Warning: half-baked thoughts, theories, and opinions to follow…..
I think I understand what Gord & Fran is trying to say.
Having both the PCV suction point AND makeup air return point….in the valve cover, on an inline 6….makes a guy wonder how much ventilation the crank case is really getting.
In theory, it should still be placing the crankcase under a slight vacuum. But those two points being that close together, might also mean there’s more-than-ideal passing of fresh air straight from one to the other.
In a typical V8 arrangement, you are drawing from one valve cover, and adding clean air to the other. And the two are basically unconnected if not for the crankcase.
With the factory 261 PCV, the big alien looking (closed) draft tube apparatus is truly drawing from the crankcase. Probably somewhat better than the GM retrofit solution (which still seems better than an open road draft tube) being discussed here.
Last edited by JW51; 03/08/2024 7:44 PM.
