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-   70-73 Firebird & TA TECH (https://forums.maxperformanceinc.com/forums/forumdisplay.php?f=437)
-   -   Alternator 902 903 904 (https://forums.maxperformanceinc.com/forums/showthread.php?t=857549)

Ramairnacho 03-25-2022 04:08 PM

Alternator 902 903 904
 
2 Attachment(s)
Hi group.from what I seen hear and read Im confused a little on alternators for 1970. They are all open face and finned I believe. But seen black.fans zinc fans ,black pullies,zinc pullies,and gold. Then spokes. Are they 6 spoke, 5 spoke or both.i was told 5 only but seen 6 and then was also told 6 and 5 spoke. I realize it's a small detail but still curious. School me please. My car assembled In March of 70

68bird400HO 03-25-2022 05:06 PM

The earlier open face alternators for 1969-70, including the 902, 903, and 904 were 6 spoke. For the 1971 model year including the 927 and 928, they changed to five thicker spokes.

Also, from what I have seen, the fans and pulleys were both silver cadmium.

Ramairnacho 03-25-2022 05:24 PM

902903904
 
Quote:

Originally Posted by 68bird400HO (Post 6329512)
The earlier open face alternators for 1969-70, including the 902, 903, and 904 were 6 spoke. For the 1971 model year including the 927 and 928, they changed to five thicker spokes.

Also, from what I have seen, the fans and pulleys were both silver cadmium.

Thanks

Formulabruce 03-25-2022 05:26 PM

As said, and I agree 1970 are 6 spoke. However, and was JUST DISCUSSED in another thread in this very forum, the Pulley is Gold Cad and fan is Galvanized ( which I have been doing in silver cad paint as The Galvanized paint is weird, and seems a 1 use deal per can. )
So, PULLEY WAS GOLD CAD ( I have Originals to prove this)
FAN WAS GALVANIZED
Are we done yet?
Want your pulley done Correctly? This involves bead blasting, treating, Silver zinc plated, and then DiChromate coating.

Formulabruce 03-25-2022 06:48 PM

2 Attachment(s)
lets do some pics
https://forums.maxperformanceinc.com...4&d=1648248456
https://forums.maxperformanceinc.com...5&d=1648248465

Ramairnacho 03-25-2022 07:45 PM

Alternator
 
Quote:

Originally Posted by Formulabruce (Post 6329543)

Wow that's a lot of detail. Is the pullies all the same because I got about 10 alternators at home . Like to see pics of correct fan too

Formulabruce 03-25-2022 10:23 PM

Pullies I have pulled 70 and 71 and 72 were ALL Gold "cad" .
I have a correct fan, will have to look again, the Galvanize gets gray and dull and makes it hard to see the flakes on the coating.
They didnt last a year in appearance in normal use.

Held for Ransom 03-31-2022 07:37 PM

https://forums.maxperformanceinc.com...d.php?t=715554

My '903 was pictured here and was a 5 spoke. Can't tell what the plating was...

RamAirBirds 04-01-2022 04:44 PM

I am almost certain that some of the very early/first run 1970 alternators 902/903 had the 5 spoke front and the changed came pretty shortly into the 1970 run...
TellyS.....didn't we discuss this before? I think there were known examples out there...

RamAirBirds 04-01-2022 04:48 PM

I think i had that backwards.....Maybe strike what i said....I may be thinking that the 69 had 6 spoke (correct) and that some of the later built 69's went to 5 spoke...BEFORE the eventual release of the 1970 style....

RamAirBirds 04-01-2022 04:50 PM

OK Telly is texting me on the side probably laughing at the confusion i am causing...He claims 6 spoke up until sometime in May 1970.....

Uncle Judge 04-01-2022 07:15 PM

And you want to be my latex salesman!


Sent from my iPhone using Tapatalk

RamAirBirds 04-01-2022 08:06 PM

Jeff!!! WTH....Cant get away from those references after 25+ years..
SERENITY NOW!

Ramairnacho 04-04-2022 11:39 PM

formulabruce,
its ignacio and like to know where i can buy a cad pulley for my custom built 904 alternator and possible zinc fan with1 wide blade?

unruhjonny 04-06-2022 10:33 AM

Quote:

Originally Posted by RamAirBirds (Post 6331491)
Jeff!!! WTH....Cant get away from those references after 25+ years..
SERENITY NOW!

this made me chuckle.

ok, I saw this discussion before, but today I was prompted to look;
My '902 alternator is a six spoke, and is dated January 27, 1970.
I also have an unstamped front housing that is a six spoke design.
Now, many don't realize it, but the early (69/70) alternators also have a unique rear case - I swapped my rear case for a later one because the bolt boss for the rear mount is damaged - but I kept it with the front of that alternator that I swapped the rear case for.

I hope you're not losing sleep over this minute detail;
Not once was my correct alternator noticed.

Formulabruce 04-06-2022 12:03 PM

The cad looking coating used today looks different on different metals. On carbs it looks perfect. On a steel pulley, even though its zinc plated first, the gold looks a bit brighter. Ignacio. I am going to do a few pulleys this summer. I will be sure to post some pics and save one for you if you like it. Your alternator has no fan or Pulley?

Ramairnacho 04-06-2022 01:49 PM

I unfortunately don't have my original 904 or ever seen 1. Haven't been able to find1 either. I located 2 928, and 3 open face blanks and 1 diamond finned 70 back that's slightly chipped. So I got the idea to have one custom made with a blank and correct rear back cover. I could pay extra to have it professionally stamped and say I have an original but I'm not like that. So I want correct fan and pulley

unruhjonny 04-06-2022 02:57 PM

Quote:

Originally Posted by Ramairnacho (Post 6332485)
I unfortunately don't have my original 904 or ever seen 1. Haven't been able to find1 either. I located 2 928, and 3 open face blanks and 1 diamond finned 70 back that's slightly chipped. So I got the idea to have one custom made with a blank and correct rear back cover. I could pay extra to have it professionally stamped and say I have an original but I'm not like that. So I want correct fan and pulley

honestly, my suggestion would be to build an alternator with the common (not 69/70) rear case, and leave it unstamped.

I'd wager that people would notice paint/plating way before stamping, or the rear of the alternator case;
Also, without a 1970 Firebird (suppliment) service manual, or a Master Parts Catalog, I wouldn't know what the correct alternator number is for our cars - the Firebird Red book, and HPP 'numbers crunching' never mentioned the alternator - it wasn't till years after the fact that I realized I had the correct for my car alternator.

Ramairnacho 04-06-2022 05:01 PM

904
 
2 Attachment(s)
Oh it's small detail I guess. This is what I got so far. The front ooen face isn't an original but a blank. I got 2 like this when done probably sell other core.

unruhjonny 04-06-2022 05:40 PM

I was astonished when I saw what the rear cases were going for - I looked into it with hte idea of replacing my 902's original - but quickly changed my mind.
I bought an unstamped open face front case to basically make a backup or sit in replacement for my '902.


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