How to interpret Auto-Lite generator SS#s

[Nemo von Klepper]

My jeep has a mind of its own--a least that's my excuse for why it's painted Navy gray instead of red or jasper green like I planned, and why it's getting a rebuilt generator instead of an alternator.

I was scrounging around for an alternator but the one that came with this jeep had the "ears" in the wrong places and the Bosch alt that was lying around in my garage had ears in the right places but wasn't charging. About that time there was a generator out of a 58 CJ5 being offered locally on Craigslist. The lady ended up giving it to me, and though it's probably costing me more to rehab that old gen. than to install an alternator kit, I just find it cool. Anyway, installing the generator allowed me to get on with tuning the engine, debugging, etc. This also confirmed for me that it wasn't charging at all, even 6v--which was in question because it looked rebuilt, had no data plate, but appeared to have 12v stamped in where the data plate should have been.

I'm going to pick up the rebuilt generator later today. For that extra little bit of authenticity I'm mounting a 12v Auto-lite gen plate. At least now it will be obviously a 12v gen, but I have no idea what numbers to put on it. How does one determine what model number a gen was or come up with a serial number? I see that GJC-7002J, GJP-7202A and GJP-7402A are the correct models for my CJ3B and the CJ5 that this came out of. What's the difference between them?

Then there was some discussion I read when polarizing this gen to see if I could get it to charge as to whether it was an "A" or "B" generator. It had something to do with the internal wiring and short of taking the unit apart, I wasn't sure how to tell. Still not entirely confident I get the difference.

Finally, coming up with a fictitious ss#--just for a note of authenticity. I found this as a guide for the numbers http://www.wildriders.org/autolitecodes.htm Apparently the first number is the month, the second is the alphabetical year, followed by a 6 digit unit production number. I suppose I could make up anything I like. 5J001250 for May 1954, or 5C000001 for May 2022.

I imagine most of these gens produced 55 amps.

[bmorgil]

Nemo I am a sucker for the classic myself. I was not able to suck it up and convert mine back to a 6 volt generator but, if it was all there when I bought it I would have kept it.

I would guess 55 amps would be tops for a 50's era automotive generator. I think the old 50's big Chrysler's were 50 amps (whatever that meant in 1950).

[Nemo von Klepper]

bmorgil, I admit that finances play a big role in my decisions here. It's tough enough justifying what I spend on what amounts to a giant Hotwheels in my wife's mind without trying to push things a little for "a more authentic restoration". This is part of the reason the jeep is Navy gray--it's the closest finish color to primer gray ;)
When I got this thing it had a mix of 6v and 12v components. The starter and coil were were 6v but the lights and alternator scabbed in were 12v. The starter and coil were the first to be swapped. The starter had already burned out, so I had it rebuilt to 12. If I had acquired this gen before I had started on that, I might have been tempted to keep the jeep 6v. It's a 54 3B and 12v only started to phase in as an option around 56, gradually moving to 58 when 6v was the option, according to the research I've done.
Anyway having it 12v will probably be more economical. Though I keep everything not in weekly use on a battery tender, I also do the battery shuffle, putting whatever battery is the oldest into the vehicle being serviced but not being driven.

[LarrBeard]

"Then there was some discussion I read when polarizing this gen to see if I could get it to charge as to whether it was an "A" or "B" generator. It had something to do with the internal wiring and short of taking the unit apart, I wasn't sure how to tell. Still not entirely confident I get the difference."

Type A vs. Type B has to do with how the innards are wired and how the regulator controls the generator output. The early Jeeps (MB, GP) used type B generators and regulators.

Later Jeeps (The CJ versions) used Type A generators.

In a Type A generator, the regulator operates by controlling how the Field terminal of the generator is connected back to ground. If you ground the Field Terminal, the generator goes to full output.

In a Type B generator, the regulator operates by controlling how the Field terminal of the generator is connected back to the battery. If you connect the positive terminal of the battery to the Field Terminal, the generator goes to full output.

In the attached picture you can se the difference.

Don't worry about polarizing, the rebuilder had to do that when he rebuilt the unit.

[bmorgil]

Hahah.. "a giant hot wheels" Ya gotta love that. It cant be argued with and sounds like a big kids hot wheel to me!

You are correct 1957 is the year 12 volts officially appeared. In Willys speak that means around that time! Definitely a good lesson there n how to take care of the fleets batteries Nemo! The parts availability and interchangeability make these things a lot of fun to run, restore or use everyday. Portland is a great place for a "Big Boy Hot Wheel".

[Nemo von Klepper]

Inventing Serial Numbers

Thanks LarrBeard, I think I can remember the difference now.

Bmorgil: Haha! Giant hotwheels in my wife's mind is a step up for me. Only last year before I had it running out of the drive way, it was a "junked car"--I jokingly said told my neighbor that she wanted to put it on the freebies Craigslist. He said I'd have to fight off a crowd. When I showed my wife what 3Bs are fetching on BaT, she now reluctantly sees investment opportunity but now she's worried that we're missing the apex of value and that I need to cash out fast, lol.
I think the area around Portland has a lot to offer for interesting 4x4 drives once I get to that stage. I grew up in the San Juans of Colorado and so it's hard for me to get used to these gated off US Forest access roads when I had Black Bear and Imogene literally in my back yard. I have a few friends who know the area better, so finding a good adventure may not be too hard.

Inventing serial numbers: Apparently I'm not the only one who faces this, lol: https://www.motorauthority.com/news/1123445_world-war-ii-d-day-jeeps-found-second-life-normandy . I had to chuckle at the idea of car collectors coming up with numbers based on birthdays, current dates, etc.