Difference between the functions of the Cylinder head & Cylinder head gasket

The Cylinder head and the engine block contain one of the most critical parts of the engine between them, the cylinder head gasket. It is mounted between both the cylinder head and the engine block. The primary function of the cylinder head gasket is to maintain a seal between the cylinder head and the engine block. Ordinarily, the head gasket contains coolant in the relevant passageways, also prevents air & combustion gas leakage, and maintains compression of the engine cylinders.
Besides it, the Cylinder head is placed on the cylinder block or engine housing. It forms a part of the combustion chamber with the placement of the piston and the cylinder.

The major functions of the Cylinder head are discussed in brief as follows:

Major Functions of Cylinder head in brief:

• The cylinder head provides the mounting structure for various components (for example the inlet and outlet exhaust valves and ducts, spark plugs, etc.)

• The cylinder head also acts as a seal for the combustion chamber and the powerhouse for the engine’s mechanical control.

• The cylinder head passages the coolant, engine oil, and combustion gasses.

• The cylinder head dissolute the heat produced in the engine and keeps it cool.

 The cylinder head lies above the cylinder head gasket.  The cylinder head gasket not only seals the combustion chambers but actually performs several other functions also, some of which are mentioned below:

Functions of Cylinder head gasket:

1. It seals the cylinder head.

When combustion enters the cylinder, the head gasket seals the cylinder head to the engine block to prevent the pressures created from escaping the cylinder through the space between the cylinder head and block.

2. It seals the passage.

For smooth flow of the coolant and the engine oil between the engine and cylinder heads, the cylinder head gasket kit seals the passage between the engine block and the cylinder heads. Moreover, both of these also serve directly and sometimes control the flow of the coolant and the engine oil depending upon the application.

3. It transfers heat.

The Cylinder head gasket helps heat to move freely among the engine block and 12-valve head studs by allowing the free movement of heat throughout the gasket. 

However, due to the free movement of heat between the engine block and the cylinder heads, it also helps to distribute the heat evenly between all parts of the engine, and that results in the reduction in the concentration of heat in one part of the engine.

4. It varies the Compression Ratio.

When the total volume size of the cylinder is changed with the help of head gaskets, The Compression ratio is affected by the changes in the total volume size of the cylinder with the help of the head gaskets, because some head gaskets also work as Shims (A shim is a thin and often tapered or wedged piece of material, used to fill small gaps or spaces between objects) between the engine block and the cylinder head. The cylinder heads are installed with the help of 6.7 Cummins head studs.

Moreover, In the thick gaskets, the distance of the cylinder head from the block is increased due to its size. And apart from it, the compression is also decreased with the increment in the volume of the cylinder. 

On the other hand, the thin gaskets keep the cylinder head and the block together with a very thin space. Due to this, the volume of the cylinder is decreased and the compression ratio is increased simultaneously.