bump?

 

Pooled oil from periods under boost or failing PCV. Bottom line is I think increased crankcase pressure leads to oil leaks. Someone one of these days needs to datalog crankcase pressure under boost...

 

Another possible reason Ive thought about is, I have my pcv running into my catch can and then exiting and running into the breather on the greddy intake pipe. Could that be that cause also? Im wondering if the pcv must go back into the intake manifold instead of the catch can.

 

Built motor...APS TT for 12,000 miles. What I have done is have a separate
catch can for the PVC valve (PVC to catch can and and back to intake manifold)
and another one from the driver's side breather to catch can and then plumbed back to
APS air intake (air cleaner intake). While the first one takes care of things when not
under boost, the second one will evac when boosted. Works fine and relieves pressure
under both circumstances.

 

That's a problem since the vacuum generated by a single air intake is less than that generated at the plenum - less crankcase evacuation (and almost no ventilation at idle).

That may work with check valves in place, but under boost you still do not have ventilation (no source for fresh air). I ran that way for awhile until the driver's side hose kinked one day and sent oil everywhere - total mess and nightmare to clean up. Now I just run an open breather on the driver's side CCV. The passenger side PCV has 2 additional check valves. One sucks crankcase vapors to plenum at idle, the other sucks vapors from PCV under boost by hooking up to air intake. (So air flow is always from driver's side open filter -> through crankcase -> out PCV -> catch can -> plenum/air intake at idle/boost respectively).

 

^^ Two catch cans, huh? How did you find space for that?

Not meaning to to hijack this thread but since the topic is kind of related to the issue...do you install a catch can when you have a vortech in the same way you would install a catch can in a n/a setup?

 

rcdash... You do have the ultimate setup. Correct on needing a breather to
be able to evac anything. I am running the check valve between the PCV
on the pass side, but like you said, on the driver's side no real evac with no
breather. Could you make a drawing or picture of your setup? It sounds ideal.
Thanks for posting, as this might help alot of boosted Zs.

350Z006...small catch can on PCV side and a larger one off the front of the
engine between the engine and fan. Not alot of room, but just enough.

 

I don't know if it is the ultimate setup. An ultimate setup in my mind would include a vacuum pump to regulate crankcase pressure to a fixed vacuum level.

Anyway for those interested in what I think is a cost-effective and practical set up for forced induction crank case ventilation, check out this link. It is a draft article I am helping to prepare for a website (in beta - not really for public viewing but I can let one article leak).

 

RCDASH your post from what I read it seems you know exactly what you are talking about. I myself had seen that damn PVC be a cause for smoking and it seems alot of guys miss checking that.

Larry did you ever get your issues fixed with the turbos and if so what was it?

 

Does anyone know, is there a check valve on the oem tube that goes from the pcv to the bottem of the intake mani?

 

The pcv is the only stock check valve in place to my knowledge and it ain't good enough for boost! (not talking about the brake booster lines, where there is another check valve)

 

Alright because I just yesterday redid my catch lines and am now running a tube from the pcv to the intake mani and just want to make sure that thats enough and that I dont need a check valve in there.

 

I think you misread my post. I would recommend a check valve to protect the PCV from ever seeing boost.

 

Ha well I guess I did. Wheres a good place to find check valves at? Autozone, Advanced, anything like there?

 

Larry you fix it yet or what?

 

+1, as soon as I added a check valve to my passenger side PCV line and vented the drivers side thru a breather filter, I stopped getting any smoke on decel.

My setup is:

Pass side: PCV valve --> catch can --> check valve --> intake plenum
Drivers side: breather filter only

 

any pix available?

 

I'll take one for you.

 

Pass pcv to catch, then to open atmosphere. Plenum is capped. No smoke here. I had my catch can run back to plenum till my tuner removed it. He said it was a common mistake to route back to the place you are trying to prevent oil from getting into. Also from pressurizing the crankcase. Had plenty leaks from the greddy turbo lines connecting to the pan... till I got a spacer.

 

^ I dont see how that makes sense. You've totally removed the PCV's ability to actually be positive. Now any ventilation of the crankcase is passive. It also seems as if your catch can is now totally useless. Unless I'm just missing something here.

This is why me and rcdash are telling people to use check valves.