Engine camshaft cap components experience high number of fluctuating loads during engine operation. The problem is complicated in engines with variable cam timing, because the loading for these components are sensitive to engine valve timing (combustion phasing) which can lead to catastrophic overload or fatigue failures. Improving the design of these components using computer-aided tools can drastically reduce the cost and time to the market of the final acceptable design, by eliminating the number of physical prototypes. Hence, a decent and robust finite element analysis with representative load and boundary conditions can significantly reduce the premature failures in engine development. In this study, first a finite element analysis method is developed for simulating a cap punching bench test. Effect of punch radius and shape on the component stiffness is investigated and correlated with test data. In order to improve the computational efficiency of the finite element analysis, punch is replaced by equivalent trigonometric distributed loads. Sensitivity of the finite element measured values with respect to different trigonometric functions is also investigated and correlations with test data are validated. Then the developed method is used for verification of part designs as well as their durability performance improvement. Under the same engine system simulated forces, a number of fatigue factor calculation methods are used to evaluate the durability of different feasible cap designs. Based on the correlations with the engine dynamometer test data, the most accurate method is selected for enhancing the design. Depending on engine bank and camshaft cap numbers, design rules are suggested to meet cap durability requirements.