Slick has had its quality control problems for a long time, even before Champion bought them up. I have wondered if they're hiring workers off the street instead of finding people with some technical skills. A lot of this sort of stuff could be avoided if they had inspectors check every mag before it gets closed up.
Cam grease. Too little can mean cam wear, too much and the stuff gets flung into the points and fouls them and the mag quits sparking. Bendix uses a metal cam and nylon cam follower on the points arm, and there's a felt pad held by a small bracket against the cam. A few dops of oil in that felt and the cam is lubricated for a long time and the points don't get fouled.
Some years ago Slick had serious cam wear problems that caused massive retardation in the timing and some mags just quit. In the factory, someone had spilled talcum powder into the bin of plastic pellets used to mold the cams, and that talc get into the plastic and contaminated and weakened it. They should have thrown that bunch of pellets out. I think the talc was used as a mold release, but it sure doesn't belong inside the plastic. Big SB there.
Another time they didn't make sure the high-voltage tab on the coil was perfectly level with the parting face of the mag body, and the little cylindrical carbon brush that takes the spark voltage from that tab to the spark finger on the distributor gear got worn all coke-bottle-shaped and they would fail and the distributor shaft would eat the tab. Sparks and burning distributor parts. No pre-close inspection, obviously. Another big SB.
They had points sets that burned out quickly due to loss of the silver contact faces, or maybe too little thickness to that silver. They had spark fingers coming loose in the distributor gears. They had the impulse stop pins in the mag flange falling out into the engine.
All of this sort of thing makes pilots or owners look sideways at the whole concept of magneto ignition. But these defects are all due to poor QC, not to the concept of magnetos in general. Magnetos have been powering gasoline engines for a very long time and have usually worked well if they were properly designed, assembled, and maintained. My mags on my old A-65 were original to that 1946 engine, and they still work. Mags are robust and able to take the heat and vibration of aircooled engines, while much more sensitive electronics can suffer from those factors, as we have seen with Surefly and E-mag.
A local friend collected antique farm tractors. Almost all of them were gas-powered, most with magneto ignition. He must have had 15 or 20 of these things before he auctioned off most of the collection last year. He called me a year and a half ago as he had trouble with one, no spark. The mag had failed internally. It was from the 1930s or 1940s, probably the original mag. I took it off and took it apart, found the coil was burned out. Well, 80 or 90 years will do that. It had a funny way of feeding the spark voltage from the coil to the distributor of the mag: an external lead ran from the coil to the distributor's center. Handy, since mags like that are scarce as hen's teeth. I got him to buy an automobile ignition coil with an internal ballast, from, let's say, a 1980s Ford. He came back with it and I connected the coil's + to the tractor's 12V system (which had been upgraded from the old 6V), the - went to the condenser terminal used to short the mag to off (and that terminal goes to the points, of course), and stuck the lead from the distributor into the coils HV outlet. Pulled off a sparkplug wire, positioned it an inch away from the engine block, and cranked the engine. Big fat spark. Reconnected the plug and turned on the fuel and started it. Ran like a charm.
