1955 6 to 12 conversion
hondaman1974
Posted 2020-02-05 4:42 PM (#593851)
Subject: 1955 6 to 12 conversion


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Location: Northern Illinois
converted my 55 dodge cr to 12 volt. ive read in earlier thread that I have to use a resistor to the positive side of the coil. can I use a 1960's style mopar single pole resistor?would the resistance be correct. should be 8 volts to the coil if I remember right. thanks!!
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Shep
Posted 2020-02-05 6:31 PM (#593855 - in reply to #593851)
Subject: Re: 1955 6 to 12 conversion



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The ceramic resistor will work with the regular 12v coil. You will need a cranking 12v hot wire to the coil for full starting voltage.
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56D500boy
Posted 2020-02-05 7:13 PM (#593858 - in reply to #593855)
Subject: Re: 1955 6 to 12 conversion



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.
And just to be clear, we are talking one of these, a ballast resistor, that starts out passing 12V through to the coil (for starting) but once enough ignition current has passed through and the resistor heats up (it gets real hot), the resistance increases and only about 8V is passed through to the coil (while the engine is running), saving the coil and points from damage.





Edited by 56D500boy 2020-02-05 8:43 PM
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hondaman1974
Posted 2020-02-05 8:48 PM (#593860 - in reply to #593851)
Subject: Re: 1955 6 to 12 conversion


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yep, that's the one I was thinking of. just checked the 56 wiring diagram and this resistor goes in between the coil and distributor? also running pertronix electronic ignition. will this still work?
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56D500boy
Posted 2020-02-05 9:21 PM (#593861 - in reply to #593860)
Subject: Re: 1955 6 to 12 conversion



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hondaman1974 - 2020-02-05 5:48 PM
yep, that's the one I was thinking of. just checked the 56 wiring diagram and this resistor goes in between the coil and distributor? also running pertronix electronic ignition. will this still work?


I am running a Pertronix ignition with a Pertronix Flamethrower Coil. With that coil, I was able to by-pass the ballast resistor. I left the ballast resistor in place but I've connected the wire from the ignition (HOT in RUN) directly to the wire that went from the ballast resistor to the coil via a little jumper wire (with two male spade connectors). Sort of shows in the photo below, upper middle of my valve cover.

Pertronix Flamethrower coil: https://pertronix.com/plug-wires-and-coils/ignition-coils/coils-flam...



Edited by 56D500boy 2020-02-05 9:22 PM
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hondaman1974
Posted 2020-02-06 11:01 AM (#593873 - in reply to #593851)
Subject: RE: 1955 6 to 12 conversion


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I was planning on using a stock coil but I may upgrade for more voltage with electronic ignition. can somebody explain why the resistor is on the negative side in 56? 57 and later wiring diagrams have it on the positive side of the coil. maybe for 12 volt starting voltage at the coil?
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Shep
Posted 2020-02-06 5:28 PM (#593892 - in reply to #593873)
Subject: Re: 1955 6 to 12 conversion



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The resistor should lead to the pos. side of any 12v negative ground car. Now on a 55 6v, the hot lead goes to the dist. side of coil. The resistor would never go to the points side on any negative ground car.
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57chizler
Posted 2020-02-07 12:41 PM (#593919 - in reply to #593892)
Subject: Re: 1955 6 to 12 conversion



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In '56, the factory did place the ballast on the negative side. It really doesn't matter where the ballast resistor is in the circuit, it serves the same purpose on either side of the coil but the positive side is the most favored location.



(Ign Circuit 56.jpg)



Attachments
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Attachments Ign Circuit 56.jpg (134KB - 37 downloads)
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hondaman1974
Posted 2020-02-07 12:42 PM (#593920 - in reply to #593851)
Subject: Re: 1955 6 to 12 conversion


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that's what I thought. don't know why the 56 dodge wiring diagram shows it on the negative side
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