Engine Block – Definitions, Terms and Common Breakdowns

There are various parts in a car engine. All these parts have a special duty. Without one of them, lots of breakdowns may occur. One of the most important ones is the engine blocks. Furthermore, it is the common structural part of internal combustion engines. Here, you can find detailed information about the engine blocks. So, the information here;

  • What is an engine block?
  • The general construction of the engine block.
  • Types of them.
  • Common breakdowns and problems of engine blocks.
  • FAQs.

What is the Engine Block?

Engine blocks are the skeleton of the engine. They are the most important structural part of an internal combustion engine. It contains the cylinders inside the cylinder holes. Also, other important engine parts are located on this structural part.

The most important function of the engine block is, that they contain the cylinders and connecting rods inside it. It creates the required structural system to work properly. Also, an engine block must withstand the internal combustion of the air-fuel mixtures. So, the material of these parts is very important.

We stated that the general construction of the engine cylinders and connecting rods are very important. Cylinder heads and the crankshafts are connected. So, the proper working of the crankshaft depends on the engine block.

Engine block also includes the paths for the lubrication oils from the sump to the cylinder heads. Proper construction is required to maintain the lubrication of the engine.

And also, the crankshaft mechanism depends on the engine block which there is a connection between the flywheel. So, all the main parts are inside the engine blocks.

Furthermore, there are water circulation holes on it. With the help of the water pump, water circulates through these holes to prevent high temperatures in the engine. It is a very important construction for water-cooled engines.

Types of Engine Blocks

Engine types.

Types of engine blocks define the general shape and construction of the engine. For example, we call the engines inline, V, or boxer. So, this is about the general structure of the engine blocks. Let’s check which types we have.

Inline Construction

This is the most common construction around cars. In this construction, the direction of cylinders is vertical. In general inline engines, there are 1-4 cylinders.

The most important advantage of the inline construction is, that the engine works more smoothly. So, nowadays this type is generally used in passenger cars.

If you open the bonnet of the car, you will probably see that the type is an inline engine. You can see the spark plug screw sets in inlined manner.

Boxer Types

We call this type boxer because the cylinder arrangement is horizontal and opposed. They call these types boxers because the cylinder construction resembles two 4 punches of 2 boxers in the ring.

This type of construction is not common as the other ones. Some of the Volkswagen cars include these boxer types.

Some of the boxer types have air cooling systems.

Because of the different construction, the engine block shape will be also very different from others. Also in general, the placement of the crankshaft is between the cylinders. So, crankcases are part of the engine blocks in boxer types.


Also, this construction is very common around heavy machinery. Also in sports cars, the use of the V engines is very common. In general, they are V6, V8, V10, and V12.

The general angle of the V construction is between 15 and 20 degrees.

In general, these types are not common in the general use of passenger cars. But you can see these engines in classical cars. You can see angular-oriented opposing cylinders when you open the bonnets of these cars.

Radial Engines

These types also have very different construction. Cylinders are aligned around a circle. And the crankshaft structure is so different from the conventional ones. Also, the engine block structure is somewhat different. You can see discrete parts of the block for each cylinder.

Generally, they use radial engines in aerospace applications. You can see propellers on the nose of the planes that have radial engines. Furthermore, they produce much higher RPMs if we compare them with the conventional ones.

W-Type Engines

Also, this is a different engine block configuration. It is like the V-type but there are double lines of cylinders on each side. Generally, these engine configurations are used in some sports cars and marine applications.

Because of the complex configuration of cylinders, they have very complex engine blocks.

General Construction of Engine Block

Engine block parts.
Image Source: Howacarworks.

It may seem like a very complex construction. But if you know the general structural components of an engine block, it will seem very basic to you. Here we show the general parts and general constructional features of them.

Cylinder Holes

These sections are the most apparent ones on engine blocks. You can see them as big holes on them. The number of them defines the number in that engine. So, the cylinder heads are making reciprocating motions inside these cylinder holes.

