69 fan to clutch bolts

[Chris H.]

Re: 69 fan to clutch bolts

Here's a photo of mine.

[Stanley S.]

Re: 69 fan to clutch bolts

Here's a photo of mine.

Chris,

Your picture looks exactly like my clutch except on mine, I think someone has painted the rectangular spring and the metal piece under the spring a dull aluminum color. I believe these pieces are not aluminum and should be natural metal finish, is this correct?

Also, I found 4 bolts with the "A" head stamp that appear to be correct for attaching to the fan but they want $125 for the set. Maybe I will keep looking.

Stan

[G A.]

Re: 69 fan to clutch bolts

Try Richard Fortier.

[Joe L.]

Re: 69 fan to clutch bolts

Chris,

Your picture looks exactly like my clutch except on mine, I think someone has painted the rectangular spring and the metal piece under the spring a dull aluminum color. I believe these pieces are not aluminum and should be natural metal finish, is this correct?

Also, I found 4 bolts with the "A" head stamp that appear to be correct for attaching to the fan but they want $125 for the set. Maybe I will keep looking.

Stan

Stan-----


You only need a period-correct headmark for judging purposes, not necessarily an "A". Someone paying $125 for a set of "A" headmark bolts is insane.

[Chris H.]

Re: 69 fan to clutch bolts

Stanley, here's a photo of the bolt.

[Jeffrey S.]

Re: 69 fan to clutch bolts

These are the same bolts I have on my Oct '68 car. The bolts that attach the fan blade to the fan clutch are "A" headmarks.
Jeff

[Stanley S.]

Re: 69 fan to clutch bolts

Stan-----


You only need a period-correct headmark for judging purposes, not necessarily an "A". Someone paying $125 for a set of "A" headmark bolts is insane.

Joe,

By period-correct then you mean any bolt with a headmark that was used in 69? Of course it would need to be the correct size.

[Scott S.]

Re: 69 fan to clutch bolts

Stan,

The 1969 AIM (UPC 6-A4) doesn't show any bolts used for this application, but Jeff (post #10) says early '69 used bolts, which must mean they're a carryover from 1968 (the Revision Record in the '69 AIM shows that it was redrawn and redesigned on 3-19-69). The 1968 AIM (also UPC 6-A4) shows item 9, 186634 Bolt for the fan clutch hub to water pump. This is the same bolt part number used for this application in 1967, called out on UPC 6-A3 of the 1967 AIM.

According to GM, bolt 186634 is 5/16-24 x 1", regular hex head, grade 8. The examples on the '67 L79 that I'm working on are the same as the (mirror image?) picture Chris shows in post 20. Mine have the same "A S" headmark, with six lines (grade 8).

[Grant W.]

Re: 69 fan to clutch bolts

Here is a pic of the A bolt with 3 lines for 69 fan clutch.
It is a black phosphated bolt and lock washer same thing.

Hope this helps. Merry Xmas to everyone!!!
Grant

[Joe L.]

Re: 69 fan to clutch bolts

Stan,

The 1969 AIM (UPC 6-A4) doesn't show any bolts used for this application, but Jeff (post #10) says early '69 used bolts, which must mean they're a carryover from 1968 (the Revision Record in the '69 AIM shows that it was redrawn and redesigned on 3-19-69). The 1968 AIM (also UPC 6-A4) shows item 9, 186634 Bolt for the fan clutch hub to water pump. This is the same bolt part number used for this application in 1967, called out on UPC 6-A3 of the 1967 AIM.

According to GM, bolt 186634 is 5/16-24 x 1", regular hex head, grade 8. The examples on the '67 L79 that I'm working on are the same as the (mirror image?) picture Chris shows in post 20. Mine have the same "A S" headmark, with six lines (grade 8).

Scott-----


I believe what the original question here involves is the fan-to-clutch attachment. What seems to have crept into the discussion is the clutch-to-waterpump attachment.

The fan-to-clutch attachment for 1968 base engine as shown in UPC 6 (and some other 1968 applications) was STUDS. The exact same thing was true for 1969. However, applications using the GM #3937771 fan clutch used bolts for fan-to-clutch attachment. This was true for both 1968 and 1969.

As far as the clutch-to-waterpump attachment that's a completely different issue. All 1968 used BOLTS for this attachment. Early 1969 also used bolts. Later 1969 used studs.

[Joe L.]

Re: 69 fan to clutch bolts

Joe,

By period-correct then you mean any bolt with a headmark that was used in 69? Of course it would need to be the correct size.

Stan------


Yes, a headmarking that was used in 1969 and that general period of time. There are few, if any, headmarkings that are unique to a specific model year.

[Bill L.]

Re: 69 fan to clutch bolts

If you are patient the A head mark bolts come up pretty often if that is the way you choose to go. I have seen them go for as little as $15.00 on ebay.

This type of fan clutch was used for quite a few years.

Bill

[Stanley S.]

Re: 69 fan to clutch bolts

Stan,

The 1969 AIM (UPC 6-A4) doesn't show any bolts used for this application, but Jeff (post #10) says early '69 used bolts, which must mean they're a carryover from 1968 (the Revision Record in the '69 AIM shows that it was redrawn and redesigned on 3-19-69). The 1968 AIM (also UPC 6-A4) shows item 9, 186634 Bolt for the fan clutch hub to water pump. This is the same bolt part number used for this application in 1967, called out on UPC 6-A3 of the 1967 AIM.

According to GM, bolt 186634 is 5/16-24 x 1", regular hex head, grade 8. The examples on the '67 L79 that I'm working on are the same as the (mirror image?) picture Chris shows in post 20. Mine have the same "A S" headmark, with six lines (grade 8).

Scott,

As Joe indicated my original question regarded the fan-to-clutch attachment, but I appreciate your post because as this tread has developed, I have learned the bolts attaching the clutch to waterpump on my car are also wrong as well as the waterpump itself.

I offer many thanks to all who have posted here. For me, the Corvette hobby would be impossible without the experts in the NCRS.

Stan