Super A 12v conversion

[crsutton81]

I'm helping my oldest son change over his SA from 6v to 12v negative ground system. He has already obtained a 1 wire alternator, brackets, 12v coil, and lights for 12v. How is the proper way to reconnect the 1 wire alternator to the original electrical system and still have the functionality of the lights and Amp meter ? I do realize the wires will have to be swapped on the Amp meter due to going from positive to negative ground. Are there any wires that need to be tied together or such on the old voltage regulator ? Pictured above is currently the markings on the VR. He's trying to do this project without a totally new wiring harness.

 

[RandyC]

I think this may help you do the conversion.

 

[Jim in NC]

I use the existing wires as long as they have good insulation. I can't tell you every connection off the top of my head, but should be able to produce a diagram tomorrow if it will help you.

 

[DeltaRed]

The vr is not needed with a one wire. Take it off and throw it away. Next,COMPLETELY strip out the old harness. It will be nothing but trouble if you try to reuse it.Here is how you rewire: Run one 10/12 ga wire from alt to amp gage. Then that same wire from the other side of gage to battery.I like to hook to the starter end of the battery cable. Then pull power from amp gage to ignition switch. Then to coil. Done.If you want lights,pull again from amp gage to light switch then to lights. Done.14 ga works well for this. Lastly,wrap the whole thing into a neat clean sanitary 'harness'. Black electrical tape works well. Have done a dozen or so of these conversions.The first over 20 years ago. Have NEVER had any issues.BTW, currently doing a 450.

 

[RandyC]

 

[DeltaRed]

He doesnt want to buy a new harness? Make his own in about a half hour and about 20 dollarsworth of wire and fittings.And it will be far superior and significantly more trouble free than trying to reuse the old.And there wont be a bunch of disconected 'dead' wires to cause problems.Those old dilapidated cloth harnesses are corroded,have shorting issues and other potential problems. Just get rid of it, start over and be done with it.

 

[DeltaRed]

My system does not need a warning('idiot') light,or diode. A resistor at the coil if you are still useing a 6V,or non internal resisted coil to prevent burning of the points.
it starts chargeing as soon as the engine fires,doesnt run-on or have backfeed issues.And I have left them sit for months and the battery is still up.A lot/most of these conversions are unneccesarily over complicated. They dont need to be.

 

[Jim Becker]

You have gotten a lot of good advice in these replies. Unfortunately, nobody answered your original question. If your wiring is in good condition, unhook the Batt and L wires from the regulator and attach them to the output lug of the alternator. The other 2 regulator connections are just between the regulator and generator, so those wires go away with the regulator and generator.

The only other things required are what you spelled out yourself in your initial post.

 

[used red MN]

Between your post and Jim Bs one thing was missed,
changing polarity of the coil. Negative terminal of the
coil will now go to the distributor. May be obvious
when putting on a new coil, I usually just use the 6 volt
coil with a resistor.

 

[Jim.ME]

That is for a 3-wire alternator, not a 1 wire connected to the original wiring as he asked for.

 

[crsutton81]

Thank you everyone for the replies. This conversion project will be underway it seems as soon as we can finish drying up the leaky rear axles...Sigh. It ought to be good as new when he gets satisfied with it.

 

[Graysonsutton]

CRsutton81 when I get the money saved up its coming back into the shop for electronic igniton and hopefully someday a buggy top like my 140