The Effect of Bolt Tightening Characteristics and Gasket Properties on Cylinder Head Gasketing

The problem of properly tensioning cylinder head bolts, in such a way that the gasket is uniformly compressed to its design sealing load is complex. Gasket relaxation must be compensated for, and the residual gasket compression must be high enough so that the seal is maintained during the combustion cycle which relieves a portion of the clamping load provided by the head bolts. The purpose of this paper is to explore the method of tensioning cylinder head bolts, the tightening strategies employed, and the interaction between the bolt tightening and gasket characteristics which influence the residual bolt preload. Experimental techniques are used to investigate the cylinder gasketing problem and the results of one study which eliminated re-torquing the bolts are presented.