As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRECAUTIONARY LANDING MADE DUE TO POWER LOSS AND FLUCTUATING OIL PRESSURE. ENGINE WOULD MAINTAIN 1,800 RPM, AT FULL THROTTLE. NR 3 CYLINDER EXHAUST VALVE FAILED JUST ABOVE HEAD/STEM RADIUS. SECONDARY CYLINDER AND PISTON DAMAGE REMNENTS OF VALVE FOUND IN MUFFLER. STEM REMAINED FROZEN IN VALVE GUIDE. RECOMMENDATIONS: LYC SI 1425. SL L197.