Amp gauge vs volts gauge?

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Cope

Fusing with fire
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Hey folks.

I'm restoring a 1946 Dodge W series truck. It's on the home stretch and I'm getting ready to wire up the dash. The owner is adamant about keeping it as original as possible.
My question is this.

Can I just hook up the old Amp gage to power or is there some way to make this old Amp gage function as a voltage gage?

I have converted they electrical system to 12v negative ground with an alternator instead of the original 6V generator system.

Any ideas or input will be greatly appreciated.

Thank you for all your time and advice over the years.

Amp gauge is the 3 posts on the left in the back side pic.

20230130_121214.jpg


20230130_121245.jpg



EDIT- I'm not sure how I posted this in the sticky section. If a mod can move it that would be great.
 
If you are going to run a very big alternator, say 50A or larger, you need to experiment with a shunt across that one. I'd start with a length of about 10ft of no14 wire, with eyes crimped on, and just wire it across the ammeter. You can trim it if need be. Shorter makes the ammeter read more amps full scale.

If the 6V system was positive ground you'll have to revers all wires on the back
 
The other gauges, you'll need a 6V source. There used to be individual gauge regulators, I'll have to think of the name

If you have electric wipers and 6V heater blower you can run "volt a drop' resistors from the parts stores. You will need to measure the amps draw of 6V loads because the resistors have to be tapped to match that reading

Most old motors don't care about polarity. Wipers, heater, starter, should all work same, and generally won't hurt a 6V starter to operate it on 12. use a 12V solenoid, tho.

Use a 12V coil and matching resistor just like our 12V Mopars
 
No electric wipers or heater.

All other gauges are mechanical except the fuel gauge and that is a new 12v sending unit. (Not sure how well that will play with the 6v fuel gauge?)

Looks like the new Alt is 90 Amp.

I believe this was a "6V positive ground" system but I'm not 100 percent on that. I'll have to refer back to the book.


I totally forgot about using a resistor. I have not worked on a old ignition system like this in a long time. Should I just buy a 71 dart Coil and resistor?

Thank you very much for your time and advice!

20230130_140439.jpg
 
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