11B20061-1SL - Lycoming™ Crankcase Assy

11B20061-1SL – Lycoming™ Crankcase Assy

Available now on the Airparts.aero Marketplace.

Overview

The Lycoming 11B20061-1SL is a genuine OEM, factory-reconditioned "Service Limit" crankcase assembly for the robust Lycoming O-320-B series of engines. This is the primary structural foundation of the engine, consisting of two precision-machined, matched halves of cast aluminum alloy. The "-1SL" designation is critical: it signifies that this crankcase has been professionally reconditioned at the Lycoming factory, with the main bearing bores align-bored to a specific First Service Limit oversize dimension. This provides a cost-effective, fully certified, and airworthy solution for engine overhauls where the original crankcase is no longer serviceable at new limits.

Key Features

• Factory "Service Limit" Reconditioning: This crankcase has been re-machined by Lycoming to precise First Service Limit (SL) specifications. This factory process ensures that the alignment and dimensions of the main bearing and camshaft bores are perfectly restored, providing a foundation that is dimensionally equivalent to a new case, ready for assembly with corresponding service-size bearings.
• Matched Case Halves: The crankcase consists of two halves (left and right) that are manufactured and machined as a perfectly matched set. This is essential for ensuring the concentricity of the main bearing bores and the proper gear backlash in the accessory drive train.
• High-Strength Aluminum Alloy: Cast from a high-quality aluminum alloy, providing exceptional strength and rigidity to contain the forces of combustion and support the entire rotating assembly, while remaining lightweight.
• Structural Foundation of the Engine: Serves as the backbone of the engine, providing the mounting structure for the cylinders, accessory case, oil sump, and the engine's attachment points to the airframe's engine mount.
• Genuine Lycoming OEM Part: As a genuine factory-reconditioned part, it carries the full weight of Lycoming's engineering and quality control. It is supplied with a new data tag and a zero-time service history since reconditioning, ensuring full traceability and airworthiness.

Technical Specifications

• Part Number: 11B20061-1SL
• Component Type: Crankcase Assembly, Service Limit
• Material: High-Strength Cast Aluminum Alloy
• Primary Function: Main structural housing for the engine's rotating and reciprocating components.
• Key Feature: Main bearing bores are align-bored to First Service Limit (e.g., +0.010 inches), requiring the use of service-limit sized bearings.
• Certification: FAA Production Approval / Certified Factory Reconditioned

Aircraft Compatibility

The 11B20061-1SL is the specified service limit crankcase for the widely-used Lycoming O-320-B series of 160 horsepower, 4-cylinder engines.

• Primary Engine Model:
  • Lycoming O-320-B Series (e.g., O-320-B2B, -B2C, -B3B)
• Common Aircraft Platforms:
  • Piper PA-28-161 Warrior II
  • Grumman American AA-5 Traveler
  • Various other certified and experimental aircraft utilizing this engine.

Applications

The 11B20061-1SL is the ideal foundation for a professional engine overhaul:

• Engine Overhaul: The specified replacement when an engine's original crankcase is found to be unserviceable during overhaul due to fretting, corrosion, or damage, and a cost-effective alternative to a new factory case is desired.
• Restoring Engine Integrity: Provides a perfectly aligned, dimensionally correct foundation for a rebuilt engine, which is essential for ensuring proper bearing crush, oil pressure, and a long service life.

Why Choose 11B20061-1SL?

The crankcase is the single most critical structural component of your engine. A warped or fretted case can lead to bearing failure and catastrophic engine damage. The Lycoming 11B20061-1SL offers a superior alternative to field-repaired cases by providing a component that has been re-machined on the original factory tooling and subjected to the same rigorous inspections as a new part. It is a fully certified, zero-timed component that provides the same level of safety and reliability as a new crankcase, making it the smart, economical choice for a high-quality overhaul.

Order Your 11B20061-1SL Crankcase Assembly Now

Build your engine on a foundation of certified factory quality. Visit Airparts.aero to inquire about genuine Lycoming factory reconditioned crankcase assemblies today.

A "Service Limit" crankcase like the 11B20061-1SL is an FAA-approved outcome of the engine overhaul process. Over thousands of hours, the main bearing bores in a crankcase can wear or fret, becoming slightly out-of-round. During a factory reconditioning, the two case halves are bolted together, and a precision boring bar is used to machine the main bearing "tunnel" to a new, perfectly round, and perfectly aligned oversized dimension (the "service limit"). This process restores the geometric accuracy of the case. This reconditioned case must then be assembled with corresponding service limit main bearings, which have a thicker shell to accommodate the larger bore, resulting in the original factory-specified oil clearance for the crankshaft.

Note: This is a flight-critical engine component. Assembly and installation must be performed by a certified A&P mechanic or at a qualified engine overhaul facility in strict accordance with the current Lycoming Overhaul Manual. The use of corresponding Service Limit main bearings is mandatory when using this crankcase.

Description:     Crankcase Assy
Part Number:     11B20061-1SL
PMA Part Number:     SL36800-Wll
Alternate Part Number:     11B20051-1SL(-S), LW-18372, LW-13809, 78223, LW-13818 LW-11062
OEM Part Number:     11B20061-1SL-S
FAA-PMA Supplement: [Click Here]
FAA-PMA Part Information: [Click Here]
Lycoming™ Service Instruction: [Click Here]
New Superseding Roller Tappet P/N:     11B20161-1SL 

Fits in

Part of this Assembly

See O-320-E2B, -E2C Series Illustrated Parts Catalog: [Click Here]
Page 3 Figure 2 Item no. 1

AirParts Rotable Crankcases are sold as an Exchange Only sales transaction. This means that you will purchase the crankcase and send us back your core crankcase. You will use the packaging that we provide to ship back your core. You will not be charged the core charge until after 15 days if you do not return your core to us. Once the core is returned, it will be inspected by a third-party crankcase 145 repair station to determine whether it is acceptable. In the unlikely event that your core fails inspection or is out of spec, you will be responsible for paying the core charge. If the core does not fail but requires additional processing outside of normal overhaul, you will be charged for those additional small charges. This is standard in the aviation industry when purchasing core exchange items. If the core is in good shape, purchasing core exchange from AirParts provides you with the crankcase you need right away without any wait. It also lowers the price of acquiring the rotable parts you need to get your job done quickly leading to a happy client!