I've mostly been interested in Caterpillar engines but it seems that Cummins, Detroit, and John Deere have all done the same thing. Specifically, I've noticed that on most straight 6 engines, cylinders 2 and 5 don't have counterweights, and it seems like that they make up for this by offsetting the counterweights on cylinders 1, 3, 4, and 6 by 30° to compensate for that. Anyone know why they don't have crank weights on all 6 cylinders?
The front of the crank should have a torsional balancer that needs replacement after 500,000 miles. The one that does it differently is the Volvo engine where the balancer is in the middle of the crankshaft and the motor must be torn down to replace it.
Everyone is trying to shave weight to meet fuel economy /EPA standards. Paccar MX uses No counterweights. Hollow camshafts too, tubes with assembled lobes.
