As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT CAME IN TO REPAIR STATION FOR LOW, BUT WITHIN LIMITS, COMPRESSION ON #3 CYLINDER. BORESCOPE ALSO SHOWED EVIDENCE OF OIL ON CYLINDER WALL AND OIL ON SPARK PLUG. CYLINDER # 3 WAS REPLACED. UPON JOB CLEANUP, IT WAS DISCOVERED THAT THE CAPS ON THE OIL PISTON PIN COULD ROTATE. UPON FURTHER INVESTIGATION, THE CAPS COULD BE PULLED AWAY FROM THE SLEEVE AND REVEALED THAT THE INTERNAL SHAFT WAS CRACKED COMPLETELY THROUGH. WILL SUBMIT PICTURES FOR FURTHER REVIEW.