hmmm
try a cylinder pressure leakdown test. if you compression is reasonably good, and its still pressuring up the crankcase, leakdown might be it, compression gases escaping past the rings.
on the other hand, pcv valve should be connected to the intake at all times. when you have it open to atmosphere, it does not function quite properly, it needs that negative pressure downstream to operate the way it should. try the new pcv valve, hooked up properly and see what happens.