6V components vs 12V components

[Jim.UT]

My 55 Fairlane was converted to 12V before I bought it. As explained in my previous post, I found a 6V bulb still in the dash gauge panel...because it burned out. That got me wondering what else might not have been changed over.

Does anyone have a 6V to 12V conversion chart of part numbers for things like contact points, condensers, light bulbs, etc that I could reference as I go through these systems? Would 6V ignition parts survive long on 12V or is the fact that the car still starts and runs be an indication that those parts were converted?

Thanks!

[dmsfrr]

Original ignition parts will be fine on 12 volts except there should be a ballast resistor added into the Red/green power wire to the ignition coil. Also a four terminal 12v starter solenoid with a new wire from its "I" terminal to the "+" terminal of the ignition coil. See the attached diagram.

Double check the polarity of the ignition coil. It will be / should have been reversed from when the car was Positive ground.

More 6v to 12v conversion info at this link. It was written for '55 T-Birds but will be 98% applicable for another '55 Ford.
https://www.ctci.org/battery-for-6v-to-12v-conversion/
.

[evintho]

6v to 12v bulb conversion chart......

https://www.fordbarn.com/forum/attac...1&d=1761766121

[Gene F]

DMSFRR, doesn't going form 6 to 12 make the gages go babanas? What about the fuel tank gage?

[Anteek29]

Originally Posted by evintho

6v to 12v bulb conversion chart......

https://www.fordbarn.com/forum/attac...1&d=1761766121

Many thanks for posting that chart!!

[evintho]

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Originally Posted by Gene F

DMSFRR, doesn't going form 6 to 12 make the gages go babanas? What about the fuel tank gage?

Tie all your gauges into this......
Instrument cluster voltage regulator

It reduces 12v down to the proper voltage for the gauges.

[dmsfrr]

Originally Posted by Gene F

DMSFRR, doesn't going form 6 to 12 make the gages go babanas? What about the fuel tank gage?

Not usually, if they were working well before. Here's a quote from the link I included in reply # 2 above...
"The fuel and temp gauges will work on 6 or 12 V and are not polarity sensitive."

The old style King-Seeley gauges & sensors do not use variable resistance for gauge needle movement. That started in '57 when Ford upgraded them, and many other parts as well.

Pre '57 gauge circuits use current flow and heat sensitive bi-metal switching contacts. The bi-metal contacts in the sensor may cycle at a different rate on 12v but the result at the gauge is effectively the same. In some cases a voltage reducer may be helpful for pre '57 gauge circuits.

Example '55 and '57 diagrams below.
.

[rotorwrench]

The coil is the only voltage sensitive ignition component. A ballast resistor from a 1956 or later Ford would work for a 1.5-Ohm coil that was used back then. A modern 3.0-Ohm coil will function with no ballast resistor.

Fords used a chopper type voltage regulator vibrator for the King Seeley dash instruments used after 1956. The modern replacements generally use a solid state voltage regulator for gauges.