Speaking of engine maintainability, there was a fun thread on big marine engines on Reddit a little while back: https://www.reddit.com/r/Justrolledintotheshop/comments/5wr5...

>They burn approximately 200-300 litres of oil a week and have a capacity of about 1200 ltrs in the sump. Main oil filters are done every 20,000 hours or sooner if the differential pressure across them increases above 1 bar but there is no oil change schedule for them. Each engine is 33 years old and all have between 92,000 and 98,000 running hours.

>The warranty will be indefinite as long as you stick to the maintenance schedule. It's not like a car engine, almost every part with the exception of the crankshaft, entablature, bedplate and general items like pipework etc have all been replaced at some point according to the maintenance plan. Pistons are changed out every 40k hours, bearings, heads, liners etc all have their own lifetime too.