Alternator adjustment bolt

[Curt C.]

What is correct bolt configuration for a 1966 alternator? Bolt, lock washer and thick washer or bolt, star washer and thick washer. How about for a 1964? Thanks.

[John H.]

Re: Alternator adjustment bolt

Curt -

'65-6-7 all use the same split lock washer under the bolt head.

[Joe L.]

Re: Alternator adjustment bolt

What is correct bolt configuration for a 1966 alternator? Bolt, lock washer and thick washer or bolt, star washer and thick washer. How about for a 1964? Thanks.

Curt----

For 1966, it's bolt, external tooth star washer, and thick flat washer. For 1964 it's the same order, but I think a split lock washer was used instead of a star washer.

[Joe C.]

Re: Alternator adjustment bolt

Curt -

'65-6-7 all use the same split lock washer under the bolt head.

The 1965 Judging Manual has it as a star washer. Which is correct?

[Gary S.]

Re: Alternator adjustment bolt

I have lots of pictures of orig alternator adjust bolts/washers...but no 64's. Toothed washer seems most used for 65, 66 and 67. I do have one 65 with a split and another 67 with a split washer. Attached are what appears to be original pictures...one of each year...65, 66, 67. Gary

[Joel T.]

Re: Alternator adjustment bolt

I recently had my 1965 judged and lost 1 point because I had the split washer as opposed to the star washer.... My understanding is that 63-64 used the split and 65-67 used the star.....

[Michael H.]

Re: Alternator adjustment bolt

I recently had my 1965 judged and lost 1 point because I had the split washer as opposed to the star washer.... My understanding is that 63-64 used the split and 65-67 used the star.....

For 63, the AIM calls for a 187119, L washer. It's described in other GM doc as a split lock washer, medium.

For 66 with 327, the AIM calls for a 138485, external tooth lock washer.
For 66 with 427, The AIM calls for a 187119, split lock washer.

Small block and big block were different for 66???

What part numbers are shown in the 64, 65 and 67 AIM's?

[Terry M.]

Re: Alternator adjustment bolt

FWIW We expect to see a toothed washer on 1968 and early 1969, with a split lock washer after that.

[Gary S.]

Re: Alternator adjustment bolt

I recently had my 1965 judged and lost 1 point because I had the split washer as opposed to the star washer.... My understanding is that 63-64 used the split and 65-67 used the star.....

For what it is worth, here are 3 pictures of very original cars with split washers. Always a chance the lock washer could have been changed, but the thick washer and bolt look original as does the split lock washer. These are from a 65 fuel car Vin 11774, 65 396 car vin 15726 survivor and a 67 427/400 AC coupe vin 20460. The 396 pictures when enlarged looks to be a split washer. So the question is, was the toothed washer really used 100% of the time. Also, in my prior post of 3 pictures, the toothed washer has squared ends unlike the pointed end lock washers the supply houses send you.

Gary

[Timothy B.]

Re: Alternator adjustment bolt

My 67 corvette has a external tooth washer at this location and the part # called out in the 1967 AIM is 138485. The 1963 washer in the AIM is as Mike posted.

What's interesting is that the washer called out in section 12 page A-7 for the 63 horn mounting is 138485 and we know the horn bolt is 5/16" (same size as alternator) and the horns ground at the core support to work properly so I think it's safe to say star washer here and lock washer at alternator for 63.

[Joe C.]

Re: Alternator adjustment bolt

For 63, the AIM calls for a 18711, L washer. It's described in other GM doc as a split lock washer, medium.

For 66, the AIM calls for a 138485, L washer. It's described as an external tooth washer.

What part numbers are shown in the 64, 65 and 67 AIM's?

1965 AIM:

SBC: 138485 #*
#: Note 1 (6/26/64): Was 187119 (?partially unreadable)

396: 187119 *
* FWIW all lock washers shown in both drawings appear to be split

SO,FOR SBC 1964-1965 BUILT AFTER 6/26/64, THERE WAS A CHANGE IN WASHER FROM SPLIT TO STAR. NEED VERIFICATION OF PART NUMBER!!
FOR BBC (ALL) WASHER WAS 187119 (SPLIT)

[Michael H.]

Re: Alternator adjustment bolt

1965 AIM:

SBC: 138485 #*
#: Note 1 (6/26/64): Was 187119 (?partially unreadable)

396: 187119 *
* FWIW all lock washers shown in both drawings appear to be split

SO,FOR SBC 1964-1965 BUILT AFTER 6/26/64, THERE WAS A CHANGE IN WASHER FROM SPLIT TO STAR. NEED VERIFICATION OF PART NUMBER!!
FOR BBC (ALL) WASHER WAS 187119 (SPLIT)

If the 65-66 AIM's are accurate, 65 and 66 big blocks used a split lock washer and 65-66 small blocks used an external tooth washer.

For what it's worth, my 66 big block has a split lock washer. It doesn't have the orig alternator but I believe the bolt and washers are probably original.

Still like to hear what's shown in both SB and BB sections of the 67 AIM.

[John H.]

Re: Alternator adjustment bolt

I'd correct my earlier post, but there's no "edit" button available. '65-'6-'7 small-blocks all used the same 138485 external-tooth star washer under the bolt head; same one that's used on the washer nozzles and under the head of the C60 passenger side horn bolt for the ground wire.

[Gerard F.]

Re: Alternator adjustment bolt

Michael,

The 67 JG calls out an external tooth star washer for both small block and big block. My late 67 S/B with my original alternator, and I believe original bolt setup, has an external tooth star washer under the head of the bolt and a thick flat washer under.

The bolt head marking is a "NAT" within 3 spokes, which varies from the callout in the JG.

Wonder if there there are other 67's with the "NAT" head markings

[Michael H.]

Re: Alternator adjustment bolt

Michael,

The 67 JG calls out an external tooth star washer for both small block and big block. My late 67 S/B with my original alternator, and I believe original bolt setup, has an external tooth star washer under the head of the bolt and a thick flat washer under.

The bolt head marking is a "NAT" within 3 spokes, which varies from the callout in the JG.

Wonder if there there are other 67's with the "NAT" head markings

Thanks Jerry. I wonder what the 67 AIM shows for big block?