Service Instruction No. 1558

DATE: March 21, 2014

MODELS AFFECTED

Lycoming engine models in Table 1.

TIME OF COMPLIANCE

As required for replacement.

This Service Instruction identifies new piston ring part numbers that are alternates to the existing piston ring part numbers. All of the alternate piston rings have been manufactured to be equivalent to the existing piston ring part numbers shown in Table 1. Each new piston ring is interchangeable with its equivalent existing piston ring. The existing piston rings and the alternate piston rings can be mixed in the same engine but use all the new rings with one cylinder and piston or all the old rings with one cylinder and piston.