Could just gut an old valve, I don't think it'll suck oil - I've done it before. I'm just real curious why it isn't pulling out all the fumes. Is there enough fresh air getting into the other valve cover? Some of them used to have a filter inside the baffles looked kinda like a brillo pad. Maybe gunked up? Far as the PCV goes, it should rattle if its good. I used to just blow thru them with my mouth to test them. If there was any difficulty at all, just chuck it and get a fresh one for 3 bucks.
Thats how they used to do it anyway, fresh air went into one valve cover and the other cover had the PCV hooked straight into manifold vacuum. Dunno about the new engines tho, I'm outta date.
***--- Wrecking Crew member ---***
"I've prolly been around longer than you think"