How does an Engine Block work? | What is a Cylinder Block?

An internal combustion (IC) engine is the most commonly used type of engine. The IC engines are used in different types of vehicles such as buses, motorcycles, tractors, cars, and many other vehicles. These types of engines consist of different components, and an engine block is one of them. The engine block is also called a cylinder block. The cylinder block is the most important component which provides safety to many other internal parts of the engine. This article mainly describes different aspects of the cylinder block.  

What is an Engine block?

An engine block is a part of the IC engine that contains the cylinder, piston and other components of the engine. The engine block is also called a cylinder block.

In the earlier vehicle engines, the engine block contained only a cylinder block, which was linked with a separate crankcase. While, in the latest engine, the crankcase also integrates with the cylinder block as a single part.  

The engine blocks also have oil galleries and coolant passages. The cylinder head uses to close the upper portion of the cylinder block.  A crankcase connects with the base of the cylinder block. Many other components of the engines are mounted inside or on the engine blocks.  

These blocks also have a separate crankcase for the crankshaft used in stationary engines, marine engines, and large engines. This separate aluminum crankcase helps to reduce weight and a quick and cheap replacement.

When the wear and tear occur in the engine, it converts into an oval due to that; the piston ring releases gas. This gas leakage from the piston ring is known as a blow-by. These gases decrease the engine efficiency. The finishing on the walls of the cylinder also influences the sealing rings.

This cylindrical wall provides a very smooth finishing. The special grinding stones create a small groove in the cylinder wall to catch the oil. These grooves assist in lubricating the piston skirts and piston rings.

In the past, gray iron or cast iron were used for the construction of cylinder blocks. This is because the machining of these materials was very easy.

Functions of Engine Block

The engine block is a structure that contains the cylinders and other components of the internal combustion engine.

The design of the cylinder block depends on the features and type of the engine model manufactured. This includes coolant channels, cylinder liners, and cylinder walls.

The water-cooled engine contains many passages around cylinders, spark plugs, and valves.

The L-head engine block has different openings for the valve and valve ports. The base of the cylinder block also assists the oil pan and crankshaft. In maximum engines, the bushing uses to support the camshaft. This bushing fixes in a borehole of the cylinder block.

In the case of L-head in-line engines, the exhaust manifold, and intake manifold connect with the sides of the cylinder block.

In an I-head engine, the inlet and exhaust manifolds are attached to the cylinder head. Other components (such as fuel pump, ignition distribution, clutch housing, flywheel, timing gear, and the water pump) are connected with the cylinder block.

As the name of the cylinder head represents that it installs on the head or top of the cylinder block.  Many other components connect with the block via a gasket. This gasket provides excellent sealing to stop gas, oil, or water leakage. Some other components are connected to the bolts, and the remaining connect with nuts and studs.

The engine block designs in such a way that it can withstand various loads and temperatures to maintain the lubricity and stability of the engine. This block has many oil passages to circulate the oil in the engine.

The block also has water galleries to cool the engine and control the optimal working temperature.

The circulating water helps the engine to work at its normal operating temperature, stops unnecessary deformation and expansion, and ultimately prevents malfunction of the associated moving components.

Read Also: Sympthoms of a Bad Gasket 

Parts of Cylinder Block

The engine block has the following major parts:

  1. Cylinders
  2. Oil filter
  3. Water pump mounting
  4. Core plugs
  5. Head studs
  6. Crankcase
  7. Deck
  8. Oil passages and galleries
  9. Coolant passages
  10. Bosses
  11. Crankcase

cylinder block parts, parts of engine block

1) Cylinders

A cylinder is the most important component of the engine and engine block. It is also known as a compression cylinder. This cylinder has a piston that moves up and down inside the cylinder. During the suction process, the air-fuel mixture firstly enters the cylinder, and the reciprocating piston compresses the air-fuel mixture. 

These cylinders have multiple holes to make a strong seal with the piston. They have a large size. The number of cylinders in an engine varies according to the type of the engine and power requirements.

