PCV system

[The S is Silent]

I am convinced that my lack of a PCV system is causing my intermittent smoking problem, so I'm going to fix it by putting the PCV system back on my car.

I'm using a cone filter right now, so I'm going to tap into the PVC intake pipe that I have on the van with a nipple. I'm also going to make a PVC catch can out of some extra PVC that my roomate has from porting sub boxes.

The plan is to run a tube from the back of the valve cover to the PCV valve, then from the PCV valve to the inlet on the side of the catch can. From the top of the catch can, I'm going to go to the nipple on the intake pipe. Sound good?

One question with this setup: How much vacuum can I expect on an intake pipe? Is there a three port PCV valve that I can get that will use the manifold as a vacuum source at idle, and switch to the intake pipe at boost, or will pulling from the intake pipe all the time work just fine? Do I need to add a breather filter to the valve cover?

I don't want to hear about just running a tube to the bottom of the engine bay, because that's what I'm doing now, and obviously it isn't the best for evacuating crankcase pressure. I am also aware of the exhaust evac kits, and that is not an opion for this car, becasue I don't want to have to get it welded in.

[turbovanman²]

Sounds right. I jun ran a K@N filter on my inlet side of the catch can, looks neater and you get the same results, :thumb:

You'll probably see a few inches of vacuum, remember how much air you need at full boost, :eyebrows:

[The S is Silent]

Simon, what do you mean by a K&N filter on the inlet side of the catch can? Wouldn't opening the loop to the atmosphere defeat the whole purpose of pulling vacuum using the intake pipe?

I have a 2 inch intake pipe...would reducing to 1" and then expanding again to 2" hurt the performance of the turbo? I think by placing the nipple for the vacuum source inside the small section (much higher gas velocity) would give me a little more vacuum. Good ole' Bernoulli!

[turbovanman²]

Simon, what do you mean by a K&N filter on the inlet side of the catch can? Wouldn't opening the loop to the atmosphere defeat the whole purpose of pulling vacuum using the intake pipe?

I have a 2 inch intake pipe...would reducing to 1" and then expanding again to 2" hurt the performance of the turbo? I think by placing the nipple for the vacuum source inside the small section (much higher gas velocity) would give me a little more vacuum. Good ole' Bernoulli!

Not really, a catch can is simply a way for the oil and air to seperate. It doesn't need vacuum to work, just a fresh air vent IE air filter or intake piping. The PCV provides the vacuum at cruise and idle and the catch can provides the new found fresh air so you dont' suck up the oil out of the valve cover. Then when you boost it, air goes up thru the hose to your catch can, thru the can, now the cleaned air goes out into the atmosphere or into your intake hose. Does this make sense?

You don't need to mess with your intake pipe size, the venturi effect will be in full force, lol! Yes, reducing your piping will affect your performanc.

[The S is Silent]

Not really, a catch can is simply a way for the oil and air to seperate. It doesn't need vacuum to work, just a fresh air vent IE air filter or intake piping. The PCV provides the vacuum at cruise and idle and the catch can provides the new found fresh air so you dont' suck up the oil out of the valve cover. Then when you boost it, air goes up thru the hose to your catch can, thru the can, now the cleaned air goes out into the atmosphere or into your intake hose. Does this make sense?

You don't need to mess with your intake pipe size, the venturi effect will be in full force, lol! Yes, reducing your piping will affect your performanc.

Ok, the catch can being a separator makes sense. It really makes no difference wheather or not I tie it into my intake pipe or not...it just needs filtered fresh air. But I still don't see how the PCV provides the vacuum at cruise and idle.

http://boostedmopar.com/forums/attachment.php?attachmentid=51&d=1122387693

That is how Kevin has it drawn. Does the PCV have 3 ports like this is showing? It looks like at vacuum, the intake pulls the crankcase vapors out, and at boost, the PCV valve shuts, and the pressurized crankcase just vents to the catch can (or atm if you don't care about cute little animals). All the pictures I find on the internet show only 2 port PCV valves.

[turbovanman²]

http://boostedmopar.com/forums/attachment.php?attachmentid=51&d=1122387693



Yep, thats bang on. The pcv valve only works during periods of vacuum, at WOT or in boost, the valve is shut.
You can run an air filter on the hose instead of the line to the air intake setup if you want. 2 drawbacks are if your engine is badly worn out, you could get an oil smell inside your car at boost, you will fail a emissions check if they look under your hood.
The 3 way tee at the valve cover is stock. One side goes the valve, one to the v/c and the other to the fresh air source or catch can.

[The S is Silent]

Well, I checked...I had a PCV system the whole time. So what's the deal with the smoking? Bad PCV valve?

But now seemed like as good a time as any to re-do my intercooler pipes, so I'm moving the filter up front with the intercooler, and I'm adding a nipple for the PCV system in the suction pipe. I just need to get the pipes welded together now and it should be good to go.

Thanks for you help explaining it to me Simon.

