HiYa Mark-
Congrats on your early 9N and restoration projects. Now, let’s do this right. I’ll try to keep it short. You have some incorrect information. The first 1939 FORD 9N used GENERATOR 9N-10000-A; a 2-WIRE/2-BRUSH, 7-AMP, B CIRCUIT DESIGN unit, w/ a small barrel & pulley. This was only used with the square VOLTAGE RSGULATOR, p/n 9N-10505-A. Both NLA, and rare as hen’s teeth to find originals. This VR was bolted to the lower steering box. The GEN was soon replaced with p/n 9N-10000-B; now a 1-WIRE/3-BRUSH, A CIRCUIT DESIGN, 7 AMP, w/ a small barrel & pulley and now used the ROUNDCAN CUTOUT CIRCUIT, p/n 9N-10505-B. The 9N-10000-B GEN had a ‘HI-LOW’ Slider Button on the back panel for 3RD Brush Adjustment. The 9NA & 9NB units are totally different, and parts do not cross over. Even the brushes are different. SEE MY DOCUMENT on Early 9N GENS. Understand the differences between an “A” Circuit and a “B” Circuit Design.
Next, a new GEN was released soon after, p/n 9N-10000-C, and now had a larger armature, barrel, and pulley; an 11.5 AMP output; still a 1-WIRE/3-BRUSH, “A” CIRCUIT, and still used the ROUNDCAN CUTOUT. The 9NC now had an adjustable screw pot for 3rd BRUSH adjustment on the back panel.
FORD was constantly battling the 9N Charging System. Farmers wanted lights and this put more strain on charging. Despite various changes like pulley sizes and a bigger armature, poor charging still was a problem for farmers. In 1942 FORD realized that the GEN needed proper fan belt tension in order to charge the battery. Up until then the design on the GENS was to maintain belt tension only via the mounting bolt thru. The units often failed in the field as the bolt loosened up and the slack caused little or no tension. Many farmers can attest to being left with a dead battery at the end of the day. May realized that unless you stopped every few hours to reset and tighten the bolt and tension, this would be the case. The solution was to design a belt tensioning device and attach it to the GEN. It had two parts, one on the GEN and another that bolted to the head for a positive stop anchor, SEE PIC. The 2N-10000 Unit was then released. It was virtually the same specs as the 9NC unit except for the new Tension Bracket bolted to the barrel. At the release of the 2N GEN, there was a belt tension kit with all the same parts except would allow the 9NC unit to attach via a steel band. The kit did not fit the prior 9N or 9N GENS. With the release of the 8N Model in 1947, the GEN was now a 3-WIRE/3-BRUSH, 11.5 AMP “A” CIRCUIT DESIGN unit and now used a new VOLTAGE REGULATOR, p/n 8N-10505. It was soon revamped with a larger armature & barrel at 20 AMPS now and only a 2-BRUSH unit. ALL GENS after the 8N now had a belt tensioner device affixed.
FYI: If you have the early 9N-10000 2-WIRE/2-BRUSH GEN but not the required VR, you can use the later FAG-10505-A Voltage Regulator, used 53-64. ALL GENS used the “B” CIRCUIT beginning with the 1953 NAA. You will need to modify the mounting for it, Also, caution must be used as possible burn out may occur when using unit with lights.
ALL 9N & 2N GENS were the same after 1940 using 1-WIRE and 3-BRUSHES; and required the ROUNDCAN CUTOUT.
I have some OEM brushes for both the 9NA and 9NB GENS somewhere but in storage now. I also have a repop pulley for the 9N-A GEN I had cast, exact-as-original. You can get a perfect wiring harness for the early 9N and later from Jim Guarno at AGRI-SERVICES in New York,
www.wiringharnesses.com Do you have the OEM Early 9N 'IGNITION ON' DASH LAMP? Read more. Early 9N MPC’s show and list parts. You can email me for more info.
Tim Daley (MI)
