A Peek Inside The Lycoming Factory
What happens to your engine when Lycoming overhauls it
By Greg Napert
April 1999
After decades of producing aircraft engines for everything from military war efforts to recreational aircraft and business aircraft — through industry good times and bad — the Lycoming aircraft engine factory is in the process of being renovated into a modern facility with a more streamlined production process.
The company has undergone many piecemeal changes in the past, but none has been more comprehensive and has brought the factory closer to a modern manufacturing facility than those being made today. The uneven, hand-poured floors, and generally drab gray overcast of this once heavy industrial facility, reminiscent of an era long gone, makes modernizing the facility challenging at best.
But AMT's interest in visiting the new Textron Lycoming facility was not to evaluate the real estate. Instead, we were more interested in taking a look at the significant changes that have taken place over the last decade or so — namely, a shift away from manufacturing, to that of an assembly plant.
As one who has visited in the past, the shift is noticeable upon entering the plant. Once ringing with the sound of machinery, milling and manufacturing equipment, it is now a relatively quiet environment that includes little more than teardown and assembly operations.
For those that may not be aware, the company now has outside vendors manufacturing close to 99 percent of all parts used in Textron Lycoming engines. There is some manufacturing of select parts at the Lycoming facility, but this is done on a very limited basis.
The evolution of the company over the years to outsourced parts was based on several factors — some that the marketing people are proud to speak of and others that they would rather not go into. Some of these include well-known union labor disputes, as well as tough times in the economy and changes in business philosophy.
According to Paul Lefevre, director of sales and marketing for Textron Lycoming, "There are currently no plans at this time to go back to manufacturing components at the factory. Right now, the only parts we manufacture in the plant are connecting rods, however, this will probably change in the future."
For those that think this change in philosophy over the years may not bode well for engine manufacturing quality, Lefevre settles those fears with an interesting statement — "I have never seen better, more precise crankcases and better manufacturing quality on our parts since we started outsourcing. That's no cut to the people that used to be involved manufacturing these parts at our plants, but it's simply because we were using outdated manufacturing equipment. While manufacturing was taking place in our facility, we were still moving parts from station to station to machine them. Today, our vendors are using sophisticated, computer-controlled, 5-axis milling machines that keep the components in one place and perform all of the machining operations with precision that we never had before."
Lefevre explains that outsourcing has afforded the company the ability to look into continuous product improvement as well. This is apparent in the new product introductions and technological offerings suddenly available, which have been noticeably absent over the last 20-plus years. As well, customer service and support are being evaluated and scrutinized in hopes of providing improvements to customers.
Lefevre says, "There are many improvements yet to be made. It's difficult sometimes to explain why certain things were done the way they were at the factory, but you've got to remember that the industry has been through some lean times."
A trip through the factory
To get an idea of the current process involved in overhauling or remanufacturing an engine at Lycoming, AMT was taken on a factory tour for the purpose of following a Lycoming engine through the overhaul process from start to finish.
But, before beginning, keep in mind that Lycoming has basically two different levels of refurbishing that it offers on its engines — an overhaul and a factory remanufacture. It's also important to remember that Lycoming is the only place that can remanufacture its engines. No other overhauler has the ability to return an engine to service with a zero-time logbook. Remanufacturing wipes out the history from the engine and it is essentially treated as new.
The process of rebuild vs. overhaul, however, is nearly the same — the only difference being adherence to new versus overhaul tolerances.
Receiving
When an engine arrives at the factory, it is set in a temporary holding area where it is identified as a core exchange for an overhauled or
remanufactured engine, or as an engine that someone wants back. An inventory of all of the accessories and parts that are attached to the engine is taken and a general evaluation of the reusability of the engine is made.
Lefevre says, "If somebody wants their own engine back, it takes a little longer, but we will overhaul their engine and send it back to them. An exchange engine, however, is usually available in a relatively short time because we forecast the engines we're going to build and typically have an engine available. We have about a dozen engine models that are quite popular and we keep a good supply on hand. If a customer wants their own engine, however, it has to go through the entire overhaul cycle so it will take a bit longer — typically we're looking at four to six weeks."
Because of the extent of parts which are discarded and replaced with new as a matter of practice, however, a customer has to understand that they are only essentially getting their crankshaft, camshaft, and crankcase back. Everything else is replaced with new or overhauled components.
Whether an engine belongs to a customer or is in the exchange pool, the magnetos are almost always thrown away and replaced with new. "There are some exceptions," Lefevre says. "We were overhauling the dual mags at one time, but we recently decided to go to all-new to eliminate some of the problems we were having with the overhauls. Slick doesn't overhaul the mags so we were already replacing the Slick mags with new. Bendix single mags are overhauled if the customer desires to continue using them," says Lefevre.
