actually consider quite lasting, the honda piston rings.. because considered I never changed the rings when I converted, the mileage of my car + mileage of halfcut is already 200Kms, and I'm still getting those numbers on piston 2-4, only piston 1, and even then I'm not sure that the ring seal is totally gone case, because I can't hear any air leak through the oil cap hole, but that's because it's drowned by the sound of the LMA rattling, (hydraulic tappet? I'm not sure of the terms, seems like these two names are referring to the same thing.. it looks like a bullet, that's all I can describe it) which I'm going to change sometime in november when I'm not using the car, since it is my daily driver after all.
I suspect it's the valves not sealing properly, because I don't seem to see any black smoke from the exhaust, and i'm noting a lot of unburned fuel coming out of the exhaust (compression stroke leakage, maybe?) and LM-1 is showing very lean readings (unburned fuel is not detected by 02 sensor, for aspring tuners out there that wonders how they leaned their engine and blew them by mistake, never trust the 02 sensor totally, unless you tapped 4 into each header pipe for individual cylinder reading) (I ran open loop to test) which is rapidly corrected by the o2 sensor in closed loop a.k.a. FC goes to hell!, hence why open loop is good for observing part throttle fuelling, which is unavailable on piggyback systems, although they could cheat by supplying a constant .5v (I think that's the voltage for stoich, but better double check to make sure, if you're thinking of doing something like this) to the o2 D14 pin.)
Well, I'm going to do consider lapping the seats and cleaning the valves for better seal first (including LMA/tappet change, plus maybe new aftermarket v/s, 9.5K rpm, here I come? :P), then if it's still leaking, looks like I have to shop for some pistons and rings, crank bearings, rod bearings and a new gasket.
or maybe just a new bottom block :P
B20 is nice, but 8K is probably the safe limit for a daily driven ride, while B18C is nice for higher rpm runs, but a tad on the expensive side.