Wednesday, 31 August 2016

Difference between 2 Stroke vs 4 Stroke Engine

Today I am going to tell you about main difference between 2 strokes vs 4 stroke engines. We all heard about both of these engines but few of us know the basic differences between them. Before discussing on this topic first you should know about stroke. The stroke in an engine is the distance covered by the piston from top dead center to the bottom dead center. In simple words, stroke is the distance of cylinder between piston moves. If a piston moves 2 times in the cylinder, that means, engine is known as two stroke engine and if it moves 4 times in a four stroke engine. The crankshaft rotates one time between 2 strokes.

Difference between 2 Stroke and 4 Stroke Engine

The basic and main difference between two stroke and four stroke engine is that the crankshaft complete one revolution in one power stroke in 2 stroke engine and complete 2 revolution in one power stroke in four stroke engine. So the 2 stroke engine give high power compare to 4 stroke engine but the 4 stroke engine is more fuel efficient. There are many other differences which are given below.

Difference between 2 Stroke vs 4 Stroke Engine

S. No.

Two Stroke Engine

Four Stroke Engine


It has one revolution of crankshaft within one power stroke.

It has two revolution of crankshaft between one power strokes.


It can generate high torque compare to 4 strokes engine.

It generates less torque due to 2 revolution of crankshaft between one power strokes.


It used port to inlet and outlet of fuel.

It used valve to inlet and outlet.


2 stroke engines require lighter flywheel compare to other engines because it generates more balanced force due to one revolution for one power stroke.

It requires heavy flywheel because it generates unbalance force due to two revolutions for one power stroke.

The charge is partially burn and mix with the burn gases during inlet. It is due to port mechanism.

In four stroke engine charge is fully burn and does not mix with burn charge in ideal condition.


Easy lubrication due to lubrication oil mix with the fuel.

Comparatively complicated lubrication.


More lubricating oil requires because some oil burns with fuel.

Comparatively less lubricating oil requires.


These engines give less thermal efficiency.

These engines give more thermal efficiency.


It has high power to weight ratio compare to others.

4 stroke engines have less power to weight ratio.


It creates more noise.

It is less noisy.


Two stroke engines are less efficient and generate more smoke.

Four stroke engines are more efficient and generate less smoke.


These engines are comparatively cheaper.

These engines are expansive due to valve and lubrication mechanism.


These engines are easy to manufacture.

These engines are comparatively hard to manufacture.


These engines are generally lighter.

These engines are comparatively heavier than 2 strokes due to heavy flywheel and valve mechanism.


These are mostly used in ships, scooters etc.

These engines mostly used in car, truck, and other automobiles.


Due to poor lubrication more wear and tear occurs

Less wear and tear occurs.

These are all about between difference between 2 stroke and 4 stroke engine. If you have any query regarding this article, asks by commenting. 


  1. Sir also describe by what influence piston reach at bottom dead center & how it take air mixed fule inside the cylinder in first inlet stroke ?

    1. Hi Saurabh,
      At the initial stroke piston moves at BDC by manual cranking using kick (in motorcycle) or by automatic cranking using starting motor (in Cars) and it sucks fuel due to partially vacuum created inside the cylinder. The pressure difference between carburetor and cylinder inside works as driving force for charge.