The transfer case splits engine power between the front and rear axles of four-wheel drive vehicles.

Cylinders act as a guide for the pistons that translate the heat energy of combustion into the mechanical energy necessary to move a vehicle. Piston rings seal the piston to the cylinder to contain combustion gases and also regulate the oil distribution between the piston and cylinder wall. A cylinder head closes in the top of the cylinder forming the combustion chamber which is sealed by a head gasket (head). The head provides space for air and fuel intake valves, exhaust valves, and mounts for spark plugs and fuel injectors.

The engine (or cylinder) block is the large casing that contains the cylinders and many of the internal components of the engine.

An inline cylinder configuration places the cylinders in a single row either completely vertical or slanted. Due to this arrangement, an inline cylinder configuration makes the engine longer and, although it works well in four cylinder engines, performace suffers in larger engines due to the difficulty in evenly distributing the air-fuel mixture over the length of the engine.

The combustion chamber is located in the cylinder head and contains the combustion of the air-fuel mixture. This mixture is delivered by an intake valve and the waste gases from combustion are removed from the combustion chamber by the exhaust valve.