Pistons and Connecting Rods, Disassembling and Assembling

Pistons and connecting rods, disassembling and assembling

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

1. Connecting rod bolt 30 Nm + 90° (1/4 additional 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, Refer 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, Refer to Fig. 7.
3. Bearing shell
^ Note installed position
^ Do not interchange run-in connecting rod bearing shells (mark)
^ Measuring radial play, Refer to Connecting Rod, Testing and Inspection.
^ 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, Refer 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, Refer to Fig. 7.
5. Snap ring
6. Piston pins
^ For difficulty of movement, warm pistons to approximately 60°C
^ Use VW222a pilot drift to remove and install
7. Pistons
^ Installed position and allocation piston/cylinder, Refer to Fig. 5.
^ Arrow on piston head points to belt pulley side
^ Checking, Refer to Fig. 3.
^ Install with piston ring tension strip
^ Piston and cylinder measurements, Refer to Piston, Engine, Service and Repair.
^ Checking cylinder bore, Refer to Fig. 4.
8. Piston rings
^ Shift by 120°
^ Use piston ring pliers to remove and install
^ Marking or identification "TOP" i.e. marked side must face toward the piston head
^ Check end play, Refer to Fig. 1.
^ Checking height play, Refer to Fig. 2.








Fig. 1 Piston ring-Checking end gap
- Insert ring at a right angle to cylinder wall from above to lower cylinder opening approximately 15 mm cylinder edge. When inserting, use pistons without rings








Fig. 2 Piston ring-Checking height play
- Before measuring, clean piston ring groove








Fig. 3 Checking piston
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
Specified dimension piston and cylinder measurements, Refer to Piston, Engine, Service and Repair.





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-.
^ Deviation from nominal dimension: max. 0.08 mm
Specified dimension piston and cylinder measurements, Refer to Piston, Engine, Service and Repair.





Fig. 5 Installed position and allocation 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.

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





Fig. 6 Marking connecting rod

Notes:
^ 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.





Fig. 7 Connecting rod installation position
^ Molded tabs (arrows) at the bevelled 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