Points for Pilots

Rotax 912 engine The  Rotax 912 engine  in o ur plane, a Zenith 601HDS, has reached an important milestone. Over the past 28 years, it has run 2,400 hrs without major repairs. Zenith 601HDL, N314LB It's appropriate to reflect about this performance and muse how this is possible. After all, when we bought the engine, in 1994, the suggested TBO was 1,200 hrs.  Since then TBO has gone up, first to 1,600 hrs, and more recently to 2,000 hrs. Of course, those increases apply to later engines, not to our early model. Let's see how the engine performs after all this time. Performance after 2,400 hrs Compression is 76-80 lbs/sq.in. on all cylinders. Oil consumption is less than 1/2 qt per 25 hours.  During each oil change, we cut open the filter and look for metal. There is almost none, just one or two tiny specks. Essentially, the engine shows no sign of wear. The engine performs well up to the legal limit of 14,000 ft MSL for flight without oxygen. When flying