2G Oil in intake manifold

[Bedicine]

This afternoon I removed my JMF smim and notice some oil sitting in the runners. Motor is still in break in after being built by MAPerformancd, have about 60km on it since then. I’m running a catch can off the valve cover with a check valve. I don’t have any smoke and haven’t seen oil anywhere else. Is this something of concern or normal even with the catch can?

I’ve added a photo where you can see it sitting on the manifold for reference

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Oil catch can has a small amount of oil in it. No oil in throttle body except a film on the side that’s attached to manifold. Everywhere else seems dry

 

[curt-s]

What's the inside of your catch can? Does it have any condensing material? It also should be far enough from the engine to allow the vapour to condense due to cooler material.

How are the rest of your intake pipes? Are your couplers wet as well on the inside?

How is your catch can routed? check valves aren't needed if the can is being ventilated by a pre-turbo vacuum source, even slightly, as it can't be pressurized from that side. Check valves only serve to reduce air flow at that point.

Or is your PCV setup like: VC to catch can to check valve to IM?

 

[DSMPT]

This afternoon I removed my JMF smim and notice some oil sitting in the runners. Motor is still in break in after being built by MAPerformancd, have about 60km on it since then. I’m running a catch can off the valve cover with a check valve. I don’t have any smoke and haven’t seen oil anywhere else. Is this something of concern or normal even with the catch can?

I’ve added a photo where you can see it sitting on the manifold for reference

You must be logged in to view this image or video.

Assuming the engine condition including all the intake valve seals are good and only the intake manifold is wet, this is not abnormal in a new engine while breaking-in or a very loose built engine.

 

[Bedicine]

All pipes and couplers are dry. Was just in the manifold and coming off the head at the runners.

I have the catch can down by the overflow tank. Currently route like so.

FP intake, drilled into the side of it and that feeds the side of the valve cover. PCV valve goes into catch can then check valve coming out of it before it goes into intake manifold.

Looks to just be oil in the catch can

 

[DSMPT]

Oil come up into intake manifold from crankcase through piston rings/combustion chambers more than imagined, especially in a newly built engine.

 

[Bedicine]

Should I remove the check valve in the meantime?

 

[curt-s]

Not if your catch can is plumbed into the manifold. Is your checkvalve installed in the right direction, preventing positive pressure into the catch can?

To get this straight, your pre turbo intake sucks directly from the valve cover

Also, valve cover to catch can to check valve to intake manifold?

That's technically fine if it is, though you are now pulling oil vapour directly into your turbo. That will deposit oil into your IM, but you'll also see oil collect at the lowest intercooler pipes.
Both should be catch canned, either one or two.

 

[Bedicine]

Not if your catch can is plumbed into the manifold. Is your checkvalve installed in the right direction, preventing positive pressure into the catch can?

Yes, that's how i currently have it

 

[DSMPT]

In a newly built engine or a loose built, the oil come up into intake manifold/combustion chambers more than usual, because the rings are not seated yet or loose ring gap/PTW clearance. If that's your case, the PCV has nothing to do with the oil.

 

[curt-s]

Oil that doesn't get scraped by the rings (what's in the valleys of the honing marks) atomizes/aerosolizes after combustion and flows past the intake valves against positive pressure flow or vacuum to settle in the intake manifold? That would mean you're allowing the intake to be (partially, even minutely) filled from the cylinders, wouldn't it?

Honest question, I didn't think our cam timing allowed for the intake to be even partially open during an upward stroke of the piston, allowing spent combustion gas and oil vapour back into the intake.

What about shit intake valve seals? Most of that should be going around the valve but possibly turbulence allows aerosolization into the IM.

 

[DSMPT]

Oil that doesn't get scraped by the rings (what's in the valleys of the honing marks) atomizes/aerosolizes after combustion and flows past the intake valves against positive pressure flow or vacuum to settle in the intake manifold?

Yes.

There are several possibilities that could cause this and we can't be so sure by seeing only one pic, but if everything is working properly, like the engine has good compression, good leakdown test number and the PCV system is installed properly etc etc, I wouldn't be worried too much.

 

[curt-s]

Huh, I did not think that it was possible that oil vapour coudl travel from a lower pressure area (cylinder) to a higher pressure area (IM), or against the vacuum draw that a cylinder exerts on the IM.
Although, there is that one brief moment when cylinder pressure and IM pressure are nearly equal, right before the intake valve closes and everything is a'swirlin around, so I suppose it's possible. Add thousands of times a minute, and it builds up over a couple hours.
Good info, thanks Hiroshi!
Never too old to learn.

 

[chrysler kid]

eh pull an intercooler pipe. could be the turbo

 

[DSMPT]

respectfully youre smoking crack. if the rings were that loose he would be burning oil before it would be seeping oil against the engine vacuum, going against compression, and several laws of thermal dynamics.

You are not even thinking about cold starting, cranking, long idle... Again, you see some oil in intake manifold from cylinders is kinda normal. (How much oil is depending on the engine setup/condition) It's just usually you don't remove the intake manifold especially with a new engine, so you don't see it often.

eh pull an intercooler pipe. could be the turbo

OP said piping/throttle body is dry.

 

[Bedicine]

You are not even thinking about cold starting, cranking, long idle... Again, you see some oil in intake manifold from cylinders is kinda normal. (How much oil is depending on the engine setup/condition) It's just usually you don't remove the intake manifold especially with a new engine, so you don't see it often.


OP said piping/throttle body is dry.

Everything else is dry. Was just on that inside, I was using break in oil with the new motor and still working out some gremlins with the tuning

 

[Bedicine]

Wondering if I should also relocate my catch can, not sure if that will make a difference. Currently relocating the battery to the trunk so I will have that location open. Currently it sits down by the rad behind the passenger headlight

 

[curt-s]

The cooler, the better. Helps the oil vapour condense and collect when you can keep the can a much lower temp than the oil itself.

 

[Bedicine]

should i be running the factory pcv or should this just be a nipple since it goes right to the catch can?

 

[steve]

The factory PCV also meters the flow under vacuum and is intended to seal under boost.