Posted by Tim Stevens on 03/04/2017 21:28:00:
Yes, there were such things as magneto files. They date from the early days of motoring, when the contact-breaker (and not just for magnetos) was faced with platinum. As erosion damaged the surfaces, they could be 'dressed' back to shape using a light hammer and skill, or filed away with the appropriately named tool. As soon as tungsten came into use, the files ceased to be useful for this job, as the tungsten was too hard. But makers carried on using them, and selling them to innocent motorists. Just as they do, still, with small brass brushes 'to clean sparking plugs'. No-one tells the punter that this is not a good idea as modern (post WWII) plugs have hard alumina-ceramic insulators, which can become coated with brass particles – which then short out the HT …
If you can find one that has not been used on tungsten, a magneto file is a handy tool in the workshop. But not on a magneto, please.
Regards, Tim
My 1968 Vauxhall Viva used to transfer material from one contact to the other. After 3000 miles, one would have pointy bit, the other would have a depression. If you left it alone it would develop a misfire. Take them out, grind off the pointy bit on the bench grinder, put them back. After 6000, the depression was a hole, so replace the whole assembly. I tried changing the capacitor, no difference. Parts shops had racks of points, I never understood why manufacturers couldn't agree a standard design. And then we look back with rose tinted glasses. Yes you can't just wade in with modern cars, but they very rareley go wrong in my experience, and I run them to 160,000 miles before even thinking of changing.
Edited By duncan webster on 03/04/2017 23:16:36