Starter mounting bolts

[Cotuit Boy]

I need to install the starter in my 63 R1. It was removed by a 3rd party so I didn't benefit from the exercise of taking it out and don't have the bolts that were removed. The Avanti parts catalog indicates the bolts to be #529367 and that they are "special".  The nuts are 7/16-20 and locks are 7/16.  The catalog gives no indication of type, size, length, grade of the bolts or what is special about them.

Can you shed any light on what is the correct bolt to use?

I'd appreciate any help you can offer.

 

Cotuit Boy

R1 - R2262

[64studeavanti]

The "special" part is the shoulder. It is larger in diameter than regular bolts. Later this pm i will be able to get to the shop so i can measure them.

[64studeavanti]

Here is what i found. A regular bolt has a shank diameter of .435. The starter bolts are .4375 which is precisely 7/16. 

I measured 3 of each and the measurements are consistent.

The overall length of the starter bolts is about 2 1/4 with the unthreaded part at about 1 1/16 and the threaded part at about 7/8.

This assumes i read the micrometer correctly. 

Old tools and even older eyes.

The bolts are grade 5.

Edited August 4, 2017 by 64studeavanti

[64studeavanti]

Forgot the grade of the bolt.

[Cotuit Boy]

Hey 64studeavanti,  Thanks for digging into that. The parts manual mentions 7/16-14 (course thread) nuts.  A 7/16 (0.438) shoulder screw would be consistent with the hole diameter of my starter mounting flange which is 0.470D. Your 0.375 diameter shoulder doesn't seem to make sense for this situation.  Unless my starter is different from the original (it is a rebuild starter from what I can see).

What is the thread size of your mounting screws? Is it a hex head?

 

[Cotuit Boy]

I think I may have solved my mystery with the info from 64studeavanti.  What he has described to me is a conventional 7/16-20 x 2" long grade 5 hex bolt.  The diameter of the unthreaded portion of that size bold is about 0.432 and is about 1.063 long as he stated. the threaded portion is around 0.88 long.  So, with the hex head, the total length would be about 2-1/4" long.  We don't typically include the head dimension in the  length of a bolt so the approximate length would be that for a 2" bolt.  I assumed the pitch size to be a UNF 20 pitch since that concurs with the thread size of the nuts listed in the parts manual.

The bolt isn't a "shoulder bolt" per se since the industrial catalogs don't' list 7/16 dia "shoulder bolts".  I found a 2-1/4 " long bolt in my shop that has all those dimensions but for the longer length.  If I buy a 2" long bolt and the shoulder section doesn't measure up, then I assume that a 2-1/4 inch bolt has been modified in total length which may answer why the Avanti catalog calls it a "special".

Let me know if my assumptions seem correct to anyone else besides me!

[64studeavanti]

That is .4375 not .375. The correct starter bolts are 7/16 x 20 fine thread. The bolt head is 5/8 hex and the nut is 11/16 hex. I checked several bell housings and the special bolts fit snugly whereas the standard are loose. 

[Cotuit Boy]

We are all in agreement.  Thanks

[64studeavanti]

Yes, i included the head in the measurement, so you are looking for about 2" bolt. You do need the larger diameter in order to properly register the starter in the housing.  I have heard of issues ruining starter gears and flywheel ring gears using improper bolts .

[64studeavanti]

A standard 7/16 bolt has a smaller diameter and should not be used. I suspect several of the Stude vendors have the correct bolts. If not, let me know and i will send a couple. 

[regnalbob]

https://www.studebakerparts.com/studebakerparts/store/s/agora.cgi

529367 is available.

Edited August 4, 2017 by Regnalbob

[Cotuit Boy]

Thanks Regnalbob for your response and the link for a source.