As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXHAUST VALVE INBOARD ROCKER ARM SHAFT BOSS BROKEN OFF CYLINDER ASSY. ROCKER ARM AND SHAFT LIFTED UP CRACKING CYLINDER ON OUTBOARD SIDE WHERE SHAFT PASSES THROUGH CYLINDER. SUBMITTER SUSPECTED DEFECTIVE CASTING AS THERE IS NO EVIDENCE OF PREVIOUS CRACK.