Arthur1958
Junior Member
I have a question about armored ignition switches.
My generic switch (no armor) broke, but I had three armored switches among my spare parts. Each is the common replacement version, like the 1931 Electrolock but without the pop-out feature. I checked their continuity and all tested fine. Installed, each displayed an intermittent ground fault. No surprise, each had at its core an asphalt & cotton insulated wire more than half a century old.
I took one apart. Indeed the wire was frayed, so I replaced it, from switch contact to cable end plunger. When installed the distributor grounded out. This is an OEM distributor with OEM points and condenser.
While checking whether the cable end might be screwed in too far, the armored conduit (the big spring) pulled out of the cable end assembly, but the wire remained. Suddenly, everything worked! Put the conduit back in the cable end and it grounds out; pull the conduit out, even if it still touches the cable end, and everything works.
But why? Of course, the outer part of the cable end and the conduit are always grounded. The cable end is screwed into the distributor body and the conduit is screwed into the switch body, as well as passing through the tunnel under the fuel tank (it has a grommet, so doesn’t touch anything in the junction box) but both are insolated from the internal wire, and neither grounds out the points and condenser independently, only when screwed back together. That should make no difference.
Has anyone else experience this? Do you know why?
My generic switch (no armor) broke, but I had three armored switches among my spare parts. Each is the common replacement version, like the 1931 Electrolock but without the pop-out feature. I checked their continuity and all tested fine. Installed, each displayed an intermittent ground fault. No surprise, each had at its core an asphalt & cotton insulated wire more than half a century old.
I took one apart. Indeed the wire was frayed, so I replaced it, from switch contact to cable end plunger. When installed the distributor grounded out. This is an OEM distributor with OEM points and condenser.
While checking whether the cable end might be screwed in too far, the armored conduit (the big spring) pulled out of the cable end assembly, but the wire remained. Suddenly, everything worked! Put the conduit back in the cable end and it grounds out; pull the conduit out, even if it still touches the cable end, and everything works.
But why? Of course, the outer part of the cable end and the conduit are always grounded. The cable end is screwed into the distributor body and the conduit is screwed into the switch body, as well as passing through the tunnel under the fuel tank (it has a grommet, so doesn’t touch anything in the junction box) but both are insolated from the internal wire, and neither grounds out the points and condenser independently, only when screwed back together. That should make no difference.
Has anyone else experience this? Do you know why?
