The detachable portion of the engine, usually fastened to the top of the cylinder block and containing all or most of the combustion chambers. On overhead valve engines, it contains the valves and their operating parts. On overhead cam engines, it contains the camshaft as well.
The part of the above the engine block that contains the combustion chambers and the valves. The spark plugs screw into the top or side of the cylinder head. On most cars, a valve cover, camshaft cover, or a rocker-arm cover is located on top of the cylinder head.
That portion of a motor that caps the open (generally top) ends of the cylinders. In modern engine designs, the cylinder head(s) generally house the spark plugs and the intake/exhaust valves.(empty)(empty)(empty)(empty)
In an internal combustion engine, the cylinder head sits atop the cylinders and consists of a platform containing part of the combustion chamber and the location of the valves and spark plugs. In a flathead engine, the mechanical parts of the valve train are all contained within the block, and the head is essentially a flat plate of metal bolted to the top of the cylinder bank; this simplicity leads to ease of manufacture and repair, and accounts for the flathead engine's early success in production automobiles and continued success in small engines, such as lawnmowers. This design, however, requires the incoming air to flow through a convoluted path, which limits the ability of the engine to perform at higher rpm, leading to the adoption of the overhead valve head design.