Cessna 120-140 Association

Is the cam slipping on the shaft?

Is the wicking for cam lubrication ok - finger nail test - OH shop would have checked. Is the Time Rite the one with the mechanical arm and sliding scale - I have one if that's it but I quit using it years ago. I use a digital with a similar name IIRC. Rubbing block on points worn down, again, shop should have caught but that would cause limitation to point adjustment. Since you had problem with cam, possibly change cam and new points. Obviously, if you have been operating since 2014 until now with normal operation, mag drop, etc. something has slipped or worn. How many hours on mag since OH?

Update from the mag shop:

The cam wasn't soaked in an oil bath during previous overhaul and was causing premature cam follower wear. The tech also noted several "new", but obsolete parts used during the overhaul. Sending both for inspection/repair.

Silas