Last month's "How It Works" story gave you the basics of the four-stroke cycle, describing the motion of the intake and exhaust valves in relation to the piston moving up and down in the cylinder.

There's no doubt that the valvetrain is the most complex part of any racing engine. It's also pushed the hardest against some incredible stresses. Nextel Cup teams and some manufacturers are putting ...

This installment of Toyota's Engines 101 series takes a closer look at one of the most critical parts of an engine: its valvetrain. The video establishes what parts comprise a valvetrain, looks at ...