Oil Catch Can Question? (little Confused Here)

[sidewazegtst]

Hey everyone what's up.

Well I just wanted a little clerification on something with regards to oil catch can set up's as I finally got mine and want to install it.

Now from what I have heard it's not good to pressurize the valve cover's by running the hoses from the breathers directly to the catch can and not back to the motor, is this true? I know it can be vented in to the air however....yeah thats a BIG emissions no no where I live.

I have searched on here, my local Skyline board and here as well but have not gotten a clear answer. I've also seen pic's of different set up's so that's kinda confused me as well when it comes to figuring this whole thing out.

What I thought of doing was blocking one end of the breather by the turbo, keeping both breathers attached by a hose and have a single hose go to the catch can. Then run a hose from the catch can back to the intake plenum of the motor. So the system has normal pressure but will this set up work for removing most of the oil vapour from going back in to the motor or no?

Any help or thoughts would be greatly appreciated and thanks VERY much.

Take care.

Cheers

Edited May 8, 2006 by sidewazegtst

[rb20inside]

hard to read, but from what i understand your idea sounds fine.

on mine, i joined the two breathers, then went to the catch can then ran a hose from the catch can to the intake plenum. i made new turbo intake pipe (or could just block it). seems to catch the vapours fine.

[Chris32]

I'll try and explain my setup, as it doesn't vent to atmosphere and works pretty

well

1) PCV valve to cam cover - leave this, as it allows pressure in the crankcase/cam cover to be sucked into the plenum at idle and negative boost pressure.

2) My catch can is plumbed into the line that went from the cam cover to the intake pipe. By placing your catch can here, it picks up all the crap coming out of the cam covers when on boost. Inside my catch can, it contains stainless steel wool, which is stuffed into a stocking to keep it all in place.

So the path of the air goes out of the cam cover, through the steel wool/stocking filter, and then into the front of the turbo

3) Here you can see the orientaition of the pipe work, in and out

P.S - sorry the picture is a bit dodgy

By doing it this way, smelly (and illegal) catch can vapour is eliminated, as its all contained within the filter. You just need to change the filter setup once every 6 months or so, or whenever its dirty

Hope this helps,

Chris

[sidewazegtst]

Thanks a lot for the imput guys it was really helpfull.

I installed it tonight (the way I mentioned in my post) and so far I think it's gona work out ok. I want to secure the can better then how it is now but it'll do for the time being.

One other small question though, when the car is idling can you hear the air passing through the can, kinda like it's leaking air but it's not? I'm wondering if it's possible that one of the connections to it is not tight enough or, I may have to put some teflon tape on the nozzels coming from the to ensure that it is in fact air tight.

Thanks again for your help on this.

[Busky2k]

The problem is that if you have the catch can venting to atmosphere, you've created a 'vacuum leak' in the rocker cover. This is because at idle and cruise speeds, the PCV valve is open and the vacuum is pulling air from the rocker cover into the plenum (oil vapours to be burnt). The air im referring to makes it way through the catch can --> rocker cover---> PVC ----> intake plenum meaning you have a new vacuum leak. I found that when I had my catch can set up like this, I had a lean idle (rough) and light throttle applications got a bit funny sometimes. Remedy? Pull out the PCV itself from the rocker cover and have the hole venting to the catch can aswell (or out to atmosphere). Don't forget to block up the plenum side.

[sidewazegtst]

Well my catch can is not venting to the air at all.

Basically I've blocked off one side of the valve cover where a hose would go to the turbo intake tube. There's a hose the connects both valve covers together, from there a single hose goes to the catch can, from the catch a hose goes back to the intake plenum. So the system is under normal pressure with no venting what so ever. I'll take a pic tomorrow and post it up so you can see what I'm talking about.

Again I don't "think" it's leak from anywhere however I will just put some teflon tape on both nozzels from the catch to ensure no leaking. I'm only curious if anyone else using a catch can hears the air going through it and thought it was leaking only that it was'nt.

[osiris23]

my mate decided that he could hook up his catch can him self on his R32. Not thinking it out properly as far as i remember he hooked one upto a breather and the other onto the intake somewhere. Cant remember exsactly. But then driving out that night he was wondering what was going wrong with his car, The oil dipstick has blown out spraying oil every where. put it back in and topped it up with oil. Same thing again. Asked what was going on and he said he had hooked the catch can up, looked at the set up and it was presurising the motor and blowing the dipstick out every time he boosted it haha.

Pointless story but pretty funny all the same

[sidewazegtst]

^^^^

YEAH THAT EXACT SAME THING HAPPENED TO ME!

After I got home from work last night (teehee, im able to work on my car work) I just went to check on things and there was oil all around and my dipstick was pushed out too. Now there was'nt a huge amount of oil but enough that I was pretty pissed. How did he solve this???

I have the pic's but I'm getting ready to go to work now but there uploaded to my computer and I'll post them later tonight so you guys can see exactly how I did things. I plan on using teflon tape on the connections to the can it's self and secure the hoses to the nozzles better as I "think" air may be leaking from there.

Anyway, pic's coming soon and again I do appreciate all your help with this guys.

