HEAD GASKET: Describes the gasket that sits at the top of the cylinder between the cylinder and the head, keeping coolant out of the cylinders while retaining compression in the cylinder.

BLOCK: Describes the part of the engine that contains its cylinders.

CROSSFLOW CYLINDER HEAD: Describes a cylinder head design, especially in an Overhead Camshaft (OHC) engine where the inlet manifold sits on one side and the exhaust manifold on the other side of the head.

CROSSFLOW HEAD: Describes a cylinder head with the intake valves on one side of the combustion chamber and the exhaust valve(s) on the other

DECARBONISE: Describes the action of removing carbon build-up from the surface of the cylinder head and the dome of the piston.
FIRING ORDER: Describes the sequence in which cylinders must be fired: 1, 5, 3, 6, 2, 4. Firing order differs from the cylinder sequence, which starts with cylinder number one and goes to the last cylinder: 1, 2, 3, 4, 5, 6.
FIVE-VALVE HEAD: Describes a cylinder head fitted with five valves per cylinder, usually three intake valves and two exhaust valves.
HIGH COMPRESSION HEAD: Describes a cylinder head with a smaller combustion chamber area raising the compression.
INLET PORT: Describes a passage situated in the cylinder head that connects the intake manifold to the intake valve allowing the fuel-air mixture to proceed to the cylinders.
ROCKER ARM: Describes a curved lever that pivots in the middle while the other end is attached to the pushrod in overhead-valve engines. As the camshaft rotates, the rocker arms pivot, causing the valves to open and close.
ROCKER ARM COVER: Describes a form of metal lid located on top of the cylinder head on vehicles fitted with valves activated by an overhead cam or by rocker arms.
ROCKER ARM SHAFT: Describes the shaft upon which the rocker arms are mounted to allow the rocker arms to pivot
ROCKER COVER GASKET: Describes a valve cover gasket that sits between the cylinder head and the valve cover, usually made from flat paper or cork.
SHIM-TYPE HEAD GASKETS: Describes a hard thin, high-performance steel head gasket used to raises the compression ratio in an internal combustion engine.
SWIRL CHAMBER: Describes a small cavity in the cylinder head that promotes swirl in the diesel engine's indirect injection combustion system.
T-HEAD: Describes a type of cylinder head found in a side-valve engine where the valves are on opposite sides of the piston in a configuration resembling a "T".
TWIN PORT: Describes a type of cylinder head design fitted with twin exhaust ports.

 ROCKER COVER: Describes the long metal lid located on top of the cylinder head on vehicles fitted with overhead camshafts that can be removed to allow the valves to be adjusted.
ROCKER COVER GASKET: Describes either flat paper or cork gasket that sits between the cylinder head and the valve cover.