I was thinking this issue over and over too.
Got a 1959 235 with a 216 cover and wonna get a PCV because of the oil mess and milage reasons (price for a gallon of standard pump gas here in Germany $6,25
in the moment)
I saw factory modified draftubes that come with a PCV that goes to the aircleaner in a 1958 Chevy.
I think this is not a good idea for milage.
What do I want to suck from the crank case?
Answer: burned and unburned gases.
How do they come in there?
Answer: Blowby.
My first common sense solution:
1. Close the draft tube
2. taping in a nipple at the upper draft tube and T it via rubber hose to the wiper/manifold vacuum with a PCV valve.
Question: do I need a vented cover or must I close the vents to make sure it is not sucking to much air in to the intake?
The air from the blowby comes throu the carbs anyways, so do I need more fresh air comming in?
I just rebuilded a 1945 Willys Jeep engine that works exactly that way.
On the other hand, the vents in the cover relief the water boiled out of the oil. Will the steam get sucked down the pushrod holes or will it condense again?
An other issue is: The unburned gases I want for milage are lighter than air so they will cumulate in the upper valve cover right?
So my second solution is:
The draft tube makes a relative low vacuum and only at high speed. I don`t belive it is enoug to suck air down from the Valve cover.
So no whatever vent, I don`t need aditional fresh air. To get the gases I want, and get rid of the water, I need two hoses, one from the valve cover and one from the closed draft tube.
The Willys work that way, but it is a flathead and the valvecover is on the side with big enough oil backflow holes to suck the gases from the crank case to.
I also going to route one of these
Condensator in the line
My thoughts so far.
Any ideas?
Frank
