Black Oil In Intercooler Pipes And Intake Plenum Rb20Det

[Leeroy94]

I took my intercooler piping off to do a compression test and there was heaps of really black oil inside the piping. I pulled the accelerator cable to check inside my intake plenum and the oil was also in there.

So far I've had people tell me its my turbo. But I had a look and its all fine. Seals are all intact.

What else could it be?

[scotty nm35]

Ahhh, all engines recirculate a little oil, which is why people run catch cans, instead of letting it all drain back into the intake.

[Leeroy94]

I'm running a catch can

[scotty nm35]

Did you clean out the piping before you fitted it?

Is the catch can baffled or stuffed with stainless steel wool?

[Leeroy94]

It's just an empty catch can, two hoses going to it from each side of my rocker covers

[scotty nm35]

Aannd? There should be another hose... Or does it have a silly breather filter on top?

Empty catch cans don't do anything from my experience.

[GTRPSI]

On GTRs the left rear breather pipe runs to the rear turbo inlet, if you get oil pooling in the head while under boost it will pump some into the intake system.

Once our GTR was pumping blue smoke while under hard boost, we thought one of the turbos had shit itself or the engine had done a ring, intercooler and piping had oil in them, cleaned it out and it never returned.

So maybe check your breather system (not sure on your model), if you see a tube running from the breather to your turbo inlet it may be the cause of your issues.

[Leeroy94]

Yeah there is a pipe running from my turbo inlet to one of the breathers on my rocker cover.. Could that be the cause?

[boostn0199]

Yeah there is a pipe running from my turbo inlet to one of the breathers on my rocker cover.. Could that be the cause?

Disconnect it from the intake and vent it to atmo and check to see if still getting oil. How much are we talking? Because you will always have a little bit in there when running a plumped up catch can unless u have a proper can that actually seperates.

Also if u do plan to test it make sure u clean all the pipes and cooler first or else it will just throw the oil in the cooler again into the pipes giving u false results.

[Trex]

Hate to tell you mate, you're up for a new engine. Once you start getting oil in your intake it's all over. Or you could run one pipe to the cam cover and the other to the intake. Running both lines to the cam cover won't do anything. Google search catch can setups and why and how they work. It's amazing that something sucking can pull an object or liquid to that direction.

[KiwiRS4T]

So how many breathers does your rocker cover have? 2 pipes going into a catch can and one into the turbo inlet? You need your cam covers to vent to the catch can which needs some sort of baffling and then the catch can should vent to the turbo inlet. Also maybe do a compression and/or leakdown test if you are worried about the state of your engine.

[Leeroy94]

My engine is on its way out already. I knew that from the start but it refuses to die (rb20det)

Compression test results

Dry test:

Plug 1 - 135psi

Plug 2 - 120psi

Plug 3 - 120psi

Plug 4 - 125psi

Plug 5 - 126psi

Plug 6 - 135psi

Leak down test (roughly 10ml oil down each spark plug hole):

Plug 1 - 142psi

Plug 2 - 144psi

Plug 3 - 145psi

Plug 4 - 150psi

Plug 5 - 145psi

Plug 6 - 154psi

I've taken all my intercooler pipes and intercooler off. They have all been cleaned thoroughly.

I removed my stock rb20 turbo. Next to no shaft play, nor is there any oil besides the dripping oil lines. Exhaust housing wasn't even that fowled.

I have an empty catch can with no breather on it. Two hoses go from the top of the catch can. First hose runs to a breather on the left rocker cover (closest to the intake) which is then blocked off on the other side. Second hose runs to a breather on the right rocker cover which then has another hose on the other side running to my intake, before my turbo and after my AFM.

I didn't install the catch can. I bought it like that.

Does anyone know of a good catch can setup? It's a drift car so I don't need to abide by any laws.

Also, in terms of my compression, I have no plan on rebuilding the motor. I have a rb25 turbo stamped 45v4 on the compressor housing and 21U on the exhaust housing. Can I bolt this turbo on until my motor blows up? And what effects will the motor blowing up have on the turbo?

[KiwiRS4T]

That's not a leakdown test but no worries at least you don't have a blown piston. When you say your catch can has no breather I presume it has a hole on top where a breather could go? Just pipe both/all of your cam cover breathers to the catch can and nothing to the turbo intake pipe. That way you can see how much oil is getting into the catch can and keep it out of the intake.. It may not be all that much. Engine failure is unlikely to damage your turbo although I would have thought that was the least of your worries! Some RBs will go for ages in that condition so don't assume its going to blow up soon (although you never know).

[Trex]

Just connect 1 pipe from the catch can to the intake before the turbo. Connect the other pipe from the catch can to a cam cover. Or get a T piece and put it inbetween the U hose that connects both cam covers together.

I was kidding about the oil in the intake being bad, that's how these engines are setup. I'd be worried if you didn't have any oil in your intake with no catch can.

Also look at re baffling your cam covers, that works too.

You will always have oil in your plenum as it has a hose connecting to the drivers side cam cover. But you can manage the oil in your intake by putting a working catch can in. Or put another can can in so you run 2, one from your plenum to the drivers side cam cover and the other from the intake to the passenger side cam cover.

[Leeroy94]

Okay. Ill try switching the hoses around both ways suggested to see which one works the best. Ill post pics once done.

[jay-rod]

Hate to tell you mate, you're up for a new engine. Once you start getting oil in your intake it's all over. Or you could run one pipe to the cam cover and the other to the intake. Running both lines to the cam cover won't do anything. Google search catch can setups and why and how they work. It's amazing that something sucking can pull an object or liquid to that direction.

your kidding right?

Perfectly normal for oil to go back into the intake with the oil breathers.

EDIT : haha oops i see you were joking lolz

Edited January 28, 2014 by jay-rod

[Trex]

your kidding right?

Perfectly normal for oil to go back into the intake with the oil breathers.

EDIT : haha oops i see you were joking lolz

I would never joke about something so serious.

yes, please do leeroy. The best way to remove the oil in the intake would be the "connect 1 pipe from the catch can to the intake before the turbo. Connect the other pipe from the catch can to the pass side cam cover." Preferable a T piece in between the covers connecting line. If that makes sense?

I just searched on google and found some of the stupidest setups i've ever seen, no wonder you were confused.

[Leeroy94]

Okay so I understand the hose between the catch can and the intake before the turbo.

Both of my cam covers have one breather each with two sides to them. Are you suggesting I block off one side of each breather, then connect hoses from both the breathers into a T-piece which then connects to the catch can?

Just trying to clarify.

[Leeroy94]

Excuse my engine bay..

[R_34]

Mine is hooked up like this (sorry for the crappy pic and engine bay) :

In your case it all depends if you want/need recirculation of the blow by to the intake or not, and you intake manifold setup (oem or ffp).
I didn't needed any recirculation and my can has a breather so I plumbed it like this.

Just be careful not to place the catch can on the hot side of the engine like you pics shows it. If for any reason the can start to spill oil , you don't want it to fall on any glowing parts.