Auburn 680 Starter (I Rebuilt)

I was having major starting issues with my 8-125 Auburn and over the winter I decided to fix the problem. I bought a new 6 volt Optima battery, made a new battery cable and sent the starter out to be checked. Found it needed a new starter switch ( I got a rebuilt one). Put it all back togetherand it starts far better than I ever thought possible.

I would be tempted to try it in the car and see what you get using a good 6V battery.

You need really good grounds and look at not only grounding of batter to frame, but also grounding of the bell housing.

Well, I just tested the starter with a 12V battery 3 times. It definitely spins the pinion gear on the Bendix drive all the way out. But I don't want to conclude the starter was modified with 12V field coils until I've done a couple of things: 1) re-charge the 6V Battery. I just bought it a few weeks ago, but that doesn't mean it was fully charged. 2) Check the generator output voltage, I assume it doesn't do much good to use a 12V battery if the generator is only outputting 6V, does it?

I rebuilt my Delco Remy 716C starter. Completely disassembled, cleaned up everything and re-painted the exterior. I re-wrapped the field coils with a 3M cloth insulating tape and replaced the brushes even though the weren't that bad. I chucked up the armature in my drill press and sanded the commutator lightly with 400 grit. I disassembled the bendix drive and cleaned it up, then re-lubricated it with white lithium grease. Everything slides & turns nicely on the drive.

I have been testing it on a bench with a 6 Volt battery, using positive ground. The motor seems to spin up fine. But I'm not sure if the pinion gear on the Bendix drive is spiraling out far enough. Initially, the pinion gear spins out about 3/16" to 1/4" from the initial position. If I let the motor run for 20 seconds or so, then it will spin out about halfway. I can manually turn the pinion gear back and forth on the spiral shaft. I have noticed after the first 3/16" of travel, I encounter just ever so slightly some resistance, but it's not binding at all.

I'm assuming when the pinion first engages the flywheel teeth, then it will advance deeper into the flywheel teeth because it encounters resistance. But I'm not sure if the initial travel is enough.

Is this normal? I'm going to order a laser RPM meter to check that. Does anyone know how many RPM's it should be at the pinion gear? Fyi, my starter has a gear reducer; it's not direct drive.

Also, I have no idea if someone modified it with 12V field coils, and I haven't done anything with my generator yet.