The Leyland L60 engine is a two-stroke opposed piston design intended for multi-fuel use so that it could run on whatever fuel was available. In practice the engine did not deliver the expected power and was unreliable, estimated to have a 90% breakdown rate but improvements were introduced to address this. Primary problems included cylinder liner failure, fan drive problems and perpetual leaks due to vibration and badly routed pipework. However, as the engine power improved the tank itself became heavier.