Our engines are certified with fuel systems and ignition systems because essentially it can't run without them. Returned engine cores must include all of the components needed to run the engine. The engine is certified with the magnetos and we can't ship the engine without the magnetos. So, if a client keeps their accessories, they will be charged for any missing component.
One unique feature of Lycoming overhauls and remanufactured engines is cylinder assemblies, which include the cylinder, piston, rings, piston pins, etc., are replaced with all new parts, in all cases.
Also, according to Lefevre, "It is cheaper, in many cases today to buy new components than to overhaul the old ones. For instance, we used to overhaul intake pipes and now we buy new — it's not worth it anymore because it's cheaper to buy new."
Teardown
Once the engines are logged in and torn down, they proceed to a collecting area where they are pieced out. The parts that are repairable are placed into a holding area for inspection and rework, and the parts that are not repairable are thrown away.
"At this point, we also pull all of the cylinder components, including the barrels and heads and throw them into a scrap pile regardless of their condition. We also scrap all hardware (to include case bolts), valve covers, gaskets, valve springs, harnesses, pushrods and tubes, etc. We really don't reuse anything except for major components (crankshaft, camshaft, engine cases, and connecting rods)," he explains.
At a point in the inspection process, the parts are separated depending on the tolerances they meet. If they are within new tolerances, for instance, they will be used for remanufacture instead of overhaul.
However, Lefevre explains, "Because of the condition of the case in most instances, we actually use brand new engine cases in about 90 percent of our remanufactured engines. Most people may not realize it, but a remanufactured engine is very close to being an all new engines."
All of the engine accessories (alternators, mags, etc.) are boxed and returned to the respective manufacturer for core credit. In some cases, the manufacturer will actually trash the old accessory (as in the case of Slick magnetos) and in some cases they use certain parts for overhauls.
"The parts that we save go through a cleaning process, then into a nondestructive testing area to insure it is useable again," says Lefevre.
Preparation for the line
While the used components are being inspected, repaired, and prepared, new cylinder assemblies are assembled and new incoming hardware and
other components are inspected.
All of these components are assembled at one point onto a build cart (containing all parts necessary for building the engine) which travels down the assembly line along side a crankshaft and crankcase. There are essentially two lines, one for remanufactured and one for overhauls.
On the line
As the engine travels down the line, all necessary adjustments and final inspections are conducted, magnetos are timed, accessories are added,
the engine is cleaned and painted, and it is prepared for the test cell. In the test cell, all engines are tested to the same specs. The overhauled engines have to meet the same specs as new engines. If it doesn't (due to a fuel problem, or misadjustment) the engine is fixed to meet specifications or it returns to the line for teardown to determine why it doesn't meet the specification. Depending on the engine, the test cell procedure can take anywhere from 1 1/2 hours to 5 hours, depending on the size and complexity of the engine and any problems that might be experienced.
Although the engine is configured in its certified condition, Lycoming uses slave starters on the engines to prevent wear and tear to the new starter assemblies. Lefevre says, "Starting a new engine can really wear a starter down, so we don't want to degrade its performance in the test cell."
After the test cell run, the oil filter is removed and cut open to inspect for metal particles.
Lycoming also has a quality control department which tears down every 20th engine off the new engine line, and a random engine off of the overhauled line. They look for wear, interference, etc., in particular areas to insure that the machining manufacturing processes are being done correctly. By checking on every 20th engine, if you find a problem, you've got it isolated to a small family or group of engines.
The engines that are now ready for shipping are then cleaned, finished off with any necessary belts, hardware, etc. that wasn't installed on the assembly line, and treated with a preservative oil. Any scratches or blemishes in the paint are touched up and final lockwiring is done, then the engine is mounted and installed on a pallet.
"We never ship the engine with the carburetors on it because it sits down so far below the engine and could get damaged. The carbs are boxed and shipped in separate containers within the pallet," he explains.
Lefevre says right now, the factory is producing around 12 to 15 overhauls and around 8 new engines per day — but that' s just the industry demand right now — Lycoming actually has a much higher capacity than that. In fact, Lefevre says, "With the current improvements in workflow and factory upgrades, the company could easily add an additional 1,000 engines a year without an increase in manpower.
"An individual engine actually travels down the line for assembly and testing in around two days. But including all inspections and rework, I would say that our average delivery of an engine ranges from 12 to 15 working days."
