Re: AMC 360 timing issues
That is a strange one for sure.
I wonder if the breaker plate - the plate the pick-up coil is mounted on - is loose? As I remember, the clearance between the PU coil's metal core and the reluctor is normally about .008".
Normally the plate rotates as the diaphram's arm moves it. Could be it's pulling the PU too far away from the reluctor?
You should see that by looking and using the Mity-Vac.
The plate's mounted on a flimsey bushing arrangement, could be worn or the clip's come off.
If not - then you might want to measure ohms from the PU as you move it like that. Could it be losing connection?
And - the ground tang - loose? The ground tang in the rubber feed through has to ground on the housing, not the plate. Or cut the black wire off and run it to a decent ground engine elsewhere.
Let us know what you find - interesting.