Also, at the top of the cylinder holes, there is an engine head that contains the exhaust and intake valves and sparks plug. So, the total of these systems creates the general cylinder construction. So, the internal combustion of the air-fuel mixture takes place in the cylinder holes.

And also, the walls of the cylinder holes have a very good surface finish, which we obtain with honing operations. These very good surfaces provide better movement of the pistons.

In general applications, there are liners inside these cylinder holes. With the liners, we prevent corrosion and damage to the engine block and hole.

Coolant Holes and Passages

Cooling in engines is a very important phenomenon. Without sufficient cooling, very harsh damage to the engine will take place. So, very efficient cooling systems are important for engines.

Some of the engines are water-cooled and some of their air cooled. In general, car engines are water-cooled. And also, the motorcycle engines are air-cooled. If the cooling system consists of water, there are cooling holes inside the engine block.

Around the cylinder holes, you can see the minimal coolant holes around the cylinders. These holes are connected to the cooling system. In the cooling system, there are hose systems that have a connection with the coolant holes and a water pump. Also, the water goes through an intercooler, while a fa applies forced convection on the water. This is a very efficient cooling system for car engines.

The design of coolant holes requires very important engineering know-how. Because the production of the internal shapes like them with the casting operations is very hard. So, you need to make a design both for efficient cooling and easy production.

Oil Feed Passages

A sufficient oil supply to cylinder heads is very important. Because, if there is no sufficient lubrication, the friction between the engine blocks and the cylinder heads will cause very big damage. And also, the engine will not work properly.

On engine blocks, there are oil-feed passages and holes. The oil pump pumps a sufficient amount of lubricant oil through these passages. So, very good lubrication takes place for efficient working.

The same facts for the coolant holes are also valid for the oil feed passages. So, you need to design it well for the casting operations. Also, lubrication efficiency must be very good.

Deck of Engine Block

We call it the top side of the engine block deck. This top side is a very good finish where we attach the engine head. Also, the top edges of the engine cylinder holes are on the deck.

The reason for the good surface finish, we attach the engine head to this deck structure. So, the surface attachment between these two parts must be superior. This will prevent possible leakages.

In the deck section, you can see different kinds of holes. The biggest ones are the cylinder holes. Also, the smaller ones are the attachment bores for the engine head. And you can see the coolant and lubrication holes on the deck.

Core Plugs

Also, they are very important to have core plugs. Because they prevent the water coolant to leak to the outside of the engine. You can see the places of core plugs at the sides of engine blocks.

Form the core plugs, you can adjust the water coolant and unload it from the block. Also, you can adjust the pressure from these plugs.

Oil Filter

The place of the oil filter is the side of the engine block. The oil filter filters the oil lubricant. The contaminations inside the oil can very very harmful to the engine. So, an oil filter is a very important part.

In each cycle, oil goes through the oil filter. So, the possible contaminants that come from the exhaust gases and air hooked on the oil filter.

The maintenance of the oil filter is very important. Because the oil filter accumulates filth because of the oil. So, you need clean it for a specific period.

Camshaft Housing

We mount the camshaft also in the engine block. The camshaft is a very important part of car engines. They are responsible for the general working principle of the intake and exhaust valves.

At the right or left side of the engine blocks, you can see the general assembly place of the camshafts. Lubrication of the camshaft depends on the lubrication holes of the engine.

Crankshaft Housing

Also, the crankshaft is a very important part that is responsible for the production of the rotational motion. We attach the crankshaft to the engine block. So, you can find the holes for the crankshaft bearings at the sides of the engine block.

Cylinder Liners

Cylinder liners are very important in cylinders. They are protective parts inside the cylinders. We can remove the cylinder liners with new ones. So, it prevents the engine block from wearing because of the movements of cylinders.

Thanks to the cylinder liners, we do not need to change the engine block completely because of the wear and corrosion.

Also, there are two types of cylinder liners; dry and wet cylinder liners.

Wet cylinder liners contain a coolant liquid before the liner. So, better cooling of the engine takes place. The primary advantage of the wet cylinder liner is less time for the cold start of the diesel engines.

Dry liners are generally made from the block’s material. And in general, we use dry liners in engine constructions.

