Service Bulletin No. 574 A

Cylinder Stud Hole Cross-Threaded

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Supersedes Service Bulletin No. 574

July 20, 2007


Any Lycoming engine model listed in Table 1 that was manufactured, rebuilt, or overhauled between September 7, 2006 and October 18, 2006.

Any cylinder kit listed in Table 2 that was received between September 7, 2006 and October 18, 2006.


At the next maintenance event or within 50 hours of engine operation, whichever occurs first.

Certain cylinders either installed in an engine or received in a cylinder kit listed in Tables 1 and 2 between September 7, 2006 and October 18, 2006 may have a cross-threaded cylinder stud hole. This stud holds the shroud tube retaining components. If the stud is loose due to the cross-threading, the shroud tubes will also become loose and subsequent damage to the engine may occur due to the loss of engine oil.

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