12.10.4(h) . camshaft; 

12.10.4(g) . valve operating mechanism; 

12.10.4(f) . valves; 

12.10.4(e) . crankshaft; 

12.10.4(d) . connecting rods; 

12.10.4(c) . pistons; 

12.10.4(b) . cylinder heads; 

12.10.4(a) . cylinders; 

(Pictures)

12.10.4. Explain the function of the main components of a four-stroke cycle piston engine including: 

Cylinders – provide the enclosed space for combustion to take place
Pistons –    moves back and forth within the cylinder and provide a gas-tight seal
Connecting Rods – connect the piston to the crankshaft
Crankshaft – converts the reciprocating movement of the piston to a turning motion and transmits the power developed in the cylinders to the propeller
Crankcase –
Camshaft – is gear-driven by the crankshaft of the engine and rotates at half crankshaft speed
Valves – the Intake Valve admits the fuel/air mixture to the cylinder and the Exhaust Valve allows the burnt gasses to be expelled
Spark Plugs – ignite the compressed fuel/air mixture in the cylinder
Injectors –

12.10.2. Identify typical cylinder configurations used for aircraft piston engines.

Radial – have their cylinders arranged in a circle around the crankshaft
In-line – cylinders are arranged in one or more lines

Inverted in-line – the crankshaft / propellor shaft is at the top of the engine

Horizontally exposed – the “standard” is the air-cooled piston engine with horizontally exposed or flat configuration and four, six or eight cylinders arranged horizontally in two lines on opposite sides of the crankshaft
(Pictures)