I have a full write up of bore sizes and ovality in the paperwork somewhere from last time it was apart. It's done a couple of thousand miles TOPS since then. I'll be measuring them as a matter of course, but the bores really aren't the problem.
I also have absolutely zero issue with rebuilding it with the same rings. As long as the ring gaps still spec up, which I will be checking, then it will go back together as is. Absolutely no reason to hone and change rings just as a matter of course! Just because the rings have come out of the barrel, what is suspected of changing?
Obviously while it's apart, if there is any issue, you would correct it. But hone and 're ring just because? That's crazy. If its somehow managed to go oval from sitting under a sheet for 5 years, then ill bore it. But it wont have. The rings have done no work and the bores look great. It's not that far past run in from the last rebuild!
Yes, not just no4 that's been burning oil. As I said, it used to wet sump and burn oil on start up. An issue with the fact its only ever done a couple of hundred miles a year.
But you can see from the exhaust valves that 1/2/3 stopped burning oil. When cleaning up the head the blackness on 2/3/4 Was just dry soot. The blackness on 4 is sticky and oily.
I've been rebuilding engines, vehicles, machines, for 30 years. I constantly have at least one vehicle in parts, being restored, rebuilt. This is familiar territory for me, I just can't find any solid reason for how so much oil was getting in. I half expected to find a hole in the piston it was that bad, or a completely open passageway past the head gasket.
