Correct 70 350 hp 1100990 alternator?

[Joe L.]

Re: Correct 70 350 hp 1100990 alternator?

I don't have measurements, and when I decide to brave the cold I am more likely to take a photo than measurements -- but that looks about the right configuration, much as one can tell from a photo. The finish, however, looks yellow gold, and original 1970 LT1 alternator pulleys were silver. Of course that yellow hue in the photo could be from the lighting. I know everyone likes photos, but I don't for the above reasons.

Terry-----

I'm sure the one Dave pictured has had the chromate dip treatment. This is common in later SERVICE pullies but was not done on original pullies from the C2 or early C3 era.

It's easy to remove if one so-wishes, though. A short dip in a slightly acidic solution will do it. Not too long or too acidic or the base zinc plating will go, too.

[Ron G.]

Re: Correct 70 350 hp 1100990 alternator?

I have owned a couple 70 350/350 Corvettes, and one of them I believe had a 900 alternator. Except for one repaint, the car was original and I am betting the alt. was too. Don't remember about the number of fins, just the number of the alt.

[Patrick B.]

Re: Correct 70 350 hp 1100990 alternator?

IMG_0799.jpgIMG_0802.jpgIMG_0803.jpg

Mike------


Attached is a photo of the rear of the split ring end case of an NOS GM #1100543 alternator [not for sale]. This unit was manufactured on July 3, 1970 for the 1971 model year. This case half is similar to the 1970 I described above except it does not have the "7 fin" heat sink. If any split ring case half other than the one I described in my above post was used for 1970, I would expect it would have been this one. Note the differences from the one you pictured.


[ATTACH=CONFIG]44470[/ATTACH]

Here are pictures of the original alternator manufactered on June 19, 1970 for my July 3 built 70 LT-1. It is a 61A 1100884 unit as Terry reported on his LT-1. It is different from Joe's July 3 alternator, perhaps indicating a design change taking place between June 19 and July 3, 1970. I don't know why the attached photos appeared above the quote rather than at the bottom of post.

[Joe L.]

Re: Correct 70 350 hp 1100990 alternator?

[ATTACH=CONFIG]44517[/ATTACH][ATTACH=CONFIG]44518[/ATTACH][ATTACH=CONFIG]44519[/ATTACH]

Here are pictures of the original alternator manufactered on June 19, 1970 for my July 3 built 70 LT-1. It is a 61A 1100884 unit as Terry reported on his LT-1. It is different from Joe's July 3 alternator, perhaps indicating a design change taking place between June 19 and July 3, 1970. I don't know why the attached photos appeared above the quote rather than at the bottom of post.

Patrick-----


Yours is the typical 1970 Corvette alternator split ring frame end. All known-original examples that I have seen have this configuration. I only speculate that it's possible that some very late units might have a different split ring end frame. However, if any did, I would expect they would be like the one I pictured. It could also be that the typical 1970 end frame was used for all 1970 Corvette alternator part numbers and the frame I pictured was used only for 1971 Corvette alternator part numbers. It could very well be that the split ring frame configuration was part of the specifications for the particular alternator part numbers.

[Bill L.]

Re: Correct 70 350 hp 1100990 alternator?

[ATTACH=CONFIG]44517[/ATTACH][ATTACH=CONFIG]44518[/ATTACH][ATTACH=CONFIG]44519[/ATTACH]

Here are pictures of the original alternator manufactered on June 19, 1970 for my July 3 built 70 LT-1. It is a 61A 1100884 unit as Terry reported on his LT-1. It is different from Joe's July 3 alternator, perhaps indicating a design change taking place between June 19 and July 3, 1970. I don't know why the attached photos appeared above the quote rather than at the bottom of post.

Is that a typical configuration for the wire support on the alternator? What is the head mark on the bolt that holds on the wire support and ground wire?

I posted a pic of my 70 900 alternator earlier in the thread.

Thanks,

Bill

[Patrick B.]

Re: Correct 70 350 hp 1100990 alternator?

Is that a typical configuration for the wire support on the alternator? What is the head mark on the bolt that holds on the wire support and ground wire?

I posted a pic of my 70 900 alternator earlier in the thread.

