1949 Wraith Posted February 25, 2017 Report Share Posted February 25, 2017 (edited) My 1938 Dodge was converted to 12 volt negative ground by the previous owner. The system has a ballast resistor between the ignition and the positive post on the 12v coil. The resistor has no markings and looks like the oldest item on the car. Can I replace the 12v coil and ballast resistor with an 12v coil that states no resistor required? If I still should run a ballast resistor what is the resistance I should be looking for in a spare? Thanks Edited February 27, 2017 by 1949 Goat Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted February 25, 2017 Report Share Posted February 25, 2017 coils with internal resistor often keep voltage higher for a longer period and increases wear on points.....the ballast is most effective and simple system....age has no bearing on the average...just mount so it will not get a rush of cold water when hot during rain, hood raising or the frequent bath... Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted February 25, 2017 Report Share Posted February 25, 2017 I have been running a ballast resistor on my car for a lot of years with no problems. Quote Link to comment Share on other sites More sharing options...
1949 Wraith Posted February 26, 2017 Author Report Share Posted February 26, 2017 Thanks guys I will order some spare ballast resistors. Don what is the additional wire that you have hooked to yours? Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted February 26, 2017 Report Share Posted February 26, 2017 start on 12, run on 6 the second wire is the 12 volt supply direct to the coil off the solenoid when in start mode...you should have similar if your vehicle was properly set up on conversion Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted February 26, 2017 Report Share Posted February 26, 2017 I am using a Ford 4 pole 12 volt solenoid. Post #3 on this solenoid is hot with a full 12 volts when the start button is pushed. I have connected this pole to the coil side of the resistor to by pass it and supply a full 12 volts when starting the engine. Quote Link to comment Share on other sites More sharing options...
dale Posted February 26, 2017 Report Share Posted February 26, 2017 Why would anyone convert to 12 volts without going to a negative ground. Must be a reason. Quote Link to comment Share on other sites More sharing options...
1949 Wraith Posted February 27, 2017 Author Report Share Posted February 27, 2017 8 hours ago, dale said: Why would anyone convert to 12 volts without going to a negative ground. Must be a reason. Sorry, typo error on my part. Post has been corrected, thanks. Quote Link to comment Share on other sites More sharing options...
The Oil Soup Posted March 3, 2017 Report Share Posted March 3, 2017 You can also check the resistor to make sure it is dropping the input to the coil by 3 to 5 volts. 1 Quote Link to comment Share on other sites More sharing options...
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