A hydraulic roller valve tappet (6500)
that provides automatic lash adjustment and rides on a
camshaft lobe that transfers its up-and-down motion to the rocker arm (6564)
through a push rod (6565)
.
The roller valve tappets
are prevented from turning by eight valve tappet guide plates (6K512)
which are held in place by a spring steel tappet guide plate and retainer (6K564)
.
The rocker arms
are pedestal-mounted and pivot on fulcrums bolted to the cylinder head (6049)
.
The valves are arranged alternately for intake/exhaust.