Determination of Cylinder Head Bolts Force Distribution and There’s Life in Real Condition of Marine Diesel Engine

Cylinder head bolts in high-speed diesel engines must meet classical standard requirements. Moreover, they should seal cylinder head gasket due to uniform distribution of clamping forces with high durability under thermal and mechanical cyclic loads. In present study, to evaluate the performance of newly designed bolts, at first, the clamping force in cold assembly was calculated using theoretical and experimental results. Then in real engine condition, the amount of clamping force variation was derived with combustion load under hot condition. The most critical force was used to test the bolt durability in a uniaxial high cycle fatigue test. The experimental test confirmed infinite life of the bolt. Also, results show preload of used bolt could be increased about 8% that is important for maintenance and repair services. In addition, torque-angle assembly procedure precisely tightened the bolt near yield stress condition and improved sealing of the cylinder head gasket. Fuji paper test confirmed this analytical uniform clamping force results too.