05K21104 - Lycoming Genuine OEM Cylinder Power Assembly Kit

05K21104 – Lycoming™ Genuine OEM Cylinder and Piston Power Assembly Kit

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The Lycoming 05K21104 is a genuine factory OEM Cylinder Power Assembly Kit, providing all the flight-critical components required for the complete overhaul of a single cylinder on Lycoming 360-series parallel-valve engines. This kit is engineered and manufactured by Lycoming to their exacting material specifications and production standards, ensuring the highest level of safety, reliability, and performance. It is the definitive, certified solution for restoring the power-producing section of a cylinder to zero-time condition, containing a perfectly matched set of factory-new components from the cylinder barrel to the piston, rings, and valve train.

Using this genuine Lycoming kit is the only way to guarantee that the correct metallurgical properties, heat treatments, and dimensional tolerances are maintained within the engine's core. Each component has been designed to work in concert, managing the immense thermal and mechanical stresses of combustion to ensure the engine can reliably achieve its full time between overhaul (TBO). This assembly is the heart of the engine's power production, and its integrity is paramount.

Key Features

• Genuine Lycoming Factory Parts: The only way to guarantee 100% compliance with the engine's type certificate and ensure factory-level performance and reliability.

• Nitrided Steel Cylinder Barrel: The barrel is machined from through-hardened steel alloy and undergoes a specialized nitriding case-hardening process, creating an extremely hard, durable surface for optimal piston ring seal and minimal wear.

• Aluminum Alloy Head: A high-strength, lightweight aluminum alloy cylinder head with deep cooling fins is shrunk and threaded onto the steel barrel for superior thermal conductivity and efficient air cooling.

• Sodium-Cooled Exhaust Valve: The critical exhaust valve features a hollow, sodium-filled stem, providing an exceptionally efficient heat transfer mechanism to prevent overheating and ensure valve longevity under extreme combustion temperatures.

• Complete & Matched Piston Assembly: Includes a new, weight-balanced aluminum alloy piston, a complete set of piston rings (compression and oil control), piston pin, and plugs, all engineered to match the cylinder for optimal compression and oil management.

Technical Specifications

• Part Number: 05K21104

• Component Type: Cylinder Power Assembly Kit

• OEM Manufacturer: Lycoming Engines

• Kit Contents (Typical):

  • Cylinder Assembly (Nitrided Barrel & Aluminum Head)

  • Piston, Piston Pin, and Pin Plugs

  • Piston Ring Set

  • Intake Valve

  • Exhaust Valve (Sodium-Filled)

  • Valve Springs, Retainers, and Keepers

  • Rocker Cover, Cylinder Base, Intake, and Exhaust Gaskets

  • Push Rod Shroud Tubes and Seals

• Cylinder Barrel Material: Through-Hardened Nitrided Steel Alloy (e.g., SAE 4140 Nitralloy)

• Cylinder Head Material: High-Strength Cast Aluminum Alloy

• Governing Specifications: Manufactured under Lycoming Engines' FAA Production Certificate.

Engine Compatibility

This power assembly kit is specifically intended for the overhaul of Lycoming direct-drive, 360-cubic-inch engines with parallel valve configurations. Common applicable engine series include, but are not limited to:

• O-360

• IO-360

• AEIO-360

• HO-360

Crucial Note: The specific engine model and serial number must be checked against the latest revision of the official Lycoming Parts Catalog to ensure correct part number applicability. The engine parts catalog is the final authority.

Applications

The 05K21104 kit is used for a major engine repair or overhaul. Primary applications include:

• Top Overhaul: Replacement of all cylinder assemblies on an engine.

• Single Cylinder Replacement: Used to replace an individual cylinder that has been deemed unserviceable due to low compression, cracking, excessive barrel wear, or other damage.

• Compliance with TBO: Replacing cylinders as part of a complete engine overhaul when reaching the manufacturer's recommended Time Between Overhaul.

Why Choose 05K21104?

The combustion chamber of a piston engine is one of the most violent environments in all of aviation. Choosing a genuine Lycoming 05K21104 kit is an investment in safety and reliability. Aftermarket or non-certified components often lack the correct material alloys, precise heat treatments (like nitriding and sodium-filling), and stringent quality control of the OEM. Such deficiencies can lead to premature wear, loss of compression, or catastrophic in-flight engine failure. The factory OEM kit is the only path to ensure that every component within the cylinder meets the engine's type design, a requirement for legal and safe operation.

The extreme durability of the Lycoming cylinder barrel is achieved through a thermochemical case-hardening process known as gas nitriding. After being machined from a tough SAE 4140 steel alloy, the barrel is placed in a furnace and exposed to a controlled atmosphere of ammonia gas (NH3​) at approximately 975°F (525°C). At this temperature, the ammonia dissociates, and nascent nitrogen atoms diffuse into the surface of the steel, forming extremely hard iron nitride (Fe2​N) and alloy nitride compounds. This creates a wear-resistant case with a hardness of 65-70 HRC, while the core of the barrel retains its ductility and toughness to withstand combustion pressures. Concurrently, the sodium-filled exhaust valve addresses the critical issue of heat management. The metallic sodium sealed within the hollow valve stem melts into a liquid during engine operation. The reciprocating motion of the valve violently shakes this liquid sodium, creating a "shake-transfer" cooling effect. This mechanism efficiently transports thermal energy from the valve head—which can glow red hot in the combustion chamber—up the stem and into the cooler valve guide, where the heat is conducted into the cylinder head and dissipated by the cooling fins. This prevents the valve head from failing due to thermal stress.

Note: This kit contains flight-critical engine components. The installation of this assembly constitutes a major engine repair and must be performed by a certified A&P/IA mechanic in strict accordance with the latest revision of the applicable Lycoming Overhaul Manual and all relevant Service Bulletins. Proper engine break-in procedures are mandatory after installation to ensure correct seating of the piston rings.

Documentation

All technical data, installation procedures, torque values, and final airworthiness determinations must be sourced from the official Lycoming publications, including the Overhaul Manual for 360 Series Engines and the Illustrated Parts Catalog for the specific engine model.