FMJ4B3 Magneto Teardown, Cleaning, and Reassembly
J - Fairbanks Morse Model FMJ
4 - Four Cylinder
B - Flange Mount - an A here would designate Base Mount
3 - Originally shipped to Allis Chalmers
It is quite dirty and has been sitting for a long while
The coil had already been removed and the spring on the points was broken
The grease in the bearing is old dirty and stiff
a Spring clip keeps the bearing in place
The bearing cleaned and repacked with grease, a spring clip holds the rotor in place
A washer covers the bearing
A seal is pushed into place
Then a cover washer is staked in place
The cleaned and rewound impulse coupler is back in place with a 30° Lag Angle
The new coil in place and the point gap set
The description of the Safety-Gap just says
It should be wide enought that spark will not jump there if the standard ignition circuit is available.
Yet narrow enough that the spark can jump there if the standard ignition circuit is broken.
The inner and outer cap are cleaned and back in place
The Safety Gap is important to think about when installing a coil
The Bendix Scintilla Magneto builds in the safety gap
When one rotor lug is pointed up at the cap the other is pointed down at a brass plate safety gap
B C RC WC WD all Impulse Spark on the Horizontal Center Line
