The Camshafts and Timing Gears Are Removed from the Cylinder

The camshafts and timing gears are removed from the cylinder head. A technician covers the return oil holes in a camshaft with electrical tape and applies compressed air to the other oil hole. With the camshaft held stationary, the timing gear rotates a few degrees counterclockwise. When the air pressure is released, the timing gear rotates clockwise back to its original position. This proves that the ____________________ is working properly.