914 2.0L Crank Case Ventilation

[Nemos]

Hello,

I just got the 914 2.0L installed in my 1972 Bus... wow, now this van is so much fun to drive!

I bought the 2.0L engine used and already pulled from the car. I have no idea how the stock crank case Ventilation system is set up. any help with this would be great.

Right now I have two hoses coming from each cylender head coming to meet at a "PVC? " valve by the dip stick. from there I have a hose going to the top of the air cleaner of one of my dual 40mm delortto carbs. There is also another fitting om the side of the Oil fill top, this one i have pluged,

The engine had dual two 40mm Del's. what is stck and how can I get this set up for carbs?


Thx !!

[aircooledtechguy]

This is how I did mine for installation into my type-3. I used a spare rubber "Y" from a bus (the one that goes from the plenum to the brake booster and the decel valve) in-line so as to connect the heads and the crank case before going to the plenum (in my case) or the air cleaner (in your case)



Hope this helps. . .

[raygreenwood]

Nate...there is a problem with what you have done in your picture. You could greatly increase your ventilation with one hose change. Right now you have the ventilation running backwards from what factory did.

The correct order was inlet air from air cleaner....to the three-way flame trap mounted in thefront of the picture on the fan housing. From there...as you correctly have it plumed...it flows to each head....is pulled through the PR tubes...through the case...into the breather box.....and out through the PCV valve (which yours still seems to have). From there is should go directly to the PLENUM...so it will be under vacuum pressure. The PCV works better when you remove the guts from teh valve that is in teh breather box and simply put a 2-3mm restriction orifice in the line...or you can leave the PCV.
But...the mistake is plumbing the PCV outlet to the "Y" you see with the 12mm hose...and running to the intake upstream of the TB. In that position vaccum is almost "0"...and because of the "Y" the system will rebreathe a fair portion of the case gasses. Ray

[aircooledtechguy]

Thanks Ray. I had to read that a couple times to visualize. . . I'll give your way a try and see how it works. Thanks for the heads-up.

[raygreenwood]

It can help to look at the original flow for the fuel injected 411/412 engine. That was a very high efficiency set-up. Its only week point is teh PCV valve iytself. It was not good for D-jet because it bled air into the manifold at inoperatune times because it was not controlled by the ECU.
When you replace that PCV valve....usually by simply knocking the disc out of it....and then put a singel controlled orifice inline...small enough that you can simply readjust the baseline fuel mixture to work around it.....the car runs much more evenly and it has much higher crankcase vent flow. Ray