The
rocker stud leans into the valve on the Small Block Chevrolet. It is easy to see that the higher the rocker arm needs to be
to accommodate longer valves, the shorter the distance between the
trunnion and the valve will end up being. If you use this linear
thinking (straight line position of where the roller sits atop the
valve), then you will easily miss setting the rocker arm's angle, which
is what the priority is. There is no way to accurately place the roller
in the middle of the valve AND have MID-LIFT geometry, UNLESS you are
using rocker arms designed for these specific dimensions. That is why we
standardized the
VALVE TIP HEIGHT dimensions many years ago, just to
avoid this.
What needs to be
understood is that no matter where
the roller tip sits on the valve, what is important is the angle of
pressure. If
the roller is rolling across the valve tip, instead of pushing straight
down on it for the majority of its arcing motion, then it will see the
side load harmonics that go with this, even though in theory there is a
"roller" tip. The roller does NOT roll anyway. The roller is only a
pivot point of rotation.
(ABBREVIATED)
