Pistons and weight group markings: question
 

I have a set of 6 new Mahle 3.2 euro p's and c's. The weight group on all pistons is marked ++, so looks to be 630-634 grams per the book.

Question: do you guys weigh these on a balance (precision scale) to get the heaviest pistons closest to the flywheel, or am I overthinking it? 4 grams seems like nothing.

Thanks in advance.

When I did my last build I balanced to within 1g or less. It wasnt that hard. Pretty much shuffling around pins, rods, and pistons. The RR rods were spot on. If you have heavy assemblies you can put them opposite of each other and the heavy ones closer to the flywheel.

You should balance and may be able to get the weight difference to +\- a gram or two just by matching pistons, rods and pins. Time again, and I’d go one step further and send it to a machine shop to have it balanced within a gnat’s arse. It probably makes no difference, is likely moot bc of varying oil weight, but it’s cheap to do. Someone here once did the math on what a gram spinning at 7000RPM translates into and it was actually kind of shocking (as in a lot).

Balance 3/6, 1/4, 2/5. I’d wager that the total assembly (piston, wrist pin and rod) can get within a gram or two. Mine was 1gram. Balancing the reciprocating assembly (piston, wrist pin and small rod end) seems to be what’s more important. Mine across the above was 3g, 1g, 3g. Was a bit shirty when the mechanic that was taking me for a ride at the time left good enough alone. He was probably right, but there’s an imaginary world where my engine lives above 7000rpm regularly