0Jeff @ TPE

I have been trying to figure out how exactly to set up my catch can. In some cases I hear its best to run it to the valve cover vent, and in other cases some people tell me to run it to the PCV system.
Well....Prior to this install, the valve cover vent was ran to the air filter and it was capped off at the TB. The PCV system was in stock trim.

I was noticing that I was getting a ton of oil splattering out of the BOV, which obviously means I was getting oil coming from my Valve cover.

As you can see in the pictures, I ran a T off of the PCV system and Valve cover vent.
I left the stock PCV valve in place and installed another PCV valve off of the valve cover vent. This way they can never push pressure back into either system.
Being the fact that you dont want any pressure to blow back into the TB or Intake, both of them were capped off.

Now, both the PCV system and Valve cover vent, vent into one catch can and exhaust into the air filter.

What do you think, It seems to be fine, I just want to make sure I'm not causing a problem.

BTW, Notice the stainless steele catch can bracket I made that bolts to the S/C bracket??

ICULUKN-C5

when I installed my catch can



I didnt 'T' it off.I ran it from the valve cover to the catch can and catch can back to the motor.

IM QUIKR

This one is a real head scratcher. It's not that you don't want the crankcase pressure going into the intake, you do. You want to draw the crank case pressure out as fast as possible in fact you want vacuum in the crank case. The reason for the PCV re-routing is to prevent the pressure in the intake from entering the crankcase and stressing the seals and rings. The catch can is intended to intercept the oil stirred up from high revs from entering the intake. Basically what I see you have done is made a $200 valve cover breather. There is no air moving thru your system. The front valve cover vent is a fresh air source for the PCV system when intake vacuum is present.
You need to install a check valve on the intake port, then route the line to the lower catch can port and then from the top catch can port to the crank case line. Since you have the check valve there is no reason to keep the stock PCV valve anymore. Give this a try and see how it works.

0Jeff @ TPE

OK, You've got me kind of confused. First off, does the crank case pressure "Have" to vent into the intake? You mention that it draws the pressure out of the crank case. Do you mean that as in Vacum related/dependant?

What do you mean dy this statement? as you see in the pictures above both the PCV and Valve cover vent have PCV valves on them. A PCV valve is pretty much a check valve anyways. It lets pressure go one way but not the other.

So what your saying is, Uncap the fitting at the intake port and install a check valve, then connect the line off of the bottom of the catch can to this fitting. Eliminate the PCV valve off of the crank case hose, but keep the the PCV valve at the valve cover vent so it cant cause back pressure in the valve cover.

Is this right??

If not, please explain. Cause I think I just confused the **** out of myself.

IM QUIKR

The intake draws vacuum on the intake to remove the combustion gasses that get by the rings and reburns them in the intake. Sadly the gasses also carry up some of the oil atomized by the rotating mass of the crank shaft. Why do you want the gasses drawn out? To remove the condesation of water and corrosive contaminants which would otherwise be left in the crankcase. You can vent these gasses anywhere you'd like but the smell terrible if vented to atmosphere. And yes I mean "vacuum" generated by the intake will relieve the crank case pressure generated by combustion.



Why do they have check valves on those lines? What are you attempting to stop? The crank case line and valve cover line are an open system in equilibrium together. There is no pushing or pulling taking place there.
Let's start from the beginning on the PCV valve. NA has it to prevent a back-fire situation from allowing the flame ball from leaving the intake and entering the crank case where a catosrophic explosion could occur. The valve itself is a metering valve that can close altogether if need be. Now in an FI application, when you get into boost, you pressurize the intake and it will flow out of the intake and down into the crank case via the PCV line. This is bad. The seals and rings want vacuum in the crank case not positive pressure. So we stop this with a stronger-than-stock check valve(only one is needed when installed up close to the intake port). But if we connect it as you have(PCV line and front VC(valve cover) port there will be no source of fresh air to cycle through the engine as the intake draws vacuum on the PCV line. You not only want to suck the crud out but also need to replace it with fresh, clean air. So you suck out the rear thru the PCV line and replace that air with clean air in the front VC port. I hope that's clear.




YES

YES

what pressure? NO get rid of it. You already have one valve on the intake line.


1) rear valve cover ports connect to form the PCV line
2) The PCV line connects to the Catch can top port
3) the bottom AMW catch can port connects to the check valve(air flows TO the intake)
4) the check valve connects to the intake port.

xtream1

Pull off the checkvalve and blow thru it both ways. It's not really as you expect. You're better off changing it out to a real checkvalve.



Yes on the intake port.

Intake port goes to top of catch can and valve cover/valley PCV port goes near bottom so oil in catch can falls and only air comes out of can to intake.

I would "T" both valley port and valvecover ports together. Then go to catch can. This is how mine has been working successfully for about 1 year.

If you still have oil issues,
1. add a vapor filter with a long remote drain between catch can and intake port
2. relocate catch can to lower area of car like under headlight.
3. get a bigger catch can with an integral oil baffle or some kind of screening inside.

xtream1

I agree with most but....why would you go from the bottom of the catch can to the intake. The catch can collects oil which by gravity sits at the bottom. Plumbing to the intake should be taken from the top of catch can to facilitate an oil free system.

Also, adding an intake port for air to enter the motor isn't necessary. enough air will enter past the rings through the combustion process (otherwise you wouldn't have any oil smell with just an air filter on the valvecover) and the seals on this motor and very good so they will hold up.

One thing though. If you do connect all ports as I have described you will need to "T" in an extra line between the catch can/vapor filter and the intake port with a checkvalve pointed outward as a "blow off port" should this system become accidentally pressureized

0Jeff @ TPE

I just pulled the schematics of my PCV system and realized where I screwed up. I was under the assumption that I had the later model LS6 PCV system. I just realized that the shop who installed my motor used my older LS1 valley cover. I was under the assumption that the PCV and Valve cover vent were 2 seperate systems. Knowing now that they are a balance system, I now know that I have to completely re-do my setup. Thank you for the info. I appologize for my ignorance. For some reason I just couldnt get a handle on routing this catch can. Now it crystal clear.

0Jeff @ TPE

Its actually about 75% of the way up the side. Not directly on the bottom.

IM QUIKR

2 reasons: the instructions from the engineer who designed it said to and because the air flows thru the filter media and then to the entire outer ring where it is drawn up and out the lower port. Running it the other way creates a soda straw effect, meaning that any oil on the filter media will be drawn up to the top port by means of the air velocity like you would find in a wind tunnel. Think about it, the air enters thru a narrow area(fast moving) and exits a wide area(slow moving) so that the oil can easily drop down to the bottom. In this case I'll agree with the instructions.

I guess, if your rings are shot then sure. But the General seems to disagree with you. It's their design. The fresh air port is in the TB so that it can provide fresh clean air to one side of the valve cover while it sucks out the other side into the PCV. The reason for the nasty smell is not because of the tremendous blowby but because of the oscillation of the crank shaft constantly pushing and pumping air in and out that you get the expulsion of crank case gasses and oil. If you put your hand over the oil fill and feel only air exiting, then it's time for new rings.

Blow off port? you lost me here. Under boost the system is pressurized. This one's new to me.

screw991le

Very simple answer, NO.

The line has to pass thru the can into the PCV then into the intake.

You have a loop. You have both intake line pluged. The intake one needs the PCV. You are not getting rid of the vapor and air.

I did a home made version

http://forums.corvetteforum.com/show...V&forum_id=103