1988 Pontiac 6000, 2.5 Iron Duke. Tooling along the highway, it ate the plastic camshaft gear at about 90,000 miles. Not that unusual of a problem, they often let go. Thankfully it was a non-interference engine. Dad and I had the engine out in a few hours, and took the camshaft to a shop to have a new gear pressed on. Changed the oil to get the shredded teeth out of the oil pan, and the engine ran fine for another 90,000 before the body rot got to the point the car had to be retired.