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 ...

A recently filed patent details a new GM cylinder deactivation system that appears to be heading to the next-gen V8 engines ...

The rocker arm employs the use of a fulcrum or pivot to increase the cam lift by a given ratio. That increase in lift is the result of moving the pushrod pivot point closer to the fulcrum. That ...

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 ...

Q I own a '99 Chevy Lumina with a 3.1-liter V6. This weekend I got a flashing check-engine light with a severe misfire. I took the vehicle to a shop, which told me I had two rocker arms blown right ...