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Lycoming Engine Terminology Explained

Thank you for considering a high quality factory Lycoming engine offered by Rotorcorp! We realize that there is a lot of different terminology that is used (and sometimes misused) to describe the various aspects of an engine.  The term “Factory” means that all service has been performed by the original manufacturer- Lycoming.  All Lycoming factory new, rebuilt and overhauled engines are built on the same production assembly line by the same skilled workers.  The term “Field” means service has been performed by a repair facility  which has been authorized by a recognized Civil Air Authority (FAA, EASA, Etc.)

It is important to distinguish that while approved engine service, including field overhaul,  may be performed in accordance with technical data, only Lycoming can provide New, Rebuilt and Factory Overhauled engines. Additionally, engines receiving major field service, including field overhaul, are subject to Lycoming Service Instruction 1427 which gives recommendations for test running and break in of field overhauled or field repaired engines. Service Instruction 1427 does not apply does not apply to Factory Lycoming engines.

Factory Overhauled

The parts used to build the engine meet or exceed service limits and specifications. The engine carries the previously accrued total time since new, but has zero time since major overhaul.   This engine also carries a one-year factory warranty up to the hourly overhaul period. Best for the customer who is looking for the most cost-effective engine option.

Rebuilt “Zero Time”

Every part used in building the engine meets or exceeds new part specifications; or the engine is like new. It has a zero time since new and a zero time since major overhaul. Some parts may be used, but they meet the same specifications as a new part. Like new engines, this engine carries a two-year factory warranty up to the hourly overhaul period.


Everything in the engine or installed on the engine is brand new. The engine has a zero time since new and zero time since major overhaul. These engines are identical to what an OEM customer (such as Robinson) would be installing into their brand new aircraft. New engines carry a two-year factory warranty up to the hourly overhaul period.

Outright vs. Exchange

If you have purchased aircraft parts in any capacity, you’ve likely heard the terms “Outright” or “Exchange”.  All Lycoming factory engines are available to be purchased either outright or on exchange. Purchasing an engine outright is the most straightforward option: you pay the part’s outright value (full market price) and the engine is shipped for you to keep. There are no core deposits paid and no core article needing to be returned to the manufacturer/distributor. With Exchange, suppliers offer an exchange fee (core deposit) that includes a set “standard” cost to put towards certain repairs or overhauls that is not to be exceeded. If repair or overhaul costs do exceed this standard amount, the client will be billed the difference, known as over and above (O&A) charges.

With respect to the Exchange sale of Lycoming engines, a refundable core deposit is paid at the time of purchase.  The buyer has the opportunity to provide an acceptable core engine prior to shipment of the exchange engine to receive the core deposit back.  Generally, if more that 60 passes, Rotorcorp will pay the core deposit to the manufacturer and the buyer has about two years to submit a core and receive a refund.