rb20 piston measurement question

[styc]

hello there. i have a question on piston measurements.

when mic'ing the piston the FSM tells you to take a measurement 20mm from the bottom of the piston skirt. it says nothing about measuring above the top ring land.

is it normal for the top of the piston to be smaller than the skirt? the difference is .003"

thanks for your time.

[Carl H]

yes, you'll find if you measure most pistons they are slightly smaller at the top