As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED RIGHT ENGINE MANIFOLD PRESSURE DROPPED TO 20". AFTER FULL POWER WAS APPLIED THE RIGHT ENGINE STARTED TO SURGE. MAINTENANCE INSPECTED AND FOUND DAMAGE AND DEBRIS IN THE 1,3 & 5 CYLINDERS, FURTHER INVESTIGATION SHOWED METAL SHAVINGS IN THE OIL SUMP & OIL FILTER. THIS APPEARS TO BE A PRE-IGNITION EVENT IN CYLINDER #3. THE ENGINE IS BEING REPLACED - FURTHER DETAILS AVAILABLE UPON TEARDOWN.