The aeroplane that has the engine has a lot to do with the overall reliability of the engine as the engine itself. Each different type has different cowl and other geometries which greatly affects the cooling and vibration that the engine experiences when in service.
A good example is the Lycoming TIO-540. Very reliable in the saratoga and navajo/chieftain fleet, but has a bundle of problems in the malabu and mirage...
Bevan..