12 volt or 6 volt that is the question

'Course, if you get bitten by the restoration bug, you'll be buying the 6V parts anyway so that it is true to the original design. ;^)

• Wire Diagrams

More or less up to you. Do you want to keep it original or stock?

I havn't checked prices.. but I'll guess it is pretty cheap to get a 1 wire gm alternator... probably cheape rthan a generator, but you never know.

I chose to keep min 6v... I'm not bothered by the slower sounding starter, and my headlights are plenty fine.

Do a price comparison on the rest of the conversion vs. going back to 6v.... you're almost in the middle, depending on the condition of the battery.

Might check to see if the starter was replaced with a 12v starter.. that will effect the decision.. most though just keep the 6v starter and change the relay.

What year is your 8n? Does it have a front or side mount ignition?

Later,

Soundguy

The tractor is a 1949 with the front ignition.
Thank for your reply and any help will be greatly appreciated.

As for converting to 12 volts. I'm a 12 volt advocate for the right reasons.

Use the 6 volt starter, it don't care, positive or negative ground, still turns the right way. Use 6 volt starter solenoid, not a problem on 12 volts.

Ignition points and condenser, don't care 12 volt ok. Ammeter only semi-cares, may have to exchange wires to get ammeter to show charge (+). Lights do care, 12 volts mak'em flash dark.

12 volt alternator CARES, negative ground only.

Ignition coil cares. If you decide to use the OEM 6 volt frontmount coil, you MUST use both the "infamous ballast resistor, mounted on the backside of your dashpanel AND a 12 to 6 volt converting resistor. Wire them in series like flashlight batterys.

If you decide to use the new 12 volt frontmount coil, (which I advocate) DO NOT USE the ballast resistor. understand??? BUT you still need a current limiting resistor to keep your coil from burning out.

This is really tricky. Get a 2-pack of 1 ohm 10 watt resistors from Radio Shack. Twist and solder the resistor leads together in parallel. You now have about 1/2 ohm current limiting resistor to keep the 14.7 volts of alternator output from melting your 12 volt coil. (yeah I know, lousy designers)

Now for the Delco SI-10 alternator, (most commonly used and cheap) you have to decide wheather to use the 1-wire version that takes about 2000 rpms to start charging or the 3-wire version that starts charging at 450 rpms. I personally don't like to jazz a cold engine to get it started charging.

I know of 6 different ways to wire a 3-wire alternator scheme. General Motors uses the idiot light scheme to excite the alternator P-1 from the igntion switch. And P-2 sense gets a short loop of wire from alternator BATT terminal. BATT is usually wired to the BIG battery terminal of the starter solenoid.

If you don't isolate P-1, the built-in voltage regulator backfeeds power to the same "ON" terminal that the ignition coil is fed from and you will NOT be able to turn your engine off without some sort of isolation, idiot light (use a trailer marker light), 10 ohm 10 watt resistor, 1N4001 diode, DPST ignition switch, pushbutton doorbell switch.

Your call, but do it right and be proud of it..... .....Dell

Resistors, like flashlight batterys, don't care who is first, just as long as the 6 volt frontmount ignition coil is last in line..... ...Dell

Ford-man

If it were me, I would go back to 6...but then, you may want 12 to run common automotive appliances with it, etc. Just depends on your wishes, and the price of the two options.

Soundguy