Abstract

A device having a first and second rocker arm, and a control linkage. The first rocker arm has a first end receiving a first roller and a second end riding on a camshaft lobe. A second roller travels along an upper surface of the first rocker arm. The upper surface of the second rocker arm receives the first roller. When the control linkage is in a first position, the first rocker arm and roller slides along the upper surface of the second rocker arm towards the first end of the rocker arm, such that the valve head has maximum duration and lift from the valve seat. When the control linkage is in a second position, the first roller slides along the upper surface of the second rocker arm towards the second end of the rocker arm such that the valve head has minimum duration and lift from the valve seat.