Is that engine running a little rough?

I was flying my airplane back from Dayton General after a horribly expensive annual inspection that took six weeks. On the way back to Middletown the engine sounded strange. After landing, I decided to go around the pattern again. Over the end of the runway, 200 or 300 feet off the ground, there was a loud POP. Then the whole plane shook with the rough-running engine.

I was not sure if the engine had enough power to maintain flight, so I looked straight ahead to see what I could land in or on. The Miami River looked like the best option. Fortunately the airplane kept climbing, so I made a cautious turn back toward the airport. I reached traffic pattern altitude on downwind. Once I had arrived abeam the numbers, I pulled the power back to idle and glided in to land. Examination of the engine revealed a failure of the exhaust valve on Cylinder #3.