I'm doing some re-wiring work and have a question about the black metal cable that runs from the coil to the ignition. There is a stranded wire that runs down the center of this flexible metal cable. Is that wire supposed to be shielded? The one I have comes out of this outer cable bare and it seems to be electrically connected(shorted) to the outer metal case. Is this normal because it seems kind of strange to run a bare wire down a metal tube. The whole thing would be a conductor. I was wondering if there was originally some kind of insulator between the stranded center wire and the outer cable and that it has disintegrated over time.