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

The rocker arm is possibly the third most abused part in your engine. The connecting rods take the cake for the most abuse, followed closely by the piston assembly, but we like to think the rocker ...

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

The debate over the optimum rocker arm ratio has dragged on since the invention of the pushrod V-8. Even though Chevrolet made the decision easy for us when it engineered the small-block to run around ...

Any gearhead worth his or her salt knows that whether it's a SOHC, DOHC, or OHV engine, the camshaft is considered the brain of a four-cycle internal combustion power plant. The camshaft's profile ...

Some early Captivas fitted with the diesel engine may have experienced a condition whereby the camshaft rocker arm bearing could fail. In some instances this rocker arm failure was known to result in ...