2JZGE Cam Breathers - vac leak?

[takai]

Bit of a strange one, im getting a decent vac leak when i hook up my exhaust cam breather to the catch can on the 2JZGE. The catch can is -ve pressure as it vents back to the intake, but i suspect that the exhaust cam for some reason isnt supposed to be at -ve pressure.

Thoughts or ideas?

[oldcorollas]

does it have the PCV in there? (and the associated/incorporated restrictor)

[takai]

Nope, looks to be a straight line into the cam cover. Unless its in the splashback tray

Bloody big fitting too, 14 or 15mm.

[oldcorollas]

if catch can goes direct to intake, with no valve/restictor, then the catch can will be at manifold pressure.

if no valve stuff between catch can and cam cover, and the manifold has vacuum, then it will suck as much as it possibly can through the cam cover....
usually there is one PCV line, and one breather... the breather goes to atmosphere to let air IN when manifold is in vacuum and air going into plenum from PCV, and to let air OUT under throttle with blowby

is the catch can venting to the intake before the throttle (atm pressure) or after the throttle (manifold pressure)

[takai]

Yeah, looking at the pics of other 2JZs it appears that the PCV goes to the post throttle section while the breather goes inline before throttle plate but after filter.

Makes sense.

Interestingly the 4AG doesnt have a breather at all, just a PCV.

[oldcorollas]

that is odd...
just has PCV and pipe from crankcase to head (oil drain/air flow path)

usually needs a breather to pass air over the oil to remove pterol vapours.... maybe the 4AG had enough blowby designed in?

[Cuzzo]

Isnt there some sort of valve built into the 4age manifold/throttle body? Or its the chamber im thinking of.