Looking closer those scratches are really uniform and evenly spaced apart like the oil ring scrapers are not holding the center section of the oil ring in place. Maybe that rough crosshatch wore the oil ring scrapers down letting the center section rub more than it should or, one of the scrapers seated above or below the center spacer letting it come out and rub the cylinder wall. Whatever the problem is that oil ring center spacer should not be out against the wall making those marks.
Hows that even possible for the oil rings to move around in the cylinder like that when the rings are properly assembled? And belive me they are properly assembled, i have been almost redicoluos meticulous with this engine.
Hey, Just reading what the pic shows. You said all the other cylinders look good and this one has the marks so there's something causing them. I'm sure you installed the rings correctly. We always hear the snapping of the rings as you install the pistons into the cylinders upon assembly, one oil ring scraper could have snapped out of place during the piston installation into the cylinder. That's all it would take.
Im greatful for your answer, im just wondering hows it possible and should it not be any recistance when you turning the engine over after assembling the pistons, i remember i check for any additional recistance after each piston been assembled with a torque wrench and when i have all 8 assembled i had 20 ft lbs to start the crank rotate and between 10-15 ft lbs to keep it rotate even through the whole revolution, but maybe the spacer between the oil rings doesnt do much to recistance i dont know but thats how you use to do for check if their is some error, i not record anything strange on the cylinder walls either after turning the crank over and over checking for some recistance during the revolution.
