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Old 04-15-2007, 01:24 AM
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Positive Ground

I have a 1950 Dodge Wayfarer it is a positive ground vehicle with a generator. I want to go to a alternator upgrading the system to 12 volts northing fancy or high drain. The last time I had to get it jumped it cooked all the bulbs that were on. Head lamps marker lamps etc. Where would you rate this jobs difficulty and would/ should this vehicle remain positive ground?

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Old 04-15-2007, 02:09 AM
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Doc here,

The Vehicle would need to be converted to Negative Ground Because the alternator is a grounded case and the diodes only flow one direction..

To convert, you need to change the following:
  • All lamps, including the ones forgotten until they burn out..such as back up lamps, dash lamps, hood lamps , trunk lamps, vanity mirror lamps, Tag lamp, glove box lamp, Dome lamp.
  • Coil must be changed to 12 volts.

  • Horn relay and Horns.

  • Flasher relay.

  • Hazard flasher (if equipped)

  • Electrical gauges (probably only Fuel) must have a dropping resistor/regulator.

  • Heater motor and speed control.

  • Windshield Wiper and speed control (If not vacuum) If Vacuum, would be a good time to add vacuum reservoir to stop wiper dropout on hills and throttle..

  • Starter Solenoid.

  • Starter motor...(while it is perfectly acceptable to run a DC motor at 125% of it's rated value..It does shorten it's useful life..now would be a time to find (or fabricate) a 12 volt motor that just bolts in..from over the counter stock..6 volt stuff is getting hard to find..and you might not want to hang around some small town for a week waiting for a starter to ship on a road trip..)

  • The stock Radio Can prove problematic..dropping the voltage is not a problem, getting the electrons to flow in the right direction IS..

  • Alternator, If you go standard 63 amp SI , internally regulated , 3 wire alternator, you should be fine..simple hook up..big terminal to a fuse link hooked to the starter solenoid battery cable, the Smaller red to the horn relay power wire, and the brown wire to the idiot lamp (if used)..that's it..

  • Regulator..if internally regulated as above..remove and abandon the wires EXCEPT for the REDS..those supply power to various parts of the vehicle, and must remain connected together.

If your wiring is good, (not fray , gas or oil soaked or full of tape, butt splices or other messes..) The system should work fine..

It should be something you can do over a weekend once you have all the parts..

Clean , burnish all contacts at the lamp sockets and switches, inspect all the old switch gear, replace any you have doubts about.

Install a ground buss system..

Run a properly gauged Ground cable from the battery to any handy bolt at or near the starter, From that same bolt get a Battery cable at the parts store, that has two 3/8 ring terminals on each end and attach it there and to the Frame.

Next get some 10 gauge wire and ring terminals and run two wires from your bolt on the block to the Firewall, and the other to the Alternator bracket or mount bolt.

Next get some Wire Braid, (Radio Shack) and install braid from the radiator support to the frame, Fenderwells to frame , hood to firewall, Doors to door posts, gas flap to body, tailgate / Trunk to body.

At each point the wire is grounded, Burnish ALL the paint and grease off to bare metal. Use a proper star-washer and lock. Use sheetmetal or Tech screws where no screws are available.

It sounds like a lot of work, but after you assemble all the parts, it's only a few hours to do..and you'll end up with a system that will work reliably for many years to come..and can eliminate that from your troubleshooting list.

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Old 04-17-2007, 07:29 PM
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You can buy volt alternators. I have had one in my '40 chev for about 10 years. Never a problem in the charging system. Send the starter to a place like Precision in Mich for a complete rebuild and you won't have any problems.
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