Solution:
Install an evacuation pump, and/or smog pump.
Evaddave
WRONG. Problem isn't solved with a band aid.
Fix what's causing the problem...plain and simple! A bad PCV system will cause crankcase pressures under boost. Make sure that is working 100% first. If you've already got that PCV system working as good as possible then you must have other issues.
Piston rings: They need to seal very good to eliminate blow-by. If they don't seal properly high cylinder pressures blow past the rings and into the crankcase causing pressure. This forces the oil out of the breathers. To help cure this you'll need to install gapless piston rings or make sure the rings in your newly rebuilt engine is seated or installed properly.
Valve Guides and Seals: Another cause of pressure in the crank case is worn out valve guides and valve seals. Since there is positive pressure in the intake, the pressure can travel up the intake valve stem and past the seal into the crankcase. Remember, 20psi of boost can leak past a worn guide/seal quickly. This is especially true on the exhaust. Since the exhaust pressure is usually almost twice as much as the boost pressure, burnt gases from the exhaust can enter the crankcase through worn valve stem seals.
Head gaskets: Leaky cylinder head gaskets. High cylinder pressure can leak past the head gasket and into the crankcase also. Obviously, this is probably the majority of where all the pressure comes from in a higher mileage Turbo Buick engine that's been pounded to death.
Misc: Most likely not the cause but worth mentioning. Leaking intake gaskets, a crack in the intake manifold or head. Even the turbo could be causing some but again it's a possibility that could be true. Got to cover everything...
If you don't cure these first you will ALWAYS have excessive blow-by more than normal.
You're not going to get rid of back pressure 100% but it's nice to know that you took all measures to try.
I don't care if your engine is rebuilt or brand new and has less than 200 miles on it you have at least one of those problems listed above. If all of those problems above are in good working condition YOU DO NOT NEED A VACUUM PUMP TO GET RID OF EXCESS CRANKCASE PRESSURE!!!