Do you have a vacuum gauge on this engine? What does it pull at idle?
Assuming it has an
oil filler neck, what happens if you cap it off with your hand. Does the PCV ever create a vacuum on your palm? It should; assuming the engine has no other breathers. If it doesn't, you either have an ineffective PCV, or too much blowby to make it work. If you have noticable puffing out an open breather opening (like a locomotive), you have problems.
Byron