Location of Serial Number on Cylinder Block
WARNING: This page is about a different car, the 2002 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The spark plug is installed in the center of the roof-shaped combustion chamber to ignite the air/fuel mixture in the combustion chamber. The central location of the spark plug causes the flame front to be evenly spread across the combustion chamber, which also reduces spark knock.
Both camshafts are driven by a shared timing belt, and operate four valves per cylinder by means of mechanical valve tappets. One valve spring on each valve is used to close the valve.