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 ...

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

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 ...

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 ...

One of the most common valvetrain upgrades for pushrod-style engines is roller rocker arms, which are often said to increase horsepower through reducing friction. But is it true? You’ll find out on ...

Can roller rocker arms actually help add horsepower? The mechanically savvy will likely consider that question and say: “If you have more lift, and open the valves more, then you’ll make more power.

Changing the rocker arms in your C5 or C6 Corvette may not deliver the dramatic results that a cam swap can, but it's a lot less work. And the power increases you'll experience make the change a good ...

Some 2013 Acura RDX SUVs may intermittently illuminate the check engine light and store trouble code P3400 and/or P3497 in the PCM. One likely cause, reports Acura, is a sticking rocker arm oil ...