[bossbirdta]

Originally Posted by Transamric

Not sure about his date code interpretation. He says April 7th, 1971, which would be 1D7. But to me, it looks more like I("eye")07. What do you guys see?

does look like an I, but i thought the General never used an I so as not to get confused with the # 1?????

[The Boss]

Originally Posted by bossbirdta

does look like an I, but i thought the General never used an I so as not to get confused with the # 1?????

Only in the 1967 model year castings.

[johnta1]

does look like an I, but i thought the General never used an I so as not to get confused with the # 1?????

I thought the middle position looked like a zero?

Anyway, the first position of the date codes would be for the year, a '1' in this case.
There would be no alpha letters here.
The second position would be the place for an 'I' if it were used, but it was not on stamped date codes.
(the letter was for the month btw)
And the last digits were the day of the month.

[Judge273]

Originally Posted by 2manyT/A'S

Round port alternators are hard to find...

What's latest date on an "open face" alternator?

I have one that looks like August 71,but stamp is very faint.........

Mine is on my car built around third week of August 1970.



Looks like 0H12 but very faint...

[2manyT/A'S]

Originally Posted by Judge273

Mine is on my car built around third week of August 1970.



Looks like 0H12 but very faint...

Now that's REALLY interesting.......mine looks exactly like yours,but even LiGHTER on the date stamp....thought it was IHI2,but likely the SAME as yours...

Think I might have saved the data from the car it came from......I'm ON a mission.....

[Judge273]

I can only capture date with my camera phone, its that faint.

When was the change from open face to closed?

BTW:The one on ebay is too late for Judge for sure

['ol Pinion head]

Originally Posted by Judge273

I can only capture date with my camera phone, its that faint.

When was the change from open face to closed?

BTW:The one on ebay is too late for Judge for sure

The change from open face to closed face was in late May of '71.

[1971455HO]

Originally Posted by Transamric

Not sure about his date code interpretation. He says April 7th, 1971, which would be 1D7. But to me, it looks more like I("eye")07. What do you guys see?

First, it's a 1100927, not a 1100928. I think the 928 is correct for the '71 37 amp Firebird Alternator. It may be for the GTO.

Secondly, Pontiac didn't use the letter "I" for stamped letters because it could be mistaken for the number 1. They only used the letter "I" when it was cast. September was a stamped "J"

Most of you guys have been at this longer than me, but., it's been my experience that alternators are date coded using 4 alpha-digit type stamps. This one only has 3. Example, if you are looking for a 1100928 for August 15th, 1970...it would be stamped...0H15. Or even for September 7th, 1971, it should be 1J07.

See my point. I don't recognize or trust the 3 digit thing.

Eddie

[68bird400HO]

928s are the 55A alternators. This 927 looks original to me, just looks like a factory mis-stamp on the date code.

[2manyT/A'S]

Originally Posted by Judge273

Mine is on my car built around third week of August 1970.



Looks like 0H12 but very faint...

You show me yours.....I'll show you mine.......

My pictiure in not clear at all on the date code but I can definately make out _HI2....with the naked eye (and glasses).....I previously assumed it was a 1 and NOT a O....so that is GOOD NEWS for me as I have a Sept build HO than needed a correct # alternator...

[Pepi]

Originally Posted by 1971455HO

First, it's a 1100927, not a 1100928. I think the 928 is correct for the '71 37 amp Firebird Alternator. It may be for the GTO.

Secondly, Pontiac didn't use the letter "I" for stamped letters because it could be mistaken for the number 1. They only used the letter "I" when it was cast. September was a stamped "J"

Most of you guys have been at this longer than me, but., it's been my experience that alternators are date coded using 4 alpha-digit type stamps. This one only has 3. Example, if you are looking for a 1100928 for August 15th, 1970...it would be stamped...0H15. Or even for September 7th, 1971, it should be 1J07.

See my point. I don't recognize or trust the 3 digit thing.

Eddie

My 73 80 amp P/N 1101015 has a very clear date code of 3D4. I know you guys are talking about 70's and 71's. I wonder if and at what point then they switched to 3 digits.

On mine I would have to go out and double check, but either all of it or the bottom line with 3D4 12V NEG was double stamped. I rebuilt it either last year or the year before, and when I disassembled it, all the parts inside were date coded just before the date on the case.

[68bird400HO]

Originally Posted by Pepi

My 73 80 amp P/N 1101015 has a very clear date code of 3D4. I know you guys are talking about 70's and 71's. I wonder if and at what point then they switched to 3 digits.

On mine I would have to go out and double check, but either all of it or the bottom line with 3D4 12V NEG was double stamped. I rebuilt it either last year or the year before, and when I disassembled it, all the parts inside were date coded just before the date on the case.

There was no "switch" in the number of characters. The date coding for these was last digit of the year followed by the month code followed by the day of the month. If the day was a single digit, then you would have 3 characters total in the date code. 1971455HOs example of September 7th, 1971 would be 1J7, not 1J07. The 927 on my 71 TA is date coded 0J1. The only reason why I think the Ebay one is a mis-stamp is because that "D" sure looks like a "0" which doesn't make any sense. Distributors used the same date coding convention.

[Pepi]

Originally Posted by 68bird400HO

There was no "switch" in the number of characters. The date coding for these was last digit of the year followed by the month code followed by the day of the month. If the day was a single digit, then you would have 3 characters total in the date code. 1971455HOs example of September 7th, 1971 would be 1J7, not 1J07. The 927 on my 71 TA is date coded 0J1. The only reason why I think the Ebay one is a mis-stamp is because that "D" sure looks like a "0" which doesn't make any sense. Distributors used the same date coding convention.

Okay, good to know. I had no clue about the earlier ones, just trying to give an example of 3 digits.

[Sport71]

Here's the open-face '927 on my GTO (before and after resto), also dated 0J1.

[2manyT/A'S]

Originally Posted by Sport71

Here's the open-face '927 on my GTO (before and after resto), also dated 0J1.

Nice stamp (and resto)..............I'm envious...

[bossbirdta]

I gotta 0H4 982 on my 71 FWIW.....looks to be stamped pretty deep....

[Brewster]

I'll be checking mine tonight and posting too!

[1971455HO]

Good, Good, Good. Like I said guys, you been doing longer than me. I was glad to be corrected and learned a bunch myself. I forgot about the 37 amps being 927's & the 55 amps being 928's.

[Transamric]

So to be clear, the concensus is, after '67, "I" was still used for September casting dates, but not for stamped in date codes?

BTW, IIRC, this method of dating is called Julian dating.

[1971455HO]

Originally Posted by Transamric

So to be clear, the concensus is, after '67, "I" was still used for September casting dates, but not for stamped in date codes?

BTW, IIRC, this method of dating is called Julian dating.

Transamric,

I know for a fact they still used the "I" for September when casting blocks. I have been operating under the mindset listed below for a long time.


Casting: A, B, C, D, E, F, G, H, I, J, K, L

Stamped: A, B, C, D, E, F, G, H, J, K, L, M ( no "I" )

You may be right. it may have started in 1966 for the '67 models. It's been so long since I read it, I can't remember who said it here. I'm sure I learned it here on the forum. But I have not saw an alternator for '70 and up stamped with an "I" for September. I do stand corrected about the use of 3 & 4 character stampings being used for date coding and that it was common place.