Read Also: Different types of Engines

2) Oil Passages and Galleries

The lubrication of the engine parts is very important for their maintenance and proper working. The oil passages and galleries of the cylinder block are used to lubricate different parts of the engine. They use to provide oil to different engine parts (such as crankshaft and cylinder head) and hydraulic power systems.

3) Water Pump Mounting

A water pump installs at the end of the block. It couples to a coolant housing. It uses to supply water to the engine. This pump supplies water so that engine can maintain its cooling and can operate at normal temperature.

Read Also: Different types of Pumps

4) Deck

A deck is the upper part of the block where the ends of the cylinder remain.

5) Oil Filter

The oil filter usually installs on the side or under the cylinder block. These filters are available to remove as many contaminants as possible from the circulating engine lubricating oil.

6) Head Studs

A round rod of alloy steel is used for the manufacturing of the head stud. There are threads on both ends of the head stud.  These threads allow a tight-fitting of the stud into the block and prevent the stud from loosening when the stud nuts are eliminated.

7) Crankcase

This component surrounds the crankshaft. It installs under the block in the latest engine.

Read Also: Working of Crankcase

8) Core Plugs

The core plug acts as a cap of the engine block at the end of the coolant passage to stop water and coolant from leaking out of the engine.

9) Crankshaft

It a rotating component of the internal combustion engine. It connects with the piston via a connecting rod


Read More: Working of Crankshaft 

Material Used for Cylinder Block Construction

The gray cast iron is used for the manufacturing of the engine block. In some cases, it is also manufactured with chromium and nickel. Sometimes blocks are manufactured from aluminum, with the addition of steel sleeves or cast iron.

Cast iron has more wearing properties compared to other materials. Therefore, it is considered to be a best suitable material for the construction of cylinder walls.

Some small engines have chromium cylinder walls. This is because chromium is a very hard metal that increases the life cycle of the cylinder block and reduces wall wear.

High silicon aluminum alloys were tested to determine their potential as crankcase and cylinder block materials. These alloys have high wear resistance and a low coefficient of thermal expansion.

Types of Engine Blocks

The engine or cylinder block has the following major types:

  1. Inline engine cylinder block
  2. V Engine Cylinder
  3. Opposed engine cylinder block

1) V Engine Cylinder

It is the most famous type of engine cylinder block. It is most commonly used in the engines of different vehicles. In this configuration, the cylinders of the engine arrange in two rows. These two rows of cylinders are arranged in such a way that they make a V shape. Therefore, such a type of engine is known as a V Engine.

V Engine Cylinder block

The two-cylinder rows fix at a specific angle to each other. This angle keeps very small (i.e., between 15° and 20°). If this angle is higher, the engine balancing will be very tough.  The V engine is difficult to balance with the counterweight on the crankshafts.

The crankshaft contains only two cranks, and the connecting rods of the two opposite cylinders’ rows connect with the same crank pin. A single crankpin connects with two connecting rods.  The V-type engines have different types of cylinder blocks, such as V4s, V8s, and V16.

Read Also: Working of V4 Engine

2) Inline Engine Cylinder

The cylinders of the in-line engine arrange in a single line. The vehicles which have inline engines work very smoothly. Therefore, they are mainly used when high speeds are required.

Inline Engine Cylinder

The automobiles which have such type of engine block run smoothly. The inline engines are employed for passenger cars.

3) Boxer Engine Cylinder or Opposed Engine Cylinder

The boxer engine is a flat pressed V-engine. The cylinder block of this engine has two rows of cylinders. Each row contains two cylinders. The cylinders of these two rows set opposite to each other.

Boxer Engine Cylinder

The boxer engine is also called a pancake engine. This requires very little head space, which makes a compact compartment of the engine.

The Volkswagen engines contain this type of four cylinders arrangement. This is an air-cooled engine. It installs on the car rear. This type of engine block is also used in advanced engines like Porsche and Subaru.

What are the Cylinder Block Problems?

