PCV line clean and dry, breather line oily and wet

[wontonjohnny]

is something wrong here?

so i have a catch can on the pcv line with the slashcut method - the catch can is empty and clean however;

the breather line is now browning throughout and wet at the valve cover port

anybody know if im doing something wrong?

my setup looks like this

[Mazstyle]

I'm pretty sure that pic is wrong, you need to go FROM the valve cover to the intake.

I'd put it on the blue line...

[wontonjohnny]

what do you mean? the valve cover is going to the intake.

the easiest thing is to just put the catch can on the breather line, but im worried something is really wrong here, isnt this entirely backwards?

[Cooked Rice]

huh? your suppose to route the purple line back to where the original line was place - OEM PCV VACUUM SOURCE. Because the intake manifold provides vacuum to suck out all the blow by gases. Now that you plugged it up and routed it back to the intake, the gases are going through the breather line (which is suppose to provide fresh swirl air to mix with the blow by gas in the engine crankcase to exit via the PCV). It's going to gum up your turbo and intake tract. Put the purple line back to where the stock PCV line went, and stick some steel wool in the catch can. It will provide surface area for the oil vapors to condense on to catch more oil.

[wontonjohnny]

Originally posted by Cooked Rice
huh? your suppose to route the purple line back to where the original line was place - OEM PCV VACUUM SOURCE. Because the intake manifold provides vacuum to suck out all the blow by gases. Now that you plugged it up and routed it back to the intake, the gases are going through the breather line (which is suppose to provide fresh swirl air to mix with the blow by gas in the engine crankcase to exit via the PCV). It's going to gum up your turbo and intake tract. Put the purple line back to where the stock PCV line went, and stick some steel wool in the catch can. It will provide surface area for the oil vapors to condense on to catch more oil.

thats not gonna work either, your setup will only work during idle, how is that PCV gonna open with boost on it?

thanks for trying tho

anybody else?

[Cooked Rice]

Your PCV shouldnt open during boost. Or it will pressurize your crankcase and damage your seals and send oil shooting out eveywhere. At zero vacuum is when the PCV valve is open the most. If you boost, it closes again.

Idle - Open slightly
Open throttle (but not boosting) - Open max
Boosting - Closed

Positive blow by gases created in the crankcase during boost and heavy throttle will escape via the breather.

With your setup your totally defeating the purpose of the PCV system.

[wontonjohnny]

you dont want to hold the pcv closed during boost or else why not just leave it stock?

on a n/a engine the pcv always see's vacuum. putting the end of the pcv hose pre turbo with the slashcut is supposed to make vacuum opening the pcv and venting at high rpm's

im pretty sure this is one of the many ways to run the pcv, i didnt draw this pic myself.

i just wanna know why im getting fluid in the breather instead of the pcv line.

[Cooked Rice]

Under near 0 vacuum or during boost (heavy throttle) the PCV valve becomes basically inoperative. And the blow by exits via the breather because it is easier for it to escape via the top of the crankcase (as its hot oil vapor). Vacuum before your throttle body is very weak. The reason all the vapours are going through your breather is because its the path of lowest pressure.


1) No you want your PCV closed at boost

2)At high rpms/acceleration blowby exits via the breather instead of the PCV. PCV is there so all the blowby isn't gunking up your entire intake when the car ISN'T boosting/under high load.

Problem: You don't have vacuum on your PCV line.

You can consult with a mechanic if you don't believe me. I'm telling you what your problem is and you keep shooting down my answers.

From wikipedia: http://en.wikipedia.org/wiki/PCV_valve:

"Should the intake manifold's pressure be higher than that of the crankcase (which can happen in a turbo charged engine or under certain conditions, such as an intake backfire), the PCV valve closes to prevent reversal of the exhausted air back into the crankcase again. This is where the positive comes from in the name. Positive is basically a synonym for one-way (see check valve)."

[wontonjohnny]

weird thing is my pcv is on my valve cover, so you are probably right.

so your saying i should put back the line to the plugged pcv vacuum source and run the breather to the catch can?

does this breather port ever take air in? even at idle i get puffs of air... what is the purpose of those breather filters?

thanks for making me understand.

