CCV and PCV

What is the difference between Closed Crankshaft Ventilation (on Jeep Grand Cherokees 4.0L) and Positive Crankshaft Ventilation (On 4.7L)? Is CCV simply a vacuum based system sucking out Crankshaft gases, while PCV has a valve to ensure no reverse vacuums due to backfires? What are the pros and cons of both?

If these questions are not meant for this groups, please suggest where I can ask such questions. I am a Jeep Grand Cherokee 2004 limited 4.0L owner learning the engine internals - just for kicks and maybe to do self-maintenance.

Thank you.

What is the difference between Closed Crankshaft Ventilation (on Jeep Grand Cherokees 4.0L) and Positive Crankshaft Ventilation (On 4.7L)? Is CCV simply a vacuum based system sucking out Crankshaft gases, while PCV has a valve to ensure no reverse vacuums due to backfires? What are the pros and cons of both?

If these questions are not meant for this groups, please suggest where I can ask such questions. I am a Jeep Grand Cherokee 2004 limited 4.0L owner learning the engine internals - just for kicks and maybe to do self-maintenance.

Thank you.

One works and the other doesn't. Convert to PCV:

The CCV is just vacuum constant through a metered hole. The little plastic tube plugs up easily on them then the air filter gets oil spits.

The metered hole in the rubber grommet can be cleaned with a paper clip and carb cleaner works well on the tube.

Mike

One works and the other doesn't. Convert to PCV: