I think the Vanagon system is just a vent. The diesel, on the other hand,
has a diaphragm valve that qualifies it as a "positive" crankcase
ventilation. On the waterboxer it is technically a "positive-negative" vent
and in no way a valve at at.

Jim

On Sat, Aug 19, 2023 at 9:43 PM Alistair Bell <ragnarhairybreeks@icloud.com>
wrote:

> Wasn’t being critical.  Was just throwing that out there.  I really
> haven’t got my head around how the stock system works.  Diaphragm, wee
> little vent in tower..,,
>
> Was dashing off comment before trip. Back from trip now.  Old engine still
> did it.  It’s tired but had to work hard
>
> Ab
>
> > On Aug 14, 2023, at 03:56, Dennis Haynes <d23haynes57@hotmail.com>
> wrote:
> >
> > Yes I am aware of the rubber diaphragm. As passive device to help
> control flow during idle-low speed operation. There is also the restrictor
> which is heated to prevent it from being blocked by icing.
> > I was just trying to explain the concept of a PCV system as used on
> other vehicles.
> >
> > Dennis
> >
> > -----Original Message-----
> > From: Alistair Bell <ragnarhairybreeks@icloud.com>
> > Sent: Sunday, August 13, 2023 7:47 PM
> > To: Dennis Haynes <d23haynes57@hotmail.com>
> > Cc: vanagon@gerry.vanagon.com
> > Subject: Re: [VANAGON] Positive Crankcase Ventilation
> >
> > There is a rubber diaphragm in the stock tower at the top.
> >
> > Ab
> >
> >> On Aug 13, 2023, at 9:44 AM, Dennis Haynes <d23haynes57@hotmail.com>
> wrote:
> >>
> >> Looks like my repaly was blocked again. So here goes cut and paste.
> >>
> >>
> >> PCV=Positive Crankcase Ventilation.
> >>
> >> This is the method of extracting piston blowby and other fumes from the
> crankcase for many vehicles. Note the Vanagon does not use a PCV system. It
> is basically an open vent leading to the engine intake between the air flow
> meter and throttle. The job of the tower is to let some of the liquid
> separate and return to the crankcase.
> >>
> >>
> >>
> >> A PCV system usually consists of some type of metering device that
> connects under the throttle plate so that so that especially at low speeds
> the blow by and stuff is actually sucked out and fresh air pulled in.
> >>
> >>
> >>
> >> Dennis
>