GT55 Keyway Parallel Key OS29708200 O.S. Engine  [OS29708200]

GT55 crankshaft key — service guide

This O.S. Engine parallel key is intended to sit in the shaft keyway of GT55 engines and lock hubs or flywheels to the crankshaft, providing torque transfer and preventing slip under load. Its machined profile ensures consistent seating and alignment of mounted components.

Fitting is performed by matching the shaft slot and hub keyway, inserting the key to the required depth, then assembling the flywheel and confirming stable rotation with no play. Regular inspection after bench tuning or road tests is recommended, and any sign of distortion warrants replacement.

When preparing setups, use the key to establish repeatable orientation for external parts. Do not overforce the key into an undersized slot; light tapping or pressing is normally adequate. This component is offered as a standard spare for GT55 engine service.