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Block center vent to intake?
Posted: Mon Oct 14, 2013 5:54 pm
by macipusy
So I have been studying the PCV system, since I'm making all custom lines for my 2.35T build. The right way to plumb the center block vent would be a three way connection between RH head, center block vent and LH head. The second vent on the heads is then connected to the intake elbow for light vacuum.
The heads I am using only have I vent port (ej205), so my question would be, is it better to vent the block straight to the intake elbow or just plug it for now?...until I use dual vent heads, or install an AOS system.
I think with an AOS, it should be OK, since the dual vent valve covers are essentially that. But without, I'm kind of skeptical about sucking up a lot of oil.
Thoughts please.
Re: Block center vent to intake?
Posted: Mon Oct 14, 2013 7:59 pm
by dankberries
It is possible to tap another hole into the valve covers, use a barb fitting, and continue to use the conventional PVC system.
You could also block the center vent and just only use the head vents.
Or use a catch can setup. At one point I had all three vents plumed into a CC and then back to the intake, this worked but my CC was filling daily. I now block the center vent and just vent the covers to a CC.
And another idea would be a dual CC setup. One for the valve covers and one for center vent.
One note, a CC seems like a good idea once you see how much crap could get into the intake.
Re: Block center vent to intake?
Posted: Tue Oct 15, 2013 3:46 pm
by cj91legss
I blocked my center block vent. I have Twin Turbo heads.
Re: Block center vent to intake?
Posted: Wed Oct 16, 2013 3:09 am
by Legacy777
The vent on the block is really meant to help equalize pressure between the main crankcase and heads. There is going to be a lot of oil vapor in that vent and in the stock setup it just dumps back into the heads.
The vents on the heads that go to the intake normally supply fresh air from the intake to the engine, and the main vent on the back of the block is the typical outlet. In theory I think you could tee the center block vent into vent on the heads. The reason I say "in theory" is because there may be certain circumstances where you may get crankcase gasses venting out from the heads as well. In this scenario you will carry the oil vapor back to the intake. I really can't say how often or if this scenario is going to happen a lot or really happen much at all, but if I were doing it that'd be my only hesitation to just teeing into the vents on the heads.
What I would likely do is try teeing into the vents on the heads and see if I had increased oil vapor carry over in those lines. If I didn't I'd leave it and wouldn't worry about it. You really want to put your catch can on the vent line coming from the back of the engine block.
Also, just for reference here are the scans from the FSM that talks about the PCV system routing
Non-turbo EJ22
http://www.main.experiencetherave.com/s ... system.jpg
Turbo EJ22
http://www.main.experiencetherave.com/s ... _turbo.pdf
Overseas Engines
http://www.main.experiencetherave.com/s ... erseas.pdf