On some engines, a metal chain is used to connect the crankshaft and camshaft gears. Most push-rod engines and some OHC engines have chains.

• 在一些发动机上，金属链被用来连结曲轴和凸轮轴齿轮。大多数推杆发动机和一些顶置凸轮轴发动机都有链。