Hey everyone,

So I've swapped out my old points dizzy for a new electronic one with an internal ignitor. It runs fine and everything but the ballast resistor is causing issues, occasionally the engine dies and I just have to fiddle with the connections on the ballast resistor and off it goes again. I've just had a quick google about upgrading points dizzies to electronic ones and from what I've read you no longer need the ballast resistor once you've upgraded to an electronic dizzy as the resistor is just to prolong the life of the points. So tomorrow I'm going to remove the ballast resistor, but now I'm wondering, will I need to upgrade the coil as the voltage would increase with the removal of the resistor? Or will the standard coil be fine? I don't have a very good understanding of how it all works and this may just be a silly question but any pointers or input of any kind would be great.

Thanks, Rian

will I need to upgrade the coil as the voltage would increase with the removal of the resistor?

Yes, you'll have to upgrade the coil to one for a electronic dizzy.

I still run my ballast resistor with my electronic dizzy. It is not necessary to upgrade the coil.

The ballast resistor is there to save the coil from destroying itself, limiting current draw and makes up for the voltage drop during startup.

Most modern cars now have solid state ignition which is why they have different setups.

You can get away without one in a 4 cylinder motor because the voltage drop is less severe and only require to get one or two cylinders fired up

and the engine will start.

 

So, in a nutshell:

 

For a 6 volt coil, run the ballast (tighten up the connections on the resistor, the bolts holding the tabs themselves may be loose)

For a 12 volt coil, do not run the resistor.

The ballast resistor is there to limit current draw thru the point. To stop them arcing and killing themselves.

 

Non-electronic coils are just made to cope with the lower voltage they receive as a signal.

 

The start circuit bypasses the resistor to give the coil a full 12v to aid start up. As soon as the key flicks back to the ignition circuit, voltage is dropped back thru the resistor.

 

No point changing to an electronic dizzy, then leaving a coil that operates at 8v. Thats the whole point of going to electronic ignition systems. MORE power to the coil = MORE spark power.

& never changing the points again :D

Okay thanks guys, now the next question is what coil do I use? I recall reading somewhere that a Bosch GT40 is one I can use, but I had a look and there are a few different kinds like GT40, GT40R, GT40T etc. What have some of you guys used?

Just get the gt40 or the gt40t. Don't get the R unless you have the Resistor.