 These trials were interrupted by breakage of the crank axles, these being replaced by axles from 36002 only for these to break in turn at approximately the same mileage as the originals.The sleeve valves, used to give greater volumetric efficiency and control over valve events, suffered frequent breakages at the "ears" where they attached to the valve gear.The sleeves had a complex motion, combining rotation and reciprocation, to try and even out wear, and this was another untried design.