Mazda 6 Training Manual page 18

Structure
• The balancer unit is configured with two balancer shafts (No.1 and No.2) with weights, the balancer unit case
and the adjust shim which adjusts the amount of backlash in the crankshaft.
• The two balancer shafts (No.1 and No.2) are driven by the drive gear which is attached to the crankshaft.
• The balancer unit cannot be disassembled because it is a precision unit.
Operation
• The rotary motion is transmitted from the drive gear, which is between the back of the No.3 cylinder and the
No.4 main journal, directly to the No.1 balance shaft with driven gear. Then the balance unit transmits the
rotation motion to the No.2 balance shaft. The ratio of gears, which are attached to No.1 and No. 2 balancer
shafts, has been set so that the gear rotates at twice the velocity of the crankshaft. The balancer shaft's rotation
velocity counterbalances (generate the force in the opposite direction) the rotation inertial force (secondary
inertial rotation force) from the crankshaft.
.
1 Adjust shim
2 Crankshaft
3 Engine front
4 Balancer unit case
• Replace the adjust shim to adjust backlash. There are 40 kinds of adjuster shim depending on the thickness.
To determine the kind, check the engraved identification mark (2 digits) on the adjust shim.
B–10
ENGINE
5 Weights
6 No.2 balance shaft
7 Drive gear
8 No.1 balance shaft with driven gear
AME2224N402