How about this, measure your first oil ring with a tape measure, and take the number and divide by pie (3.14159). [Circumference = pi x Diameter ] If you don't have a tape measure use a piece of string and measure the length of the string with a ruler. Using a spare ball with no flare would make seeing and measuring the oil ring easier.
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dR3w
"I did nothing. I did absolutely nothing, and it was everything I thought it could be. "