1970: Alternator wire harness ground strap?

[Keith M.]

I came across this picture. Can someone tell me if that metal strap holding the wire harness was stock for a 1970 BB? And if so, doesn anyone know where i could get one? Thanks.

[Terry M.]

Re: 1970: Alternator wire harness ground strap?

I came across this picture. Can someone tell me if that metal strap holding the wire harness was stock for a 1970 BB? And if so, doesn anyone know where i could get one? Thanks.

Keith,

My first observation is that is not a picture of a 1970 large motor alternator, or at least not one as built by Chevrolet.

That said, I believe 1970 large motors had a bracket similar, if not exactly like that; however I would have to check my AIM at home to see if a bracket is illustrated. I very much doubt that bracket was ever available individually since it originally was a part of the wiring harness as delivered to St Louis. Joe Lucia would be able to give the final word on availability, however.

[Monte M.]

Re: 1970: Alternator wire harness ground strap?

Keith,
I cannot speak to 1970 for sure, but the late 71 and all the 72 big blocks I have owned had it.

I am only speculating that it would also be on a small block too unless it was part of the harness.

PM sent about where to locate the bracket.

Monte

[Dino L.]

Re: 1970: Alternator wire harness ground strap?

1970 base motor alternator with bracketalt 1970.jpg

[Alan S.]

Re: 1970: Alternator wire harness ground strap?

Hi Keith,
I believe there was a slight difference in the bracket as the model years went by.
At some point the 2 'prongs' at the end of the bracket were long enough that they both extended beyond, and wrap the side of, the alternator case, the picture you posted illustrates that). In 71, (and I'm how much before or after that) the lower prong didn't extend as far and slipped into a slot in the rear of the case.
Perhaps some one can clarify that difference and time period for you so you know just what to look for for your 70BB.
Regards,
Alan

[Monte M.]

Re: 1970: Alternator wire harness ground strap?

Alan,
What you may be seeing is the prongs just being bent at different angles and locations.
After looking at my cars, a handful of pictures, and the spare alternators I have here, all the prongs look the same length, from what I can tell. The way it is mounted seems to be the difference.

EDIT: However, the second bend does appear to be in a different location.

Monte

[Thomas H.]

Re: 1970: Alternator wire harness ground strap?

I searched for one for a while for my 71 LS5. Tough to find (at least for me).

Last year while walking through Carlisle, one vendor had a bunch of wire harness parts, cut off connectors, light sockets, etc, in a bin. I looked in and saw the bracket sitting right on the top. $5 later it was mine. Best find of the day!

Tom

[Alan S.]

Re: 1970: Alternator wire harness ground strap?

Hi Monte,
Since I'm the original owner of the car I'm pretty confident the prong wasn't re-bent. The alternator hadn't been touched until I started disassembly for the restoration.
As you noticed the prong is bent at a particular angle to fit into the slot.
If that the shadow from the radiator hose on the alternator in Dino's picture wasn't right where it is, we might get a better look at his prongs. But it appears to me only the upper prong extends over the edge of the case in his picture.
Regards,
Alan

[Joe L.]

Re: 1970: Alternator wire harness ground strap?

Keith,

My first observation is that is not a picture of a 1970 large motor alternator, or at least not one as built by Chevrolet.

That said, I believe 1970 large motors had a bracket similar, if not exactly like that; however I would have to check my AIM at home to see if a bracket is illustrated. I very much doubt that bracket was ever available individually since it originally was a part of the wiring harness as delivered to St Louis. Joe Lucia would be able to give the final word on availability, however.

Terry and Keith------


This bracket was never available from GM in SERVICE. It was supplied as part of the harness only. I don't know of any reproductions. However, I would think that harness manufacturing sources like M&H Electrical Fabricators would have them. Whether they would sell them separately, I don't know.

