It's springtime! Time to start working on your project car, learn a new wrenching skill, discover what everything is under the hood (and how it works), or just spruce up your daily driver. All month, ...

Something I've been kicking around for a while, and wanted to get opinions on: Is there a reason we can't use variable intake valve timing to "optimize" engine operation for E85 operation, while still ...

Variable valve timing has been available in cars for almost half a century, first appearing in the Alfa Romeo Spider as far ...

March 30, 2007 Over the last century of automobile development, we have seen an enormous range of valve actuation technologies, ranging from pushrod, through single then double overhead camshafts, ...

To celebrate HOT ROD's 75th anniversary, we teamed up with CASTROL GTX to bring you some of the stories that exemplify the core of what HOT ROD is and reflect the brand's influence on America's car ...

Getting air in and exhaust gases out of the combustion chamber under all speeds and driving conditions is essential for a car’s fuel efficiency and low emissions. That’s why virtually all Chevrolet ...

In order to set a stage for what follows, let's first revisit some of the fundamentals involved in how valve timing relates to power output. And to further clarify how "power" is defined in the ...

Valve overlap—that crucial interval when both the intake and exhaust valves are open, expressed in degrees of crankshaft rotation—is typically a fixed parameter and always a compromise. For example, ...

A variety of two-stage, or discrete, variable valve lift (DVVL) and continuously variable valve lift (CVVL) systems have recently been incorporated in production vehicles. Several systems that have ...

When you check out the features of a new car, you’ll probably be bombarded with glowing words about its engine’s “advanced valvetrain technology.” How did this happen? They don’t shower us with ...