We have firm evidence that engines not flown frequently may not achieve the standard expected overhaul life. Engines that are flown occasionally deteriorate much more rapidly than those that fly consistently. Pilots have asked, “What really happens to an engine when it’s flown only one or two times per month?” An aircraft engine flown this infrequently usually accumulates rust and corrosion...

Paul McBride, a former Lycoming employee widely known as “Mr. Lycoming,” likes to tell the story of the Mooney owner whose preowned Lycoming IO-360-powered single wouldn’t get up to the specified maximum RPM setting of 2700. After an adjustment at a shop, the engine did obtain 2700 RPM on the gauge, but the power plant failed in flight shortly thereafter. After a safe emergency landing, Canadian...

The flow of oil through a Lycoming reciprocating aircraft engine is known to be a necessary function during the operation of the engine. Pilots are often not at all concerned about how this function occurs, as long as the oil pressure and oil temperature indicators show a proper reading. A&P mechanics, on the other hand, often need to know how the system works and what parts control the flow of...

Even the “pros” of our industry admit they need to be reminded from time to time of the basics of General Aviation maintenance. Therefore to review, the term maintenance means the inspection, overhaul, repair, upkeep and preservation of an aircraft and engine, including the replacement of parts, according to the FAA. The owner/operator is responsible for the proper maintenance of his aircraft and...

People who fly should be concerned about the reliability of the aircraft they fly and the engine that powers that aircraft. One key to reliability is regular maintenance by a knowledgeable A & P mechanic. “Knowledgeable” does not necessarily mean the mechanic must have every detail of every job locked in his or her memory. It does mean that the individual should have relevant information readily...

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...