72 BB spark plug ground wire attachment

[Hank H.]

I understand that the valve cover bolts at the loacations securing the spark plug ground wires to the valve cover were not painted. My question is about the triangular retainers. Were they used at the ground wire attachment locations, and if so, were they painted?

[Terry M.]

Re: 72 BB spark plug ground wire attachment

Yes the triangular retainers were used at the locations with the spark plug braid ground straps. Most would not have been painted, but we have seen some very original cars with an occasional painted retainer at the ground position.

I am told what happened was Tonawanda installed all seven fasteners, with retainers on each rocker arm cover, and then painted the engine assembly. ALL fasteners and the exposed portions of the retainers would have been painted. At St. Louis the fasteners that received the ground details (generally two per rocker arm cover) were removed and discarded. A slightly longer fastener was installed to accommodate the thickness of the ground details. In most cases when the original fastener was removed the triangular retainer fell off, and a new one was installed. In some cases the paint held the original retainer in place, and I suppose it is possible that some of the fallen retainers might have been retrieved and reused -- but I have never seen evidence of that.

This process often results in different head marks on ten of the rocker arm fasteners. The four installed at St. Louis usually are different on original Mark IV engines.

[Hank H.]

Re: 72 BB spark plug ground wire attachment

Thanks Terry, I will remove paint from the retainers at those locations with ground wires.

[Terry M.]

Re: 72 BB spark plug ground wire attachment

I expect the need for a good connection to ground may have driven the retainer replacement, as much as assembly line convenience.

[Sal C.]

Re: 72 BB spark plug ground wire attachment

Terry,
Remember the very low milage 454 we "Survivor" judged at Bloomington that had the original painted bolts laying in the recesses of the intake? That was pretty cool!

[Terry M.]

Re: 72 BB spark plug ground wire attachment

Terry,
Remember the very low milage 454 we "Survivor" judged at Bloomington that had the original painted bolts laying in the recesses of the intake? That was pretty cool!

Thanks for the memories. I had forgotten that one. That, and the spare tire with the yellow chalk writing on it that I can't repeat here. You know some of us are pretty lucky, or we work hard. That is work, isn't it??

[John H.]

Re: 72 BB spark plug ground wire attachment

I am told what happened was Tonawanda installed all seven fasteners, with retainers on each rocker arm cover, and then painted the engine assembly. ALL fasteners and the exposed portions of the retainers would have been painted. At St. Louis the fasteners that received the ground details (generally two per rocker arm cover) were removed and discarded. A slightly longer fastener was installed to accommodate the thickness of the ground details. In most cases when the original fastener was removed the triangular retainer fell off, and a new one was installed.

Terry -

That's also what the '67 JG says for those four plug wire shield ground attachments (4 new bolts and 4 new retainers), but the Assembly Manual doesn't support it - the A.I.M. only calls out part numbers for new bolts, not new retainers. We'll be reviewing that for possible revision for the 5th Edition.

[Terry M.]

Re: 72 BB spark plug ground wire attachment

Terry -

That's also what the '67 JG says for those four plug wire shield ground attachments (4 new bolts and 4 new retainers), but the Assembly Manual doesn't support it - the A.I.M. only calls out part numbers for new bolts, not new retainers. We'll be reviewing that for possible revision for the 5th Edition.

The 1969 AIM, (the good one that says "Drafting Graphic" at the top) which is the only one I have handy, shows only the bolts also, but has a 4th change listed (handwritten) of "180020 RPO L36 & L71 & L88" Tell me how strange that is. With a 1967 date? I will bring you a xerox copy to the swap meet in a couple of weeks. By then I will have dug out the good 1968 AIM also. You will have to 'splain this to me. because I am The bolts are 180018, so could 180020 be the retainers? some more.

Edit add: When I used to work in the research field, we used to say that a good piece of research generated more questions than answers. Of course we were in the business of making more work for ourselves, so that made sense. Now half a century later, I am not so sure.

[John H.]

Re: 72 BB spark plug ground wire attachment

The 1969 AIM, (the good one that says "Drafting Graphic" at the top) which is the only one I have handy, shows only the bolts also, but has a 4th change listed (handwritten) of "180020 RPO L36 & L71 & L88" Tell me how strange that is. With a 1967 date? I will bring you a xerox copy to the swap meet in a couple of weeks. By then I will have dug out the good 1968 AIM also. You will have to 'splain this to me. because I am The bolts are 180018, so could 180020 be the retainers? some more.

Terry -

The '67 JG also shows the 180018 bolt. Generally, successive increments on threaded fastener part numbers indicates a size (length) change of the same part; Joe L. would know for sure, but I doubt if 180020 is the retainer.