Ignition curves on electronic dizzy

[carl]

Was it ever established that the 79/80 carbed motors had a different advance curve on the electronic dizzy than the later FI dizzys? I ask because the 124 motors were set at zero degrees at idle for the carbed versions and later FI version were set with less advance to run at 10 degrees at idle.

And if they are different via advance curve, how do we identify which is which?

 

[lookforjoe]

The factory spec doesn't indicate any variance for FI version

 

[Dr.Jeff]

I'm sure others here will know much more about this. But if I were to venture a guess I'd say there is no difference. Mostly based on production cost/process of having Bosch redesign it, and partly based of what Fiat seems to have done with other X components (not a lot of progression compared to the higher selling 124). However I also do not necessarily believe everything the factory manual says. So it is possible there were changes, as you noted with the 124. Seems there would be part number changes to correspond with any such design changes. Is there more than one part number listed for this component? Curious, can the 124 box be fitted to the X's system?

 

[MikeHynes]

I know of three versions. (Sorry for the crappy pics)

0 287 002 041 came out of a '79 that I believe was originally sold new in Cali. It did have an air pump.


0 287 002 020 came out of a '79, don't know where it was sold new. No idea about an air pump.


0 287 002 050 came out of an FI car.


Could it be that the difference between the two '79 dist. is the vac advance?

 

[Dr.Jeff]

It just occurred to me, I completely misread the original post. I thought Carl was asking about the "module" part of the electronic ignitions (the box that is easily replaced with a GM ignition module), and the dwell control. Not sure why I was thinking that, after re-reading it is obvious the question is about advance curves and distributors. Sorry for the senility.

 

[dllubin]

I know of three versions. (Sorry for the crappy pics)

0 287 002 041 came out of a '79 that I believe was originally sold new in Cali. It did have an air pump.
View attachment 19389

0 287 002 020 came out of a '79, don't know where it was sold new. No idea about an air pump.
View attachment 19390

0 287 002 050 came out of an FI car.
View attachment 19391

Could it be that the difference between the two '79 dist. is the vac advance?

Looks like the specs for centrifugal advance is different for carb vs. FI. Vacuum is also different and for carb cars there is a difference between air pump/no air pump. Here is the info from the 79-82 factory manual:

 

[maz124s]

There was a fantastic thread, which ill see if i can dig it were someone detailed the difference between the carb and fuel injection elec ignition advance curves and how to modify them, from memory i think the advance curve went to full advance a lot earlier in the rev range for the fuel injection much later for than carb elec distributor

 

[carl]

With the 124 dizzy, it was the advance weights and springs that were the only difference. I'm not looking to modify mine, I have a whole box of electronic dizzys for Xs and wanted to know which were the "good" curve ones, i.e., the FI ones.