[edizio]

If a well modified skyline has a PCV system that vents to the road using the vacuum created by the exhaust gases creating the negative pressure on the crank case.. What would be the point of having a catch can with a filter at the top sitting on the oil dipstick tube.

I'm actually finding that the can is filling up steadily on high boost which is pretty weird as this indicates that there is positive pressure on the crank case. It never used to do this so this is why I've caught on to it. I have done the following checks: -

Compression test - very good results indicating no compression leaks
Blue smoke - none at idle nor at high boost
oil fill level - normal
Smooth idle - very smooth, even with cams
PCV system: -

valve on the engine still rattles as it should, no obvious leaks on the tubing.

The only part of the PCV system that I haven't checked is the exhaust connection. I jacked up the car yesterday to get under and didn't have the right size crows foot so I'll do that today. I guess that if the attachment that creates the vacuum is not positioned correctly, it will not create the appropriate pressure relief and thus vent through the dip stick tubing.

 

[edizio]

Okay, so I checked the PCV into the exhaust and everything seems fine, the positioning looks normal and should be creating the vacuum on the crankcase.

Anyone have any suggestions? I'm still pretty bamboozled as to why the catch can would be connected to the dip stick tubing.