Bosch vaccum cannister interchangeability, can you swap between dizzies? Options

[bbrock]

I rebuilt my Bosch 2.0L dizzy (p/n 039 905 205) but the vacuum canister is bad so I used a good one from a 1.7L dizzy I have on hand. The PET lists these as different part numbers and now I'm wondering if I need to track down the correct canister for this dizzy. Anyone know how much difference in advance between canisters and if it will make a difference? I'm going to be running Webers for now but may eventually restore the D-Jet and install.

[porschetub]

I rebuilt my Bosch 2.0L dizzy (p/n 039 905 205) but the vacuum canister is bad so I used a good one from a 1.7L dizzy I have on hand. The PET lists these as different part numbers and now I'm wondering if I need to track down the correct canister for this dizzy. Anyone know how much difference in advance between canisters and if it will make a difference? I'm going to be running Webers for now but may eventually restore the D-Jet and install.

Can't be totally sure,seem to remember the vacuum cans aren't constant and list several different numbers from different years which is for 1.7,1.8 and 2.0.
Someone on here must have tried a 1.7 one to see??,but think the advance may be set for the motor you are using with original fuel system.
However running carbs will most likely not be noticed @ all if you are getting full vacuum signal.
No one wants to pay NOS prices for there units ,most want mental prices for them,good luck and by the way amazing work on this car.

[IronHillRestorations]

You'd be better off using a 1.8 distributor

[bbrock]

You'd be better off using a 1.8 distributor

I've read that the 1.8 is the preferred "stock" dizzy for carbs but my thought is to try one I already have first and if I have to buy a different dizzy, I will probably buy an SVDA for carbs. I've been curious why the 1.8 is better though. Does it have a better advance curve, or is it just because of the lack of injector triggers? I pulled my triggers and made a blanking plate for the hole.

(IMG:http://www.914world.com/bbs2/uploads/post-20845-1558413627.jpg)

[bbrock]

@porschetub , you are correct. The PET lists seven different part numbers for dizzies and five different part numbers for vacuum canisters. Dizzies that came with a rev limiting rotor got a different p/n from one that had a regular rotor so that is part of the alphabet soup.

All of the dizzy numbers end with 205 and in his Weber book, Tomlinsons recommends the "205" distributor but doesn't specify a particular version. The 1.8L dizzy is 022 905 205 S which does appear to only be used on that engine.

I found some answers in the Tech/Spec book (see below). It looks like the 1.7L vacuum canister should work fine on the 2.0L dizzy as they are essentially the same. The difference is that the 2.0L canister has an adjustment screw that allows some adjustment of the advance and retard where the 1.7L is statically set near the midpoints of the 2.0L adjustment range.

For advance curves, it looks like the 1.8L advance kicks in later (both mechanical and vacuum) than my 2.0L dizzy and provides a few degrees more advance through the curve and considerably more total advance. I don't understand this stuff very well but suspect that means the 1.8L dizzy would potentially make more HP at WOT and maybe stronger pull?

[914_teener]

You'd be better off using a 1.8 distributor

I've read that the 1.8 is the preferred "stock" dizzy for carbs but my thought is to try one I already have first and if I have to buy a different dizzy, I will probably buy an SVDA for carbs. I've been curious why the 1.8 is better though. Does it have a better advance curve, or is it just because of the lack of injector triggers? I pulled my triggers and made a blanking plate for the hole.

(IMG:http://www.914world.com/bbs2/uploads/post-20845-1558413627.jpg)

Get the 123 with bluetooth.

Good luck.

[bbrock]

Get the 123 with bluetooth.

Good luck.

That would be cool but a couple problems with that. First is $$$. It's not in the budget. Second is the good chance I'll be restoring the original D-Jet and putting it back on after a few years depending on my experience with the carbs. From what I can tell, that would require a different model of 123 dizzy than for carbs. I definately don't have the budget to buy two of them. They look cool though. (IMG:style_emoticons/default/smile.gif)

I did put a Pertronix in mine though so at least I'll be points free. I think this stock dizzy will at least be a step up from the 050 I bought back in the 80s for this project but never used. (IMG:style_emoticons/default/beerchug.gif)

[porschetub]

Get the 123 with bluetooth.

Good luck.

I did put a Pertronix in mine though so at least I'll be points free. I think this stock dizzy will at least be a step up from the 050 I bought back in the 80s for this project but never used. (IMG:style_emoticons/default/beerchug.gif)

You will like the Pertronix especially for starting ,also IMO the initial warm-up is better with carbs that have no chokes,they just seem to run better and less "cold blooded'' till up to temp.
The above was the first thing I noticed when I fitted Ignitor I to my VW T2 camper years ago,been real happy with these units ever since.