The butt is the engine top, that closes the combustion chambers from above. In modern engines it is also where the Válvulas and Camshafts. That is why it is one of the most important parts of the mechanics of our car.
It is one of the three basic parts that make up a combustion engine. pistons. Listing them from bottom to top, they are: the bench, which is where the crankshaft moved by the Rods that go to the pistons, the engine block, which is the middle part where the combustion chambers and these pistons go up and down, and finally the cylinder head, which closes the engine from above.
cylinder head parts
The cylinder head itself has few parts, although inside it contains many parts necessary for the operation of the engine. In general its parts are limited to four:
- cylinder head cover: upper part that covers the cylinder head and keeps the oil inside to keep everything lubricated.
- cylinder head cover gasket: is responsible for maintaining the seal between the cover and the head
- Head: This is where the camshafts, valves, etc. are located.
- head gasket: is responsible for maintaining the tightness between the cylinder head and the block.
What's inside the butt
Although they are not parts of the cylinder head itself, inside it we find the Camshafts, intake and exhaust valves, guides Where do the valves go up and down? springs so that the valves close again when the tree opens them, in some cases rockers to actuate the valves, checkpoints y semicones to fix everything in its place and platillos to prevent any part from damaging the cylinder head.
Also, the cylinder head is where the plugs in gasoline vehicles or heaters in diesel vehicles. In the same way, in the butt also we find the injectors that allow fuel to enter the interior of the cylinders.
Nor can we ignore the lubrication system that the cylinder head must have, since it is very important that the camshaft and the valves must be perfectly lubricated, to ensure the proper functioning of the engine. Hence, it also has one or more O-rings that prevent the leak from escaping. engine oil. As for its fixing, it is screwed to the engine block by means of very high-strength screws. Between the cylinder head and the block we find the cylinder head gasket.
cylinder head types
air or liquid cooled
Depending on the type of engine, we can find different types of butt. First of all, they can be differentiated depending on whether the engine is air-cooled, so they have fins for this purpose and can be found on some motorcycles. Second, if the engine is liquid-cooled, the design of which is much more complex so that the antifreeze flows everywhere and dissipates heat evenly. Otherwise, unwanted deformations could be generated that could cause breakdowns.
Depending on the number of valves
We can also find cylinder heads that have two valves per cylinder or models with four valves per cylinder. We can even find other more strange configurations with, for example, five valves per cylinder. The number of valves per cylinder directly influences the engine performance.
There are also very old combustion engines that did not have valves in the cylinder head. These are the so-called Side Valve (SV) distribution engines, which had the valves in the engine block, on the sides of the cylinders. An example of this type of motors are those that mounted the famous Ford T of the beginning of the XNUMXth century.
According to the material
The materials with which a cylinder head is built can be diverse. The most common is that the cylinder head is steel, aluminum or alloy. A material that does not have to be the same in which the block is built, although it is often the case.
The aluminum cylinder heads They have the advantages of conducting heat better and being lighter. But their disadvantages are that they are more expensive and less resistant to wear in the very long term. This conductivity has another important effect for motors, which is the lower thermal inertia. Explained in mundane terms, it means that the less time it takes for the metal to heat up, the less time it takes for it to cool down. The result is that it reaches service temperature sooner but takes less time to lose it.
The steel cylinder heads instead they weigh more and have more thermal inertia. They are also cheaper and more resistant to wear and tear over time.
Breakdowns
Together with the block and the main frame, the cylinder head forms a structure that has to withstand the enormous pressures and temperatures that are generated inside. They are joined together by means of highly resistant screws and gaskets that ensure that there are no cracks.
When the engine overheats, a very common fault is the cylinder head deformation and loss of tightness due to head gasket. This is because, being the part that seals the combustion chambers from above, it is the one that suffers the most from excess heat. That is why the cylinder heads have to be very firmly attached so that there are never any sealing problems.
car engine cylinder head price
The price to fix or change a cylinder head is high, both due to the cost of materials and the number of hours needed in a workshop. If it is only the gasket, the price of the materials can be around 100 or 200 euros, but if you also have to change the cylinder head itself, the price can go up to around 800 Euros.
Workshop hours can be between 10 and 20 hours of work depending on the model, which can mean an increase in the bill of between 400 and 1.200 euros Depends on which shop you go to.
Images 3,4 and 5 – LC Nøttaasen Follow, Timitrius, Mirko Junge