[Cooked Rice]

You install the catch can in line with the PCV line. You leave the breather alone. The fresh air goes from the air filter, into the breather line, it then mixes with the crankcase gases, then gets sucked out via the PCV line during vacuum. When There is no vacuum, or when there is boost, the PCV can't "suck" anything so the crankcase gases go out by the easiest means, and thats the breather line. But a lot more blow by gases go through the PCV because your engine is under vacuum a lot more than it is under 0 vacuum(full throttle) and boost. Some people install a breather filter on the breather line, so when its boosting and such, the blow by gases won't re-enter. But that causes a small vacuum leak, because air is able to enter through the crankcase and into the manifold via the PCV system and that air does not get accounted for by the car's MAF making it run rough. So some people will install 2 catch cans. 1 for the PCV and 1 for the breather.


Re attach everything like it was stock. Cut the PCV line in half. Install the catch can there. Stick steel wool in the catch can for better performance. Throw in a new PCV valve while your at it, they are cheap.

[wontonjohnny]

what should i do with the breather line? leave it pre turbo? should i put the catch can on that in order to keep the turbo clean? that is the purpose of the catch can right?

[Cooked Rice]

Purpose of the catch can is to keep your intake manifold cleaner, and prevent the harmful substances in the blow by gas from re-entering the combustion chamber which can lead to detonation. If you want your turbo and intercooler to stay cleaner, you can install a second catch can inline with the breather. I wouldn't install a breather filter there, because of reasons I mentioned above and that they get soaked up in oil after only about a month.

You can build small catch can using a inline water filter used for air compressor lines. You can get them at home depot.

[wontonjohnny]

also why would i need to put the catch can inline with the pcv and the original vacuum source? its just sucking back into the manifold like a stock system isnt it?

[Cooked Rice]

A catch can acts like a filter.

[wontonjohnny]

from honda tech official crankcase evac thread

"Intake Manifold Vacuum Assisted Ventilation
----------------------------------------------------------------------------------------

In Turbocharged vehicles the Intake manifold sees both vacuum and boost pressure unlike in naturally aspirated cars. The PCV valve acts as a check valve blocking any pressure in the rare occasion their is backfire in the Intake Manifold. I have heard that some individuals placing a check valve in-line and allowing the Intake manifold to assist in ventilating the crankcase. The check valve insures that boost pressure doesn't enter into the crankcase through this line.

Ideally one would want to induce a gradual amount of vacuum up to 15 in/hg under full load. Connecting the evacuation line to the intake manifold would do the exact opposite of this. On a boosted vehicle the Intake Manifold will read 25in/hg at idle and 20-15in/Hg in low load conditions and quickly disappear when any moderate to high load conditions appear.

In a stock vehicle this is acceptable because the PCV valve meters the vacuum as shown:

Idle, Low load--- high vacuum pressures fully retract the pintle causing only a small vacuum draw on the crankcase.

Mild load conditions--- vacuum present in the intake manifold is not as strong so the pintle sits in the middle of the pcv valve allowing more vacuum to evacuate the crankcase.

High load + WOT conditions--- their is almost no vacuum present and the pintle is almost completely extended allowing the most amount of gasses to be drawn into the intake manifold.

Engine backfire--- the pintle fully extends and seals to eliminate any gasses from flowing from the intake manifold to the crankcase.

Not only are you pulling excessive vacuum at low load conditions you are contaminating the Intake charge with oil and unburnt fuel blow-by.

I cannot recommend this setup to anyone."

isnt this like what your showing me?

[Cooked Rice]

Yes. But thats what a catch can is for....

to reduce:
"contaminating the Intake charge with oil and unburnt fuel blow-by"

You can't run a car with nothing sucking out the crankcase gases. The harmful substances in the vapour will deposit in your oil creating sludge build up, and bigger problems.

And when the person says "I cannot recommend this setup to anyone"

Well he doesn't have to because the majority of cars on the road N/A and boosted run a PCV system. He is basically saying you shouldn't run a PCV system to suck harmful vapours out of your crankcase.

What exactly are you so concerned about?

Maybe your concerned about performance loss? Well I can tell you now, maybe a 1 hp loss for having cleaner oil and no sludge is worth the sacrifice any day.

Did you even try what I told you to do and see if it works? I bet it will...

[wontonjohnny]

hey man.. you probably right.... jsut realized most of normal daily driving is done under vacuum.. gonna do a bypass type of system

[wontonjohnny]

so what ive decided to do is what cooked rice suggested.. haha... hooked the PCV back on the manifold... idles alot better. bought a breather filter and put that on. my car is MAP so no airflow problems.

ordered a check valve to install in the PCV line as a safety.

no catch can because it appears i have no blow by fluid at all just slightly oily fumes.

black idle smoke has dissappeared and returned to the natural grey color.

thanks man