Camshaft cover

Encloses the camshaft and valve mechanism

Camshaft carrier

Locates the camshaft and provides upper bearing locations

Camshaft

Operates the valves and provides a means of driving the auxiliaries

Cylinder head

Provides for (in some cases) the combustion space, inlet and exhaust gas ports, supports the valve gear and part of the cooling system passages

Cam followers

Provide a bearing surface between the rotating camshaft and valve stem

Collets

Lock the valve spring to the valve

Valve spring

Keeps the valves closed, but allows them to be opened when required

Valve

Controls the flow of mixture into and out of the cylinder

Camshaft gear

Provides the drive to the camshaft at half crankshaft speed

Tensioner

Ensures the drive belt is maintained at a constant tension

Timing belt

Transmits the drive from the crankshaft to the camshaft without slipping

Pistons

Transmit the pressure of combustion down to the con-rod

Piston rings

These form a gas- and oil-tight seal

Gudgeon pin

Connects the piston to the con-rod

Connecting rod

Connects the piston to the crankshaft and converts the straight line motion of the piston to the rotary motion of the crankshaft

Crankshaft

Transmits the power from all the cylinders to the flywheel and transmission

Shell bearings

These form the bearing surface for the crankshaft journals