Lesson 1/Learning Event 1
The downward force on the piston is transmitted through the connecting rod to the crankshaft throw. The
result is a powerful twist on the crankshaft which gives it a spin. Due to the heavy flywheel, the crankshaft
now continues to turn through the nonpower strokes without cranking.
FIGURE 14. EXHAUST STROKE.
When the piston reaches BDC, the timing gears have turned the camshaft far enough so the cam lobe under
the exhaust valve contacts the tappet and opens the exhaust valve. The rotating crankshaft moves the piston
up, pushing burned gases out of the cylinder past the open exhaust valve.