Rocker cover

Rocker covers are covers that are bolted on over rocker arms in an internal combustion engine. They are called valve covers in the United States, Canada, and in situations where Rocker Arms are not present, such as some Overhead Cam, and most Dual Overhead Cam engines. and rocker boxes in the United Kingdom. Rocker covers are covers that are bolted on over rocker arms in an internal combustion engine. They are called valve covers in the United States, Canada, and in situations where Rocker Arms are not present, such as some Overhead Cam, and most Dual Overhead Cam engines. and rocker boxes in the United Kingdom.