O.S. Engine OS27901000 Crankcase for 61SX-H, 61SX-HG, 61SX-HGL  [OS27901000]

Crankcase for 61SX series

This crankcase is an RC-scale replacement component intended for use with O.S. Engine 61SX-H, 61SX-HG, and 61SX-HGL glow engines. It serves as the central housing that locates the crankshaft and oil seals and is offered as a direct replacement part to restore mechanical alignment and combustion chamber integrity in model engines.

Installation is typically done as part of an engine rebuild, where careful inspection of bearing seats, gasket faces, and mating surfaces is required. The part is supplied as a single housing intended to replace a worn or damaged original crankcase, and fitting should be checked for correct crankshaft endplay and seal compression before final assembly.

For tuning and maintenance, the crankcase role is primarily dimensional and sealing; it does not change engine timing by itself but ensures the crankshaft and internal components run true, which supports consistent carburetion and ignition behaviour in glow-powered RC models.

Use this crankcase when replacing a damaged housing or when performing a full engine rebuild to recover proper alignment and sealing in the engine assembly.