Disconnecting the battery will prevent you from shocking yourself or causing any blown fuses while you work. The car will not be able to start with the battery disconnected.
Make sure you check the service manual for your specific year, make and model vehicle. Do not pull on the spark plug wire itself, but rather from its base, when removing spark plug wires.
The spark plug will stick in the spark plug socket thanks to a rubber ring inside it. Check the spark plug for any signs of damage, then set it aside someplace safe.
Be extremely careful not to allow any debris to fall into the spark plug hole as you switch it out for the piston stop tool. You can purchase a piston stop tool and most auto parts stores. The piston stop tool doesn’t have to be too tight. Simply make it snug by hand.
Be sure to use the correct size wrench or socket, otherwise you could damage the bolt on the pulley. It may take a decent amount of force to rotate the motor. Larger motors will be even more difficult than smaller ones.
With the battery disconnected, you won’t be able to start the engine. Never attempt to start the engine while you have portions of it disassembled.
Be sure you can clearly make out the mark you draw on the harmonic dampener. A sharpie or paint pen will both work to make your mark on the harmonic dampener.
Mark the second spot on the harmonic dampener where the pulley stopped turning because of the stopper tool. Be sure both marks are clearly visible on the harmonic dampener before moving on.
Be sure to remove the piston stop tool and return the spark plug prior to starting the engine. Reconnect the battery to restore power to the vehicle once you’re done.
Make sure to remove the spark plug using a spark plug socket, otherwise it will simply unthread and remain in the hole. Be extremely careful not to allow anything to fall in the hole while the spark plug is removed.
Make sure your thumb is positioned to it creates a seal over the hole.
Pay attention as your friend rotates the motor so you’ll notice when your thumb is pushed off the hole. As soon as your thumb moves it will relieve the pressure, allowing you to place it over the hole again.
This process is accurate to within 15 degrees, so it should not be used to install new camshafts. Make sure to reconnect the battery after reinstalling the spark plug.