[Sydneykid]

Try reading this thread.............

http://www.skylinesaustralia.com/forums/in...atch+plumb+back

or this thread.....................

http://www.skylinesaustralia.com/forums/in...topic=40402&hl=

or this thread...................

http://www.skylinesaustralia.com/forums/in...topic=55083&hl=

or this thread...................

http://www.skylinesaustralia.com/forums/in...topic=33330&hl=

They will be more helpful when the Gallery upgrade is finished (hint Prank)

cheers

PS; the search button is your friend

[sidewazegtst]

Thanks man, I'll for sure read those threads to see if theres any info I can use.

See I know what I'm doing, I just wanted some clerification on a couple of things, peoples thoughts or opinion's and so on. I love owning a Skyline and just want to make sure everything I do to the car is done properly, so I don't mind putting the extra time in for doing research and getting advice.

Well here's the pic's of my oil catch can set up,

Pic1 - this is where I capped one side of the breather that attaches to the intake on the turbo.

Pic2 - the tube that joins both breathers on the valve covers together.

Pic3 - the hose leading from the breather to the catch can and the "L" bend I made so the hose would'nt kink going to the intake plenum.

Pic4 - where the hoses attach to the catch can.

Pic5 - a shot of the full set up.

Over all I'm happy with how it turned out and as long as it's working right, I'll be even more impressed. I will be changing a few things to make it look cleaner and more professional but at least it's installed and I don't think it looks to bad.

So thats it but please let me know what you think and if it's done properly, which I think it is. Any comment or advice is totally welcome.

[Sydneykid]

The problem with that system (50% plumb back, no breather) is the PCV valve closes under boost pressure and you get no crankcase ventilation. You only get crank case beathing when there is vacuum. This is covered in the thread links I sent you.

You will end up with oil out of the breather system under boost, it will find the path of least resistence and leak all over the place.

cheers

[Chris32]

As Sydneykid said, under vacum there are no problems, but as soon as you get boost, the PCV valve gets shut of, and then there is no where for the blow by to go, hence your dipstick getting blown out

[sidewazegtst]

Ok yeah that makes sence for sure.

So is it possible to "gut" out the PVC valve or can I remove it and substitute something else?

I'm at work right now so I don't have the time as yet to read all those links if the answer is there. If the answer I'm looking for IS in one of those links, could you let me know which one and then when I get time I'll read through it to find out?

[Busky2k]

The PCV comes out very easily. Just disconnect the hose to it and then use a set of pliers to wiggle it out. Done. Be sure to block up the hose going to the plenum and run another hose from the cam cover to somewhere else or you'll get oil going all over the place.

[sidewazegtst]

Alright I may be able to find a bolt here at work that will fit in properly where the PVC valve was but once I block that off, where would I attach the hose (coming from my catch) to instead?

[Chris32]

To get it setup properly, and not venting to atmo, it has to be setup like mine is, as per my post/pic

[sidewazegtst]

^^^^

Ok so I have it set up like your pic. Basically I removed the cap on the recirc tube that goes to the intake on the turbo and capped the PVC valve, which is good enough for now, but over all I am not really happy with it this way. One of the reason's I was getting this can (aside from getting rid of oil vapour in my intake) was to get rid of all the stock crap like the oil breather tube, bov recirc tube and of course the rubber intake tube on the turbo which all that other shite is attached to. Now thats not gona really be possible unless I get a custom metal tube fabbed up with a nipple on it to run the hose to from the catch can.

Now where the PVC valve is there are 4 other hoses attached to it. One is the vacum line for the stock fpr and then there's 3 other hoses (I'm guessing also vacum lines) so why can't I "T" off one of those lines instead? I mean I don't see what the difference would be as long as it's a vacum line because it'll work the same way as if the hose coming from the catch can was attached to the tube it is now.

What do you think?

[FATGTS-R]

Those other lines run coolant through them so you cant tee off them.

The way you have it now, with the PCV bunged off and the hose running back to the inlet pipe is the only way it will work correctly in a sealed system. Other than having the pcv pipe to rocker left in place and running the other breather to can and then to inlet pipe.

So basically yes, if you plan on making up a new metal intake pipe you will need a nipple to connect the hose to if you want to keep a sealed system.

[sidewazegtst]

Ok so if I can't use the hoses by the valve area, what about this one?

[Chris32]

I don't think so, as far as I know, they go down to your carbon canister near your airbox, and get rid of fuel vapour etc.

The only way to do it really, is the way I have mine if you want it to run properly without venting to atmo. And this requires some sort of filter like steel wool in a stocking inside the catch can to trap the oil vapour

or block off your PCV valve, and the pipe that goes to the turbo intake, and run the catch can to atmosphere with a filter of some sort on the catch can itself to stop dirt and shit getting in

Using any other lines is pointless, as they have no purpose for venting crankcase gasses

As for getting rid of the BOV return on the intake pipe, just blank that off on the actual pipe near the AFM if you want to run a BOV that vents to atmo

All of the other pipes serve a purpose, and from my experience only make your car run worse with them disconnected or blocked running a AFM based ecu

Chris

Edited May 10, 2006 by Chris32