Resolved 1G Catch Can/Crank Case pressure struggles...what in the world?

[CrackedDSM]

First up: I should've gotten pictures but I didn't. If it does it again I'll update this post with them. Anyway.


The Problem: I have been struggling with oil spray in my engine bay. There is starting to be a frankly ridiculous amount spraying out of the filter of my catch can, and it's smoking a bit under WOT/full boost. I have tried a bunch of stuff to stop it. It seems to defy the laws of physics in some cases.


Background/details: I use the stock PCV and VC vent lines running to a "baffled" catch can(ebay/amazon special) that has a filter vented to the atmosphere. Once it sprayed more out of the filter, I've tried a couple different routing.

1) Routed the stock PCV line back to the Intake Manifold with a check valve in-between the VC and intake manifold. Put the (sealed w/o filter) catch can running in line from the VC to the turbo with a little fuel filter in line. This resulted in the car smoking in every situation, where before it was only smoking a little under WOT/full boost. I'm talking a little smoke at idle, heavy smoke under decel, moderate amount under WOT. Was worse in every way.

2) Put two lines into the can, and ran a line from the top of the can to the turbo (again, with a filter in line that ran to turbo). This resulted in the smoke going away, but somehow oil/water mixture got all the way from the VC, through the can, through the line, THROUGH THE IN LINE FILTER, and in to the turbo/intercooler track. Enough to spray out of the BOV when I let off the throttle. Something it never did before. It wasn't straight oil, it was legitimately the same stuff that's in the can itself. The in-line filter was clean/no oil. What? How?



Anyway, I have no clue where to start or how to solve this issue. Has anyone had any similar struggles in the past? How did you solve it? Would going to bigger/-10an lines to a bigger can solve all my woes? Please have pity on me.

 

[93xsg]

How much boost are you running? Displacement? Turbo???



I just got my build finished and it blew the dipstick every time I hit anything over like 20psi and sprayed oil everywhere.

Since then she's been parked. After about 3 months, I finished a valve cover with -10an breathers. Did it proper. Removed the baffles, sand blasted it and welded in RavenFab baffles and the -10an fittings. And then had it powder coated.

I got a feeling this will alleviate my problem.

I don't have experience yet unforunately.

But I'm running an almost identical setup (minus the filters. and it definitely is not sufficient for a 20g and 25psi).
I have an ebay special catch can, using stock pcv into intake. and the breather to the can, with a seperate hose plumbed into the intake pipe preturbo to help suck it out...

Anywho, hopefully someone with more trial and error will chime in. Id like to know too!

 

[bastarddsm]

It sounds like it's broken. You should fix the problem, not try to band-aid the symptom. But for humor, throw the f***ing china catch can in the trash. find a hose barb that fits in place of the pcv check valve and run 2 3/8" hoses into a Gatorade bottle.
JFC. It's slow, it blows oil all over, and it was built by a shop with questionable abilities. The motor is cooked. Stop trying to break it worse.

 

[1990TSIAWDTALON]

Blow by is a result of crankcase pressure (that includes turbo boost) getting past rings and valve guides.

 

[CrackedDSM]

Blow by is a result of crankcase pressure (that includes turbo boost) getting past rings and valve guides.

I do know that. It just mystifies me that the compression test yielded great results. If it was a bad engine wouldn’t the compression test suck?

No oil burned or used or sprayed out at anything under like 18/19 lbs. Ever since I modified the can to flow a little better there’s no oil coming out of the filter or the lines even at full song/boost.


IDK. I guess despite the compression test being great the engine is bad. I just don’t know how that could be the case. And I don’t have a couple thousand to throw into an engine rebuild.

But the turbo is fine. Zero in and out shaft play. It can only be the engine.

 

[1cleangsx]

Dude I would just switch to a dual -10an valve cover. That’s what I switched to when my dipstick was moving at 30 plus psi on an FP Red. Again, that was on a freshly rebuilt stock motor, so I’m sure my ring compression was a little better, but at some point boost is gonna get past those rings, I bought the valve cover, lines, and the vented Real Street catch can and haven’t had a crank case issue since

Another thing to remember is, if your crank case pressure is bad enough the oil trying to drain from your turbo is also fighting that pressure, everytime I see a PTE hater comment on they’re turbos smoking I think it’s some idiot that doesn’t realize they’ve got a restrictive drain/breather issue

 

[CrackedDSM]

Dude I would just switch to a dual -10an valve cover. That’s what I switched to when my dipstick was moving at 30 plus psi on an Fp Red. Again, that was on a freshly rebuilt stock motor, so I’m sure my ring compression was a little better, but at some point boost is gonna get past those rings, I bought the valve cover, lines, and the vented Real Street catch can and haven’t had a crank case issue since

It’s in the works but gotta get funds in order first. Did you remove your baffles and get them re welded?

Another thing to remember is if your crank case pressure is bad enough the oil trying to drain from your turbo is also fighting that pressure, everytime I see a PTE hater comment on they’re turbos smoking I think it’s some idiot that doesn’t realize they’ve got a restrictive drain/breather issue

That makes sense to me.

 

[1cleangsx]

The factory baffles were removed, they welded a plate under the fittings.

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[CrackedDSM]

To update this thread, the issue was resolved by going with a new valvecover that had -10AN breather lines welded onto it, and running 1/2" lines to a catch can that's vented to atmosphere. No more oil blowby, no more oil spraying out of the filter on the top of the can, and engine makes noticeably more power. I also haven't noticed smoke at WOT/full boost anymore.


I did also modify the can though. I removed the little "micron filter" element that's extremely restrictive, and added some steel wool in it's place. I kept the baffling. The result is not a single drop of oil spraying out. Even at almost 30lbs of boost.


So yeah. Big AN fittings/big lines from your VC is the answer, folks. Car made noticeably more power too after changing nothing but bigger breather lines.

 

[1990TSIAWDTALON]

It can BREATH.

 

[diambo4life]

Great to hear. That's all I run in my cars.