I think that the most amazing aero-engine I have ever seen is a German hrizontally-opposed Diesel. It has one block and two crankshafts, one at each end of the block.
Each pair of pistons coming towards each other provides the compression, the injectors & valve train being mounted in the centre of the block.
The twin crankshafts are geared together to one output shaft.
This monster (I can't remember its designation - DB-XYZ) is on show at RAF Cosford.
Was the problem with Napier Sabres differential expansion of the sleeve liners? I seem to remember reading that the engines had to be run up every few hours in the winter of 44-45 to keep them warm. If the engines where constantly going though a hot-cold cycle, then this would increase their wear rate - but it they were constantly hot, the rate should reduce and the engines should last. If they did last for 3000 hours, perhaps we should be fitting them into Cessnas!!
