A new casting process has been developed for the widely-used unplated aluminum-lead passenger car engine bearing alloy A1-6Pb-4Si. This new process, which imparts a very high quench rate to the alloy, results in a much finer metallurgical structure as compared to the current product. The fine structure is responsible for a significant improvement in bearing fatigue life. Data are presented which demonstrate this improvement both in dynamometer engine testing and in fatigue test machines. Score-seizure testing shows no loss in anti-seizure properties.