Earliest failure I saw was about 10. That was a brand new engine out of the crate that went south in the parking lot with the new owner in it. Still bought the car, though. Think about that. You're looking at buying your first Rover, and the engine grenades while the salesman is going over the features. Doncha' think God was trying to tell you something? We had replaced the engine because it used a quart of oil a week. All the piston rings were lined up straight, she gulped oil since new.
Second, towed in at 1,200 miles, came apart with such force that it took out the timing chain, stopping it dead. Crank, and all internals were perfect. Longest failure I saw was just under 60K. The outer gear cracked, and pressure was low at idle causing the light to come on. Again, the internals were perfect. Customer ate this one.