FSa-72 Crankcase Replacement OS44301000 by O.S. Engine  [OS44301000]

Replacement crankcase for FSa-72 engines

This crankcase is an RC-scale replacement part produced by O.S. Engine for the FSa-72 family of model engines. It serves as the primary housing for the crank assembly and is intended for use during engine rebuilds, repairs, or when keeping spare parts on hand for track or field work.

Compatibility is limited to the FSa-72 designation shown in the product name, so confirm the engine model before ordering. The crankcase functions as the structural interface for bearings, crankshaft alignment, and mating with the cylinder and gearbox components; proper alignment during reassembly is essential to preserve bearing life and overall engine smoothness.

Installation notes: remove the engine from the model, disassemble following the engine manufacturer's standard sequence, transfer bearings and internal parts as required, and reassemble while checking end-play and alignment. Avoid introducing foreign debris into the crankcase during rebuild and inspect mating surfaces and threaded holes for wear.

Tuning and service role: while the crankcase itself does not change performance tuning parameters, a correctly fitted and undamaged crankcase helps ensure consistent crankshaft rotation and reliable sealing, which supports predictable tuning results from carburetor adjustments and exhaust selection.

Use this crankcase as a like-for-like spare when servicing FSa-72 engines, and follow standard engine rebuild practices to ensure longevity and reliable operation.