Dust or some form of dirt is frequently the principal factor in premature piston ring, ring groove and cylinder wear. If a worn or poorly fit air filter allows as much as a tablespoon of abrasive dirt material into the cylinders, it will cause wear to the extent that an overhaul will be required. Evidence of dust or other dirt material in the induction system beyond the air filter is indicative of...

There are two basic types of FAA-approved aviation oils used in general aviation aircraft piston engines. 1. Straight mineral 2. Ashless dispersant (AD) Many Lycoming engines use straight mineral oil for “break-in” purposes with a new, rebuilt or overhauled engine. The operators should then switch to AD oil after “break-in” has been accomplished. In those engines that use straight mineral oil...

It has often been said that regular doses of clean, fresh oil provide the least expensive maintenance an owner can give an engine. Lycoming Service Bulletin No. 480 makes these specific recommendations for oil changes under normal operating conditions: A. 50-hour interval oil change and filter replacement for all engines using a full-flow oil filtration system. B. 25-hour interval oil change and...

Many of the aircraft engines produced today are equipped with fullflow, spin-on oil filters. For long engine life, it is necessary to change both the oil and the filter at regular intervals. The information we receive indicates that problems are sometimes encountered because proper procedures are not followed when changing the spin-on filter. Therefore, it is appropriate to provide a few tips from...

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...