AD 80-14-07

80-14-07 AVCO LYCOMING: Amendment 39-3826. Applies to O-320-H series engines, S/Ns L-101-76 thru L-7608-76, O-360-E series engines, S/Ns L-101-77 thru L-455-77; LO-360-E series engines, S/Ns L-101-72 thru L-451-72 and all remanufactured engines of these models shipped prior to November 16, 1979. Compliance required as indicated, unless already accomplished. To prevent failure of valves due to installation of improperly hardened upper exhaust valve spring seats, accomplish the following: Within the next 25 hours in service after the effective date of this AD remove the valve rocker box covers and visually inspect all upper exhaust valve spring seats for part number identification. (a) If all four upper exhaust valve spring seats are identified as Part Number LW-16475 followed by the letters "KLI", in a curved pattern as shown in Lycoming Service Bulletin No. 447, the engine may be returned to service. (b) If any of the upper exhaust valve spring seats are identified asPart Number LW-16475 without the letters "KLI", they must be removed and replaced with seats marked as described in paragraph (a) above. Installation of these valve spring seats shall be accomplished per instructions in AVCO Lycoming S/B No. 435 or Lycoming Overhaul Manual P/N 60294-9 or an approved alternate. Compliance with paragraph (a) of AD 80-04-03 or AVCO Lycoming S/B 447 dated January 11, 1980, will constitute compliance with the requirements of this AD. Equivalent methods of compliance may be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration (FAA) Eastern Region. Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region may adjust the compliance time specified in this AD. This amendment is effective July 7, 1980.