The boxer design provides good vibration mitigation due to the principles of a balanced engine because the movement of each piston is largely countered by a piston in the opposing cylinder bank, eliminating the need for a counter-weighted rotating crankshaft ( harmonic balancer ), but with some vibration from offsets.
12.
Parts peculiar to this system include a toothed disc between the harmonic balancer and the crank pulley, the adjacent sensor ( which predated the modern-day crankshaft position sensor, which Oldsmobile used with their Quad 4 in the late 1980s with a cast-in toothed section of the crankshaft ), a special distributor, an engine temperature sensor, and a rudimentary computer mounted inside the car, under the dash.
13.
Several components had design changes, longer rods ( 152 mm c-c, longer ), pistons with a lower compression height, lower friction bearings ( smaller in size ), a crankshaft with 8 counterweights ( instead of 4 on the older Bxx engines ) and a heavy harmonic balancer ( aka damper ) in the crank pulley . 1989 saw an upgrade to the crankshaft, with a relocated axial thrust bearing back to the number 5 journal, bigger main bearings, rods were enlarged to from in 1990.
