The cylinder head is mounted on top of the cylinder block, sealing the cylinder from above and forming the combustion chamber. It is often in contact with high temperature and high pressure gas, so it bears a large thermal load and mechanical load. A cooling water jacket is made inside the cylinder head of the water-cooled engine, and the cooling water hole on the lower end face of the cylinder head communicates with the cooling water hole of the cylinder block. Use circulating water to cool high temperature parts such as the combustion chamber.
The cylinder head is also equipped with intake and exhaust valve seats, valve guide holes for installing intake and exhaust valves, as well as intake and exhaust passages. The cylinder head of gasoline engine is machined with holes for installing spark plugs, while the cylinder head of diesel engine is machined with holes for installing fuel injectors. The cylinder head of the overhead camshaft engine is also machined with camshaft bearing holes for installing the camshaft.
The cylinder head is generally made of gray cast iron or alloy cast iron. The thermal conductivity of aluminum alloy is good, which is beneficial to improve the compression ratio.
The cylinder head is an integral part of the combustion chamber. The shape of the combustion chamber has a great influence on the operation of the engine. Due to the different combustion methods of gasoline engines and diesel engines, the parts of the cylinder head that make up the combustion chamber are quite different. The combustion chamber of the gasoline engine is mainly on the cylinder head, while the combustion chamber of the diesel engine is mainly in the pit on the top of the piston

Measures for Cylinder Head Cracks
1. The cylinder head bolts should be tightened evenly, and the oil supply time should be adjusted correctly.
2. Soft water should be added to the water tank, and the water should be changed as little as possible.
3. The diesel engine should avoid working under overload for a long time.
4. When the engine is working and the water tank is occasionally short of water, it should not be turned off immediately, but should be run at a low speed and slowly add water. Do not add cold water after the engine is hot, and wait for the water temperature to be below 40°C before draining the water after parking. In the cold winter season, you can’t add boiled water immediately, but you should heat the water first and add boiled water.
5. Check whether the cooling water holes are unblocked during assembly. Regularly clean the cooling system with alkaline solution to remove scale and oil in time.