1) do they bolt right into the 914 /4 motors?

2) are they mechanical or vacuum advance units or is advance taken care of electronically?

3) anyone have a picture of one taken apart or the insides of one??

4) is the "trigger" method inside optical or magnetic?

Mike,

On the 86-91 Digifant Vanagons they do the following:

1.Yes, looks just like a Bosch dizzy and it drops in.

2. No advance or retard. Solid shaft from clutch tang to rotor and no rotatable plates in the dizzy body. Digifant brain box reads the signal from the dizzy and advances the timing based on rpm. Great for home grown EFI,

3. Ain't nutin inside other than the sensor, the rotor and shaft, and a plastic insullating cover plate that seperates the cap area from the dizzy body. An upside down trigger wheel "can" is hard mounted to the shaft and has 4 cutout windows for the hall effect.

4. Hall effect. VW sensor craps out and costs a fortune for a rebuilt unit- twice for me in 160k miles. at $200-400 each time.

The 85 and earlier water cooled Digijets are different. The distributor is bigger, has a solid shaft and similar trigger wheel, centrifugal advance and a vacuum unit can (2 ports). Also has a seperate idle control unit, and a hall control unit. Bet the brain box doesn't control timing so this might be more friendly for some projects.

Ken