I believe the bend at the end was an anti-rotation feature. However, it really only worked for the 1969 model year. For that year the lug on the rear case half was pretty much flush with the rear case. In this configuration, the bracket was flat against the case and the "bent-over" ends of the bracket were positioned over the side of the case, preventing rotation of the bracket as the bolt was tightened. However, for the 1970 and later model years, the lug on the rear case half was in a boss raised about 1/4" off the rear of the case. This caused the bracket to be mostly unsupported by the back of the case and the bent-over ends to not reach the sides of the case. Thus, the anti-rotation feature became an anachronism.

The bracket was not redesigned for the 1970+ model years. If it had been, it would have differed in ways other than the length of the "bent-over" ends. Why it was not redesigned, I have no idea. Possibly, it was because the anti-rotation feature was not deemed to be all that necessary so they just left it the way it was.

I do not think that the bracket was ever designed so that one of the bent-over "tangs" would fit into a hole on the rear of the case even though that may have coincidentally occurred.

[Paul O.]

Re: 1970: Alternator wire harness ground strap?

Here is a photo of a 1972 454 Bowtie alternator.

[Monte M.]

Re: 1970: Alternator wire harness ground strap?

Guys,
I have three of the brackets here. All three of mine are off mid 71 to 72 alternators. They are not all bent the same, but they are all bent.
I appears the bends on the end that sticks out over the edge is bent in a was to hold the bracket in a certain position. I cannot imagine the end being cut the way it is for no reason. I guess there is a chance that 70 may be different than the later ones, but only in the way they were bent.

Paul, The one on my 40K original mile 72 LS-5, 4-speed, A/C, car is also original to the car. It looks just like yours does. We know they were on the 71 and 72, but........

The original question was "Is this original to 70 big block cars.

We are still looking for a 70 big block owner to confirm it was on those cars as well.

[Joe L.]

Re: 1970: Alternator wire harness ground strap?

Guys,
I have three of the brackets here. All three of mine are off mid 71 to 72 alternators. They are not all bent the same, but they are all bent.
I appears the bends on the end that sticks out over the edge is bent in a was to hold the bracket in a certain position. I cannot imagine the end being cut the way it is for no reason. I guess there is a chance that 70 may be different than the later ones, but only in the way they were bent.

Paul, The one on my 40K original mile 72 LS-5, 4-speed, A/C, car is also original to the car. It looks just like yours does. We know they were on the 71 and 72, but........

The original question was "Is this original to 70 big block cars.

We are still looking for a 70 big block owner to confirm it was on those cars as well.

Monte-----


The bracket was on all 1969 to at least 1972 Corvettes, big blocks, small blocks and, most likely, medium blocks (if they had made any).

As I mentioned above, the brackets were configured for the 1969 alternator configuration. They do not fit properly for 1970 or later alternators. As a result of the poor fit on these alternators, the brackets are easily distorted or bent during their years in service.

[Monte M.]

Re: 1970: Alternator wire harness ground strap?

Keith,
After looking at a ton of these the difference seems to be where they are bent on the hoop end.
My guess is, if you were to loosen yours and rotate it a bit it, there is a very good chance that one of the tabs will drop into a hole on the alternator.

Of the three that are here, two had one tab in a hole while the other tab hung over the outside of the alternator. The third was was like the picture you posted. The hoop end of the bracket was very close to the middle of the alternator. I loosened the bolt on the bracket, moved the bracket to where it was on the other two and it tightened right down.

It did NOT look like it would fit as the others did, but it did, no problem.

Loosen the bolt and see if it will line up like the rest of the pictures.

Let us know how it turns out.

[Joe L.]

Re: 1970: Alternator wire harness ground strap?

Here is a photo of a 1972 454 Bowtie alternator.

Paul------


In your second photo, notice how the bracket is bent down on the inner end. It did not start out this way. As a result of the fact that the bracket designed for the 1969 model year did not rest flat against the case for 1970 and later alternators, this sort of distortion is quite common. Distortion of the "bent-over" tabs on the outer end is also common on 1970+ alternators.

[Monte M.]

Re: 1970: Alternator wire harness ground strap?

Terry,
Does your LT-1 have the bracket on the alternator?

Monte