Automotive springs are subjected to dynamic loads that results critical for their fatigue life. In this thesis, developed in collaboration with Dayco, a torsional helical spring of an Overrunning Alternator Damper was studied. An analytical model was implemented by means of a spreadsheet to calculate static characteristics and stresses of this spring, presenting a trapezoidal cross-section, loaded simultaneously by compression and torsion. After a quick description of the production process and heat treatment and the benefit that an OAD has on the performance of the Front End Accessory Drive System (FEADS), the analytical model is presented. The analytical model is based on the formulas of A.M.