151 Engine Service and Repair Technician Handbook Displacement The piston’s stroke is the distance between the farthest points on the piston’s path of travel. • Top dead center (TDC) is the highest point of the piston’s stroke. • Bottom dead center (BDC) is the lowest point of the piston’s stroke. To calculate the engine’s displacement (such as 5.7 liters), determine the cylinder volume when the piston is at BDC and multiply it by the number of cylinders. Technical Training 13