Engine Displacement
The total swept volume of all cylinders in an internal combustion engine, typically measured in liters or cubic inches.
Engine displacement is a fundamental engine specification that measures the total volume swept by all the pistons in their cylinders as they move from Bottom Dead Center (BDC) to Top Dead Center (TDC). It is commonly expressed in liters (e.g., 2.0L, 5.0L) in modern vehicles, or in cubic inches (e.g., 350 CID) in classic American cars.
Displacement is mathematically calculated based on three factors: cylinder bore (diameter), piston stroke (distance traveled), and the total number of cylinders. Generally, larger engine displacements are capable of drawing in more air and fuel per cycle, enabling them to produce more torque and horsepower. Smaller displacement engines are lighter and have less friction, yielding better fuel economy.
Modifying engine displacement can be achieved during a rebuild by boring out the cylinders to a larger diameter (using oversized pistons) or installing a crankshaft with a longer stroke (creating a stroker engine). If an engine has lost power, mechanics perform cylinder compression and leakdown tests to ensure the pistons are sealing correctly within the displacement volume.