Balance Shaft Backlash

WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

Install the Crankshaft TDC Timing Peg and rotate the crankshaft slowly clockwise until the crankshaft balance weight is up against the Crankshaft TDC Timing Peg. The engine is now at Top Dead Center (TDC).

Fig 1: Locating Crankshaft TDC Timing Peg
Courtesy of FORD MOTOR CO.
Mark the balancer unit and shafts on the top for reference that the balancer unit is at TDC.

Fig 2: Locating Locating Balancer Unit Shaft Marks
Courtesy of FORD MOTOR CO.

NOTE: Due to the precision interior construction of the balancer unit, it should not be disassembled.

Fig 3: Locating Balancer Unit Bolts

Courtesy of FORD MOTOR CO.

Remove the 4 bolts and the balancer unit.
Remove the adjustment shims from the seat faces of the balancer unit.

NOTE: Visually inspect the balancer unit gear for damage and verify that the shaft turns smoothly. If there is any damage or malfunction, replace the balancer unit.

Install the master adjustment shims (No. 50) on the seat faces of the balancer unit.
With the balancer unit shaft marks at the TDC position, slowly install the balancer unit to the cylinder block to avoid interference between the crankshaft drive gear and the balancer unit driven gear.

Fig 4: Locating Balancer Unit Shaft Marks
Courtesy of FORD MOTOR CO.
Install the balancer unit bolts.
- Tighten in the sequence shown in 2 stages.
- Stage 1: Tighten to 25 Nm (18 lb-ft).
- Stage 2: Tighten to 42 Nm (31 lb-ft).
Fig 5: Balancer Unit Bolts Tightening Sequence
Courtesy of FORD MOTOR CO.
Remove the Crankshaft TDC Timing Peg.
Rotate the crankshaft to confirm that there are no meshing problems between the balancer unit gear and the crankshaft gear.

Fig 6: Locating Crankshaft TDC Timing Peg
Courtesy of FORD MOTOR CO.
Install the Crankshaft TDC Timing Peg and rotate the crankshaft slowly clockwise until the crankshaft balance weight is up against the Crankshaft TDC Timing Peg.
Remove the Crankshaft TDC Timing Peg.

Fig 7: Locating Crankshaft TDC Timing Peg
Courtesy of FORD MOTOR CO.

NOTE: Measure the backlash and verify that it is within specified range at all of the following 6 positions: 10 degrees, 30 degrees, 100 degrees, 190 degrees, 210 degrees and 280 degrees. It will be necessary to reset the measuring equipment between measurements.

NOTE: The measurement must be taken with the Dial Indicator Gauge with Holding Fixture, a 5-mm Allen wrench and worm clamp set up as shown. Mark the Allen wrench with a file 80 mm (3.149 in) above the driven gear shaft center. Make sure the worm clamp and Allen wrench are not touching the balance shaft housing.

NOTE: For an accurate measurement while measuring the gear backlash, insert a screwdriver as shown into the crankshaft No. 1 crankweight area and set both the rotation and the thrust direction with the screwdriver, using a prying action as shown.

Fig 8: Positioning Dial Indicator Gauge

Courtesy of FORD MOTOR CO.

Position the Dial Indicator Gauge with Holding Fixture as shown. Measure the gear backlash.
1. Position the Dial Indicator Gauge with Holding Fixture (1) on the Allen wrench 80 mm (3.149 in) above the driven gear shaft center (2) on the balancer unit.
2. Rotate the crankshaft clockwise and measure the backlash at all of the following 6 positions: 10 degrees, 30 degrees, 100 degrees, 190 degrees, 210 degrees and 280 degrees.

NOTE: If maximum backlash exceeds 0.120 mm (0.0047 in), install a new balancer unit.

Fig 9: Adjustment Shim Selection Table

Courtesy of FORD MOTOR CO.

Using the backlash measurement, select the proper shims from the Adjustment Shim Selection Table.
- Remove the balancer unit from the cylinder block.
- Install the selected adjustment shims on the seat faces of the balancer unit.
Install the Crankshaft TDC Timing Peg and rotate the crankshaft slowly clockwise until the crankshaft balance weight is up against the Crankshaft TDC Timing Peg. The engine is now at TDC.

Fig 10: Locating Crankshaft TDC Timing Peg
Courtesy of FORD MOTOR CO.
With the balancer unit shaft marks in the TDC position, slowly install the balancer unit to the cylinder block to avoid interference between the crankshaft drive gear and the balancer unit driven gear.

Fig 11: Locating Balancer Unit Shaft Marks
Courtesy of FORD MOTOR CO.
Install the balancer unit bolts.
- Tighten in the sequence shown in 2 stages.
- Stage 1: Tighten to 25 Nm (18 lb-ft).
- Stage 2: Tighten to 42 Nm (31 lb-ft).
Fig 12: Balancer Unit Bolts Tightening Sequence
Courtesy of FORD MOTOR CO.

NOTE: Remeasure the backlash and verify that it is within specified range at all of the following 6 positions: 10 degrees, 30 degrees, 100 degrees, 190 degrees, 210 degrees and 280 degrees. It will be necessary to reset the measuring equipment between measurements.

Fig 13: Positioning Dial Indicator Gauge

Courtesy of FORD MOTOR CO.

Position the Dial Indicator Gauge with Holding Fixture as shown. Measure the gear backlash.
- Position the Dial Indicator Gauge with Holding Fixture (1) on the Allen wrench 80 mm (3.149 in) above the driven gear shaft center (2) on the balancer unit.
- Rotate the crankshaft clockwise and measure the backlash at all of the following 6 positions: 10 degrees, 30 degrees, 100 degrees, 190 degrees, 210 degrees and 280 degrees.
- If the backlash exceeds the specified range of 0.020 to 0.120 mm (0.00078 to 0.0047 in), install a new balancer unit and repeat the procedure.