If of interest,,,Taken a few measurements of 100k piston and rings csl motor to compare with spec sheet, Top ring just on outer spec, ...2nd ring look like it takes the biggest hit, and found 2nd worn outside bmw spec, So for me,this says a new rings wouldn’t hurt . Wonder how typical this is on higher mileage motors?? ..... top ring end gap 0.35 ....2nd ring 1.0 Even piston ring axial play near to max wear on 2nd ring , Piston Ring height in spec. 1.2 and 1.5mm .. a new ring set wouldn’t do any harm putting motor back in ballpark.... be interesting to know how much Bhp these motors have lost with time/use ???