Materials to Produce Engine Blocks

The proper material selection for the engine blocks is a very important task. Firstly, we need to know what we are expecting from the engine blocks.

Ductile and Brittle Balance

The most important expectation from these blocks is very good mechanical strength. We expect both good ductile and brittle behaviors from these parts. We expect ductile behavior because of the dynamic movements and loads on the engine block. The piston movements and also fuel combustion are very serious loads on the block structure.

Also, we are expecting very good brittle behavior from these structures. Because the integrity of the block shape is very important. The loads should not harm the engine block. So, if the material is very ductile, it will deform with the effect of loads.

The general materials for engine blocks are not ductile. They are brittle if we compare them with steel. But their resilience and toughnesses are very high that they can absorb the dynamic load effects.

Vibration Damping

Another important property that we are expecting from engine blocks, is very good vibrational absorption capacities. Because there are lots of dynamic loads due to the movements of engine cylinders and combustion. It is better to have a good vibration damping property to prevent affecting the other parts of a car.

Good Thermal Properties

Thermal properties are also very important. If the engine block material has good thermal conductivity, the cooling of the engine will be easier. Otherwise, the temperature of the engine will rise and harm the components.

With consideration of these aspects, the general alloys that they use in the manufacturing of the engine blocks are cast irons and aluminum alloys.

Cast Iron Engine Blocks

They produce most of the engine blocks from cast iron material. In the general composition of the cast iron; 95% iron, 2.2% carbon, 1.2% silicon, 0.63.5 manganese, 0.12% sulfur, 0.85% phosphorus.

The mechanical properties of cast irons are suitable for big engine applications such as locomotive engines, trucks, and heavy-duty machine engines.

The toughness of the cast irons is very high. They can absorb the dynamic loads of the cylinders and combustions without changing their shape. It can be brittle but also very tough.

Cast irons are renowned for their very good thermal properties and vibration damping properties. So, they are good for engine block applications.

And also, they are very good vibration dampers around other materials. Because of this reason, they are suitable materials for engine block applications. As you understand from its name, the casting of these materials is very good.

Aluminum Alloys

Aluminum alloys are also very common in engine block production. A typical aluminum alloy composition of these machines; is 91% aluminum, 2% tin, and 7%, copper.

Also, aluminum alloys are very good for the applications of small engines such as passenger cars and motorcycles. They provide sufficient amoınt of structural and mechanical strength for these applications.

And also aluminum alloys have very good thermal and vibrational characteristics.

Common Breakdowns and Problems in Engine Blocks

Like the other parts of the engine, you will face some problems and breakdowns of these parts. Also, they are the most expensive problems that you can face with your engine.

Coolant and Liquid Leaks

This is the most common problem of engine blocks. There can be liquid and coolant leaks from different sides of it. This leakage can come from the plugs. In this case, you can change the plugs with newer ones.

Also, this leakage can arise from the cracks on the engine blocks. This is a very big problem that can cause a change in the engine block with a new one.

And also, the other important cause of the liquid leaks is the gasket between the engine head and the engine block. You may change the gasket between them to prevent liquid leaks.

You can understand whether there is a leakage or not at the surface. The surface of the block will wet and you can inspect if it is a coolant liquid or oil.

Porous Engine Block

This problem may be an inherent problem of the engine block. Porous surfaces can cause very big damage and inefficient working of the engine.

Also, this problem can be caused by the contaminants between the moving parts. Because contaminants can harm the smoothness of the contact surfaces of the moving parts.

Engine Block Crack

Engine block crack.

This is also a very important problem that you can face with your engine. If there are cracks on the engine blocks, it is very easy to understand the symptoms.

According to the place of the crack, there are different kinds of effects. Repairing engine cracks is a very tough business. You may need to change the complete engine block.

Mixing of Coolant and Oil

Also, if the crack is between the coolant and the oil passages, these liquids will mix. This is also another important cause of the engine block crack.

White Smoking

If there is a crack between the coolant holes and the cylinders, the coolant will leak into the cylinders. This will cause white smoke at the tailpipe of the car. Because the coolant will burn with the fuel.

