2. Insert a long screwdriver or other straight object into the spark plug hole.
3. Turn the crankshaft slowly until the piston reaches the top of its travel.
4. When the piston is at TDC, the screwdriver will be at its highest point.
5. Mark the position of the screwdriver on the engine block with a grease pencil or other marking device.
6. Turn the crankshaft 360 degrees and check that the screwdriver is still at the same position.
7. If the screwdriver has moved, then the piston is not at TDC. Repeat steps 3-6 until the piston is at TDC.
