Without the manuals it's easy to mess up things you're working on. I have both the service and parts manuals to help get things right.
I have a tube of magneto grease so while I had the mags off I repacked the bearings. The grease in them was certainly over 40 years old.
On my Cabin WACO the 240 HP Continental motor had a distributor ignition system on one side which was notorious for the point gap being wrong. Shortly after acquiring the plane the points weren't opening on a couple cam lobes. Rather than set them with a feeler gauge, which had been done every 50 hours since 1941, I made a fixture to hold my wife's dial indicator. There were 7 lobes on the cam so it was easy with the dial indicator to adjust the points so all the lobes were close to spec. It worked great and when I sold the plane 350 hours later the points were still working fine.
I used the same idea to mount the dial indicator on the Eisemann magneto housing. The 2 screws pick up the cover mounting holes the little hole beside the one screw is clearance for the dowel pin. The mounting rod for the indicator is a 1/4" bolt with the head cut off.
The ball end of the indicator is riding on the center of the rivet end of the movable contact point.
Just zero the indicator at the bottom of the cam and rotate the shaft to the high spot on the cam lobe. The gap should be between 0.018" and 0.022", it was at 0.015".
The 2 outer screws are the mounting screws, which must be loosened to adjust the gap. The middle screw is a small, very sensitive, cam. I don't know how you would ever get this right with feeler gauges. The screw cam was incredibly sensitive. After about a dozen tries I got there with both lobes right near the middle of the spec., same on the other mag.
I also replaced the condenser in each mag with new ones from Fresno Air Parts.
I had 2 other Eisemann LA-4 mags I hoped I could just install. They worked great. One small problem they had the wrong impulse on them. They must be off an engine where the mags turn counter clockwise. The coupling also wouldn't fit my gear. Probably so you couldn't put them on the wrong engine. The pin which operates the impulse is also on the wrong side to just swap the coupling. Oh Well, they provided parts and lots of learning.
In order to grease the bearings you have to remove the gear which drives the rotor. With the rotor in the cylinder 1 firing position there are timing marks on the gears.
I needed some way to tell if the coil and points were working without installing all the covers and spark plug leads. I clamped a little piece of copper so the spark could jump the gap, showing me it was working. The originally dead mag would not do this at all. The small gap worked with my mag without an impulse coupling. With the impulse the mag would easily jump the big gap.
The mags are back together, working, and ready to reinstall on the motor.
