As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LYCOMING PISTON PIN PLUG PART NUMBER 72198---IMPROPER MACHINING.--- SIX PISTON PIN PLUGS HAD TO BE MEASURED UNTIL WE FOUND ONLY TWO THAT WERE WITHIN THE LYCOMING TABLE OF LIMITS SOME WERE TRUNCATED--- IE BIGGER AT ONE END THAN THE OTHER