As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CYLINDER SHOWED LOW COMPRESSION. DETAILED INSPECTION REVEALED CRACK IN EXHAUST VALVE AREA ON HEAD NEAR VALVE EXHAUST PORT. CYLINDER WAS PREVIOUSLY WELDED IN THIS AREA. CYLINDER SCRAPPED. EXCHANGE UNIT INSTALLED. NO WAY OF KNOWING TIME SINCE NEW ON THIS CYLINDER. CYLINDER CHROME PLATED. SUBMITTER SUGGESTS RETIREMENT LIFE BE ESTABLISHED ON CYLINDERS AND TIMES TRACKED AND DATA PLATES INSTALLED.