Engine capacity

The engine capacity is:

(Vd - Vu) * Nc

Where Vd is the volume in the cylinder with the piston down, Vu is the volume with the cylinder up and Nc is the number of cylinders

The following volumes are cancelled out and are not included:

• Piston dish
• Ring land (the gap down the sides of the pistons, above the rings)
• Deck clearance (piston to block deck)
• Gasket volume
• Head chamber

The volume that IS counted is the rest, usually called the swept volume (the volume the piston displaces when it sweeps).

That's why some people refer to 'capacity' as 'displacement'.

(see also Bore/Stroke ratios and Overbore Sizes and A-series engines for common capacities)