The Importance of a Cylinder Head

The Importance of a Cylinder Head

A cylinder head is the crucial component that sits atop the engine block, sealing the combustion chamber and hosting the valve gear and spark plugs. It also houses various oil and coolant passageways. It’s the mechanical control center of a vehicle’s engine and is designed to withstand high levels of heat, pressure, vibration and stress.

Cylinder heads are specially constructed, dimensioned and produced for each type of engine. A cylinder head for a two-stroke engine, for instance, has different flow channels for the inlet and outlet of the gas mixture. In addition, a water channel is integrated for cooling. It is therefore extremely important to know how your cylinder head is configured and the ultimate effect it has on performance, power and reliability.

The function of a cylinder head is not simple, but it can be simplified. Its job is to seal the combustion chamber and host the intake and exhaust valves, controlling the flow of air, fuel and exhaust gases. It must do this at the right temperature and with the proper timing so that the alchemy of combusting air and fuel produces power and not smoke.

Air makes its way into the combustion chamber through the intake manifold and combines with fuel from the fuel injectors. These air/fuel mixtures are then combusted and the excess fuel is released through the exhaust valve. The valves must open and close at just the right time to achieve maximum performance.

Cylinder heads are typically made of cast iron or aluminum, with most manufacturers now choosing to use aluminum as it’s lighter and better conducts heat, preventing engine overheating. A common problem that many drivers encounter is a cracked or warped cylinder head. The main reason this happens is due to the expansion rate of aluminum and cast iron differing, causing the cylinder head to crack or warp when it’s hot.

In order to prevent this, it’s important to get a quality cylinder head that is matched to your specific application. For example, if you’re using hydraulic roller cams in your performance street engine, it’s important to purchase a cylinder head with an intake port configuration and valve springs that can handle the higher valve lift.

Cylinder head construction can be either cast or machined, with casting being more affordable but machining being much faster and more precise. In the automotive industry, machining is preferred as it can produce closer tolerances than casting, making it an excellent choice for high-performance applications. However, it’s worth noting that a machinable cylinder head can still be prone to cracking or warping if subjected to excessive heat and pressure. It’s therefore important to follow the manual for your particular vehicle when installing a new cylinder head. If you do experience any issues, it’s best to act swiftly before the problem worsens. Otherwise, you could be putting your vehicle and passengers in danger. Fortunately, most cracks are easy to spot and can be repaired relatively easily by a professional technician.

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