OS Speed 12TZ Spec-2 Crankshaft - Model OS21532120 by O.S. Engine  [OS21532120]

Replacement crankshaft for OS Speed 12TZ Spec-2

This crankshaft is an OEM-design replacement part for RC-scale nitro engines identified as OS Speed 12TZ Spec-2, intended for direct engine rebuilds and maintenance. It serves as the rotating core inside the engine case, providing the counterweight and journal surfaces required to convert piston motion into rotational output within a model engine.

During service, confirm that bearing seats and case alignment meet specification before fitting the OS21532120. Careful inspection of journals and seals will help ensure the rebuilt engine maintains correct mechanical timing and reliable operation.

Replacing the crank can address vibration-related issues and help restore stable idle and predictable throttle response in normal running conditions.

Select this OS21532120 crankshaft for servicing OS Speed 12TZ Spec-2 engines and always check associated bearings and seals during installation.