what size is this?

blasty98

New Member
May 11, 2009
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i put a mic to my piston, theres no numbers on top it came out to 2.65" converted to 67.31mm. what size piston should i buy?
 
2.650"? or 2.65?"

Two significant digits is not enough to accurately measure piston diameter. The tolerance for piston to cylinder clearance on the stock piston is .0015" or 1.5 thousanths.

If your mic doesn't have a vernier scale to .001" accuracy, you need to get a dial caliper or digital caliper accurate to that level.

You also need to use an inside caliper to measure your current bore size, taper, and out of round to confirm that the cylinder is or is not in spec.
 
what exactly are you using to measure it? if your using verniers my shop teacher said that they are good up to +-.005, anything you want to get closer than that use a micrometer. and did you measure all around it and make sure there werent any bumps or burrs that could throw off your measurement?