Silly idea in the middle of work; VTA hotside, hot side routed to catch can/ air-oil separator, routed back to IM via an MS-controlled solenoid valve, triggered on/off via boost/vac signal. Overcomplicated AF, but would love to give it a go.

Check valves prevent the proper operation of PCV valves.

I wish you all the best but I fear that will be a nightmare to tune.

Not sure what you base that on. PCV ever is never supposed to flow gases from IM to VC. Check valve assures that.

I suppose it would depend upon the additional restriction required to open the check valve.

And they certainly prevent boosted Air/Fuel mixture from flowing from IM to VC.

this.

stock pcv/breather plumbing + check valve.

I guess I was thinking of a check valve that would require too much effort to open to allow the PCV to work properly. I guess there are ones that flop open and closed rather easily. I was visualizing it wrong.

not a flippy floppy one. one just like mazda uses in the NBs.

they make metal ones, but I just used one just like this:

Thanks for this input guys. I will be adding the check valve ASAP.

Following along perfectly until we got back to street cars using the pcv with a check valve.

What would be the benefits for a street car to keep the pcv (and check valve) with both sides of the valve cover vta through a catch can breather setup?

Everything I have seen discussed on here so far has said for a turbo car ditch the pcv and then vta.

Is this just to pass emissions?

I should have multi-quoted LukeG, as this post is in response to his question.

This is what I meant... There will be those who want to keep PCV as opposed to double VTA. Some for emissions testing; some for love of the planet; some because the oil does not get black so fast, or oxidize, or get gasoline in it, or keep water in it.

In that case:
1) Don't use stock PCV valve by itself.
2) Don't use MSM PCV valve by itself.
3) Don't use GTX PCV valve by itself.

Use one of those stock PCV valves with a check valve.

On the dyno i saw dark smoke shooting out my hot side valve cover port, which just had a breather filter on it. and that filter is pretty oily and i see oil specs all over my turbo manifold.

So i got a dual port vented catch can, and routed both valve cover ports to the vented catch can.

I think my turbo was pressurizing the valve cover during boost through the pcv valve....

Gotcha and thanks for the response!!!

Does the height of the catch can in relation to the valve cover outlets matter?

Example, would a catch can installed 6 inches lower than the two outlets going to it result in excessive oil drainage to the catch can?

Is having the catch can higher, same or lower height in relation to the valve cover outlets preferred?

Thanks!

I don't think it matters a whole lot. I bet the higher you moved it, the less stuff you would collect. Is that good? I don't know. If you put it low and collect a ton of stuff, is that good? That just seems like a pain in the ass. Probably just some happy medium.

How is that for speculation and useless noise?

Yeah, pretty much what I was thinking. Was hoping someone had experience with this and might be able to chime in and confirm.

I agree that if you move it lower it would definitely collect more oil, but absolutely no idea if that is a good thing and if that would mean filling the can every few hundred miles. I have a really good mounting spot about 4" lower than the outlets, but I'm hesitant to put it there.

I'm struggling with a head breather setup on a friend's Rotrex VVT engine.

​​​​​​To try to prevent oil coming out on the hot side vent, removed the cold side breather from the inlet manifold (taped on the inlet side of course) , and vented directly to a can to help remove pressure from the hot side breather.

Strangely, no oil sign on cold side can, but keeps just puking oil on the hot side. Like almost a QT per 20 minute session. What am I missing here? I know that possibly the engine was assembled with incorrect ring gap, but I don't understand how does a side keeps puking oil and another is completely dry even though our tracks run clockwise.

BtW, head had venting ports opened up as per many tutorials on here.

https://cimg4.ibsrv.net/gimg/www.mia...f8c6c04e26.jpg

You are using a digital watch, I presume?

Of course if you pull vacuum only on the hotside and go around many right turns you will fill the hotside catch can quickly. Like a straw you suck oil into the port, while G forces "help" it staying there.

​​​​​​​if you cap the coldside vent the hotside is an "out" port all the time. If you had the coldside connected to the inlet manifold you'd suck air through the hotside into the VC during overrun, thus sucking some oil back into the valve cover

There where several iterations with the same result: V1: Cold side stock connection, Hot side to Catch Can, to Air filter; V2: Cold side to catch can to "air", Hot side to air filter; V3: Cold side to catch can to "air", Hot side to Catch can to "air":

In all of these iterations, 0 oil on cold side, ALOT of oil in Hot vent. Now that i remember, before Algarve Race Circuit we Went to Ascari wich is CCW circuit, same result.

You have a PCV valve on the cold side and it isn't attached to a vacuum source. The PCV is probably staying closed or creating a restriction and all the pressure is going out the hot side. Try removing the PCV valve and replacing it with an open fitting or hose there so it flows freely.

To save some people the hassle I went through of finding a fitting to work with the factory pcv grommet...

A 5/8" barbed brass PEX elbow fits the pcv grommet in the valve cover perfectly and stays in firmly. They are a bit tough to find (none of my local hardware stores had them), but can be had for less than $2 on ebay. And because they are sized differently, the 5/8" brass elbow fit my 1/2" hose perfectly as well and then the hose connects to the 1/2" barb on my catch can. Didn't even have to remove the valve cover.

https://cimg1.ibsrv.net/gimg/www.mia...75840237ec.jpg