Scratchin my bald-ass head here.

[fastpakr]

Same. 100% not a giant vacuum leak.

 

[85_Ranger4x4]

Yeah, that side of it isn't a vacuum seal, it is just pulling air from atmosphere rather than the air filter housing on mine.

I have never had an engine that cared.

 

[pentode]

I woke up this morning thinking about PCV valves, dang it

I'm obviously not aware of every design that's ever existed but I believe the principle is always the same. High vacuum situations (like at idle) pull the check ball/disc /flap against the spring to close the valve. As vacuum drops, the spring has enough force to open the valve and more gases are scavenged.

I'm thinking if you put a breather where the oil filler cap is, you might reduce the scavenging effect on the other bank to almost nothing, which might lead to deposits etc in the long run.

Edit: so, you have minimum scavenging and no big vacuum leak at low RPM/ throttle closed and max scavenging at wide open throttle/high rpm, which is when you'd want it.

 

[85_Ranger4x4]

I woke up this morning thinking about PCV valves, dang it

I'm obviously not aware of every design that's ever existed but I believe the principle is always the same. High vacuum situations (like at idle) pull the check ball/disc /flap against the spring to close the valve. As vacuum drops, the spring has enough force to open the valve and more gases are scavenged.

I'm thinking if you put a breather where the oil filler cap is, you might reduce the scavenging effect on the other bank to almost nothing, which might lead to deposits etc in the long run.

Edit: so, you have minimum scavenging and no big vacuum leak at low RPM/ throttle closed and max scavenging at wide open throttle/high rpm, which is when you'd want it.

The oil cap side is just a breather, literally.