About 100 miles into the race I felt the engine hang. At the time I wasn't sure what it was, although it turned out to be a dropped valve which put me out of the race 40 miles later. I was able to keep on driving for a few laps, though, and did have a rather hilarious dialogue with my pit crew.
After I felt the engine hang, I came around and pointed at it. They flashed a sign: ENGINE HOT?
The next lap I shook my head and held seven fingers out the window, as best I could, to indicate I thought I was missing a cylinder.
OIL PRESSURE? they asked when I came around the next time.
NO BITE? they tried.
ENGINE MISSING? was the question on the following lap.
Aah, success. I nodded.
2ND IGNITION? they showed, indicating I should try the car's backup starting system. I did. It didn't cure the problem.