Results 1 to 5 of 5

Thread: Ballast resistor for coil?

  1. #1
    President Member
    Join Date
    Feb 2007
    Location
    Las Vegas, NV, USA.
    Posts
    751

    Ballast resistor for coil?

    I am converting from 6V pos. ground to 12V neg. ground and also adding an electronic ignition distributor from Dave Thibault. The 12V coil I purchased from Randy Rundle has an internal resistor, and warns that any external ballast resistor must be removed.

    Question: I can't find an external resistor in my car or on the wiring diagram. Was this contained within the harness? Or did the original 6V coil not require this?

    Dave's electronic ignition states that the ballast resistor must be used, or included in the coil (but not both!). I don't want to fry this expensive piece of equipment, so please offer any advice.

    Las Vegas, NV
    '51 Champion Business Coupe G899965 10G-Q4-1434
    Salina, KS, by way of Las Vegas, NV
    \'51 Champion Business Coupe G899965 10G-Q4-1434

  2. #2
    Golden Hawk Member
    Join Date
    Dec 2005
    Location
    Ferndale, WA, USA.
    Posts
    17,609
    Paul; 6V cars do not have or need a resister, that would only be on 12V cars to allow them to run on 8-10 volts after starting on 12 volts. Your car should not have one and you should be good to go with the coil only, if that is the OHM rating coil that Dave T recommends!

    quote:Originally posted by vegas paul


    Question: I can't find an external resistor in my car or on the wiring diagram. Was this contained within the harness? Or did the original 6V coil not require this?
    StudeRich
    Studebakers Northwest
    Ferndale, WA

  3. #3
    President Member
    Join Date
    Feb 2007
    Location
    Las Vegas, NV, USA.
    Posts
    751
    Thanks... looking for that resistor was driving me nuts!

    Las Vegas, NV
    '51 Champion Business Coupe G899965 10G-Q4-1434

  4. #4
    President Member
    Join Date
    Feb 2005
    Location
    , , USA. Seminole , OK.
    Posts
    1,444
    I just put a 12 coil with an internal resistor on my 1955 car, it is a 12 volt conversion. I have been told the points, in the distributor, will burn fast if the coil operates on 12 volts. Some cars without an external resistor used a pink resistance-wire from the ing. switch to the coil, instead of the external resistor. This pink wire statement should be true ONLY on an original 12 volt Stude car. Your 6 volt will not have a pink wire.

  5. #5
    President Member
    Join Date
    Aug 2006
    Location
    Renick, MO, USA.
    Posts
    875
    If memory serves me correctly, in the good old days, 6V coils usually had 4 ohms resistance on the primary winding. Later 12V jobs with the ballast resistor or the resistance wire were usually 2.5 ohms...I've never had reason to measure a Stude resistor, but I wouldn't be surprised if they're around 1.5 ohms. When electronic ignitions came out, most of those coils had 1.5-1.7 ohms resistance. Chryslers used a dual ballast resistor, 1 ohm for starting and 4 for running which gave around 2.5 ohms for starting and 5.5 for running. Average those two out and you have 4 ohms, just like the good old days. Modern distributorless twin lead GM coils have around .9 ohms and some Chrysler jobs have 2.5 ohms.

    All this is actually leading somewhere, believe it or not. Modern electronic ignition boxes are picky about coil resistance, so be careful when replacing the coil with another one. I recently put GM coils on my motorcycle and had to add a 1.35 ohm ballast resistor to get a total of 2.25 ohms, right in the middle of factory specs. Get too much resistance and the spark will be so weak your engine will never start and not enough and you can be putting extra current through that high dollar black box. Any coil with too little resistance will work with your ignition AS LONG as you have a ballast resistor that makes up the correct resistance value for your ignition box.

Similar Threads

  1. Internal Resistor Coil
    By royvaldez in forum Tech Talk
    Replies: 4
    Last Post: 02-11-2009, 10:24 PM
  2. ballast resistor on a 12V setup...Question
    By dan0 in forum Tech Talk
    Replies: 16
    Last Post: 11-28-2008, 01:14 PM
  3. Avanti ballast resistor
    By nels in forum Tech Talk
    Replies: 7
    Last Post: 09-12-2008, 03:00 PM
  4. Coil Resistor - for '59 Hawk
    By Champion51 in forum General Studebaker-Specific Discussion
    Replies: 1
    Last Post: 06-23-2008, 11:15 PM
  5. 1963 R2 Hawk Ballast Resistor
    By R2GTHAWK in forum Tech Talk
    Replies: 2
    Last Post: 04-01-2007, 09:39 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •