Intake valve seat recession and subsequent valve leakage were experienced during the late development phase of a new DOHC aluminum engine. This type of failure was not observed in the earlier development phase during engine break-in.
To resolve this valve burning issue, a three-dimensional finite element model was used to study the thermal/mechanical behavior of this engine. A parallel experimental program was conducted to evaluate the effect of the hardware changes between the early and late engine development phases on engine performance. The experimental effort also provided engine temperature and measured distortion data for validating the analytical model. The finite element analysis was able to identify the root cause of this condition and to propose structural modifications to remedy this problem rapidly by predicting the distortion and stress distribution within the cylinder head.