63 Alternator pivot bolt

[Michael G.]

The bolt used for alternator pivot on 63's is is listed as part number 191163. Does anyone have the GM drawing of this part?

Thanks,

[Rich P.]

Re: 63 Alternator pivot bolt

Michael,

I don't have a drawing but I do know the specifics. 3/8-16 X 4" grade 5 zinch plated, 9/16" hex head.

Rich

[Michael G.]

Re: 63 Alternator pivot bolt

Rich,

I wanted the drawing because I'm trying to determine the body shape above the threads. Pivot bolts are usually kinda specialized, so I'm wondering if the body above the threads is supposed to be the same diameter as the threads, or smaller, ie full body or reduced body or something else?

Thanks

[Rich P.]

Re: 63 Alternator pivot bolt

Mike,

I have dozens of them. I will pull one out and mic it up.

Rich.

[Rich P.]

Re: 63 Alternator pivot bolt

Michael,

I miched up 15 different pivot bolts. 1 6" long for AIR pumps, 2 4-1/2" BB w/power steering, 10 4" SB and 2 3-3/4" BB with out power steering.l bolts and here is what I found . All shoulders fell within .368-.372. Also all 15 bolts had 1-1/8" threads. In ths batch is 6 different manufactures, TR, M, C, RBW, A and O.

Hope this is what you were looking for,
Rich

[Rich P.]

Re: 63 Alternator pivot bolt

one last picture.........

[Michael G.]

Re: 63 Alternator pivot bolt

Rich,

Thanks a lot! Those are all trimmed-hex full-body bolts, not the fully threaded part that I took out of my car. I'll see what Paragon or Richard Fortier has for this. Hopefully it'll be like your parts.

Thanks again,

[Joe L.]

Re: 63 Alternator pivot bolt

The bolt used for alternator pivot on 63's is is listed as part number 191163. Does anyone have the GM drawing of this part?

Thanks,

Mike------


The GM #191163 bolts are just as Rich pictured. They are a standard, hex head bolt of 3/6-16 X 4" and GM material grade 280-M (SAE grade 5). This bolt was actually used in PRODUCTION over the course of many years. It was last used for Corvettes for the 1978 model year. After that, metric size replaced it.

The GM #191163 was also once available in SERVICE. It was discontinued in January, 1976 and replaced by GM #456958. As far as I can tell, this is an identical bolt except it's GM material grade 300-M (SAE grade 8). It was discontinued without supercession in October, 2000.

[Joe L.]

Re: 63 Alternator pivot bolt

Rich,

Thanks a lot! Those are all trimmed-hex full-body bolts, not the fully threaded part that I took out of my car. I'll see what Paragon or Richard Fortier has for this. Hopefully it'll be like your parts.

Thanks again,

Mike-----


As you probably know, GM would NEVER have used a fully threaded, 4" bolt for a pivot bolt application like this. As a matter of fact, I don't know where anyone found one to use as a replacement. A 4" long, all-thread bolt is not easy to find and even more difficult if it's a Grade 5 or Grade 8 bolt.

Except for manufacturer's ID headmarking, I think you could easily find a bolt just like the 191163 in a good hardware store that carries grade 5 fasteners. Orchard Supply is one. Most grade 5 bolts today are zinc plated, just like the 191163.

[Michael G.]

Re: 63 Alternator pivot bolt

Joe,

I guess I could have looked at the bolt in my other car, but I hate taking that one out just to see it.

I suppose a thread would work just as well as a pivot in this type of application, but I agree, we would have never used one.

It would have been difficult to find one with all those threads because its difficult to roll a part with all those threads. You can make them on a lathe. A local company here in the Detroit area used to stock such bolts six or seven inches long, then cut them to order for prototypes and specials for the auto companies. Maybe that's where it came from.

If I don't like the repros I find, I can make one if I have to, I just wanted to know what it was supposed to look like.

Thanks,

[Joe L.]

Re: 63 Alternator pivot bolt

Joe,

I guess I could have looked at the bolt in my other car, but I hate taking that one out just to see it.

I suppose a thread would work just as well as a pivot in this type of application, but I agree, we would have never used one.

It would have been difficult to find one with all those threads because its difficult to roll a part with all those threads. You can make them on a lathe. A local company here in the Detroit area used to stock such bolts six or seven inches long, then cut them to order for prototypes and specials for the auto companies. Maybe that's where it came from.

If I don't like the repros I find, I can make one if I have to, I just wanted to know what it was supposed to look like.

Thanks,

Mike-----


I think the Paragon PR-1041 bolt ought to "fill the bill" for you. It's "TR" headmarking with 3 radial lines is virtually identical to some of the original bolts that Rich P. pictured.

As you know, most standard bolts up to about 1" in length are all-thread. However, as bolts get longer they receive varying amounts of non-threaded shank. In almost every case, GM used bolts of pretty much "standard" configuration although certain applications called for a shorter-than-normal length of threads. The 9/16-14 rear spring retainer plate bolts were an example.

However, there was at least one application in which GM used a longer-than 1" all thread bolt. In fact, the bolt was 1-3/4" long and it was all thread for a good reason. Do you know what the bolt's application was?

[Rich P.]

Re: 63 Alternator pivot bolt

"However, there was at least one application in which GM used a longer-than 1" all thread bolt. In fact, the bolt was 1-3/4" long and it was all thread for a good reason. Do you know what the bolt's application was?"

2 quick ones. 63-67 gas tank strap bolts (carraige style) and 68 up Gas Tank Strap bolts. (hex style)

Rich

[Michael G.]

Re: 63 Alternator pivot bolt

Joe,

Ok Paragon it is.

Rich is correct, the gas tank straps on all GM cars were always fully threaded. This was done for two reasons 1) to use the threads to "pull" the strap into place, and 2) to compress the tank, which was often ballooned slightly by the air pressure test it had before assembly.

I know this because it was one of the first uses of my MAThread invention. They use it on all these parts so the threads don't jam up when they put them in at severe angles to draw the parts together.

Thanks,

[Joe L.]

Re: 63 Alternator pivot bolt

Mike and Rich-----


You both got it right on the first try.

[Grant W.]

Re: 63 Alternator pivot bolt

Joe,

I guess I could have looked at the bolt in my other car, but I hate taking that one out just to see it.

I suppose a thread would work just as well as a pivot in this type of application, but I agree, we would have never used one.

It would have been difficult to find one with all those threads because its difficult to roll a part with all those threads. You can make them on a lathe. A local company here in the Detroit area used to stock such bolts six or seven inches long, then cut them to order for prototypes and specials for the auto companies. Maybe that's where it came from.

If I don't like the repros I find, I can make one if I have to, I just wanted to know what it was supposed to look like.

Thanks,

Hi Michael

If you don't like repops which paragon mostly carries and want the right stuff, Then why don't you PM Rich Pasqualone and see what he can do for you. Rich is one of the best nut and bolt Guru's.

Just my 3 cents worth.
Thanks, Grant