Seen scored cyl from piston pins rubbing cyl, piston pin snap ring come out of place, stuck ring from carbon packing or way they were installed, ring can catch at the top when piston/rod was installed in the engine, then orings on the liner rolled out of place (wet liner engine). Then there's tuning was it ran lean? There's plenty of oil being splashed around
The engine came from a stock truck its an F150 5.0. The guy bought the truck new 4x4 no tune. If he telling the truth, i'll never know but I'm going to take his word for it. The bad tune as you put it puts the #8 cylinder in jeopardy not #2 which is the bad cylinder in this case. A bad ring absolutely I'll buy that. But why after the first oil change? The ford tech I spoke to says some 5.0 are experiencing cylinder distortion as he puts it to what degree I can't say. He also said its usually the #3. Distortion to me is excessive clearance, not scoring I'll try to take a pic of the cylinder to post the findings. Like I said this shouldn't be happening at 31k, too new.