Crank balancing 23, Mitsubishi 6G72 rods and pistons.

A comparison of aftermarket weights to stock weights. These cheap China rods are about 100g lighter than stock so that requires a lighter bobweight to balance it properly.
From that, 524.3g for the aftermarket piston complete with rings, 542.0g for the stock equivalent. The conrod complete with bearings, 556.2g for the China rod and 675.1g for the stock equivalent. From those numbers take off 150g for the small end of the stock rod and 145g for the china rod. From that the difference in rotating mass is near enough 120g and the difference in reciprocating mass is about 23g.
A stock crank will balance quite well with an 840g (or was it 820? I forget) bobweight, it's going to need to rebalance with more like a 710 ish g bobweight to work properly with these pistons and rods.
Another comparison is with Pauter rods, got a set of those in the next engine I need to balance. According to the Pauter website they're 619g in total, 423g in the big end leaving 196g in the small end. That's more in the small end than a stock rod. 3sx has them at 623.9g. One of them is wrong, maybe both. When measured for length, the Pauter rod is 0.008 inch shorter than a stock red. The cheap china ones are the same length as stock.
So many problems?
Totally pointless even thinking that the pistons all need to match by 1g and that all the rods need to match by 1g when the required bobweight is about 100g (more like 130g) out. That's times 6 so a 600g error.
The piston pins with the forged pistons, they're stock TT pins that I've shortened and champhered the ends to fit the clips and pistons. They're also the strongest.
If we were using the weak thin light pins that come with the pistons, we'd need to reduce the bobweight even more.
Read up on the forums, there's always someone making a claim that the cranks aren't strong enough but it's the bad workmanship that's to blame every time. Plenty of money to be made by selling low quality parts that don't work any better than stock. www.3si.org/th...
That was 2014. However doing a search we get this from 2005 when Hanz was asking.
www.3si.org/th...
Both wrong.