Alternator 1100884

[Jim 25993]

Greetings,

I have an alternator with these stampings on the front casing half:
1100884 61A 0E25 12 Volt Neg.
The stamping look exactly like my other 1100884 alternators
and the rear casing half has the correct configuration for a '70 Corvette.

However the casting does not have the open front it, has the
closed front.

Did GM start to change the front half before the end of the '70 production year
or do I have a restamp or...?

Thank you in advance for your help.

[Joe L.]

Re: Alternator 1100884

Jim-----

Well, a "restamp" is always a possibility. It's possible that someone stamped a SERVICE alternator case half with the stamping that you see. So, I'd carefully compare the characters against the known '884' units that you have, but it sounds like you already have done that.

Notwithstanding the above, I have always believed that the change to the drive end case half case configuration (i.e. from "open" to "closed") occurred before the end of the 70 model year. I don't know that there was a specific point when it occurred and both type drive end case halves may have been used for awhile.

[Jim 25993]

Re: Alternator 1100884

Joe,
Thanks for your insights.

It would be nice to be able to confirm your theory that GM started to change over in the middle of the year.

It looks like my next step is to take the thing apart and look for clues on the inside.

That leaves me at a little disadvantage since my primary focus is on '69 vettes and all my other alternators are '69 models.
I can probably compare parts and get a good idea they are original or not.

Can you give me any clues to look for?

Thanks again.
Jim

[Joe L.]

Re: Alternator 1100884

Jim----

ALL 1969 Corvette alternators used the "open" drive end case half. Also, all 1969 alternators used the split ring end case half with the "7 fin heat sink", the Delco-Remy script with NO raised boss below the script, and the flush-mounted grounding lug. 1970 alternators split ring case halves had the same "7 fin" heat sink, but usually had the raised, rectangular boss below the Delco Remy script and a raised grounding lug.

As far as what to look for to provide clues as to the originality of your drive end case half, you may find a circular, segmented casting mark on the inside of the case half. If present, there will be a number in the center of the casting mark. This represents the last 2 digits of the year the part was cast. Information regarding the month may be found in the "segments" surrounding the center. So, if you find such a casting mark with the numbers "69" or "70" in the center, then you're pretty well assured that this is the original. The problem is that not all GM aluminum die-castings have these marks.

[Jim 25993]

Re: Alternator 1100884

Thanks Joe,
that is really helpfull

Is there any way to identify the internal electrical componants?
It occurs to me that if all the internal componants appear to be original that would be an indication the case halves are also.

For instance most diod packages in the '69's I have taken apart (that appear to be original) have 3 wires running their length, not the smooth top like on the replacements that you can get.

When did GM start putting the plastic bottom on the Rectifier Bridge?

Any other characteristics or numbers?

Thanks again for your info.

JimA.

[Terry M.]

Re: Alternator 1100884 *TL*

Jim,
There is a date on both the regulator (ink stamp that actually can be read with the alternator assembled by unplugging the field connector)and the heat sink for the bridge (stamped in the aluminum heat sink). It has been a while since I have looked at these parts, but I think they are Julian dates. Early 1969 (maybe built in 1968 - the first 884s) bridges were different configuration and color as well. There are a few folks who are knowledgeable on these - John Pirkle, Jr. is probably the easiest to contact.

[Jim 25993]

Re: Alternator 1100884

Gentlemen,
Thanks for your insight.
It will be a help to me this winter when I tear into them.

Joe,
Is there any information that I could collect that would help confirm/deny your thought that the change to the front case occured before the end of the '70 model year?

Thanks again.

[Joe L.]

Re: Alternator 1100884

Jim-----

At present, I don't know of any way to document it.