Engines

Thielart and SMA aero diesels may have dazzling economy but the question of durability has yet to be answered.

Aviation Consumers trusty Mooney ends its days in a swamp after an engine failure. And no one knows why.

If there’s a failsafe way to buy an engine overhaul that will absolutely, positively make it to TBO without so much as a snort, we havent unearthed the formula.

Although the majority of engines probably do make TBO with little more than oil changes and a couple of sets of spark plugs, many engines roll over long before that. And even reputable shops with years in the business turn out the occasional lemon engine that starts making metal 50 hours after it leaves the shop.

Thats what warranties are for. Savvy buyers realize that a shops reputation for standing behind its work matters as much, if not more, than the quality of the overhaul itself. Since the factories bullied their way…

Permit me a war story: During the summer months, the air around New Braunfels, Texas is as thick as concrete. At the airport, the ramp temperatures begin to soar at first light and pitchers of iced tea are downed for breakfast.

Id flown there on a warranty trip put together in a hurry. Inadvertently, the wrong ring set was installed in all 12 cylinders attached to a very nice, but older Cessna 310. While it was in for maintenance, the cylinders were to be pulled and the rings replaced before anyone got wise to the error.

The job took about eight hours longer than normal because the heat slowed everything down to a crawl. During one of the many iced tea breaks, a wiry man with an…

When aircraft owners, brokers and mechanics talk about engines, the word bulletproof comes up occasionally. We don’t have a precise definition but we know what it means: An engine relatively free of operating foibles and likely to make TBO without undue strain.

On the other hand, no single adjective seems to describe the opposite end of the spectrum: Dog comes to mind, but when applied to some engines, its an insult to every canine that ever lived.

How ever you describe them, the world of aircraft engines is defined by extremes: The good is very good, the bad is usually unspeakable and often enough to cause the owner to take up boating or golf instead of flying. Fortunately fo…

[IMGCAP(1)]Among all the uncertainties when overhauling an engine, you can count on one thing: A bad case of buyers remorse if you make the wrong choice.

Judging by our reader mail and interviews, a surprising number of owners do make the wrong choice or at least they select a shop or engine source that theyre not entirely pleased with two years later. Even when the engine performs as expected, there are sometimes intangibles that lead the buyer to another shop next time. Its not often, however, that you can compare two of the same engines side-by-side, but provided by two overhaul sources. Yet thats exactly the opportunity we had in the spring of 1996. The 1100-hour Lycoming IO-360…

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When light aircraft production took its final serious nosedive in the mid-1980s, the die was cast for engine overhaul shops and for Lycoming and Continental. Until then, the two engine makers had been happy building motors for new airplanes.

The Great Downturn changed the rules. With only a trickle of new airframes coming into the market, Lycoming and Continental sought new business from the only source available: Overhaul work.

This has proven a mixed blessing for aircraft owners. It has brought unprecedented competition to the overhaul market, putting downward pressure on prices, especially for new cylinders.

On the other hand, factory competition has driven many f…