Which component is typically found inside a cylinder head of an engine?

The component that is typically found inside a cylinder head of an engine is the valve stem seal. The cylinder head is responsible for housing several critical components of the engine's valvetrain, including the valves themselves, which control the intake of air and fuel and the expulsion of exhaust gases. The valve stem seal is specifically designed to prevent engine oil from leaking into the combustion chamber. It does this by sealing the space between the valve stem and the cylinder head, ensuring appropriate lubrication of the valve without allowing excessive oil consumption or emissions.

In contrast, piston rings are located on the pistons within the cylinders, acting as seals between the piston and the cylinder walls. The crankshaft is found in the engine's lower assembly and plays a vital role in converting linear motion from the pistons into rotational motion. While valve stem seals are indeed a part of the assembly within the cylinder head, the other components mentioned serve different functions and are located elsewhere within the engine.