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AMC's inventory methods and dates

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billd View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Topic: AMC's inventory methods and dates
    Posted: Feb/11/2018 at 1:45pm
In doing a full restoration for an alternator from a 1968 Rebel, because I stamp date codes back on when all done I thought I'd try to find the original date code and duplicate what it had originally.
The car was built in early 1968 and the engine date code if I recall was January, 1968.
So I figured IF I were lucky enough to find the date code on the alternator it would be close to that, perhaps six months ahead tops. (I find them on less than half of those I work on due to the environment and so many are in such rough shape)
Imagine my surprise when I found the stamp to be 185 602
HUH?? That's TWO YEARS before the engine code.
That means the alternator was made by Motorola in the second week of 1966 - January 1966
So if the date of the engine is January 1968 that means the two are a full TWO years apart.

I never knew a factory to purchase stock so far ahead............... is this a more common thing than I am imagining? Would there be a reason anyone can think of?
Most of the time I find dates on AMC stuff, including alternators, that's fairly close to the build date of the car, within  a few months.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote rocklandrambler Quote  Post ReplyReply Direct Link To This Post Posted: Feb/11/2018 at 4:18pm
Do you know, for a fact, that the alternator is the original one for the car?  Could a previous owner have needed to replace a bad alternator and bought a used good one?  
Past AMC's
1974 Hornet X (new)
1975 Gremlin X (new)
1964 Classic 660 Cross Country
1965 American 440-H
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Feb/11/2018 at 5:19pm
That's what I'm trying to find out. The wiper motor date code is December, 1967 which fits perfectly, roughly a month or so before the engine.
The A12NAM455 was first used by AMC in 1966 as the "standard" for all, then it's listed in later years for specific models and combinations - so it's possible it came from an earlier AMC.
I hope to find out.........
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mramc Quote  Post ReplyReply Direct Link To This Post Posted: Feb/11/2018 at 5:41pm
Bill it is entirely possible they pulled an alternator from the bottom of the pile . My friend Jim Harris has a 1972 Gremlin X V-8 car that had an original AM script logo battery that they had stropped using after 1969 in favor of the later  A-mark logo .
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve_P Quote  Post ReplyReply Direct Link To This Post Posted: Feb/12/2018 at 12:32pm
99.9999% it's not original. From what I've seen, common parts like alternators, fuel pumps, starters, etc, that every V8 used were built close to the build date- a few weeks or months, because these parts were used on every V8, were built regularly by the vendors, and moved thru the system quickly.

Specific parts that were used on very few cars, like a 1968 390 4spd AFB were batch built, and from what I've seen, not necessarily every month. An early April 1968 built car can have a December 67 carb and an late April car can have a March 68 built carb. I don't think I've ever seen a January or February 1968 build 390 4spd carb, but I've seen a lot of December 67 and March 68. Same is true with AIR pump hoses, proportioning valves, etc- you will see a lot of them with identical date codes. These parts were not made every month at the vendors.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Feb/12/2018 at 2:18pm


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lyle Quote  Post ReplyReply Direct Link To This Post Posted: Feb/12/2018 at 3:15pm
A little confused. I read this article when I was doing my rebuild:
https://www.hemmings.com/magazine/hmn/2013/06/Motorola-Alternators/3726991.html
and could not find an alternator so went the Delco three connection route.
You have been doing this a long time Build so I think you probably have the correct information.
Can you please post in "restoration" the correct Motorola numbering system and year.
I would like to have parts available for restoration as I find them.
Also believe the alternator of the era would be within months and not years.
Vehicles today are sometimes within days.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Feb/12/2018 at 7:37pm
Oh boy is that article full of mistakes and ASSUMPTIONS. Let's see about some corrections:

>>Pre-1970 units are identified by a nine-digit casting number that starts with "A" (alternator)<<

NO. Wrong. It was NOT a casting number, it was a model number stamped onto the tag.
A does not stand for alternator (geesh) it's the series of alternator, there were several although AMC used one series with several specific model number designations.

 >>"12" (12-volt) "N" (negative ground) "AM" (AMC) <<
this part is true - voltage, ground, and OEM with AM for American Motors - Motorola did this up until about April 1969 then stopped as it was too expensive to be buyer-specific with model numbers.

>>followed by three numbers, usually between 450 and 700. The higher the number, the higher the amp rating.<<

Not the way they say it. Generally speaking the first of the three last numbers did seem to follow that  was 35 amp, 5 was 40 amp and 6 was 55 amp but 451 was not lower amperage than 455. And prior to 1966 even the first of the three didn't necessarily follow amperage, a 551 was only 35 amps in 1965 but was 40 amps in 1967.
The last digits indicated pulley size, how it was clocked as well as amperage.
Not sure why they say "between 450 and 700" because 605 was the highest, 451 was the lowest.
A A12NAM451 was 33 amps in 1963 and 1964 and became 35 amps in 1965.
A12NAM604 and A12NAM605 were both 55 amps but one was used on the 6's and the other used on V8s. 

>> Post-1970 alternators are also date stamped with a six-digit number in black ink on the rear of the case. The number starts with 185, the next digit should be 1-5 and indicates 1971-'75. The last two digits indicate the week of the year produced. <<

Not really true - the product series and date code was stamped in ink on the back of alternators BEFORE 1971 as well. This goes WAAY back into the early 1960s. It was inked onto the rear bearing boss on the rear frame.
I don't know why the person who wrote that decided to print that it was only post-1970 units.

185 602 means 1966 second week.
In fact that's exactly what's in my first post so Hemmings writer was guessing - a bit too much for my tastes. 
185 is automotive electronics (or a term like that) and then year and then week of that year for the last two.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote S Curry Quote  Post ReplyReply Direct Link To This Post Posted: Feb/13/2018 at 9:03am
The 6 digit number is an EIA code. First 3 digits are the manufacturer the last 3 are date and year. 185=Motorola 6=56 or 66 and 02 would be the week. These codes are found on most electrical components from the 50's 60's and into the '70s
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Feb/13/2018 at 11:10am
Motorola had multiple partners and divisions according to their documents and they say the code, 185, is more specific to their automotive electronics division........that's according to documents I have in their fat books and bulletins.
You'll find these codes and dates on the genuine Motorola regulators, too - 185 followed by date code.

Along this topic, you can find who made the later radios for AMC - look up 345 or 349, for example.

Oddly, I have radios with date codes like 688, etc. - if the norm was followed, year and week of the year, well, that's one LOOOONG year with 88 weeks so apparently other codes were used as well?
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