As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AN IRAN INSPECTION, IT WAS NOTICED THAT THE AMOUNT OF VALVE SHOWING ABOVE THE KEEPER WAS LESS ON ONE CYINDER THAN ON THE OTHERS. UPON DISASSEMBLY IT WAS FOUND THAT #3 CYLINDER EXHAUST VALVE WAS 1/16TH INCH SHORTER THAN THE OTHER VALVES. A SLIGHT MUSHROOMING LIP WAS ABLE TO BE FELT AROUND THE TOP OF THE VALVE. IT APPEARS THAT THIS IS THE SAME TYPE OF WEAR AS INDICATED IN CSB98-1B ON CONTINENTAL VALVES.