Difference between a Cylinder Head and a Head Gasket

The components of a car are closely associated with each other and one cannot function without the other. There are hundreds of parts that work in harmony to keep a car up and running. Engine overheating is a common problem with old and new cars and this may be caused by a faulty cooling system or a problematic combustion chamber. In most of the cases, this issue can be resolved by taking a closer look at the cylinder head and the head gasket. The cylinder head looks like a small block on the top of a crankcase. Air is received and mixed with the fuel by the cylinder head to enable intake, compression and combustion cycle as well as the exhaust cycle. The head gasket separates the cylinder head and the engine block by providing optimal pressure for the combustion chamber.

In order for the head gasket to provide a proper sealing between the cylinder head and the engine block, the surface of cylinder head should have proper surface finish. The manufacturers usually recommend a range of surface finish to ensure durability and cold sealing. As the engines and castings are made of lightweight materials, cylinder heads are made of aluminum, replacing traditional cast iron. As a result, a smooth surface finish is required in these cylinder heads.

When it comes to head gasket sealing, the smoothness of the cylinder head becomes a crucial factor. Surfaces that are not flat will cause abrasions in the head gasket. Cracks and leaks in the gasket can cause abrasions on the cylinder head, resulting in improper sealing. That is why manufacturers recommended that the cylinder head is always kept smooth. Even a minor scratch on the cylinder head should not be ignored as it can cause coolant leaks and ultimately head gasket failure. Combustion gases may easily go past the gasket due to the cracks and this will cause the head gasket to blow completely.

The Cylinder head needs to be resurfaced when it develops cracks or pits. With the increasing use of mixed metals, there are lots of variables accounting for metallic friction, resulting in cylinder head cracks. When overheating is avoided with proper care, cracks can be prevented from forming. Otherwise, it can result in poor sealing of the head gasket, cascading the overheating problem. A cooling system failure can result in hot spots in the engine which can also cause cracks on the cylinder head.

While repairing or replacing the head gasket, the surface finish of cylinder head should also be tested. Warps can be seen with naked eyes. You can use comparator gauges available which are widely available to ensure that surface finish falls within the recommended specifications range of your car manufacturer. A visual comparison and feeling of the cylinder head should let you know about the acceptable smoothness. If you want precision, then you can go for an electronic surface profilometer. You can use any method to establish the surface finish, but milling and grinding are the most common resurfacing techniques used with cylinder heads. If there is a problem only with the head gasket, then you can simply use the belt sanding method to ensure a proper surface finish.

If you find this information helpful and valuable we would appreciate you paying it forward by sharing this page with people on your social networks.