Almost all timing chain sets have dots on both the crank and cam gears. When these are aligned directly across from each other, you know the cam is installed "straight up," or with zero advance or retard. Notice how this crank gear has multiple keyways to allow you to advance or retard the cam four degrees. When installing a timing set like this, it can be easy to get confused with crankshaft location. Just remember that when the number-one cylinder is at top dead center, the key on the crank will be pointing toward the number-one cylinder (as you can see here).