Service Instruction No. 1485 A
Exhaust Valve and Guide Identification Procedure
Supersedes Service Instruction No. 1485
July 2, 2003
All Lycoming reciprocating aircraft engines unless installed in a rotary-wing aircraft.
TIME OF COMPLIANCE
Half way to recommended TBO or at 1000 hours of operation, whichever occurs first or earlier at owner’s discretion or anytime valve sticking is suspected.
As a product improvement, Lycoming has introduced a new exhaust valve guide material with an increased chrome content for improved wear characteristics. The incorporation of this guide material has significantly reduced the amount of valve guide wear (bell-mouthing) seen by some operators of Lycoming engines.
Get It Exchanged
Use our Engine Exchange Program to order a new, rebuilt, or overhauled engine to experience more airtime and less downtime.