This video describes the operation of the HONDA VTEC variable valve timing system.

Like never seen before, this animation goes into details on the mechanical principle of the VTEC system. The Honda VTEC system is a dual setting variable valve timing system. It is meant to give high efficiency and low power at lower RPM and high power and low efficiency at higher RPMs. There have been a few incarnations of VTEC, which came out in the late 80′s, but their principle is the same.

See it all here with high quality visual details.