Liquid Leaks

This is the most common cause of the cracks. So, if there is a crack at the coolant and oil holes, the leakages take place.

If the coolant leakages are very high, it will cause very high temperatures in the engine. Because there is not enough coolant to cool the engine.

Performance Loss

Performance loss of the engine caused by the cracks shows itself as the compression loss of the engine cylinders. This compression is affected by the cracks in the engine holes and cylinders.

Exhaust Gases in Cooling System

Also, if there is a crack between the coolant holes and the cylinders, exhaust gases can infiltrate inside the coolant. So, you will see lots of amount of bubbles because of this issue. Also, the pressure of the coolant will increase becuase of this reason.

Other Important Variations of Engine Blocks

In engine technology, there are different kinds of other technologies that engineers are using. Around these technologies, you can find; integrated crankcases, integrated cylinder heads, and integrated transmission. They have different advantages for different applications over conventional ones.

Integrated Crackcase Technology

In general, we call these applications monoblocs. So, they have a more compact structure and more efficient systems for different kinds of applications. The integrated crankcase is here the engine block also contains the ca-crankcase structure in itself. So, nearly all the parts are integrated into this monobloc.

In big diesel engine applications, they use this technology to improve the efficiency of the systems.

Integrated Transmission

This is another important technology that some brands are applying today. The case of the transmission and the engine shares the same block which they produce in the same casting. So, it provides the use of the same lubrication oil both for the engine and the transmission.

Also in Fordson tractors, they used integrated transmission technology.

Integrated Cylinder Head

As you understand from its name, the cylinder head is produced from the same casting as the engine block. So, there is no discrete part like the engine cylinder head. Also, some automotive brands are using this technology such as Honda. 

The most important disadvantage of this technology, the repair times are very long. Because the structure of this technology is very complex.


So, these are the general important information about the engine blocks. There are different types of them. And these types affect the general construction of internal combustion engines. And also, they use these different constructions in different applications.

Also, each shape and holes on the engine blocks have a meaning. All these shapes have a different important duties.

Automotive engineering, use different types of materials for different engine applications. But the most common materials are aluminum alloys and cast irons. You can find one of these materials in the different sized of daily passenger cars.

Furthermore, it is very important to know the general breakdowns and failures of the engine blocks. Lots of these failures originated from the cracks. And the repair expenses of these parts can be very expensive. Because they are the backbone of the engines.

Different kinds of technologies are also used in the production of engine blocks. And they are generally about combining the other main parts of the engine with the engine blocks.

So, do not forget to leave your comments and questions below about this topic.

Your precious feedbacks are very important to us.

FAQs About Engine Blocks

Does engine block sealer work?

Sealers are very important parts. They prevent the squeezing of liquids into unintended parts. So, the sealers are very important to seal the other parts from engine oil and coolants. You can understand that the engine sealers are working.

Can the engine block be repaired? 

Yes, there are different kinds of repairing techniques of them. But it changes according to the type of breakdown. The most common one is the cracks. In general, they are applying welding techniques the repair these cracks.

Can engine block cause overheat?

Yes, this is the general problem that cracks on them cause the overheating of the engine. Overheating can take place because of the loss of the coolant liquid from the block structure. So, the cooling efficiency drops, and overheating takes place.

What engine block is made of?

According to the different kinds of applications, there are different materials that we use in the production of them. But the most common materials are aluminum alloys and cast iron. Because they provide the required mechanical strength and thermal properties.

What does the engine block do?

Their main duty of them is to provide the structural integrity for other important car engine parts such as crankshafts, connecting rods, camshafts, cylinders, and others. So, we can say the engine blocks are the backbone of engines.

Why do engine blocks crack?

There are different reasons for it. Heat rises on some portions can lead to cracks. Also, heat rises can take place working the engine at higher RPMs with higher loads.

Can the engine blocks be welded?

It changes according to the materials. But in general, we can weld the cast iron materials without any problem. So, repair of the cracks can be made with welding techniques.


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