camshaft and cylinder head

                                           Camshaft

The camshaft is the shaft on which the cams that open and close the valves on each cylinder are mounted. Because the camshaft is responsible for opening and closing the valves, it is also responsible for the timing of fresh air intake and exhaust outlet. It plays a critical role in any combustion engine because it controlls the fuel/air mixture in the cylinders. Engines with one camshaft are called OHC-engines. Engines with two camshafts are DOHC (Double Overhead Camshaft) engines. The latter is the standard in modern car engines. 
   

                                          Cylinder Head

 The cylinder head of an engine is the upper portion closing off the cylinders. In the cylinder head the valves and the camshafts are mounted. The cylinder head also contains the holes for the sparkplugs.