Because the failure to look for metal in the screens and filter, or ignoring what is found, can lead to catastrophic engine failure, we’ll attempt a logical approach to the proper action to be taken when metal shows up in the oil screen or oil-filter cartridge. The lack of printed matter on this subject may be due to the difficulty in adequately describing types and amounts of metal. It’s like...

The latest revision of Lycoming Service Instruction No. 1125 specifies POB No. 4 Perfect Seal and silk thread as the generally used items for sealing crankcase finished parting surfaces that do not employ gaskets. Two other products, RTV-102 or LOCTITE-515 applied as a very thin film without silk thread, may be used as alternate materials for sealing crankcase parting surfaces. Other sealants have...

Hundreds of Lycoming engines leave the factory monthly and are marked with a variety of colors on each cylinder. These colors have a definite meaning and provide valuable information about the engine. Questions concerning these colors and their meanings have been asked by many owners and maintenance personnel. In the past, color coding of cylinders was confined to colored bands around the base of...

A. Preparation for test with engine installed in aircraft NOTE – Refer to the latest revision of Lycoming Service Instruction No. 1014 for the recommended oil to be used for engine break-in on Lycoming engine models. In most cases, turbocharged engines are to use ashless dispersant oil for break-in. Non-turbocharged engines are to use aviation grade mineral oil for break-in. Follow Service...

Break-in of helicoper engines is done by following a sequence of steps ranging from engine service of the engine on the ground to progressively increase its power output during operation. Although this Service Instruction contains detailed information about engine break-in, it is impossible to cover all aspects of break-in for individual helicopter models. For that reason, refer to the POH for a...

As airplanes and engines attain age, there appears to be a need to reemphasize the inspection or replacement of engine hoses or lines carrying fuel, oil or hydraulic fluid. The hose manufacturers definitely recommend regular inspection and replacement of all such hoses at engine overhaul even though they look good. Age limit of rubber-steel or fiber-banded hose has generally been established at...

Little things are sometimes forgotten so a reminder is sometimes necessary. In the case of the Lycoming O-235 engine, it is a little different from most other Lycoming models. Other models are equipped with hydraulic tappets which do not require frequent adjustment. Occasionally, there is a report of an O-235 which is running rough or not producing normal power. Investigation often reveals that...

It’s important to constantly stress the correct cylinder base nut tightening procedure. Operators in the field are occasionally having engine problems and malfunctioning after reinstalling cylinders, and not tightening the cylinder base nuts correctly. The latter tends to cause crankshaft bearing shifting, crankcase fretting or broken cylinder studs, and possible engine failure. Maintenance people...

Reports from operators of fuel-injected engines and from Lycoming service representatives provide some insights into the subject of clogged fuel-injector nozzles. Providing our readers with information from these sources may help some of them recognize and treat a similar problem in their own aircraft. A letter from the owner of a twin-engine aircraft with Lycoming IO- 540 engines indicated that...