Engine displacement is the swept volume of air displaced by all of the pistons in an internal combustion engine. It’s essentially a measure of the volume of all of the cylinders in a motor combined.
Displacement is used to calculate the compression ratio of an engine and is used to indicate the size of an engine.
The formula to find engine displacement is:
displacement = π4 × b2 × s × c
Where b is equal to the bore size, s is equal to the stroke length, and c is the number of cylinders.
For example, let’s calculate the displacement for a motor with a bore size of 3.4″, a stroke length of 3.6″ and 8 cylinders.
displacement = π4 × 3.4″2 × 3.6″ × 8
displacement = 0.78539816339 × 11.56 × 3.6 × 8
displacement = 261.48 cu in
Engine displacement is often measured in liters, cubic centimeters, or cubic inches. If the bore and stroke measurements are in inches then the result from the formula above will be in cubic inches. If the measurements are in centimeters then the result will be in cubic centimeters.