67542 - Lycoming Rear Camshaft Ball Bearing

67542 – Lycoming™ Rear Camshaft Ball Bearing

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The Lycoming 67542 is a genuine OEM, flight-critical, high-precision deep-groove ball bearing. Its indispensable function is to support the aft end of the camshaft within the engine crankcase. This bearing is engineered to maintain the precise alignment of the camshaft, handling both the radial loads from the gear train and the axial (thrust) loads generated by the helical cut of the camshaft drive gear. The integrity and precision of this single component are fundamental to maintaining accurate valve timing, proper gear mesh, and the overall longevity of the engine's core rotating assembly.

This is not a standard industrial bearing. It is manufactured to exacting Lycoming specifications and a high ABEC precision class, using exceptionally clean, vacuum-melted bearing steel. The internal clearances, raceway geometry, and material purity are all tightly controlled to ensure the bearing can withstand the extreme loads and high rotational speeds of an aircraft engine, while facilitating the formation of a critical lubricating oil film that prevents metal-to-metal contact.

Key Features

• Genuine Lycoming OEM Part: The only component guaranteed to meet the precise internal clearances, material purity, and ABEC rating required by the engine's type design.

• High-Precision ABEC/RBEC 3 Rating (or higher): Manufactured to tight tolerances for runout, concentricity, and bore diameter, ensuring perfect fitment and minimal rotational friction.

• Vacuum-Melted 52100 Bearing Steel: Constructed from the highest-purity, high-carbon chromium alloy bearing steel (SAE 52100 VAR), which is free of microscopic impurities that can lead to premature fatigue and spalling.

• Designed for Combined Loads: The deep-groove raceway geometry is specifically engineered to handle both high radial loads and significant axial (thrust) loads in both directions.

• Optimized for Engine Lubrication: Designed to operate within the engine's pressure and splash lubrication system, promoting the formation of a durable elastohydrodynamic lubrication film.

Technical Specifications

• Part Number: 67542

• Component Type: Deep-Groove Ball Bearing

• OEM Manufacturer: Lycoming Engines

• Application Location: Rear Camshaft Support in the Crankcase

• Material: High-Carbon Chromium Alloy Bearing Steel (SAE 52100 VAR).

• Precision Class: ABEC 3 / RBEC 3 (or higher, per Lycoming specification).

• Cage/Retainer: Typically features a high-strength steel or phenolic cage for ball separation and guidance.

Engine Compatibility

The 67542 rear camshaft bearing is one of the most widely used bearings in the Lycoming engine fleet. It is specified for nearly all direct-drive Lycoming engine families, including but not limited to:

• O-235, O-320, IO-320, AEIO-320 Series

• O-360, IO-360, AEIO-360, TIO-360 Series

• O-540, IO-540, AEIO-540, TIO-540, LTIO-540 Series

• IO-580 Series

• IO-720 Series

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

This bearing is a mandatory replacement part during any major engine work that involves separating the crankcase halves.

• Complete Engine Overhaul

• Crankcase Separation and Repair

• Camshaft Replacement

Why Choose 67542?

Choosing a genuine Lycoming 67542 bearing is an absolute necessity for a reliable engine overhaul. The use of a non-certified or industrial-grade bearing introduces unacceptable risks. An incorrect bearing may have improper internal clearances leading to overheating, or it may be made from inferior steel with microscopic inclusions that can initiate fatigue cracks under load, causing the bearing to fail and sending hardened steel debris throughout the entire engine. Failure of the camshaft bearing will lead to immediate, catastrophic damage to the gear train and valve train. The genuine Lycoming part is the only way to guarantee the certified materials and precision required for this flight-critical application.

The successful operation of the 67542 bearing under extreme load is dependent upon the formation of an Elastohydrodynamic Lubrication (EHL) film. Under the immense, highly concentrated Hertzian contact stress where a ball meets the raceway, the engine's lubricating oil behaves in a non-Newtonian fashion. The extreme pressure—often exceeding 1 Gigapascal (150,000 PSI)—momentarily increases the oil's viscosity by several orders of magnitude, causing it to behave almost like a solid. Simultaneously, the atomically smooth steel surfaces of the ball and raceway elastically deform on a microscopic level. This combination of lubricant "solidification" and elastic surface deformation creates an incredibly thin (often less than a micron), yet extremely robust, pressurized oil film that completely separates the rolling elements from the raceways, preventing any metal-to-metal contact. The success of this EHL regime, which is the foundation of modern rolling-element bearing longevity, is entirely dependent on the bearing's precision geometry (ABEC class), the immaculate surface finish of its components, and the purity of the vacuum-arc-remelted (VAR) SAE 52100 steel from which it is made.

Note: This is a flight-critical, precision internal engine component and is a mandatory replacement during any engine overhaul. It must be handled with extreme care in a clean environment to prevent contamination from dirt, dust, or debris, which can destroy the bearing upon first startup. Installation requires specialized tools (temperature-controlled ovens, presses, and precision drivers) and must be performed by a certified A&P/IA mechanic in strict accordance with the applicable Lycoming overhaul manual.

Documentation

The definitive part number applicability and all installation procedures are detailed in the applicable Lycoming engine maintenance, overhaul, and parts catalogs for the specific engine model.