World’s Largest Engine The largest engine you can buy is Wärtsilä’s flex96c (nice name fellas), a two-stroke turbocharged 25,000,000 CC inline 14 diesel engine that kicks out 110,000hp (80MW) at 120 rpm. They cost around $40m, fuel not included (300 tons of diesel / day). There are 300 of them in service. For comparison, nuclear propulsion reactors typically output 200-400MW. So a nuclear propulsion system is equivalent to around 100 million CC of turbo-diesel. There are 220 nuclear propulsion reactors in service. Ah, but all those nuclear ships are all military vessels, well no, not quite. Russia operates a fleet of civilian nuclear powered icebreakers each producing 110MW shaft power. Anyway, the flex96c is huge. Not sure how they make the engine block?