The Mazda Z-series is a smaller inline 4-cylinder gasoline engine ranging in displacements from 1.3L to 1.6L. They are the evolution of the cast-iron block B-engine.The Z-engine has 16-valves operated by dual overhead camshafts, which are in turn driven by a timing belt. The block of the 98-02 Z5, Z6 and ZL engine is cast iron same as the earlier B series of engines. Other Z engines have aluminum alloy block and head, with cast-iron cylinder liners.