twinkle_2k86

does anyone know what the dimension should be from the center of the pin to the crown of the piston on a standard mahle piston??

i need to know so i know if my pistons have had the crown machined or not. i got a measurement off the net of 36.8554mm and the piston i took out of my car measures 36.85mm

fightingtorque

standard tolerance on a gasoline piston compression height is +/- 0.025mm. so your piston is original spec.

if you want to go for super accuracy, check the height of each piston at top dead center installed. there are tolerances on pistons, rods, crank throw, block etc. you can't measure all of these without a lab so easiest is to build the block and check the pistons are all within about .025 (1 thou) at TDC. if all parts are new you can try swapping pistons and rods around to get a match, or machine them level. it is said that you get a smoother idle from this treatment as well as knowing that when you tune to the limit (of detonation onset mainly) you know that all 4 are giving their best.