What was found
DURING A RECENT MFG SYMPOSIUM, THE PROBLEM OF UNAIRWORTHY LIFTERS IN MFG ENGINES DISCUSSED. MFG ENGINE HAVE BEEN NOT HOLDING UP WELL IN THESE AREAS AND MANY SC`S ARE RECOMMENDING AN INSPECTION OF THE LIFERS DURING SCHEDULED MAINTENANCE. THIS AC WAS UNDERGOING AN ANNUAL INSPECTION AND THE OWNERS AGREED TO HAVE THE LIFTERS CHECKED AS THE WARRANTY PERIOD ENDS THIS MONTH. WITH 308.5 HOURS TSN, WE FOUND 3 LIFTERS SPALLED AND PITTED. IT IS MY EXPERIENCE THAT THE CAUSE FOR THIS IS THE USE OF A MULTI-VISCOSITY OIL SINCE NEW. RECOMMEND STRAIGHT WEIGHT OILS ALWAYS ESPECIALLY IN THESE ENGINES. ALSO RECOMMEND 25 HOUR OIL CHANGES REGARDLESS OF THE USAGE OF THE AIRCRAFT. (EA07200501466)