Service Instruction No. 1545 

DATE: October 2, 2012 

MODELS AFFECTED

320/360  series Lycoming  engines with  crankcase  casting  part  number  C11B20061­R Revision M or later and C11B20061­L Revision M or later.

TIME OF COMPLIANCE

As required.

Lycoming four­cylinder 320 and 360 series engine models can have a tight fit at the nose area (Figure 1) in  some airframes. There is not enough clearance between the engine and adjacent airframe components such  as airframe supplied  alternator or air conditioning mounting  brackets. This Service Instruction includes a  procedure to remove crankcase material through burring from the crankcase rib for increased clearance in  the nose for these engines in the impacted airframe applications.