What was found
REMOVED AND REPLACED RH MAGNETO DUE TO 500 HOUR OVERHAUL LIMIT. NEW MAGNETO INSTALLED FOR 78.2 HOURS BEFORE A FLIGHT WAS CANCELLED DUE TO EXCESSIVE VIBRATION AND HIGH MAG DROP ON RH SIDE AT PRE-RUN. ATTEMPTED TO TIME RH MAGNETO TO ENGINE. POINTS APPEARED TO OPEN INCONSISTENTLY AND ERRATICALLY ON TIMING LIGHT WHEN PROPELLER ROTATED. REMOVED MAGNETO AND HEARD A CLUNKING INSIDE. DISASSEMBLED CASE AND FOUND ONE COIL RETAINING PIN BROKEN OFF AND FLOATING AROUND INSIDE MAGNETO. ALSO, FOUND BEARING BLOCK LOOSE IN THE CASE HALF, WITH PHYSICAL PLAY NOTED. POINTS ATTACH TO THIS BLOCK, SO THIS LIKELY CAUSED THE ERRATIC OPENING OF POINTS. WAS MADE AWARE BY "SHRIKE AERO" THAT THESE BEARING BLOCKS ARE PRESS-FIT AND SHOULD NOT HAVE PLAY IN THE CASE HALF. MAGNETO WAS OVERHAULED BY QAA, PURCHASED THROUGH AIRCRAFT SPRUCE. INTEND TO RETURN MAGNETO FOR WARRANTY PROCESS THROUGH AIRCRAFT SPRUCE.