Quote:
Originally Posted by 911pcars
If the combined weights of an opposed pair of piston/rod assemblies (e.g. 1 and 4) aren't equal to another set of opposed cylinders (e.g 3 and 6), is the crankshaft assembly still dynamically balanced or has this introduced a secondary imbalance?
If so, is the ideal solution to have all six piston assemblies weigh the same?
Sherwood
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A significant difference in static component balance (weight difference) should show up as a primary harmonic since the weight difference will be noticed once per revolution. Forces that cause second order harmonics are noticed at twice the running speed of the crank.
From what I have read, if you keep the weight of the piston/ rod assemblies to within 1 gram of each other, you should be fine. There are many other factors, like friction, oil film, windage, crank flexure that have an effect as well, will make weight matching pistons to the .0001 g not necessary.