The valve for one of the cylinders has its guide exposed, which isn't something you should be seeing. Plus, there's a hunk of piston at the bottom of the engine when the timing cover comes off.

Both pistons and valves move in and out of a space at the top of engine cylinders known as the “combustion chamber”.

The brake master cylinder is the first component in a vehicle’s braking system, activated by depressing the brake pedal. The pedal pushes a piston through this cylinder, forcing brake fluid ...

In the video after the break, [Brick Technology] uses LEGO to gain some practical insight into the world of piston engine design, from single-cylinder all the way up to radial twelve-cylinder engines.