Help me interpret cylinder measurements

[puffer@rpi.edu]

I have pulled the pistons out of my CAT22, 2F5209, and have measured the cylinders and pistons. The measurements are posted in the attached pdf file. I have also posted photos of the pistons and cylinders. You will note the excessive deposits on the top of #4 piston. That cylinder has a burned valve.

OK, now I have some questions. Please help me interpret my measurements.

First, I see that the piston measurements are very consistent from cylinder to cylinder and that the pistons are all .015" undersize above the top ring. Is that by design? It seems unlikely that it is because of wear. Next, all of the rest of the piston measurements are very close, and are what I would expect of new standard pistons. Is that correct?

Looking at the cylinder measurements there is a definite taper in the cylinders, with the top of the cylinders being as much as +.020." Also, there is excessive piston ring end gap of at least .125" at the top. I would expect around .010", correct?

Now the obvious question is what to do? Do I have the cylinders bored to +.020." and try to find .020" over pistons and rings? If so, where can I get the pistons and rings? What other options do you see? Thanks, Ray