BOLT-SOCKET HEAD 4484556 - Caterpillar

Industrial And Marine EnginesThere have been reports from the field of too much face and bore runout in flywheel housings on D353 Engines. Runout of more than 0.30 mm (.012") can be expected on these engines when the engine supports are fastened to the mounting pads on the flywheel housing, and the driven unit or equipment is not installed. Under this condition, the weight of the engine can cause a limited amount of distortion in the flywheel housing. This distortion will increase runout measurements to as much as 0.76 mm (.030") in the housing face, and 0.51 mm (.020") in the bore. These maximum measurements are acceptable because installation of the driven unit or equipment will give more support to the housing and remove the distortion. This will hold the runout measurements to normal tolerances.
At the factory, flywheel housing runout is checked while the housing is free of engine weight. Supports for the engine are in a location under the oil pan face at each side of the cylinder block when the face and bore runout of the flywheel housing are measured. Under this condition, the maximum measurement for both the face and the bore must be no more than 0.30 mm (.012") before shipment of the engine.