Jim McDonald // Extended Track // '09 HHR SS/TC Automatic

KSLunsfo

Well-Known Member
But it doesn't HAVE to. If that line runs to a quality catch can with proper baffles and filter then to the turbo, a large majority of the impurities will be removed and not routed back into the turbo. Or, the valve cover line can run to a 2 port catch can with a breather on the second port. Taking it one step further a vacuum pump could be incorporated. There is no reason the crank case has to vent back into the turbo, intake, manifold or any other place on the engine other than eco/emissions purposes.
 

Briann1177

Goblin Guru
I see what you're saying now. That does make sense. My only other question is if you plug the check valve hole in the intake, then how does it vent under light loads? I would think that you would have to figure out a way to run a line to the outside and do the same thing as the turbo line.
 

KSLunsfo

Well-Known Member
My only other question is if you plug the check valve hole in the intake, then how does it vent under light loads? I would think that you would have to figure out a way to run a line to the outside and do the same thing as the turbo line.
Yes, you're right. With the right diameter line, being simply vented to atmosphere through a breather MAY be sufficient to prevent pressure build up. At least I have seen it done this way in many cases. But, there is a chance you need to pull a vacuum on the crank case to achieve that at all times. That's where a pump would fall in nicely.
 

JBINTX

Goblin Guru
But it doesn't HAVE to. If that line runs to a quality catch can with proper baffles and filter then to the turbo, a large majority of the impurities will be removed and not routed back into the turbo. Or, the valve cover line can run to a 2 port catch can with a breather on the second port. Taking it one step further a vacuum pump could be incorporated. There is no reason the crank case has to vent back into the turbo, intake, manifold or any other place on the engine other than eco/emissions purposes.
would it be possible to take both of these oil producing points and send them to ONE catch can with a breather?
 

KSLunsfo

Well-Known Member
Deleting it? Removing it? Blocking it off? Then what happens to the pressure it is supposed to be relieving?
Here's a really crude drawing to help illustrate the basic system from a high level. This pretty much matches the factory LNF setup from what I can tell. Only difference is that the way I have it drawn it makes the PCV look as though it's external (it's internally located in the intake manifold (IM)). If the port labelled 1 (PCV port) is blocked off, you still have ports 2 and 3 to work with. These can both run to one catch can if the can has 2 IN ports or even if you simply T them together, and you would not have a check valve or anything in either line. I may need to revisit Optimize Primes thread on this, I think I mistook an inline filter for a check valve when this was being discussed on his thread.

'T' is for BOOOST.

11885
 

Ross

Goblin Guru
I adon't think methanol is as good of a solvent as gasoline either. I also think those systems like the Snow kit only spray under boost making them useless for routine driving.

Bottom line is there is no cure for it. I quit worrying about it and just go have fun with driving. If I have to drop the engine in 50k miles to clean the valves because my horsepower dropped by 10 or whatever amount, then so be it.
You don't use full throttle on routine driving? Seems like a driver issue. :)
 

Torchandregdoc

Goblin Guru
Enough to keep crank case pressure down. Since the PCV is shut during boost the only place air can go is back to the turbo and intake pipe. As a test on my eclipse years ago, I put a vacuum gauge on the VC to confirm my setup worked, and it was always at least slightly in vacuum while driving. None of my seals (front main, rear main, camshaft seals) have never leaked.



Yup! It's nothing new, using a vacuum pump for crank case venting has been done for decades I believe. The more old school versions (usually built V8s) are belt driven, but an electric probably makes more sense in an application like ours. And again, this would just be the icing on the cake. Line/s ran to a vented catch can may be sufficient. I will likely end up testing this to be sure. If it doesn't then the 2 options remaining are running a catch can that runs back to the turbo to create the pull on the crank case (still getting a little vapor back to the engine) or a pump keeping it all external. This would only require 1 appropriately sized port/line. But, a second port with just a breather could also be of benefit as you would never pull TOO much vacuum on it if that's a thing.
I think with the line going from the VC to the intake post air cleaner, you don't need to worry about to much vacuum. I do like the idea of an external vac pump.
 

