C2: 65 66 Ignition Switch Operation

[Michael H.]

There was a different part number for both the ignition switch and lock cylinder for 65 and 66. Supposedly, the new design entered production at SOP for 66. Just wondered if this was a known fact and if it was a judged item.

Both 65 and 66 designs look very similar and the change was internal. Had to do with it's operation.

Gold star by your name if you have the answer.

[David D.]

Re: C2: 65 66 Ignition Switch Operation

Mike, I believe the difference, as you stated, is internal. The 1965 ignition tumbler has different end (half-moon shape?), where it fits into igniton switch body. The 1966 ignition tumbler has a flat blade about 1/8 thick x 3/8 long, that fits into a similar notch in the 1966 switch. IMO, it would be very hard to judge. I hope I explained it correctly. Dave

[Michael H.]

Re: C2: 65 66 Ignition Switch Operation

Dave,

That would be correct for the physical part of the change. What we need to know now is how this change affected the operation of the switch assembly. It was an intentional change for a good reason.

Wonder how many 65 66 owners will be headed out to the garage to test their switch after we reveal the answer.

One of the reasons I'm concerned is the fact that the switch in my 66 operated like a 65, which is incorrect according to old GM documents.

[Peter L.]

Re: C2: 65 66 Ignition Switch Operation

Michael - The 66 key must be pushed "in" as you turn to ACCESSORY position for operating the accessories when the engine is not running. This is not required for 65. Pete

[Michael H.]

Re: C2: 65 66 Ignition Switch Operation

Yes, that's correct Peter. GM decided that the key could unintentionally be turned too far and wind up in the ACC position so this was changed for 66. Supposedly, the change was new for SOP of 66 but my Nov 65 built 66 switch operates like a 65. Not sure why. I know the cyl is original as the key numbers are still stamped in it. Wonder if the switch was changed at some time in it's life before I owned it?

[Peter L.]

Re: C2: 65 66 Ignition Switch Operation

Michael - As you know, it should be a #673 for the 66 and the 65 was a #660. It is possible that the switch was replaced with a 67 switch, #686, that would use the same lock core as the 66 but I just checked my 67 and the key needs to be pushed in to turn to the ACCESSORY position. So if that change was made the operation was still the same. Next question is the lock core a 66? And next, next is the switch a number other than #673? Inquiring minds await the answers. Pete

[Michael H.]

Re: C2: 65 66 Ignition Switch Operation

Peter,

I just removed the cyl and it is indeed a correct 66. I also opened an NOS 7031272 cyl to compare and they are identical. Not sure but if I remember correctly, the difference is the oval shaped end of the cyl that's different between 65 and 66?

Also, the NOS cyl operates the same way. I can switch to "ACC" without depressing the key/cyl.

The 66 "New Products" book states that "the 1966 lock cylinder may not be used with the 1965 ignition switch body but the entire 1966 body and cylinder assy may be used in the 1965 vehicle.

That still doesn't explain why mine is able to be rotated to "ACC" without depressing the key/cyl. I have to wonder if the switch itself is non original? Think I'll remove it later and hope to find some numbers on it.

I believe there's a way to tell the difference between 65 and 66 ignition switch just by looking onto the switch with the cyl removed but I don't remember what the difference is.

[Bill Richards]

Re: C2: 65 66 Ignition Switch Operation

Michael, I have a Nov.65 built 66 and the key switch opperates the same as yours. Dont know if mine is original or not. Bill

[David D.]

Re: C2: 65 66 Ignition Switch Operation

Mike, Checked my Nov/11/1965 built 1966 convertible (D02 AOS body), with it's original 660 ignition switch and 1966 tumbler, as far as I can tell. It also can be turned to the ACC position without pushing the key in, but there does seem to be some slight resistance moving it fron the OFF position. Pushing the key in just slightly, makes it easier to turn to the ACC position. I also have an extra used 660 ignition switch, it has a 1966 tumbler and key, it is very easy to turn from the OFF to ACC position, without pushing the key in at all, no resistance. IMO, on my 1966 and the used switch I have, it is most likely from wear and tear over the years. FWIW. Dave

[Peter L.]

Re: C2: 65 66 Ignition Switch Operation

Dave - If your original ignition switch is a #660, that's why it will move to the ACC position without having to push it in. My 66 is a late car, S/N 25,305 and has a #673 ignition switch that requires being pushed in to move it to the ACC position.

Having said that you indicate you have a 1966 tumbler (lock core). Basically by design the 1966 tumbler (lock core) cannot be used on a #660 '65 ignition switch unless someone modified the back of the lock core to fit in a '65 #660 switch.

This thread is very interesting and curious.

Pete

[Peter L.]

Re: C2: 66 Ignition Switch

The '66 Corvette AIM (UPC 6, B4) call for the ignition switch to be a 1116673 (the original Delco-Remy switches are embossed 673 on the step of the switch body. The REVISION RECORD shows "WAS 1116660" but I cannot read the date of the revision in the AIM I have. Can anyone read the REVISION RECORD date intheir AIM and if so what is it?

The question is "did early 1966 production Corvettes come with #660 ignition switches?"

Thanks, Pete

[Peter L.]

Re: C2: 65 66 Ignition Switch Operation

Michael - Please refer to Dave's posting on the configurations of the rear of the ignition lock cores that fit into the ignition switches. Basically, I would not expect an original 66 lock core to fit into and operate a 65 ignition switch and vice-versa. Pete

[Michael H.]

Re: C2: 65 66 Ignition Switch Operation

Peter, David,

I believe you are right. I just inspected the inside of a 66 switch and I'm now convinced that the 66 tumbler can not be used in a 65 switch. The configuration is much different. The 66 has a larger key that won't fit into the 65 switch. However, I believe the GM paperwork is correct in the fact that a 65 tumbler will work in a 66 switch.

I dug into the 66 and it does indeed have a correct 673 switch with a correct 272 tumbler assy.

I'll scan and post the GM paperwork on this. This was all sent prior to the introduction of the 66 model year release.

I still don't understand why it doesn't work properly unless, as others have mentioned, it's worn to the point where it no longer functions.

[Michael H.]

Found It

Info about the new 1966 models is directly from GM in about August 1965. At least this is how it was SUPPOSED to work.

[David D.]

Re: Correction on 66 Ign Switch.

Made a typo on the ignition on my early Nov/65 1966 convertible. I meant say it has a 673 ignition switch, with the slot for the key tumbler. NOT a 660 with the half-moon shaped hole for the key tumbler. Sorry for the confusion. Dave