In a combustion engine, a flywheel is coupled to a crankshaft, the flywheel and crankshaft being in splined engagement. To eliminate play between the flywheel and crankshaft which occurs under conditions of torque fluctuation due to clearance between the meshing teeth, a deformable member is provided to reduce this clearance. The deformable member includes a bore with teeth therein also in mesh with the crankshaft teeth. In one embodiment, the deformable member is a hub on the flywheel compressed by an element movable against it by a bolt. Opposed tapered surfaces compress the deformable member as the bolt is tightened. In another embodiment, the deformable member is a separate element and is tapered and fits within a tapered inner surface on the bore of the flywheel. As the deformable member is pressed against the flywheel by the bolt, it is simultaneously compressed by the action of the opposed tapered surfaces.