Note: This procedure assumes that the engine has been removed from the vehicle and the engine faceplate, timing chain, and oil pan have been removed (see chapter 2A).
Removal
1. The balance shafts are mounted in a housing secured to the lower section of the crankcase. The gears are engaged on two shafts (one per shaft), which causes the shafts to rotate in opposite directions. These gears are chain driven from the crankshaft. The system serves to balance the engine vibrations caused by the reciprocating motion of the internal engine elements.
2. Remove the timing chain and its tensioner in the cylinder block (see chapter 2A).
3. Remove the oil pump (see chapter 2A).
4. Unscrew the bolts securing the balancer shaft housing. Work in the reverse order of tightening (Fig. 9.10).
5. Remove the balance shaft housing from the engine and remove the shafts from it.
Note: Note the timing marks on the front and rear gears on each balance shaft (Fig. 9.7). These marks must be aligned when installing the balance shafts onto the lower crankcase section.
Cleaning and inspection
6. Clean all components with solvent and dry thoroughly. Inspect all components for damage and wear. Pay particular attention to the chain, sprocket and gear teeth, as well as the bearing surfaces in the housing and the balance shafts. Replace faulty components if necessary.
Installation
7. Prepare each balance shaft for assembly by aligning the marks on the front gear with the mark on the rear gear (Fig. 9.7).
Fig. 9.7. Located on the timing marks on the front and rear gears
8. Lubricate the shafts with clean engine oil, install them on the lower section of the crankcase assembly and align the marks on the shafts (Fig. 9.8).
Fig. 9.8. Install the balance shafts so that the marks on the gear are aligned
9. Check the alignment of crankshaft journal No.1. The crankshaft key should be located 180th from the balance shafts (Fig. 9.9). Double check the position of the marks on the shafts.
Fig. 9.9. Align the position of the timing marks on the balance shafts when the crankshaft key is turned 180° from the balance shafts
10. Install the balance shaft housing and tighten the bolts to the specified torque as shown in Specifications at the beginning of this chapter. Follow the correct bolt tightening sequence (Fig. 9.10).
Fig. 9.10. Sequence of tightening the control shaft housing bolts
11. Install the oil pump (see chapter 2A).
12. The rest of the installation is carried out in the reverse order of removal.