Lycoming Zero-Time Engines Explained: Rebuilt vs. Remanufactured Options
Every single pilot starts in a small piston-engine airplane, the vast majority of which are Cessna 172 Skyhawks. But unless it is the military pilot pipeline, most pilots remain in a piston-powered aircraft for hundreds of hours, transitioning from student pilot to flight instructor, and then often on to commercial flying.
Over half of the piston engines in the air are Lycoming piston engines, with over 325,000 Lycoming piston engines produced. This has created an incredibly robust supply chain for the fleet. Moreover, Lycoming continues to manufacture new engines and certified rebuilt engines, which are available through Greenwood Aerospace via the GSA Advantage website and service.
What is a Zero Time Engine?
There is some confusion about what a zero-time engine is. A zero-time engine is considered to be an engine that has been overhauled to the manufacturer’s standards, with all components replaced or refurbished to meet new tolerances.
The case is essentially an empty shell, and after it is thoroughly tested for wear, it is filled with new parts to create a new engine. The case is costly, so reusing a case while using new parts throughout the rest of the engine saves a significant amount of money compared to building a new engine with a new case and all new parts.
Only the manufacturer can officially zero-time an engine, as they have access to the original production line parts and can certify that all components meet the minimum standard. Lycoming is the only rebuild center that can zero out your engine and provide a brand-new logbook. From a potential buyer's perspective, though, this is a new engine with zero time can access the original production line parts and
A zero-timed engine is not necessarily “as new,” but rather an engine made up of miscellaneous second-hand components that have been measured to meet the manufacturer’s minimum standard. Rather than an overhaul, which involves removing an engine and sending it off for a rebuild, factory-certified zero-time engines are rebuilt and reintroduced into the supply chain. So, when you buy one and send your old engine as a core, you will not receive the same engine back.
Lycoming Factory Overhaul
Lycoming factory-rebuilt engines are taken to zero time. This means that the engine has zero time since new and zero time since its last major overhaul, providing pilots and aircraft owners with a zero-time engine logbook and increasing the value of their aircraft.
This is a major difference between an independent rebuild by an overhaul shop and a Lycoming factory rebuild. Only the factory can certify a rebuild, otherwise, the engine logbook will annotate a rebuild so zero time since major overhaul, but not zero time since new.
Rebuilt engines get built up using parts from Lycoming’s inventory, plus new parts, with a new data plate and logbook. Overhauled engines are built up the same way, but with looser specs, and retain the serial number and logbooks from the original engine. This doesn’t mean that rebuilds aren’t of a high quality; it simply means they are not rebuilt and reassembled to factory-new tolerances.
Factory-certified zero-time rebuilds are put into the active inventory with factory new engines, but they cost about a third less, give or take. For federal operators like the Department of Interior OAS, or Civil Air Patrol, Lycoming engines are made available on GSA Advantage for immediate sale without the prohibitive lead time of a contracted rebuild (some wait times are measured in years).
Rebuilt Engines
Here are a few of the key advantages to buying rebuilt versus brand-new piston aircraft engines:
- Rebuilt engines can be a cost-effective alternative to purchasing a new engine, with purchase prices usually around one-third less than brand new.
- Factory rebuilt engines offer a reliable and efficient solution for aircraft owners. These are extremely safe engines with millions of hours flown on rebuilt engines.
- Rebuilt engines are built to new limits, using a combination of new and used parts. We’ve covered this at length, but for the discerning buyer you can rest easy knowing that your engine is built to the same tolerances as new.
- A rebuilt engine is different from an overhauled engine only by a degree determined by how many new parts it might have.
- Rebuilt engines are a popular choice for aircraft owners who want a reliable engine without the high cost of a new engine.
Overhauled Engines
Overall, there is nothing wrong with an overhauled engine versus factory rebuilt, and they are less expensive than factory-certified rebuilds, but they are also not the same thing. Overhauled engines are built up the same way as rebuilt engines, but with looser specs. Also, they are built by third-party shops of frankly varying quality.
Overhauled engines retain the serial number and logbooks from the original engine. These are not a new engine at all, but are the exact same engine that was removed from the aircraft. This is the most cost-effective option and is the most common practice for private aircraft ownership to help keep costs low. The major downside is that the engine is removed, taking the aircraft out of service for the duration of the overhaul, plus however long it takes for the installation procedure.
Time Engine Considerations
The term “zero-time” is often associated with a freshly overhauled power plant from a factory, implying that it contains all new parts. However, this may not be entirely accurate, as a factory-new engine may not necessarily have all new parts, as the FAA permits OEMs to label rebuilt engines as zero-time. This doesn’t make them inherently more or less reliable, and they carry a factory warranty from Lycoming, just like a brand-new engine.
Purchasing a Zero-Time Engine on GSA Advantage
Greenwood Aerospace is working to revolutionize the government procurement process for Lycoming engines, both factory-rebuilt and brand new, by leveraging our GSA schedule and GSA Advantage shop.
We offer all the most common Lycoming piston engine models in new or rebuilt condition, with a fixed price, so you know exactly what you pay for. Here are a few models we offer:
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