When installed the rings were as follows
Top ring: 0.27mm
Bottom: 0.33mm
After 100hrs they have both worn but the top ring seems to have showed considerably more wear than the bottom. The gaps where measured at
Top ring: 0.88mm
Bottom: 0.63mm
The crank feels like it has no up anddown play but it does feel a bit like it can rock side to side. Actually side clearance when pushed up against the thrust bearing/washer is 0.8mm.
Here are the piston pictures. She sure has ran on the ragged edge from inspection of the underside. Will probably trade out the 175 main for a 178 or even a 180 as the colder months come upon us. The piston dome has been wiped down with a clean rag now and the little carbon on top wiped off easily. There are some harder carbon deposits sitting in the transfers and I would say these would have occured during a testing phase. Basically I have been running 40 N3CW#3 175 for the majority of the top end, but had run as lean as 42 N3EJ#1 178 for a small time. Obviously everywhere in between too. Interestingly, the piston underside has more carbon buildup on the intake side of the dome where you'd typically expect the exhaust to be the hotter part. The skirts look good and you can still see the remains of the coating on the piston in many places.
Wiped down
Underside (exhaust side at top)
Intake Side
Exhaust Side
