
Originally Posted by
RamAirZ
Thanks. I note this paragraph at the end of the link....
"Another balance shaft design is found in many V6 engines. While an inherently balanced V6 engine would have either 60 or 120 degrees angle between the two banks of cylinders, many current V6 engines are derived from older V8 engines, which have a 90 degree angle between the two banks of cylinders. While this provides for an evenly spaced firing order in an 8 cylinder engine, in a six cylinder engine this results in a loping rhythm, where during each rotation of the crankshaft three cylinders fire at 90 degree intervals, followed by a gap of 90 degrees with no power pulse. This can be eliminated by using a more complex, and expensive, crankshaft which alters the relationship between the cylinders in the two banks to give an effective 60 degree difference, but recently many manufacturers have found it more economical to adapt the balance shaft concept, using a single shaft with counterweights spaced so as to provide a vibration which cancels out the shake inherent in the 90 degree V6."
The last couple of sentences seem to explain why some engines have a balance shaft and why the VX does not. I just noticed this evening that the 3.5L crankshaft sells for over $1000!
Since I doubt this is an availability thing (because the 3.5L was in other vehicles), I would appear a more expensive crank -- referred to in Wikipedia -- has been utilized in the VX. IOW, it doesn't have a balance shaft because it doesn't need one.