|The MGA With An Attitude
STARTER SWITCHES, Original Quality - SS-106
After 57 years and 450,000 miles my original starter switch finally had a lost contact problem. So I opened it up for investigation, and I was pleasantly surprised about the good quality of original construction. The rubber grommet insulators were still firm and pliable. The embossed center hole in the steel back pate guiding the pull shaft was NOT worn oversize. The internal structural housing was solid Bakelite (phenolic), and all of the contact parts and terminal posts were solid copper. The final failure was dirt on the copper contact plates interfering with good electrical connection. This surprised me a bit as I always figured the copper plates were self-cleaning due to high current arcing with every connection.
Digging deeper I found the threaded tubular mounting collar was very firmly staked in place, so after more than 50 years it is still solid. A modern replacement part had this collar somewhat loose, so it was turning when tightening the mounting nut with a wrench during first installation. The internal contacts were attached to the phenolic part with good solid rivets, and the terminal posts were solid as a rock and could not be budged with force.
After drilling out the rivets I found the posts were locked in place with rectangular holes and keys as we as being firmly staked in place. This is in stark contrast to a modern replacement part where the posts could rotate while tightening the terminal nuts.
Upon disassembling the pull shaft and moving contact plate I found a key feature of the long life. The center isolating insulator was a solid phenolic grommet that was obviously molded in place in the center of the heavy copper washer. This is s a feature I have never seen in any of the modern replacement parts.
All in all I was very satisfied with the solid construction of this OEM part. If the modern replacement part will ever fail, I would be looking for a good used original part for next replacement.