I will (soon) be posting that I have painted my engine frames, picture frame, and bonnet support frame. Looking just a little bit down the road, it will be time to assemble these pieces to the car. Thinking about this, I realized that I needed to get my ducks in a row regarding subframe bolting. As in, what color are they?
The simple answer seemed to be “refer to the JCNA Authenticity Guide.” What does it have to say? It’s pretty straightforward.
Bees, GKN, RO, Cranes, Richards, or Ruby Owen – black oxide or cadmium on late 4.2. Cadmium (see footnote A) plated nylock nuts.
Although the original Jaguar production line photos such as Porter pages 163, 167, 249, 379 all show unpainted subframe bolts, from surviving original cars we know that some were painted.
If I stop right there, my approach is clear. Black oxide subframe bolts from one of the manufacturers listed. But of course, it’s never that easy. I have accrued a collection of original bolts. This fall, I bead blasted them and sent them to be plated. I had them zinc plated with a clear trivalent conversion coating at a firm in Gastonia, NC Industrial Electroplating.
Your first question may be, why not black oxide. The simple answer is that at the time, I had not researched the issue enough to know I needed black oxide. And my mind was in a mode of silver cadmium based on what I was used to seeing on my 67 2+2. Your second question might be, why zinc, versus the “more authentic” cadmium? In this case, my “save the planet’ instinct kicked in. Cadmium is listed by the EPA as a cancer causing agent. I decided to forgoe any additional introduction of this toxic metal into the world. And frankly, because of this issue, it is getting harder to find platers that will deal with cadmium. Not impossible mind you, just harder.
I reviewed Industrial Electroplating’s website and noted that they will “topcoat” their zinc with clear, yellow, blue, green, or black. Wow! I called them up and they said send the clear zinc bolts back. They can easily replate them with the black finish. It is not technically black oxide. Rather, it is a more robust anti-corrosion coating. Sounded good to me. By the way, if you refer to my article about “blackening” items in my tool roll for my 2+2, you will see how a black oxide “dip” from Caswell Plating worked out for me.
My next step was to pick out the bolts that I needed to send back to the platers. That task was made infinitely easier by reference to an excellent article posted years ago Steve Kemp regarding all things bolting related for the subframes. Based on Steve’s list of required bolting, I was able to find the necessary diameters and lengths in my stash of bolts.
An important originality issue was the head markings on the bolts. Steve’s article, Dr. Thomas Haddocks book Jaguar E-Type 6 & 12 Cylinder Restoration Guide, and the UK Etype Originality Forum were all helpful. It turned out I had a mixture of BEES, GKN, and Rubery-Owen fasteners in my selection. FYI I think “Ruby Owen” in the JCNA document is a typo. Most articles on this subject agree that that there is no definitive rule on what suppliers bolts would go on a particular car. In my case, I was able to utilize period correct fasteners for all but 1 or 2 of the bolts I required. I also have a good supply of the correct “taller” nylon insert nuts, which had been sent to Industrial Electroplating for silver zinc plating. Here is a picture of the bolts I used laid next to the applicable picture in Haddock’s book. The ones on the top are the Rubery-Owens, which aren’t discusssed in Haddock but are discussed on the UK forum.