It's well covered in the Bill Fisher book. The crank tends to flex in use at higher rpms. You can save some wear and tear on the case saddle that supports the #2 main bearing if the crank has counterweights. The counterweights make the crank balanced on each plane that you can draw parallel to the axis of the crank and thru each web to each crank throw. Once you see one you will understand better.
If the crank flexes, it will also put the rods out of line, which can push the piston pins sideways.
Most of this is of no use at low rpm, but, like balancing, it becomes more and more important as the rpms go up, because the forces involved go up with the square of the rpm.
You can get new cranks that are cast with the counterweights, but I am fond of the OE VW forged cranks. Berg does a beautiful job with these, but they are expensive.
There are many followers out there which do not have the correct Rockwell hardness and will wear out quickly. My second engine rebuild only lasted 5000 miles because of some of these (carefully labeled Made in W. Germany.) Buy from Berg.
Yes, it's fine as long as they are OE VW rods.
------------------------------------------------ Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA
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