General Motors has filed a new patent that offers a look at how the company may be rethinking cylinder deactivation for its ...

GM has filed a patent application a variable displacement valvetrain system with rocker shaft porting and insert sleeves for ...

In the valvetrain of your typical pushrod engine, the rocker arm is a critical component that also is an excellent tuning device. To properly tune with rocker arms, though, you need to understand how ...