Restoring a JI Case 811b Electrical Issues

New to the forum, looking for help on my tractor. Bought a basket case (punny) that ran enough to load it on the trailer, got it home and tore it down. I'm putting it back together with all new round gauges and a 3 wire alternator and am having electrical issues. Does anyone have a wiring diagram for the alternator conversion from a generator and the rest. I'd rather do it right the first time. Thanks

Welcome nsaroff!

I'm assuming you are using a 10SI Delco alternator, that is the most common one used.

Here is a good diagram. If you don't have a generator light, you can substitute a 10 watt, 10 ohm resistor. Or wire in an instrument type lamp as a resistor. The wire from the post of the alternator to the battery (or amp meter) needs to be 10ga. The others can be smaller.

Also remember you MUST wire an alternator with negative ground battery!
10si internal regulator wiring

I do not have a diagram as such but it is not at all hard to do. If your using the common Delco 10SI it has a 2 wire plug. The #1 on that plug goes to the ignition side of the coil or ignition switch. I go to the coil to save wire. You do need a light bulb or resister like the O'Reilly's VR-1 or a diode in that wire so you can shut the engine off.
The #2 wire on that plug goes to the charge stud on the alternator.
The charge wire goes to the non load side of the alternator.
Not really all that hard to wire up. I can almost do them in my sleep but I have done probably at least 50
You also need to put a ballast resister like the VR-1 in the coil wire ignition side so as not to burn up the points fast

Thanks very much! I am installing a full compliment of gauges
including an ammeter. Will that work in place of the VR-1
bulb?

"Will that work in place of the VR-1
bulb?"

No, you still need the bulb in the circuit. The bulb serves as a resistor. It is necessary to keep power from feeding back to the coil, which will keep the engine running with the ignition switch off.

Here is a better diagram showing the amp meter in circuit.
diagram with amp meter

No an amp gauge has no or so small of a resistance that it will not do the job a light bulb or diode or resister will. My self I do not like the light bulb since it if burns out will stop thing form working. Plus it in turn becomes an idiot light and I have never liked idiot lights

Much appreciated with the knowledge and experience. I have a few holes to fill so my plan is to install an idiot light in the dash and a resistor near the coil. I will also install an inline fuse in there somewhere and a junction block to clean up all the old jumper wires. All new gauges and wiring and my hope is to have a reliable and functioning old tractor for years to come.

The VR-1 ballast resistor has a mount that works well in dash holes and in doing it that way the metal of the dash works as a heat sink and that way the resister does not get near as hot as it does with out being mounted hat way. VR-1 or VR-2 are the O'Reilly's part number for a good ballast resister for do the 12 volt conversions

Welcome aboard.

First of all I didn't read that you're converting a 6 volt tractor to 12 volt????????????????? so if the voltage isn't changing and assuming its a gas tractor with points and condenser coil ignition YOU DO NOTTTTTTTTTTT NEED ANY IGNITION BALLAST RESISTOR IN THE COIL CIRCUIT, that's for using a 6 volt coil on a 12 volt tractor.

You mention a 3 wire alternator (I will assume Delco 10SI family) and you mention a dash "idiot light"

The Delco 10 SI does need some resistance (or a diode) in its Excitation circuit to prevent run on with ignition OFF and you can use EITHER

1) A 10 Ohm 5 or so watt resistor,,,,,,,,,,,,,,,,,,,,,,,,,,,
2) Or a diode,,,,,,,,,,,,,,,,,,,
3) OR an incandescent idiot charge indicator light which serves a DUAL purpose, when it goes off that's a charge indication PLUS it serves as the resistor to stop run on and no diode or other resistor is needed IT SERVES TWO ROLES.

NOTE for those who worry about the light burning out I place a resistor in parallel with it so she can still charge even if light burns out WELLL DUH soooooooooooo cheap simple and so easy to do

SUMMARY Cheapest and easiest Alternator excitation circuit required (to stop run on) IS A 10 OHMS RESISTOR (cheap and no worry with correct polarity) ,,,,,,,,,,,A Diode (cost more then resistor and must be wired correct polarity),,,,,,,,,,,,,An Incandescent dash idiot charge indicator light THATS WHAT YOUR POST MENTIONED and its not very expensive or hard to wire

Steve posted wiring diagrams for you,,,,,,,,if you need to use a 6 volt coil on a 12 volt tractor and require an ignition ballast resistor let me know,,,,,,,,,,,,,,,,,,,above are three methods in the excitation circuit but if you want a dash charge indicator idiot light see the above

John T

You are correct. No 6 - 12v conversion. I'm going with an easily replaceable "idiot" light in order to fill a hole and make it look complete.

Wiring is going to be a pain with the new gauges but the most concerning part is where I'm going to get a new tach cable for my setup.

Thanks again John T