Which two engine components are primarily responsible for combustion?

• A. Spark plugs and piston
• B. Cylinder and Cylinder Head
• C. Timing belt and crankshaft
• D. Head gasket and block

Answer: (B)

Combustion happens in the combustion chamber, which is formed by the cylinder and the cylinder head. These two parts create the space where the air–fuel mixture is compressed and then burned. The piston helps by compressing the mixture and converting the expansion into motion, but the actual burning occurs within that chamber defined by the cylinder and head. The spark plug provides the ignition spark to start combustion, but it isn’t the component that creates the burning environment. The other options involve timing or sealing components that don’t establish or sustain the combustion chamber.