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Discussion Starter #1
Has anyone here done a PCV delete? I'm looking at generic solutions, but something specific to the LNF would be nice.

(I'm not concerned about emissions. This is only one of many reasons that my car would never pass inspection. Turns out that they like things like e-brakes. )
 

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What's the goal you hope to accomplish by not venting crankcase pressure to atmosphere? If the idea is to delete PCV and not then install some other type of crankcase ventilation system, I recommend reconsidering, especially in a turbo application.

PCV is emissions control, but ti serves more function than that. Without PCV, I feel you're risking things like oil contamination from blow-by and damage from backfire. This seems to me a bigger risk in a turbo car.
 

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Honestly, I'm just trying to keep the intake clean. My DDM catch can doesn't seem to be doing the job. I walnut blasted the valves about 3k-5k miles ago. They looked pristine when I was done. Today, I had the manifold off and had a look, and they're gunked up again. I'm at a loss. :|
 

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I can understand the motivation. Is your car running poorly?

I'm not clear on the exact tech differences, 2.4l vs 2.0l, but I have read- and I'm sure you have too- that owners clean the valves every 25K miles or so. The valves don't get dirty on mile 24,999 logically, it's a constant dirtying process.

It can be possible that this buildup is just what happens all the time every cycle, and the prolonged presence of increasing and ever-hardening gunk is the real worry. For my original car, and this 'new' one I have too, I always wondered if it was smart move to get a spare head and polish the ports as a way to help reduce this effect. Then when it's time to clean the valves, just swap heads, and port the original too.
 

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Discussion Starter #5
Intake valves after I blasted them 3k-5k miles ago (or about three months):



And, today:



I have the DDM catch can.

I went ahead and ordered the PCV replacement. Guess I'll yank the manifold off (again), clean up the valves (again) and replace the valve. Hooray.
 

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My gut says the rough factory castings promote multiple disturbances in intake charge flow, and thus the build up is accelerated.

The hot rodder in me wants to polish those ports and paint them in Glyptal
 

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Honestly, I'm just trying to keep the intake clean. My DDM catch can doesn't seem to be doing the job. I walnut blasted the valves about 3k-5k miles ago. They looked pristine when I was done. Today, I had the manifold off and had a look, and they're gunked up again. I'm at a loss. :|
I feel your pain. I've blasted my valves four times. I had oil in my intake a year ago that gunked up my valves (again). I had the turbo rebuilt, replaced all my PCV stuff, and cleaned out any oil in my entire intake tract. I have oil in my intake again and will be blasting my valves in the next week or two.

When I saw the oil last week I assumed I got a bad turbo rebuild. I pulled it and took it down to a great local shop that's been in business over 20 years. Turbo was fine, the guy there told me that PCV issues can cause a lot of oil in the intake around the turbo. The only thing left that I can think of is that the baffling in the valve cover is letting oil pass through into the turbo intake.
 

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There are several threads covering this topic.
A summary pertaining to GXP's:
Venting to atmosphere messes up the MAF reading.
PCV valve is located inside the intake manifold.
The breather line on passenger side of engine to turbo, where my DDM catch can is located, works under boost only.
The PCV in the manifold works during non boost, which is most of the time, and dumps the vapor into the center of the manifold.
A recent video posted here about intake fouling on a GXP showed more severe fouling on the valves closer to the center.
Someone on this forum has relocated the PCV valve to outside of the manifold, plumbed it through a catch can and routed it back into the manifold with great results. It is documented well with pictures. I think it is the best solution.
Suction from the manifold or turbo is necessary to evacuate crankcase emissions in order to rid the engine of the harmful things found in crankcase vapor.
There are several dynamometer test videos of drag race engines on Utube with and without positive crankcase ventilation. They use belt driven suction pumps to remove the vapor.
If you Google PCV or oil catch can, you will be entertained, and educated on the catch can need or not and which catch can actually works or not. Then you get the catch can manufacturers accusing each other of copyright infringement to selling ineffective catch cans.
 

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Check that your check valve is clean and working. It's probably gummed open and not stopping oil flow into the intake.

See: www.solsticeforum.com/forum/f63/why-where-you-should-shouldnt-run-oil-catch-can-occ-lnf-kappa-71640/
I had pulled the one way PCV valve that goes to the intake last year and replaced it with some high-temp hose running to a generic one-way PCV valve attached to a separate filter so that I couldn't get oil in my intake from there. I put the stock PCV back last week to see if maybe my mod was causing a problem.

The DDM catch can is next. I couldn't get one before now because it wouldn't pass the visual smog inspection in CA.
 

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The PCV valve is a simple one way check valve.
When intake manifold is under vacuum, PCV valve opens and allow crankcase vapor to be sucked out of the drivers side of the engine into the cylinder and burned.
Under turbo boost, the PCV valve closes and crankcase vapor is sucked into the turbo from the passenger side of valve cover.
The crankcase vapor flowing past the intake valves coat the valves, which eventually turns to carbon.
On port injected engines, the fuel is sprayed onto the valves which keeps the valves clean.
All direct injected engines suffer from carbon fouled valves.
No fuel additive will help since fuel does not flow past the valves.
A few manufacturers are experimenting with an additional injector ahead of the intake valve for the sole purpose of washing the valves with fuel to prevent valve fouling. There are mixed results on the effectiviness of the additional injector and concerns about the additional injector decreasing fuel economy.
 

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Most catch cans available on line are marginal in their ability to catch oil vapor exiting the crankcase.
In order to catch oil, the crankcase vapor has to be cooled enough so that the vapor condenses into a liquid.
Most catch cans are sealed containers with baffles or steel wool inside. Most are not large enough to either slow or cool the vapor sufficiently to condense the vapor into large enough droplets that can be caught inside. Additionally, the catch cans are usually mounted in the hot engine compartment with short hose runs which doesn't allow enough heat to be extracted from the vapor.
The ideal PVC system for a GXP would have the PCV valve located external to the manifold as described by wifesgxp, plumbed with finned tubing to the catch can located in a cooler location near the grill and plumbed back to the intake manifold.
An alternative instead of finned tubing would be to insert an oil cooler in the vent line to cool and condense the vapor prior to the catch can.
A small plastic oil separator is available from BMW that works on the centrifuge principle spinning the vapor droplets out of the cooled crankcase vapor. This separator was designed to return the condensed vapor back to the engine, which is not desired due to the harmful compounds found in crankcase vapor. I would add a container to retain the condensed liquid captured by the separator and empty it when full.
 

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Picture of BMW Oil Separator and finned tubing.
Vapor enters side of separator, spins around and comes out the top center.
Condensed liquid comes out of the bottom tapered end and stored in a container until emptied.
Finned tubing is available in various forms/lengths and is bendable to shape.
 

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I've always felt that the bigger the catch can, the better and the cooler the catch can location, the better. One thing I learned the hard way. always follow the plumbers rule that S%&T won't run uphill. Neither will condensed oil. keep your crankcase vapor lines running downhill to the catch can and uphill back to the intake. Don't give the oil anywhere to collect in the tubing.

Bill.
 

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Discussion Starter #18

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Why not just go old school and route the PCV to the exhaust?
I have never seen that. How would it even work, since the exhaust system is generally at a higher than atmospheric pressure?
Way old school was a road draft tube that just dumped it to atmosphere, but that isn't very ecological.
 
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