[jons911]

Like John said, it's a key and the groove in the camshaft is called a key way. Basically, put a rag in any open hole in the chain housing. The key is small and can easily fly into the engine case if you aren't careful. So in your picture, definitely put rags to the right where the chain comes from the case. I used a small flat head screwdriver, as in the small ones used on glasses, and placed it on the front face of the key and gave it some light taps with a hammer. The bottom of the key (side that goes in to the key way in the cam) should be curved, so the flat head will start to follow that curve down into the groove and help to leverage the key out. If that's a bit confusing, google 911 camshaft key, and it should make more sense.