Cylinder Block Assembly: Service and Repair

Pistons and connecting rods, disassembling and assembling

Note: Oil injector jet for piston cooling go to Fig. 8.





1. Connecting rod bolt, 30 Nm plus an additional 90° (1/4 turn)
^ Always replace
^ Grease thread and contact surface
^ Tighten to 30 Nm when measuring radial clearance, but do not turn further

2. Connecting rod bearing cap
^ Do not interchange
^ Mark allocation to cylinder using a color marker -B- go to Fig. 6
^ Observe when installing bearing cap: Tabs at contact surfaces at face of connecting rod must be aligned -A- Installed position of connecting rod pairs go to Fig. 7

3. Bearing shell
^ Note installed position Do not interchange run-in connecting rod bearing shells (mark)
^ Measuring radial play
^ Tighten bolts item -1- to 30 Nm when measuring radial clearance, but do not turn further

4. Connecting rod
^ Replace only as a set
^ Mark allocation to cylinder using a color marker -B- go to Fig. 6
^ Observe when installing bearing cap: Tabs at contact surfaces at face of connecting rod must be aligned -A- Installed position of connecting rod pairs go to Fig. 7

5. Snap ring
6. Piston pins
^ In case of difficulty of movement, warm piston to approximately 60°C
^ When removing and installing, use VW222a Pilot drift

7. Pistons
^ Installed position and allocation piston/cylinder go to Fig. 5
^ Arrow on piston head points to belt pulley side
^ Checking go to Fig. 3
^ Install with piston ring tension strip
^ Piston and cylinder dimensions
^ Checking cylinder bore hole Go to Fig. 4

8. Piston rings
^ Offset gaps by 120°
^ Use piston ring pliers to remove and install
^ Marking or identification TOP i.e. marked side must face toward piston head
^ End play, checking go to Fig. 1
^ Height play, checking go to Fig. 2





Fig. 1 Checking piston ring end gap
- Insert ring at right angle to cylinder wall from above to lower cylinder opening approximately 15 mm from cylinder edge. Use piston without rings to insert.








Fig. 2 Checking piston ring side clearance
- Before measuring, clean piston ring groove








Fig. 3 Checking pistons

Special tools and equipment
^ External micrometer 75-100 mm
- Measure approximately 10 mm from lower edge, at a 90° angle to piston pin axis.
^ Deviation from nominal dimension: max. 0.04 mm





Fig. 4 Checking cylinder bore

Special tools and equipment
^ Inner bore gauge 50-100 mm
- Measure diagonally at 3 positions, horizontally -A- and lengthwise -B-. Oil scraper ring 0.25 to 0.50 0.8 Piston ring New Wear limit (Distance in mm)
^ Deviation from nominal dimension: max. 0.08 mm





Fig. 5 Piston installed position and application piston/cylinder
- Mark installed position and allocation to cylinder on piston head using chalk or waterproof felt pen.

Note: Do not use a center punch or scribe, since the piston head coating will be damaged.

^ Installed position:
Arrow on piston head points to belt pulley side





Fig. 6 Marking connecting rods

Note:
^ Replace the connecting rods only as a set.
^ Do not interchange the connecting rod bearings.

- Before removing, mark allocation of connecting rod and connecting rod bearing caps to each other and to cylinder using a color marker (arrow).





Fig. 7 Installed position of connecting rods
- Molded tabs (arrows) at the beveled surfaces of the connecting rod pairs 1 and 2, 3 and 4 as well as 5 and 6 must point toward each other.





Fig. 8 Oil injector jet for piston cooling
1 - Bolt, 10 Nm
2 - Oil injector jet for piston cooling