Too much coil voltage??

[EL5DEMON340]

fixed some problems with my ignition, main prob was a bad MSD coil drawing to much voltage. anyway i have 13.3 volts at the ballast with car at idle and i'm seeing 10.2 volts at the coil +, this is just a chrome box, msd coil was replaced with a stock part store type, the ballast is a msd .8 ohm that on my scale reads about 1 ohm. my old MSD coil always was very hot to the point you could not touch for more than a second. should i use a higher ohm resistor? the car was hot and running for about 15 min when i took readings

 

[dgc333]

I would use a stock replacement ballast with a stock coil. The ballast resistor is there to limit current flow through the coil, the lower the resistance the more current and more heat that the coil has to dissipate. The MSD ballast has a lower resitance than a stock ballast resistor which could cause premature failure of your stock coil.

 

[cudajim]

"fixed some problems with my ignition, main prob was a bad MSD coil drawing to much voltage."

You're not drawing too much voltage, you're drawing too much current. DGC333 is right. You need to drop more voltage via the ballast resistor before it gets to your coil. Since your resistor is in series with the coil you're simply dividing full battery voltage between the resistor and the coil. The higher resistance value the more voltage will be dropped.