Just trying to work out how to arrange the whole big vacuum system in the VW, since most of the hoses and unions and joints have all rotted away and fallen apart.
I think my car has the positive ventilation system, so clean air goes into the crank case and is sucked into the inlet.
From what i can work out, it looks something like this:
The plenum has the 4 big stubs for the inlet manifolds, the throttle body, and 3 small stubs.
One stub just goes to the vacuum sensor
One stub has a special rubber/metal T junction, which has one 4mm hole and one 10mm hole, the 10mm hole is for the hose which goes to the breather/PCV valve, and the 4mm is to provide vacuum for the servo thing in the air filter (which controls hot/cold air inlet? I think?).
The PCV system itself takes clean air from the stub at the side of the air filter (is this right?) and takes it through a round flashback arrestor to the two head vents either side of the engine. This air then mixes with all the various crap in the crank case and is sucked through the PCV valve (which limits its volume and also shuts it off during backfire) and is sucked into the plenum.
On the other side, the last stub on the plenum connects to the time-delayed cold start valve, which in turn takes clean air from a stub on the flexible hose that connects the filter to the throttle body.
The distributer can is fed by ported vacuum from the throttle body (is this a vac retard rather then a vac advance???)
So, does this look correct to you for a 72 411L? Im especially wandering weather it is right that the PCV air comes from a stub on the side of the filter, and the cold start bypass air comes from the flexible inlet hose. I guess it was like a design afterthought? Or is it just not how its supposed to be?
Thanks
