block is 1/8" npt and on the other side is the 1/4" npt factory gauge sensor where i added my electric sender with the 1/4" tee and reducer bushing. I think others have used this similar setup and i think that there would be a pressure drop betweent he 1/8" npt supply and where the pressure sensor is reading. What your friends truck has would read pressure correctly as supply from the reast of the engine without the drop across the 1/8" npt port

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[AcIdBuRn02ZTS]

Gotcha. What I'm saying is there shouldnt be a drop there because the clearance between the turbo shaft and the bearing is tighter then .125" so once under pressure, the restriction will always be the charger and everything prior will equalize.

 

[Shawn MacAnanny]

0.125" is an area of 0.01226". If the bearing was say 0.5" in diameter, thats a circumference of 1.57", and lets say the bearing has a clearence of 0.010", thats an area of 0.0157" Just how big is the bearing and how much clearence does it have? I know theres enough play to move a compressor shaft up and down.

 

[kcwright1979]

Its been awhile since I've posted on here....but to the OP I had the same problem with oil pressure tanking like that. Replaced the rear filter head, overfilled it to see if the PU tube had a leak and everything, I am now replacing the oil pump. I would have at the beginning but ran out of time and $$$$ had to move. While I have it all apart I am gonna put a OBS front end on my truck.

 

[Shawn MacAnanny]

Well i changed the oil a few hundred miles ago. With 5w40 Rotella T6 i could see hot idle temperatures as low as 4psi, but usually hung around around 6-8psi. Cruising down the highway at 2000rpm i could see pressure drop as low at 26psi but was usually 28 to 30. Now that i changed to delvac 15w40 i havent seen less than 8psi, and its usually 10-12psi hot idle. Going down the highway the lowest ive seen yet is 30psi and its usually 32-34psi.

I went ahead and had a stainless line made to replace the factory line since i had new olives leaking, i'm just done messing with their horrible deisgn. I had them make is 1/4" NPT on both ends and attached it to the tee i had, relocated my 1/8" pressure sender for aftermarket gauge to the other side of turbo block. When i removed the lower 1/4" npt line fitting i realized there is an extension adapter to go from 1/8" NPT at the block to 1/4" for the fitting. So changing this to 1/4" fittings was really pointless for it intended purpose. My guess is this small fitting ensure that everything below is kept at a higher oil pressure. I saw no change in pressure changing this line out but it looks better and won't ever leak.

 

[79jasper]

Very rarely see anyone run t6 in the powerstrokes and like it. Maybe 1 in 100.
That's enough to steer me away from it.
There's way better oils out there.

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[IDIoit]

thats not the best oil port for the turbo either.
it works, and thats what they did factory, but there are options

 

[Shawn MacAnanny]

I was looking up the Red Line stuff, i really like everything they have but can't justify spending $160 an oil change for oil haha. I took apark my LB7 Duramax to rebuild heads and replace gaskets at 185k, all i had ever used was delvac and the heads were so spotless i couldnt believe it. You would have thought they had 10k on them.