What Is A Piston in Engine : Types, Parts, Symptoms, Causes (& Replacement Cost)


An internal combustion engine uses several different parts that make the engine run. Some useful parts of an internal combustion engine are visible from the outside. But some of the engine’s useful parts are internal, such as pistons, rings, valves, cylinder sleeves, crankshafts, camshafts, and timing belts or chains.

An engine’s piston is an important and extremely useful part. The operation of an internal combustion engine cannot be imagined without a piston.

Through this article, you will learn in detail about the engine piston. like what a piston is, how it works, symptoms and causes of a damaged piston, and replacement cost.

What Is A Piston?

A piston is a cylindrical component in any internal combustion engine or steam engine. Pistons are used in internal combustion engines or steam engines to transfer force from the expanding gas within the engine cylinders to the crankshaft. 

The piston is attached to the crankshaft of the engine with a connecting rod. The piston is pushed by the pressure of the gases in the cylinder of the engine, and the piston moves up and down in the cylinder of the engine.

The piston converts linear motion into rotational motion of the crankshaft, which causes the engine’s crankshaft to rotate. Pistons are designed for much higher pressures.

Different rings are fitted on top of the piston and the piston is fitted in the engine cylinder with the rings. Piston rings act as seals inside the engine cylinders and prevent the engine cylinder compression from leaking.

How Does A Piston Work?

In any internal combustion engine or steam engine, the piston is a cylindrical metal component that moves up and down inside the cylinder of the engine. The piston of the engine is connected to the crankshaft through the connecting rod.

The up-and-down motion of the piston is converted by the crankshaft into rotary motion, which is used to propel a vehicle or perform some other function. The movement of an engine’s piston is driven by the combustion of fuel in the cylinder.

When the engine is combusted in the internal combustion chamber of the engine, the gases produced by the combustion of the fuel push the piston down, which in turn rotates the crankshaft of the engine. Piston rings also form a seal between the engine’s cylinder and piston, helping to contain the high-pressure gases produced during combustion.

In internal combustion engines and steam engines, the piston is located inside the cylinder, which is sealed at one end by a head and at the other end by a crankcase. The cylinder and piston form a combustion chamber, where the fuel is ignited.

The gases produced from the fuel combustion process push down the piston of the engine with high pressure, rotate the crankshaft and generate rotary motion, which is used to start the engine.

In a four-stroke engine, the pistons often have four strokes. Intake, compression, power, and exhaust During the intake stroke, the piston of the engine moves down and creates a vacuum in the cylinder, which draws in a mixture of fuel and air. During the compression stroke, the piston of the engine moves back up, compressing the fuel-air mixture.

During the power stroke, the compressed fuel-air mixture in the engine’s combustion chamber is ignited, causing the combustion gases to expand and push the piston down. During the exhaust stroke, the engine’s piston moves back up, pushing the exhaust gases out of the engine’s cylinder.

In a two-stroke engine, the process is different. There is no intake or exhaust stroke in a two-stroke engine. In this type of engine, intake and exhaust are through the ports of the engine’s cylinders.

Types Of Pistons

  • Solid pistons
  • Hollow pistons
  • Forged pistons
  • Flat-top pistons
  • Dome-top pistons
  • Dish-top pistons
  • Coated pistons
  • Dual-ring pistons
  • Boxed pistons
  • Strutted pistons
  • Slipper pistons
  • Offset-wrist pin pistons
  • Split-skirt pistons

What Metal Are Pistons Made Of?

Pistons are generally manufactured from cast iron, aluminium alloy, stainless steel, and titanium metal.

  • Cast iron: cast iron is the most common metal for the manufacture of pistons. That’s why pistons made of this metal are used in classic and turbo engines.
  • Aluminum alloy: pistons made of this metal are light in weight and absorb heat well. Hence, pistons made of this metal are used in the engines of high-performance cars.
  • Stainless Steel: These metals are hard and stable. Pistons made of this metal are used in large and heavy engines.
  • Titanium: This metal is harder and more stable. Therefore, pistons made of titanium metal are often used in the engines of racing cars.

Parts Of A Piston

  • Piston crown
  • Piston skirt
  • Piston pin
  • Piston rings
  • Connecting rod
  • Connecting rod pin
  • Piston retaining circle pin
  • Piston oil control ring
  • Piston compression ring
  • Piston scraper ring
  • Piston taper cut ring
  • Piston pin oil feed hole
  • Piston pin oil return hole
  • Empty the back hole
  • Piston cooling jet
  • Piston ring grooves
  • Piston ring expander
  • Piston ring end gap

Symptoms Of Bad or Damage Pistons

There are many symptoms of piston damage in an internal combustion engine. These symptoms can be of the following types:

1. Low Oil Pressure

A damaged or worn piston is not able to create a proper pressure, which causes oil to leak into the oil chamber and reduce oil pressure.

