[OurPTGT]

quote:Originally posted by Punch

The 2.4-liter engine operates very smoothly because of a system of counter-rotating balance shafts which counteract second-order unbalance, the predominant reason for four-cylinder engine vibration.

The two counter-rotating, eccentric balance shafts, interconnected by gears, are driven by a short chain from the crankshaft. They turn at two times engine speed to offset the reciprocating mass of the pistons and connecting rods and to achieve the desired balancing effect. The balance shafts are enclosed in an aluminum housing mounted beneath the crankshaft in the oil pan. The housing is bolted to the bottom of the main bearing webs of the bedplate and rest in the oil supply. When the engine is running, the balance shafts pump oil out of the housing to minimize parasitic drag which could occur if the shafts spun in the oil.

Yep, what he said....[?]