How are cylinder heads made?

Answer 1

Cylinder heads of gasoline or diesel engines are made of aluminium and cast iron/steel as necessary for the particular engine. They are cast with core passages inside using cores during moulding. These passages are essential for the circulation of cooling water. About machining these are done nowadays in CNC machines with programmed operations and tools. The important point during machining is the concentricity between the bores of the valve guides and valve seat for a proper sealing of the valve seat. Machining of the mating surface of cylinder head with liner is equally important to see the optimum efficiency during compression is derived. After assembly of the components they are subjected to leak test on the valve seat to eliminate blow-bye.
VR

Answer 2

Most heads for mass production cars are now cast into a mould from below (and incorporate inserts such as valve seats). This means that as the aluminium rises through the mould all the air escapes through the top so no holes (or perosity) is left in the aluminium and this gives greater reliability. The result is a blank which is roughly the right shape with various passages for air, water and oil inside. This blank is then machined to make it exactly the right shape and the smaller passages added which could not be cast. The surface which sits on the block has to be particularly flat and is very important as it has to seal tightly onto the head gasket. Other parts are fitted to complete the head.

Aftermarket heads are a different story as they are made in much smaller numbers and are usually cast in the conventional way to reduce cost. They can be much less reliable (particularly from some US suppliers!).

In both cases CNC machineing is usually used which means that, in theory, the shape is always exactly the same.

Answer 3

a block is cast from aluminium for a petrol engine or an iron mix for a diesel engine. this is then put into a machining centre and all the important surfaces are machined to very tight tolerances.

other components are then assembled inot the block which is then assembled as an engine unit then put into a car.

Answer 4

They are cast from sand molds and machined to the proper specs. Master tech 40 yrs

Answer 5

they make a mold out of styrafoan fill it with sand and pore hot alunimum or cast iron into it the hot metal desolves and burnes completly the styrafoam leaving the sand and head thain the sand is cleaned out and its machened and checked for air pockets or other defects thain they put it on your car

Answer 6

Aluminum on newer vehicles and cast iron on older ones.