What direction should the arrow point on top of a piston?

The arrow on top of a piston should point towards the front of the engine. This is because the piston moves up and down inside the cylinder, and the arrow indicates the direction in which the piston is moving. When the piston is at the top of its stroke, the arrow should be pointing towards the front of the engine. This ensures that the piston is moving in the correct direction and that the engine is operating properly.