Ballast resistor

[Shrinkdude]

I have see a couple different schematics for the Duraspark conversion and the difference is on has the resistor in the cicuit and the other does not.
Trying to get the consensous on what you have done in that regards.
Looks to me it limits/drops the voltage going to the coil in the run mode.
If you take this out do you have to run a high performance coil to handle the full 12v 100% of the time?

 

[Lazy JW]

The schematics in my 1970's Chitlin's manual show the DS2 with the ballast resistor in the "run" circuit. I am told that Ford later deleted this in the 80's. I ran the DS2 in my White Ox for several years with the stock DS2 coil and no resistor with no problems, as have several others on this board.

I have since upgraded to the Ford TFI coil with a GM HEI module triggered by the DS2 distributor. This is a good, cheap upgrade using readily available parts. I recommend it highly. Check out www.gofastforless.com for details.
Joe

 

[The Plankster Prankster]

i believe the models without a ballast resistor had a resistor wire hidden somewhere in the harness.
the reason that resistors were used was to prolong the life of your dizzy's electrical components (points or otherwise). these components will theoretically last longer on teh reduced voltage, so in that way it is beneficial

i believe that a standard coil will work just fine, considering the fact that most have "12v" or "12volt" written on them somewhere.

the only benefit in removing the resistor is increased spark energy, which improves performance, but it also wears out your spark plugs faster.
its all a trade-off between performance and longevity

 

[fordconvert]

My DS2/Hei/blaster2 setup seems to run about the same with or without the resistor in the circut. I just have not wanted to take the time to find the wire under the dash so I used a relay on the voltage regulator. Im not sure if that is a good thing or bad.

The big reason for the resistor is the points. The higher the voltage the farther it can jump and when you are talking about something like points a big jump is bad for several reasons. First it wears the contacts faster which is bad because it changes the dwell and second it somewhat changes the timing and the dwell because the arc/spark continues to conduct after the contact opens. Another reason for the resistor is that if you have the key and engine not running it is possible that the points will be closed. If there was no resistor the coil would die in a matter of seconds. With the resistor there is at least a chance that it would not kill the coil because in general as things heat up resistance goes up so the hotter it gets the less voltage gets to the coil and hopefully things will survive. This is not an issue with the electronic systems because they are 'smart' enough to know if the engine is running. The module sort of controls the dwell by reading the voltage/current going to the coil.

 

[Shrinkdude]

Sounds like it could go either way.
Looking at the circuit, the coil shouldn't be energized unless the module lets it. Basically the module completes the circuit on the 0vdc side when it reads the sensor inside the distributor.