more busted v1 polini rings
this happened at wb3 at some point. sunday afternoon i couldn’t start it due to almost no compression. i haven’t torn it down until today, and wasn’t very surprised to find (ANOTHER) broken top ring and the bottom ring stuck in the ring land. these rings were fresh, installed roughly 200 miles ago along with honing the cylinder and sanding hot spots on the piston. piston to cylinder tolerances were acceptable after honing so i chose to re ring instead of boring to 48mm. here are my summarized hypotheses:
1. after honing the cylinder, there’s too much clearance in piston to cylinder wall, giving the rings too much room to move around, any maybe get either caught on something it wouldn’t normally, or slap around against the wall, causing it to break
2. honing took the ridge out of the top of the cylinder ALMOST entirely but there was still a barely barely barely noticeable bit there. more of a difference in coloration than anything, i couldn’t even feel it with a fingernail. if it was enough to effect it the ring could have broken from hitting the ridge.
3. running synthetic oil caused the rings to stick in the ring land and the top ring stuck somewhere along the bottom, causing the top to push out too far, catch on a port, and break.
4. cast rings are just too weak for the amount of abuse they’re taking
any ideas?
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