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I’m sure that you’ve given considerable consideration to reusing rings. You have probably thought about most, if not all of this, but if it helps, here are my concerns:
Unfortunately, since rings are not reused as a rule, published design specs would not try to address wear, but rather manufacturing tolerances. The gap thickness is set to ensure rings don’t get into an interference problem when they heat up, but I believe that this an assembly fit measurement/adjustment and not a reuse tolerance range for worn or used rings (I do believe it could be a good sanity check but it would seem to be difficult to measure in this type of overlapping end gap design). The ring thickness is normally considered as a function of ring to piston land clearance for worn pistons, usually to ensure the piston can be reused. I have seen rings with visible piston ring land contact area wear on the ring and it is easy to spot, but typically pistons wear first in this area and not the ring. There is a thin layer of chrome on the outer edge of the ring that “seats” in concert with the individual way a ring moves in the piston ring grove. The ring will form a wear pattern fit on the face of a new ring for the unique piston/ring/cylinder combination as it breaks in. Over time, this thin layer will continue to wear uniformly to the patter originally developed. While it is true that chrome rings experience less wear than other rings, this is the wear that I am most concerned with. The most favorable scenario will be to install the same ring on the same piston in the same cylinder but, at best, it will experience a reduced life.
Since part of the concern in a two ring motor is to minimize leakage (intake, compression, and combustion) with only one ring, I believe there is less risk of leakage by using new, conventional gap rings than reusing old rings with no real guarantee for a new complete seat to the cylinder; however, I am not satisfied with the compromise of using a conventional gap ring for my engine build. I am not happy with the cost difference, but in the big picture, I am seeing it as an additional $65 - $85 cost for the unique engine design that, hopfully, I will feel less pain with over time when it is running great.
On another note, in the past I’ve read about the Singh grooves head mod discussed. In my last G10 (three ring) engine build (now at >100K miles) I experienced some detonation problems that I believe this could help address. I would like to hear if anyone has seen carbon build-up problems in the groves over time and, if so, how the thickness and depth of the groves may play a role.
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