C2 ground straps

[Gary B.]

I have a question about ground straps. The five ground straps at the top in the attached photo are the contents of an LIC repro ground strap kit (minus the copper ribbon for the power antenna). At the bottom is an original center exhaust ground strap. That original exhaust strap tells me the two lower straps in the LIC kit are the exhaust straps. The strap with the special clip on the RH end just above the exhaust straps is the body mount to bird cage ground strap. So that leaves the top two ground straps in the LIC kit which must be for the accelerator lever and the engine mount to frame strap. But which is which? The top LIC strap is 0.75” longer than the 2nd one down. Where does the longer strap go?

The GM part number for the ground strap that attaches to the accelerator lever is 2981858. The part number for the engine mount ground strap us 2981856. There is some discussion about the accelerator lever ground strap in the archives, but the length spec given in the archives I think incorrectly gave the length of the exhaust clamp ground straps, which are much shorter. Does anyone have access to the GM spec for either of those two part numbers?

Thanks,


Gary
C4634FD5-8CE4-451E-9721-09B0123D1413.jpg

[Russ S.]

Re: C2 ground straps

I would say the top longer strap is for the accelerator as it needs to be longer to accommodate the movement of the accelerator.

[Tom E.]

Re: C2 ground straps

Gary,
I bought the same set from LIC. All of my ground straps were still attached and although they were not identical to the replacements they most closely matched your photo in the following order.

Top - Accelerator arm
Second - Engine ground
Third - Chassis to bird cage
Last two are for the exhaust.

Tom

[Gary B.]

Re: C2 ground straps

Tom, Russ,

Thanks.

Tom, Was your original GM accelerator ground strap much wider that the LIC repro? Like 0.6” vs 3/8”?

It would help some of us if LIC simply listed the lengths of each strap on the paper sheet that comes in the bag. I guess that is too much to expect...

Gary

[Alan D.]

Re: C2 ground straps

Here is a comparison of original (64) and after market (think it's from Paragon)
Note once you make the width of the repop wider, yes it's shorter.

[Gary B.]

[Rick B.]

Re: C2 ground straps

Gary, im checking my inventory, and on the cars will report back. In the meantime could you reference the post discussing the 0.6 width.

thanks R

[Gary B.]

Re: C2 ground straps

Rick,

Here’s the posting that mentions the 0.6” width.

https://www.forums.ncrs.org/showthre...471#post597471

Note that John DeGregory agreed on the 0.6” width.

Also note that the 4.3” center to center length that Jeff mentions is from another posting, which as I said might not be the length correct, since 4.3” is exactly what the exhaust ground strap c-to-c length is.

Gary

[Alan D.]

Re: C2 ground straps

"Also note NO star washer at accelerator lever, AIM and Shop Manuals clearly show that"
No I do not have an original, naturally if you have a 0.5" - just push on ends it becomes 0.6"

[Tom E.]

Re: C2 ground straps

Tom, Russ,

Thanks.

Tom, Was your original GM accelerator ground strap much wider that the LIC repro?

[Gary B.]

[Rick B.]

Re: C2 ground straps

Gary, As I think your implying, this .6 is just not making sense to me. I have measured the accelerator ground straps on the survivor cars and the bowtie, that one was broken at the manifold, as well as organized my inventory, measured each, cross referenced with the Nolan adams specs stated in vol 2, examined my own library, read the link you provided, including finding where John Hinkley weighed in on the measurement (believed he used Nolans) and NOT a single one is .60. They are all ranging from 5/16-3/8-7/16 .30-.40. Huge difference to get to .60 and I just doubt that .60 is typical. I do caveat though that all my straps on both application are severely aged and Im sure there was shrinkage, being twisted etc. In fact that measurement range seems to be the same for original Engine mount straps I have. I believe the length is the difference (which is another debate. Perhaps there are specs stated in the parts books. I have not gotten there yet. AS a side note I am often seeing that .60 strap on restored cars.

Just a focus group of one. What do you think?

[Gary B.]

Re: C2 ground straps

Rick,

Thanks for checking. Unlike you, I have no original examples or access to Bowtie cars to check. My only thought is what I said above. Braided copper is readily available in larger widths than what LIC uses in their repro strap kit. For the most part, I think LIC does a decent job at getting these things right, so I tend to think their accelerator strap is the width that GM spec’ed. I know that amounts to a big wish. I believe there are examples of LIC paying GM a repro license fee to have access to GM engineering drawings when making repro parts. I’d like to think their accelerator strap is accurate based on what LIC has seen from GM.

Gary

[Rick B.]

Re: C2 ground straps

Gary/guys maybe I missed it. What is the current width of the LI versions? Are they indeed the .60? or the 3/8?

[Gary B.]