Torchandregdoc

Goblin Guru
I only know the LNF at this point. But it's actually located in the intake manifold between runners 2 and 3, which I'm not particularly a fan of. This makes replacing it or eliminating it much more complicated and involved than on a car where it's external. IF it was still there, a PCV swap on my eclipse would be less than 5 minutes. Anyway, I'm thinking that the PCV could be pulled then the hole could be tapped and plugged using a set screw. I have no idea what the diameter would be at this point but would guess wildly around M16. I THINK this would be the same as removing and plugging the port of an external one.

Jim, sorry we've turned your build thread into a crank case ventilation thread.. :rolleyes:
This is what started my whole study on PCV, trying to figure out how the system works so I could install an intake manifold from a Saab 9-4. I want to eliminate the 180 in charge piping as it comes down from the intercooler on top of the motor, drops below the IM and then 180's back up to the throttle body. It was suggested to just eliminate the PCV valve and plug the holes, but you really have to manage crank case vapor in a boosted motor or you will have a slobbering mess. I dealt with it most of my career with Detroit 2 stroke motors. Catch cans alone don't get it done. You still have to pull a vacuum on the motor to control where the oil will be caught. Theres gonna be oil. I think I like your ideas.

Don't worry about the build thread. I'm learning. I think its a healthy place for all of us to bounce ideas around.
 

Attachments

Torchandregdoc

Goblin Guru
Here's a really crude drawing to help illustrate the basic system from a high level. This pretty much matches the factory LNF setup from what I can tell. Only difference is that the way I have it drawn it makes the PCV look as though it's external (it's internally located in the intake manifold (IM)). If the port labelled 1 (PCV port) is blocked off, you still have ports 2 and 3 to work with. These can both run to one catch can if the can has 2 IN ports or even if you simply T them together, and you would not have a check valve or anything in either line. I may need to revisit Optimize Primes thread on this, I think I mistook an inline filter for a check valve when this was being discussed on his thread.

'T' is for BOOOST.

View attachment 11885
20200225_231626.jpg


A picture really is worth 1000 words. Your simple little drawing does a better job than my video last night.
 

Torchandregdoc

Goblin Guru
would it be possible to take both of these oil producing points and send them to ONE catch can with a breather?
I'll take another look at the valve cover tomorrow. I gotta get some sleep, but I think if you eliminate the PCV valve, plug the PCV port in the turbo, and pull a vacuum on line 2 via a catch can, you will get the best of both worlds. No CC pressure making a mess, and no oil through the intake runners. And, I don't think there will be much oil left in the air going into the catch can. Most of the oil should have condensed on the media in the valve cover.
 

JBINTX

Goblin Guru
Until I understand every working component of the system, I am not comfortable making changes. But like you, I WANT to get rid of / decrease the amount of oil getting to the intake.

I stumbled on the thread below this morning. In addition to the routing above in your diagram from the intake manifold, there is a vacuum tank? (pic below is from my engine) What purpose does it serve? The guy in this thread removed it from the system. Post #40 has a link to a pic.
https://www.cobaltss.net/forums/2-0l-lnf-performance-tech-153/bypass-valve-fix-possible-boost-mod-191361/index2.html

IMG_7558.jpg
 

Briann1177

Goblin Guru
That is the vacuum canister. It stores vacuum and provides it instantly to the bypass solenoid when you let off the throttle.
 

KSLunsfo

Well-Known Member
I stumbled on the thread below this morning. In addition to the routing above in your diagram from the intake manifold, there is a vacuum tank? (pic below is from my engine) What purpose does it serve? The guy in this thread removed it from the system. Post #40 has a link to a pic.
https://www.cobaltss.net/forums/2-0l-lnf-performance-tech-153/bypass-valve-fix-possible-boost-mod-191361/index2.html

IMG_7558.jpg
I was wondering about that little box myself but haven't put too much thought to it yet. At the moment I can't remember what it even connects directly to, I do have pictures I can dig up when it's time that I need to know. From reading the first few posts, I will likely retain that box initially. I will try it connected and disconnected and see what happens. Of course I'm a loooong way from that point.

That is the vacuum canister. It stores vacuum and provides it instantly to the bypass solenoid when you let off the throttle.
Interesting... I'm used to thinking of pressurized reservoirs, not vacuum.
 

Parson Green

Well-Known Member
Is a catch-can setup simply a way of removing from the engine perfectly good oil 99.9 percent of which would have stayed in the crankcase if the PCV valve had not been blocked off? In the case of boosted Ecotecs, especially those with low mileage and healthy piston rings, methinks yes.
 
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