Service Instruction No. 1267 D

Piston Pin Plug Usage


Supersedes Service Instruction No. 1267C

August 28, 2009


All Lycoming engines with 5-1/8 inch cylinder bore: O-320; IO-320; O-340; O, IO, HO, LO, LIO, AIO, HIO, TIO, VO and IVO-360; IO-390; GO, VO and TVO-435; GO, GSO, IGSO-480; O, IO, VO, TIO, TVO, TIVO and IGSO- 540; TIO and TIGO-541; IO-580, AEIO-580; IO-720.


Any time piston pin plugs are replaced.

There are three different piston pin plugs currently used in the above mentioned models of Lycoming aircraft engines. While the various piston pin plugs fit interchangeably, the instructions listed below must be followed any time plugs are replaced.

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