I noticed recently that the braided earth lead in the distributor was looking very wispy, as if it might break at any moment, and managed to find an ad on eBay selling earth leads for all 45 distributors. It's cheap and the right length, with an eye terminal on each end, but it's not braided. At least I don't think so, but it's plastic covered and looks and bends exactly like an ordinary bit of wire.
Anyway, I fitted it, giving it a loop that can coil/uncoil as the olate advances, which I checked by sucking. Then I noticed that the main input wire from the coil to the points terminal isn't braided either. Obviously it can't be, because it's a continuous piece of wire from the terminal, through the rubber grommet in the distributor, and on to the coil. So exactly the same conditions apply as for the earth.
Why the fuss about needing a braided wire on one but not the other ?
The car runs perfectly and idles nicely, and it's now got a good earth wire and an old spare just in case.
I tested the advance by pulling the pipe off the carburetor while idling, and it made no difference. I checked the pin-hole and it felt clear when I poked a paperclip down it, but on sucking the pipe found it was blocked, about an inch down the hole. I dug out a packed wadge of hard soot, and finally got an air passage, but on connecting up found that the engine ran much better as it had been before. The pipe has been doing absolutely nothing for several years.
Is there any point in now re-tuning to try to make it run smoothly again, or should I just block up the vacuum connection and keep it as it was? (It's a 2500S engine with HS6 carbs)