Engine PCV breathing system help!

[JamesSSB]

Hi all
I need some advice with what to do.
My "M" intake was saturated with oil a while back so I have disconnected the tube from the rocker cover and it's now capped at the air box and I have put a small filter on the rocker cover.
The small filter is still covered with oil and I am not sure what to do with it.

The other problem I have is on my Skunk2 intake manifold, there is no nipple to connect the PCV system, so it's not connected to the intake system.
Has anyone else noticed this, what can I do as the instructions tell you to plug the PCV which can't be good.

What can I do, I am thinking about an oil catch tank but I have no idea on how to plumb it in.

James.

 

[Chris-DC5]

I was running an oil catch tank for 2 years and never had a drop of oil come out.

They are simple to plumb in. Hose from rocker cover to catch tank in, then hose from catch tank out to atmosphere/floor.

I also ran without the PVC hose coneccted for a while and did not notice any difference in performance or drivability.

I would question why you are loosing so much oil in the first place.

 

[skunk2_dc5]

i noticed that the skunk2 intake did cancel out the PCV and i was also curious about it too

 

[JamesSSB]

The cam cover filter has oil inside it, I suppose because at high revs oil is pushed out the top? No idea.

At the moment I have a small filter on the cover and the PCV.

 

[pulpmelon_r]

Air is drawn in at the rocker cover and blown out of the crank case breather, I've never seen any trace of oil on the rocker cover filter?

A catch can needs to be down stream of the crank breather & under vaccum to replace the draw on the crank case that usually comes from the IM.

 

[JamesSSB]

Interesting. I always thought air was drawn from rocker cover into IM.
That's why I had traces of oil in it.

 

[Chris-DC5]

JamesSSB = Correct
pukpmelon_r = Wrong.

 

[JamesSSB]

Can any of the moderators/tech guy's tell me please the correct way to set up an oil catch tank between the PCV and the rocker cover.

Also should the catch tank be a sealed unit still connected To the intake or should it be a vented tank?

Thanks.

 

[pulpmelon_r]

JamesSSB = Correct
pukpmelon_r = Wrong.

Look up what the PCV valve does on the crank case, the hint to its mode of operation is in the name.

Also why filter air if its blown out of the rocker, think about it.

 

[Jammygit]

I've been reading up on this for some time and agree with what pulpmelon_r says.

Should be PCV - Oil Catch can - Inlet manifold, this should be sealed with no breather as it uses the inlet manifold to provide the vacuum.

Also for the Rocker it doesn't seem to matter what you do, either leave going to intake or put a filter on it. The reason you may have oil in your breather on the rocker cover is because you have blocked the PCV and there is nowhere else for the pressure to go ?

Most of what i've written is from reading other peoples descriptions/diagrams, this is a good read http://www.k20a.org/forum/showthread.php?t=10172

 

[leejw87]

The rocker cover breather will expel the gases caused by blow-by not suck air in... It is then recirculated back through the engine as these gases are not allowed to be vented to atmosphere.

Alot of rocker covers will be fitted with a Baffle plate to stop oil from being sucked into the breather and contaminating filters etc but have a clearance around it to allow the gases and pressure to escape.

 

[tricker_luke]

So an oil catch can between the rocker cover and air intake will be beneficial?

Seems mixed opinions here.

 

[leejw87]

Ideally that would be a good way of doing it as the catch can can collect all the oil vapours instead of sending them straight to the air filter.

 

[dustyvip]

So an oil catch can between the rocker cover and air intake will be beneficial?

Seems mixed opinions here.

That's how I had mine set up on my old turbo b16 and it work great

 

[JamesSSB]

Thanks for all the replys guys,
I have learnt that the best way is too fit the catch tank inline from the PCV valve to the inlet manifold.
Now there are people who say that the PCV valve needs to be after the catch tank so it does not get gunked up, now my problem is that the Skunk2 intake does not have a barb fitting for it so I will either have to drill and tap one into the manifold or tap into another vacuum pipe near the TB?

Then I will re connect the air pipe to the air box and try it out.
The catch tank has to be a sealed unit to give a vacuum in the PCV system.
James.

 

[C&S Evo7]

IMO it is best toi leave the PCV valve alone, they are also servicable and should be replacd with every air filter really, the ball valve can get stuck of spring not operate properly which can lead to problems.it is better to interupt the breather pipe.
our old evo catch can/breather/separator, from cam cover to can to intake
,

claire's s2000 , cam cover, can, intake

 

[pulpmelon_r]

Thanks for all the replys guys,
I have learnt that the best way is too fit the catch tank inline from the PCV valve to the inlet manifold.
Now there are people who say that the PCV valve needs to be after the catch tank so it does not get gunked up, now my problem is that the Skunk2 intake does not have a barb fitting for it so I will either have to drill and tap one into the manifold or tap into another vacuum pipe near the TB?

Then I will re connect the air pipe to the air box and try it out.
The catch tank has to be a sealed unit to give a vacuum in the PCV system.
James.

You could tap another vacuum nipple into the IM, I was lazy and used a T piece from the brake servo vacuum feed (brakes are still fine)

This is the setup on my Honda (£25 and half an hours effort :xaiweb5: )

I'll grab a pic of the setup on my Mazda as thats a little less ghetto...

 

[JamesSSB]

Thanks guys,
Thanks for the info again,
I don't really see any point in putting a catch tank from the Rocker Cover to the intake as the pipe is sucking air in. Just leave the small filter on it will be fine I think.

The crankcase PCV is the criticle place for a catch tank as the oil vapour is expelled from the engine and dumped back into the intake, so I think I am defiantly going to place it there.

The reason people are saying move the PCV from the block to the outlet of the catch can is because it means the expelled gas is clean of oil when it gets to the valve and so keeps the PCV clean.
You have to replace the PCV for a Barb fitting on the engine and then Screw the PCV onto the catch tank.
I will have to tap a new fitting into the intake I think.

One point I should make is that the PCV need 0.7psi to operate I'm told and that the hoses need to be as short as possible. That last picture may be causing problems as the pressure will be lower over the tube distance.

James.