As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THIS ENGINE HAD 3 CYLINDERS OVERHAULED WITH RINGS IN THE FIELD. THE FOURTH WAS REPLACED WITH A COMPLETE CHROME CYLINDER ASSY. AFTER 30 HOURS OF FLIGHT, THE OIL CONSUMPTION AND BLOW-BY BECAME EXCESSIVE. A COMPRESSION TEST SHOWED 20/80 OR THE 3 OVERHAULED AND 68/80 ON THE CHROME CYLINDER. THE RINGS IN THE CHROME CYLINDER APPEARED OK WHILE THE OTHERS SHOWED SEVERE WEAR.