Abstract: A valve activation device having a linear reciprocating cam shaft having longitudinally extending cam grooves that are engaged by captive cam followers which oscillate up and down in response to sideways reciprocation of the camshaft for activating intake or exhaust valves of internal combustion engines or other devices employing reciprocating pistons and valves. The camshaft is caused to reciprocate by a rotary linear converter of the "yankee" type composed of double helix channel at the extreme end of the camshaft and a rotary collar having two sets of diametrically opposed guide members.