Balance Shaft: Description and Operation

Fig. 28 Crankshaft, Intermediate & Balance Shaft Assemblies.:

The 2.5L/4-153, 1990 2.3L/4-135 Turbo IV and 1991-92 2.3L/4-135 Turbo III engines are equipped with two balance shafts installed in a carrier attached to the lower crankcase, Fig. 28.

The shafts are interconnected through gears to rotate in opposite directions. These gears are driven by a short chain from the crankshaft and rotate at two times crankshaft speed. This counterbalances certain engine reciprocating masses.