[T3] swapping advance cans on late model dizzys

[Chris Wright <Christopher.Wright@Sun.COM>]

<x-flowed>
Subject:
Re: [T3] Dual Vac vs Single Vac Distributor
From:
Jim Adney <jadney@vwtype3.org>
Date:
Fri, 09 Dec 2005 10:34:15 -0600

To:
type3@vwtype3.org


On 9 Dec 2005 at 10:14, Constantino Tobio wrote:


> > Jim Adney wrote:
>  
>
> > > > Of the FI models, only the '72 got the dual vacuum can. VW went back
> > > > to the simpler system in '73.
> >    

> > Ah. Do the dual vac cans and single vac cans interchange mechanically?
> > Not that I'm trying to frankenstein anything, i'm thinking more about
> > emergency spares- as I have a '71 MT (205AC, I think) dizzy laying
> > around I may try my hand at rebuilding for practice.
>  

I THINK they will all interchange mechanically. I'm sure that all the single 
vac can units will interchange, and I'm pretty sure that a single vac can will 
fit in place of a dual vac can, but it's POSSIBLE that a dual vac can might  
not fit in place of a single vac can. ISTR that the dual vac can dists have a 
slightly different cutout for the can mounting. There may also be a slight 
difference in the bolt pattern, but that can be overcome by filing the hole in 
the can mounting flange.
********************************************
Although they might fit mechanically, they may have different vac characteristics, so interchanging is probably not recommended.
If you look on the dizzy list on the attached under Type 3, you'll find at least 3 different model vac units listed for later model dizzys.
I think the dual ones which both retard and advance must be different from the single advance only type, if only for the low speed end of the advance.   ie (I'm guessing) the advance can will probably advance to the same max level but the retard will make the advance curve start from a different point?

http://www.oldvolkshome.com/ignition.htm
Chris Wright
-- Jim Adney jadney@vwtype3.org Madison, WI 53711-3054 USA

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

</x-flowed>