While working on my car this warm season I have done a lot of reading on the PCV system. Why Nissan decided to vent the crankcase at the driver's side exhaust cam cover is not clear. Why not one vent at each side exhaust cam covers? Since the engine is under boost at times, another venting locationn was provided on a "tower" on the the intake cams. This time one on each side (go figure). This means that at the top of the motor there are 2 holes exposed to the turbo intake pipes that are at somewhat reduced pressure. Don't know if these are valved or restricted or just 2 plain holes with hoses.
In any case my point here is to bring attention to the fact that the PCV system can never direct the full vacuum of the manifold to the crankcase because of a "leak", which is the intake cam boost breathers. My guess is that the manifold vacuum reaches the crackcase via the oil drip return holes through the head and block for camshaft lubrication. Up again to the intake cam covers and from there to the accordion pipes. This is a connected and opened system. Moving the sucking ports from the driver's side exhaust cam cover to the adjoining (adjoining to the boost breather one) "tower" on the intake cam covers. Makes the vacuum situation worse because the path of air is no longer through the crankcase but from tower to tower.
Follow Ups
Relocating the crankcase venting ports. - JMartz08:27:38 06/14/11
