the 2.4 is a measure of displacement. To measure the displacement, find the area of the cylinder at Bottom Dead Center ( BDC), where the piston is lowest in the block, then find the area of the cylinder at Top Dead Center (TDC), where the piston is highest in the block. Subtract the area at TDC from the area at BDC to find the area displaced by the full movement of the piston, hence displacement. Finally, multiply the displacement of that cylinder by the number of cylinders in the block.
area of a cylinder = 3.14 * Radius^2 * Height
