Hello again, last question today-has anyone converted a '42-'47 jailbar 239 to 12 volt? If so, could you please let me know what parts I will need?

 

hi ! 12 volt battery , i installed a alternator . if you want the gauges to work you need a voltage reducer . i can look up the name runtz i think !!!

 

thank you-so just the battery and alternator and voltage reducer? And yes if you could get me a link or something for that reducer I would be grateful!

 

hey will he need a 12volt regulator also? or is that in the alternator?

 

also will need 12 volts lights ,and if he has a 6 volt heater, don't use on high, or put in a resister to limit current.

 

Best advice is don't convert. There are few good reasons for converting a stock truck to 12V. A well maintained 6V system is just as good as a well maintained 12V system. I feel that those who boast "performance improvements" with their new 12V systems with new battery, charging apparatuses, new wires etc are comparing to a rundown 6V system. The 6V system would have the same improvements if all the same items were refreshed (and probably for a little less $$$ too)... make sure your 6V system is serviced with good thick battery/starter/ground cables, the generator is lubed and has decent brushes, and that the regulator is within spec.

If you really want to convert to 12V system, it is very possible and has been done, but the first question would by why - what are your goals in doing so - you may just not need to?

 

I'm very happy with the 12 volt conversion for my '39 p/u with an 8ba.That said if you want to convert to 12 volts do it. After all it's your truck. Used a one wire GM alternator. I initially ran the 6 volt starter but for no real reason I upgraded to an original looking 12 volt unit from Joe's Antique Auto with an original style Bendix. I used an instrument cluster voltage reducer for the gauges. This example is from Ebay but they are available from many suppliers.NEW 1961-1966 FORD TRUCK INSTRUMENT / GAUGE CLUSTER VOLTAGE REGULATOR
https://www.ebay.com/itm/16531733833...rSjxdFDKkI9F-c

 

Speedway Runtz 12-Volt to 6-Volt Voltage Reducer

 

So many of the above are trivializing the conversion, overlooking many aspects and considerations:

*Will need a 12V Generator, Alternator and all the necessary brackets
*Will need a 12V Voltage regulator compatible with the generator/alternator
*Will need voltage reducers for the instrument cluster
*Will need to deal with coil, ignition resistor, and potential bypass
*Will need 12V equivalent lamps for the headlights, tail lights, parking lights, instrument cluster etc etc etc
*Will need to consider isolation and heavy duty voltage reducers for any Radio, Heater and similar accessories
*Will need to consider impact on starter solenoid and starter motor
*Will need to consider impact on horn & horn relay
*Will need a 12V Battery
*Will need to consider battery cables and grounding strap strategy
*Will need to consider entire new wiring harnesses - headlight, dash, engine, tail etc etc etc
*Will need to consider adding a distribution panel
*Will need to consider adding relays for lighting

I'm sure I'm missing a few items from the list... None of this is insurmountable, but it all adds up.

This all again comes down to why the 12V conversion? If they are chasing a problem, it is likely be quicker, easier, more economical, and more true to form to address the root issue and not just fire a 12V parts cannon and hope for the best.

 

If converting to negative ground, the amp gauge sensing wire needs to be reversed, or the gauge will read backwards.

 

thanks!

 

wow thank you for this. That’s a ton of parts now I’m thinking just leaving it alone.

 

my 47 , 8ba runs fine on 6 volts! make sure you have good grounds everywhere! and thick battery cables. My 47 did stop starting one day last year, The starter didn't do anything. I took it out and it tested good,I put back in and tightened all the cables to it and mounting bolts and it's been fine since, Cranks faster now also!

 

The factory six volt switches and wiring harness will work fine on twelve volt power. Randy Rundle's booklet "The Official 12 Volt Conversion Guide", is a recommended read for anyone not familiar with what is involved.

 

Only if they haven't degraded in 80-something years...