2. Poor Engine Performance

A damaged or worn piston is unable to seal the compression in the engine’s cylinders, which affects the power and efficiency of the engine. Because for better power and performance of the engine it is necessary to have proper compression in the cylinder of the engine.

3. Engine Knocking Noise

A damaged or worn piston can cause unusual noises because there is looseness between the worn or damaged piston and the engine cylinders, due to which the piston starts hitting the cylinder when the engine is started. This causes a knocking noise to come from the engine on startup or during acceleration.

4. White Smoke From Exhaust

A damaged or worn piston can cause oil to leak into the fuel combustion chamber of an internal combustion engine, causing engine oil to burn with the fuel. So white smoke starts appearing from the exhaust due to damaged pistons or rings.

5. Piston Seizure

Sometimes the piston of the engine gets stuck in the cylinder of the engine due to overheating of the engine or due to lack of lubrication and in no time the piston of the engine gets seized in the cylinder. This is a critical condition in the engine as after this the only option left is to overhaul the engine.

6. Low Engine Power

When the piston of an internal combustion engine is worn or damaged, compression leaks between the engine cylinder and the piston. Due to this, the power of the engine decreases.

7. Low Fuel Efficiency

Worn or damaged pistons of the engine interfere with the fuel combustion action of the engine. Due to this, the low fuel efficiency of the vehicle’s engine can be seen. because a damaged piston is unable to stop the compression leak. Due to this, more fuel is consumed to get power from the engine.

Causes Of Damaged Pistons

There are many reasons why the piston of an engine gets damaged. These possible reasons are as follows.

1. Engine Overheating

Engine overheating is often the cause of piston damage in an internal combustion engine. Due to excessive heating of the engine, the cylinder sleeve and piston of the engine expand, causing the piston to get stuck in the cylinder of the engine and the piston in the engine to seize.

2. Lack of Lubrication

Sometimes, due to prolonged oil leakage in the engine, the engine oil gets reduced. Due to which there is a lack of lubrication in the internal parts of the engine and the internal parts of the engine run dry.

Due to which the internal parts of the engine get seized due to overheating due to friction. The most damage from this is to the engine’s piston rings, cylinder, crankshaft, camshaft and engine head valves.

3. Improper Engine Oil

To properly lubricate any internal combustion engine, engine oil of the appropriate grade and lubricity is used. But sometimes inappropriate engine oil is used in the engine.

Due to this, the internal parts of the engine do not get proper lubrication, which causes the pistons to get damaged due to friction.

4. Mechanical Failures

Sometimes broken piston rings and worn connecting rods can also cause engine piston damage. because the piston has to bear more jerks due to the worn connecting rod.

5. Lack of Maintenance

Many times, we ignore the maintenance and service of the engine for a long time. But if the engine oil is not changed for a long time, the lubrication from the oil gets reduced. which causes damage to or failure of all internal parts of the engine.

Engine Piston Replacement Cost

In general, piston replacement costs can range from $1200 to $4500, depending on the engine. Because piston engines have more expensive parts and require a complete rebuild of the engine. Also, rebuilding an engine takes a long time. So changing the piston also increases the labor cost of the mechanic.

This estimated replacement cost will include the labor cost of the mechanic. But this estimated cost does not include taxes and fees.

A piston for a typical engine can cost between $200 and $800. If your vehicle has a 4 cylinder engine, you may pay between $800 and $3200 for a 4-piston engine, and the mechanic’s labor cost may be between $400 and $1300.

However, the cost of replacing a piston depends on the model of the vehicle, the type of engine, and the labor cost of replacing it by a mechanic.

Keep in mind, replacing engine pistons is an expensive and time-consuming task, and replacement of engine pistons may require additional parts replacement or repair. Such as piston rings, gaskets, engine oil, filters, and engine lathes. All of these factors directly affect the replacement cost of pistons in an engine.


Q. – What are the 5 parts of a piston?

A. – The parts of the piston of any internal combustion engine include the piston head, piston pin bore, piston pin, skirt, ring groove, ring land, and piston ring.

The piston head is the topmost part of the piston, which is usually on the cylinder-head side of the engine. This part of the piston is subjected to the pressure of the gases obtained from the fuel combustion process.

Q. – What is the shape of piston?

A. – The piston of an internal combustion engine is usually cylindrical, placed between the cylinder heads of the engine. When the crankshaft of the engine is rotated, the piston moves up and down in the cylinder through the connecting rod according to the position of the crankshaft.

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