Owners buying engine overhauls have more or less adjusted to the idea that cylinders, cams and crankshafts have become a crap shoot. But valve lifters, too? These got added to the list of problem parts last fall when TCM announced that a massive batch of faulty lifters made it into the supply chain. Some showed failure wear in as little as five hours of operation. Although only engines built after June 19th, 2009, appear affected, the sudden demand has disrupted the supply chain for lifters to the extent that the industry-and the FAA-are relenting on the standard recommendation that lifters be replaced. Further, the market for overhauled lifters has become red hot and, at least we’ll into 2010, they may be hard to come by. Only owners who had engines built after the June date need be concerned about bad lifters and not all of them may be affected. The problem centers on tappet bodies with part numbers of 657913, 657915 or 657916, whether purchased individually or in a parts kit. (See special airworthiness information bulletin NE-10-09 and Airworthiness Directive 2009-24-52.) Engines affected are TCM O-360, O-470, O-520 and O-550 models. An estimated 600 aircraft are currently grounded. If these engines were overhauled or had the tappet bodies replaced since the June date, the airplane is grounded until the parts are replaced. Fallout from this AD is being felt throughout the industry. In a nutshell, TCM has no means of providing replacement parts for a few months, at least, although it shipped some emergency overhauled lifter bodies obtained from Aircraft Specialties Services, Inc., in Tulsa. TCM negotiated a waiver from the FAA to use “reclaimed” lifters as replacements in new and rebuilt engines. 
TCMs Lifter Crisis: Reclaimed Parts Rule
Owners buying engine overhauls have more or less adjusted to the idea that cylinders, cams and crankshafts have become a crap shoot. But valve lifters, too? These got added to the list of problem parts last fall when TCM announced that a massive batch of faulty lifters made it into the supply chain. Some showed failure wear in as little as five hours of operation. Although only engines built after June 19th, 2009, appear affected, the sudden demand has disrupted the supply chain for lifters to the extent that the industry-and the FAA-are relenting on the standard recommendation that lifters be replaced. Further, the market for overhauled lifters has become red hot and, at least we'll into 2010, they may be hard to come by. Only owners who had engines built after the June date need be concerned about bad lifters and not all of them may be affected.