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3.500" stroke crank... isn't?

Posted: June 13th, 2013, 8:14 am
by Knoxes
Along with the generous endplay, we've discovered another issue. As best we can tell, the 232 crank stroke is 3.475".
From the surface of the deck to the outer rim of the pistons at BDC it's 3.470" plus or minus 0.007". By "outer rim" I mean what would be the high point of the piston, not the indented area in the middle. That's the average of eight measurements, one on each of the pistons and two on cylinders #3 and #4. 0.007" is one standard deviation, so it means that the true value will be within 0.007" of 3.470" with 67% confidence.

The rise above the deck at TDC was 0.004 to 0.005 for all of the pistons based on six measurements.
I know this doesn't really change anything, but I was suprised. Is this normal?