Re: Crankcase Pressure
 

Secondary air injection, and as Glenn pointed out, not legal for stock.

Re: Crankcase Pressure
 

I only have one breather on the passenger side of my 5.0 and no breather on the driver side valve cover. Difficult to get anything to fit on drivers side valve cover because upper plenum is in the way. I have tried open breather and have tried connecting it to the throttle body like factory. I also have the PCV valve coming out the back of the block and have tried sending that to the throttle body, sending it to the upper plenum, and just plain blocking it off. I still haven't figured out the best scenario for a stocker and I still burn some oil occasionally. Leakdown shows up fine. At the risk of sounding like a fool, are you supposed to block off PCV when you run breathers or can you run breathers along with pcv? I'm thinking that sending unmetered air back into an EFI system without the computer knowing may not be as good as a Carb system.

Re: Crankcase Pressure
 

PCV system always has a way to breathe. it pulls fresh air in thru the breather as it pulls fumes/pressure out of the engine into the manifold/plenum. Factory the breather tube goes to the air filter so it always gets clean air.

Re: Crankcase Pressure
 

Apparently you can't run a Dart block in stock.......because this would be pointless if you could.
The Dart block vents the crankcase through "slots" in the lifter galley like the big blocks do.

Re: Crankcase Pressure
 

Bobby, on a Buick Grand National the passenger side valve cover oil separator/breather is connected by hose to the turbo intake which is after the air flow meter. The PCV into the intake. IIRC there are two kinds of PCV valves, normally open and normally closed, depending on the system and their location in it. On a Boss 351 for example (I remember the valve having suction at idle) the drivers side valve cover is connected to the PCV valve and the passenger side to a little filter in the air cleaner. The system sucking thru the PCV at high vacuum/low rpm, at higher rpm that closing as intake vacuum drops and it then drawing vapors out thru the valve cover into the air cleaner to the carb. As long as you can keep oil away from the suction openings it should be OK?

Re: Crankcase Pressure
 

Joe - That would be assuming one would want/allow the oil to drain back directly over the crankshaft.

Re: Crankcase Pressure
 

You'd think Maskin and gang would be well aware of that.....myself . I want the oil to get back to the sump as quickly as possible.
I'll manage windage some other way........

Re: Crankcase Pressure
 

I'm no expert for sure, but I also don't have any Dart blocks lying about. It's my understanding that the Dart blocks oil differently and likely less oil up top to contend with. Using these old GM blocks my solution just seems to make sense to me.

Re: Crankcase Pressure
 

What you did makes sense to me ..............on an OEM block , yes.

Re: Crankcase Pressure
 

Ok i'm assuming a header vac system isn't legal in stock either since no one has mentioned it? and it would seem a obvious answer.