Glossary “rocker arm geometry” Definition:
The angle of the rocker arm in relation to the valve stem. Rocker arm geometry is correct when the center of the rocker arm tip contacts the centerline of the valve stem when the valvetrain is at 30 to 50% of its maximum lift.

Glossary “rocker arm ratio” Definition:
The difference between the upper movement of the pushrod, acting on one end of the rocker arm, and the downward movement of the rocker arm acting on the valve stem. Rocker arm ratio is usually around 1.5 to 1 (1.5:1).

Glossary “rocker arm shaft” Definition:
A shaft in each cylinder head on which rocker arms are arranged and pivot..

Glossary “rocker panel” Definition:
Sheet metal along the bottom of an auto body, beneath the doors, and between the front- and rear-wheel openings.

Glossary “rocker arm” Definition:
1). A pivoting part in a mechanical fuel pump, one end of which rides on a camshaft eccentric or pushrod, and the other end of which pulls on the diaphragm via a mechanical linkage, causing the diaphragm spring to be compressed. 2). A pivoting lever in the valve train of an overhead valve system which applies motion, directly or indirectly from the camshaft to open an intake or exhaust valve.