My original caps did not fail internally. But had oxidized from age. And due to the high cost of the OEM caps. I replaced them with NGK caps and new copper core wires. NOW-After having ALL my NGK replacement caps fail internally with little mielage on them. Which I posted on another thread. FYI- This will happen to them all. They are junk.
NOW, I am wondering if anyone has found 7mm graphite or other wires with RUBBER caps like older cars use...that fit properly on our small (in automobile terms) spark plugs??? I know we are to have some resistance in the wires or caps....thus graphite type is my 1st thought.