[turbovanman²]

Smoking could be a bad pcv valve-use Mopar only, bad valve seals or rings, turbo starting to go. Next time you pull your plugs, have a good look at them. If they have oil deposits on one side, like there were sprayed from the side-the valve seals are shot. If the whole plug has them, rings are shot. If none, the turbo is going.

[The S is Silent]

I just got a replacement crap PCV from Advanced...but I'm driving by the dealership to get my IC pipes welded together, so I'll stop on the way and get a mopar one.

Which one of those would only smoke intermittently, and only at idle? Usually the smoking goes away when I drive it a little bit.

The turbo doesn't feel bad at all. I checked shaft play and it's exacly how it hould be...NONE in and out, and a tiny bit up and down.

[turbovanman²]

Won't be the pcv at idle. Turbo or rings will smoke at idle.

[The S is Silent]

Won't be the pcv at idle. Turbo or rings will smoke at idle.

Gwa! I was afraid of that. Time for a compression check, I presume.

[Whorse]

You know, I smoked at idle because of a rich mixture due to a bad O2, so it might be something simple like that. As for your PCV, I just did that exact setup as you, and if you want some pictures I can send you some of how I did it. So far seems to be working well for me.

[4cefedomni]

i have the exact same problem with mine i suspect the turbo is gone. but it blows a large cloud of blue smoke about a minute after startup and it continues to blow smoke until its at operating temp, this happens when the pcv is disconnected it also blows a little bit in vacuum and at idle once at temp but nothing like when its cold. when i connect the pcv to the manifold only it doesn't blow any smoke at idle but it blows a giant cloud literally fills the street with smoke (in the rearview all i see is whitish blue) under boost. So i think i'm going to do this system as well because it will give me the best of both.

[The S is Silent]

You know, I smoked at idle because of a rich mixture due to a bad O2, so it might be something simple like that. As for your PCV, I just did that exact setup as you, and if you want some pictures I can send you some of how I did it. So far seems to be working well for me.

It's a new O2 sensor. I put it in when I put the engine into the van. I'm pretty sure it's oil burning. I was at a autocross with a ton of Gearheads this weekend, and the first thing a bunch of the old guys said was "oil problem".

Thanks for offering the pics as well. I have that sorted out. I'm working on putting together mandrel bent pipe for my IC now, and as soon as I get that done, I'm gonna weld it all together. There will be a nipple on the suction pipe for the PCV...and it's going to look a lot better than what is on there now.

[3Bar_Mopar]

Mine's set up with the PCV valve off the VC and then the hose from the PCV directly to the intake manifold.

I think I need to get a vented oil cap because I think it's causing small ammounts of oil to come from my dipstick tube under boost.....enough to cause some drips on the underside of my hood. I didn't have this problem before I swapped heads, but it started immediately after I did.
My previous head was either cracked or warped.

I think the pistons are pressurizing the VC under boost and it has no where to go since the PCV is shut tight.
Running the engine with the oil cap off produces NO pulses or air from the oil fill.

[turbovanman²]

Mine's set up with the PCV valve off the VC and then the hose from the PCV directly to the intake manifold.

I think I need to get a vented oil cap because I think it's causing small ammounts of oil to come from my dipstick tube under boost.....enough to cause some drips on the underside of my hood. I didn't have this problem before I swapped heads, but it started immediately after I did.
My previous head was either cracked or warped.

I think the pistons are pressurizing the VC under boost and it has no where to go since the PCV is shut tight.
Running the engine with the oil cap off produces NO pulses or air from the oil fill.

I had to do that. I have pics of my setup somewhere. Search my name and catch can and you will find them, :thumb:

[Dave]

Wait, I thought the 3 way valve is SUPPOSED to be like this: T --> PCV valve --> v/c --> fresh air... now the fresh air is the main component here that we're all concerned about.

Getting that pressure out of the case is what's important. Now if you just stuck a breather on the end of that send line to get fresh air, where's the vaccum during boost?? During boost is what's important, as we get the most pressure inside the case during this. Isn't that why we tap into the intake pipe, so as to draw more vaccum from the PCV??

I'm just as confused as the next guy here with the PCV system.

[Whorse]

Yes that's why we tap the air intake. If you read the FAQ on PCV, it explains it a bit. The later TBI valve covers are good, or a modified one, as the extra nipple allows more air to come into the valve cover and flow out through the PCV port, which vents it better. The other advantage to tapping into the air intake is that it always draws vacuum because of the venturi effect (the flow of the air going by open port pulls air through it), and under boost there is a lot of air going by, so it's pulling more air through the crank case.

[3Bar_Mopar]

I had to do that. I have pics of my setup somewhere. Search my name and catch can and you will find them, :thumb:


I went and got a $4.95 oil cap/breather thingy from Advance Auto the other day and so far so good...no oil on the underside of the hood!
It's purty too....all chrome.:thumb:

EDIT: No more oil leaks too!!