SA646277 – Superior Air Parts Hydraulic Lifter Assembly
Available now on the Airparts.aero Marketplace.
Overview
The Superior Air Parts SA646277 is a high-quality, FAA-PMA approved hydraulic valve lifter assembly designed as a direct replacement for Lycoming part number 646277. This component is a critical part of the engine's valve train, engineered to automatically eliminate the clearance, or "lash," between the camshaft, pushrod, and valve rocker arm. By maintaining zero lash, the SA646277 ensures quiet operation, reduces valve train wear, and optimizes engine performance and efficiency. Manufactured with precision-ground hardened steel alloys, this lifter assembly is built to meet or exceed the rigorous standards of the original equipment manufacturer, providing reliability and longevity.
Key Features
- Precision Machining: Each lifter body and internal piston are precision-ground to exacting tolerances, ensuring proper hydraulic function, smooth operation, and a precise fit within the engine case.
- High-Strength Materials: Constructed from specialized hardened steel alloys selected for their exceptional wear resistance and ability to withstand the high cyclic loads and temperatures of the engine valve train.
- Optimized Hydraulic Performance: Features an improved hydraulic metering design that ensures consistent oil pressure is maintained within the lifter, preventing valve float at high RPMs and ensuring quiet, efficient operation at all power settings.
- FAA-PMA Certified: Holds a full FAA Parts Manufacturer Approval (PMA), certifying that it is a direct and legal replacement for the OEM part and meets all standards of airworthiness and quality.
- Drop-In Compatibility: Engineered as a direct, form, fit, and function replacement for the original Lycoming part, requiring no modification for installation.
Technical Specifications
- Part Number: SA646277
- OEM Replacement for: Lycoming P/N 646277
- Component Type: Hydraulic Valve Lifter / Tappet Assembly
- Function: Zero-lash valve clearance adjustment
- Body Material: Hardened Steel Alloy
- Internal Components: Precision-fit hydraulic plunger, spring, and check valve
- Certification: FAA-PMA
Engine Compatibility
The Superior Air Parts SA646277 is approved for use in a wide range of Lycoming reciprocating aircraft engines that specify the corresponding OEM part number. It is a fundamental component in many of the most common 4- and 6-cylinder Lycoming engines. Always confirm the part's applicability by consulting your specific engine model's Illustrated Parts Catalog (IPC).
- Lycoming Parallel Valve Engines:
- O-235, O-320, O-360 series
- IO-320, IO-360 series
- AIO-320, AIO-360 series
- AEIO-320, AEIO-360 series
- HIO-360 series
- O-540, IO-540 series (parallel valve models only)
Applications
The SA646277 is a mission-critical component used in several key maintenance and operational scenarios:
- Engine Overhaul: An essential replacement item during any major engine overhaul to ensure the valve train is restored to zero-time specifications.
- Top End Overhaul: Replaced when cylinders are removed for service to address issues like camshaft or lifter spalling.
- Performance Restoration: Installing new lifters can restore quiet and smooth engine operation by correcting issues with worn or collapsed older units.
Why Choose SA646277?
Choosing the Superior Air Parts SA646277 hydraulic lifter provides a combination of exceptional quality, certified safety, and outstanding value. As a leading manufacturer of PMA parts, Superior has a long-standing reputation for producing components that often incorporate subtle design and material improvements over the original. By installing the SA646277, you are ensuring your engine's valve train operates with the precision and reliability intended by its designers, backed by a modern manufacturing process and the full assurance of an FAA-PMA certification.
Order Your SA646277 Hydraulic Lifters Now
Restore the heart of your engine's valve train with the precision and reliability of Superior Air Parts. Visit Airparts.aero to order your SA646277 hydraulic lifter assemblies today.
The SA646277 hydraulic valve lifter assembly is a self-contained, self-adjusting hydraulic cylinder that functions as the critical link between the engine's camshaft and the pushrod. Pressurized engine oil flows through galleys into the lifter's body, filling a chamber beneath an internal piston. A check valve traps the oil, creating a solid, incompressible column of fluid. This column effectively elongates the lifter to take up all clearance in the valve train. As thermal expansion occurs, a precision-metered leakdown path allows the lifter to adjust, maintaining zero lash under all operating temperatures. This mechanism is fundamental to reducing shock loads on valve train components, minimizing wear on camshaft lobes and lifter faces, and ensuring consistent valve timing for optimal engine power and efficiency.
Note: Installation of engine internal components must be performed by a certified A&P mechanic during engine overhaul or repair, in strict accordance with the engine manufacturer's service and overhaul manuals. It is highly recommended to replace all lifters as a set during an overhaul.