Thanks,

Bill

Bill- The wire support is original. I'll check the bolt heads next time I go to my garage.

[Bill L.]

Re: Correct 70 350 hp 1100990 alternator?

Thanks Patrick,

The AIM calls out part number 3952222 and it appears to be discontinued.

I am just not sure of the head mark.

Bill

[Joe L.]

Re: Correct 70 350 hp 1100990 alternator?

Thanks Patrick,

The AIM calls out part number 3952222 and it appears to be discontinued.

I am just not sure of the head mark.

Bill

Bill------


GM #3952222 bolt was discontinued in October, 1988. The bracket, a part of the harness assembly, was a carry-over from 1969 but part of its function was rendered ineffective by the change made to the split ring end case for 1970. That change involved the boss that the bolt which retains the bracket and ground lug to the case half threads into. For 1969 this boss was nearly flush with the back of the case. The "pronged" ends of the bracket then fit over the case and positioned and prevented rotation of the bracket. For 1970, the boss was raised about 1/4". This caused the "prongs" to barely fit over the case and become mostly ineffective for their original function.

[Bill L.]

Re: Correct 70 350 hp 1100990 alternator?

Thanks Joe,

Do you have the specs of the bolt?

Bill

[David L.]

Re: Correct 70 350 hp 1100990 alternator?

The 3952222 bolt is listed in many of my vintage Chev. parts catalogs but the only catalog that has a description is in my 73-78 Chev./GMC Truck Parts Catalog (Dec. 1977). It is described as 5/16"-18 X 5/8". What does not make any sense is that the 138479 lock washer (1970 AIM, UPC 12, sheet A7) is listed in my 1969 Chev. Parts Catalog (Oct. 1968) in Gr. 8.932 as External tooth No. 10. The 5/16" external tooth lock washer is listed as GM # 138485.
My GM Standard Parts Catalog (Oct. 1988) lists GM # 138479 as External tooth #10 inside dia., 13/32" outside dia., CAD or ZN.

Dave

[Bill L.]

Re: Correct 70 350 hp 1100990 alternator?

Thanks David,

Now I just have to find the correct bolt. Currently have a replacement with incorrect head mark. I saw another thread and I thought I saw an "M" with three lines.

Bill

[Terry M.]

Re: Correct 70 350 hp 1100990 alternator?

Bill,
I looked at my 1970 1100884 yesterday. Even took some pictures, but mine has the wires connected and doesn't photograph as well as Patrick's, so I didn't post it. I can look at the headmark on that shorty bolt for you, but what is your headmark that you think is incorrect?

[Bill L.]

Re: Correct 70 350 hp 1100990 alternator?

Bill,
I looked at my 1970 1100884 yesterday. Even took some pictures, but mine has the wires connected and doesn't photograph as well as Patrick's, so I didn't post it. I can look at the headmark on that shorty bolt for you, but what is your headmark that you think is incorrect?

Hi Terry,

Here is a pic. Looks like three lines with a triangle. I know it is not original as I had to purchase from a vendor.

900 Alt 2.jpg

[Terry M.]

Re: Correct 70 350 hp 1100990 alternator?

I am not sure if this will show up, but I can blow it up and see ROCKFORD with three lines (grade 5). Please be aware this is a 1100884, and not the original subject of this thread. I am posting it for the shorty bolt holding the wire harness bracket.

1100884 alternator 006.jpg

BTW: This is what they look like if they have not been off since the UAW installed it around January 30, 1970.

[Bill L.]

Re: Correct 70 350 hp 1100990 alternator?

I am not sure if this will show up, but I can blow it up and see ROCKFORD with three lines (grade 5). Please be aware this is a 1100884, and not the original subject of this thread. I am posting it for the shorty bolt holding the wire harness bracket.

[ATTACH=CONFIG]44546[/ATTACH]

BTW: This is what they look like if they have not been off since the UAW installed it around January 30, 1970.

Fascinating. The order of assembly does not match the AIM. Of course this would not be the first time the UAW did not follow the AIM

The other thing that is becoming obvious is that the support bracket was installed in all kinds of configurations.

Now I just need to find an original bolt

Thanks,


Bill