  1. External Engine Coolant Leak: In maximum cases, this type of leakage appears from loose hoses, heater cores, radiators, or water pumps. It may also occur due to cracks in the engine block.
  2. Porous engine block: The failure of this type of cylinder block usually causes due to the ingress of contaminants into the metal. It may also appear during the manufacturing process. This problem cannot be avoided because it is the origin of the cylinder block.
  3. Cylinder Wear/cracked cylinder: After a long time of operation, the wearing problems start appearing inside the cylinder. These issues may damage the machined smooth walls and affect the piston ring’s sealing. You can stop this issue by increasing the bore size.

Composition of Cylinder Block

Following is the structure of the cast-iron engine block

  • Phosphorus 0.85%
  • Sulfur 0.12%
  • Manganese 0.63%
  • Silicon 1.2%
  • Carbon 2.2%
  • Iron 95%

An aluminum alloy cylinder block and piston have the following structure:

  • Copper 7%
  • Tin 2%
  • Aluminum 91%

Advantages of V engine Block over In-line Engine Block

  1. A V-engine block enables more rigid, lighter, and shorter engines. A rigid engine allows higher combustion pressures and higher operating speeds, and the cylinder block and crankshaft have lower difficulty in bending or flexing. The flexing can result in loss of engine control, increased wear and friction loss, and internal vibrations.
  2. It allows the intake manifold to ensure all cylinders are relatively close together so that the air-fuel mixture is distributed relatively evenly over all cylinders.
  3. The hood line can be lowered, resulting in a smaller vehicle profile. This is because the carburetor and some other components are installed between the two rows of cylinders and do not take up any headroom above the cylinder.

FAQ Section 

What are the types of Engine Blocks?

The engine block has the following major types:

  1. Opposed engine cylinder block
  2. Inline engine cylinder block
  3. V Engine Cylinder

Where is the Cylinder Block located in the engine?

The cylinder block is a structural part of the engine that extends up from the centerline of the main crankshaft bearing to the connection with the cylinder head.

What is the function of a Cylinder Block?

  1. The main function of the engine block is to enclose the crankshaft, connecting rod, and piston. These components work within the block.
  2. The cylinder block provides support to different components, including supplementary equipment (e.g., intake and exhaust manifolds alternators, air conditioning compressors, etc.).
  3. It contains lubricating circulating components like an oil filter, oil pump, and oil pan.
  4. It also plays an important role in the cooling circuit.

How much does it cost to replace an engine block?

The replacement cost of a cylinder block varies according to the model of the engine and the areas where you live. The replacement cost of a small engine block varies from $500 to $1100. Similarly, the cost of a long-block engine varies from $1500 to $2600.

What causes engine block damage?

The overheating of the engine is the most common reason of engine block damage or failure. As the internal temperature of the engine becomes very high, the thermal stress attacks on the cylinder block due to that it cracks.

This block may also crack due to freezing temperature. This happens when the cooling system is full with a high quantity of water and antifreeze is insufficient to control the temperature of the cooling system water. 

What is an engine block heater?

An engine block heater is a unit which uses to warm the fluid (i.e., oil) and the engine just before starting the automobile.  

The block heater is very useful at extremely low temperatures, as it reduces the risk of damage due to “cold starts” and idling.

How to drain coolant from engine block?

  1. First of all, eliminate the hose of the lower radiator and collect the waste coolant in a vessel.
  2. Now eliminate the hose of the top radiator and clean out the system with a normal hose.
  3. This cleaning process continues until there is no more drainage coolant in the engine and clean water starts coming out from the engine bottom.
  4. Fill up the engine with new coolant and reconnect the radiator hoses.

What are the symptoms Of Engine Block Failure?

As the engine block fails, it generates different signs. Following are the most common symptoms of engine block failure:

  • A reduction in engine performance
  • Engine overheating issues
  • Visible engine smoke
  • Coolant and oil mixing
  • Leaking coolant or oil
  • Visible extreme smoke from the exhaust pipe
  • Frozen antifreeze in the radiator
Read More
  1. Different types of Engines
  2. Types of IC Engines
  3. Types of Reciprocating Engines
  4. Latest Cost of Coolant Leak Fix

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