TeeScooby

Hey guys. Hope your all well. Merry Christmas in advance.

I have a 1991 Subaru Impreza with stroker fitted in a CDB

Just had a few questions on the PCV Valve.

What are the symptoms of a bad PCV valve?
What are the causes of a PCV Valve to fail?
Where is the PCV Valve located on my car?

Thanks guys. All help will be much appreciated.

TeeScooby

Anyone?

merlin24

iTrader: (1)

Mick

TeeScooby

Ok. Thank you very much Mick.

Just an insight into what's happened.

Engine was built 3500 miles ago with a full 2.1 stroker in a closed deck.

3500 miles later I had oil consumption and blue smoke.

Changed the turbo with a brand new SC36 and still same problem.
Had engine opened as I thought it was piston rings and all seemed fine. But the valve stem seals had gone. So got new heads, had them skimmed and pressure tested and brand new genuine Subaru valves stem seals and all the heads done properly. Pistons had same compression in a all cylinders (1-3 away from each other).

Engine all put back together and smoke has gone down A LOT. But it's still there a bit on start up, rough idle, and bad fuel consumption and oil usage.

My next option is to change the PCV Valve. Would this be a good idea? Or is this the problem?

Sorry for the long tread. But I'm really stressing over this!

TeeScooby

Any help and advice will be really helpful!

RICHARD J

iTrader: (4)

What breather system are you running, do you have a catch can & which one is it?

TeeScooby

No catch can. Not 100% sure on the breather system. I know that the engine builder has done it to the air Intake.

No catch can at all.

FMJ

iTrader: (2)

Bin it and VTA? Or catch can... I would just VTA and see if it helps to get an idea if its that. Maybe worth putting little filters on the ends of breathers to stop dirt being sucked back in. May smell a bit as well. If it works then keep VTA or route via a catch can.

TeeScooby

VTA meaning?

FMJ

iTrader: (2)

Vent to atmosphere mate. You have the breather pipes coming from the two heads and the crank case and feeding back into the intake. The PCV controls the air re-entering the intake. You can just have these pipes putting the oily air out to the atmosphere and not back into the intake. I am fairly certain in doing this you could bin the PCV and just have simple pipes running from the breathers and under the car to spit any crap out onto the road. Not the neatest solution but it will only be a tiny bit of oily vapour and it will give you an idea it thats the problem.

Obviously you have the plug the holes in the intake.

If you search "Impreza VTA breathers" you will find all sorts of info on it and pics.

Quoted from elsewhere:
In laymans terms venting the breathers for your two cam covers and crank will stop the nasty gases being returned into your induction tract (The pipework that sooks in the air from your filter to the turbo that has mad pipework going into it, the mad pipework is your breathers, the sooking of the air means that it will also sook the nasty gasses out of your breather, but it will go back into your engine, and that air is nae use because its been used already and is full of nasty gases)
A catch can on a subaru ideally needs 3 pipes going in and one coming out, and gives a "can" to collect any oil that is present. the 3 pipes going are from the two cam covers and the crank. Its hard to find a catch can with 3 ideal inlets and one outlet. I had to modify the cusco one I got off gumball to do this and its still not ideal, so I will be venting to atmosphere. I will be doing this because my outlet on the catch can isnt big enough to allow all the gas to bugger off under full load despite all my fettling. Andy F pointed this out.
Venting to Atmosphere is quite easy, and gets rid of alot of the naff subaru pipework.
Look at the top of your rocker covers and you will see in the center of each a hose coming off, take the hose off and you will see the black stubs the pipes fit onto.
Now look at the back of the engine, under the intercooler but on the turbo side and if you follow the pipework that all joins up and goes to the inlet from the cam covers eventually one will lead to the back of the engine at the tubo side and go into the block, pull that hose off and you will see what looks like a bit of plumbers copper pipe coming out of the block. That is your crank breather. take all the pipework and valves in the pipework off the car. You will have to block the holes left in your induction pipe I originally used araldite and plumbers bungs. Now look at the bore of the stubs on the cam covers and crank breather, go to pirtex and buy oil hosing, or if you want clear garden hosing so you can look for oil in it. You are going to need enough hosing to come from each stub individually , go to the bulkhead then down to the road wherever you decide to attach it. Attach the hosing with jubilee clips, and have it coming up, then down to the road, so that oil can run back in should it so desire, and to avoid kinks.
Coulty has his pipes going onto his strut brake and down, attached with plastic ties, this is a good idea. But remember you want it running free with no kinks.
Many people plastic tie it onto the suspension arms, I would personally keep it away from the exhaust side, if you do get oil coming out (Nothing to worry about!) it may hit the exhaust.
When high power cars lauch they get oil out of the crank breather and onto bottom of the car almost all the time, thats life.
Have alook at a car with it done and you will see what I am talking about.
Hope this helped

TeeScooby

Thanks mate. What do you guys think could be causing oil consumption and smoke?
Took the PCV valve out today and cleaned it all up. It was working 100% fine!

Rafo Radovan

Hi did you ever find where the oil consumption came from ?