HOME and how to join Forum Open Area General Scott topics 3 Speed Super spark plugs Reply To: 3 Speed Super spark plugs


Hi Keith

Neat job to shorten the insulator without cracking the whole thing! Watch out for overheating although because of the diminished surface area. But according to a one of my old books AC 87 could be a bit softer than Champion D21. Say could, as different old lists translate heat ranges differently. I did rummage through my little stock of NOS plugs as I remembered that I have a pair of AC’s. Unfortunately they turned out to be AC 84 wich is three steps cooler, so to say.

I suppose that you have a radiator with neck, otherwise with a tunnel radiator it’s possible to raise the radiator. This by making an offset upper bracket and substitute the lower screw with a rubber cushion that the radiator rests on. By doing this I even got place for proper plug caps.

By the way, I don’t think there are any other plugs shorter than the the AC ones. Can’t remember seeing any.

Best regards and good luck!