Cylinder Block Assembly: Service and Repair

Piston and connecting rod, disassembling and assembling

Note: Oil injector jet for piston cooling.





1. Connecting rod bolt, 30 Nm plus an additional 90° (1/4 turn)
^ Always replace
^ Lubricate threads and contact surface
^ Tighten to 30 Nm to measure radial play, do not turn further

2. Connecting rod bearing cap
^ Do not interchange
^ Mark allocation to cylinder using a color marker - B -
^ When installing bearing cap, observe: The wide thrust flange - A - must point to same side on connecting rod and connecting rod bearing cap
^ Installation position of connecting rod pairs

3. Bearing shell
^ Upper bearing shell (for connecting rod) made of wear-resistant material; identification: Bright color of bearing
^ Lower bearing shell (for bearing cap) identification: Dark color of bearing
^ Check that retaining tabs are secured
^ Do not interchange used bearings (mark)
^ Radial clearance, measuring Connecting rod radial clearance, checking

4. Connecting rod
^ Only replace as set
^ Mark allocation to cylinder with paint - B -
^ When installing bearing cap, observe: The wide thrust flange - A - must point to same side on connecting rod and connecting rod bearing cap
^ Installation position of connecting rod pairs

5. Piston pin
^ If tight, heat piston to 60°C
^ Removing and installing using a drift VW 222 A

6. Circlip
7. Piston
^ Installed position and allocation, piston/cylinder
^ Arrow on piston face points toward belt pulley side
^ Checking
^ Install with piston ring compressor
^ Piston and cylinder dimensions Piston and cylinder dimensions
^ Cylinder bore, checking

8. Piston rings
^ Offset gaps by 120°
^ Use piston ring pliers for removal and installation
^ TOP marking or inscribed side must point to piston head
^ Checking ring gap
^ Check piston ring groove clearance






Checking piston ring gap
- Push ring squarely from above down to approximately 15 mm from bottom end of cylinder. To do this use a piston without rings.









Checking ring to groove clearance
- Clean ring groove of piston before checking.








Checking piston
- Measure approximately 10 mm from lower edge, at a 90° angle to piston pin axis using an external micrometer 75 to 100 mm.
^ Maximum deviation from nominal dimension: 0.04 mm.
Nominal dimension Piston and cylinder dimensions.





Checking cylinder bores
- Using an internal dial gauge 50 to 100 mm, measure at 3 points in diagonal sequence horizontally - A - and vertically - B -.
^ Maximum deviation from nominal dimension: 0.08 mm.
Nominal dimension Piston and cylinder dimensions.





Installed position of piston and piston/cylinder allocation
- Mark installed location and allocation to cylinder on piston head using chalk or water-proof felt pen.

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

^ Installed location: Arrow on piston face points toward belt pulley side.





Mark connecting rod

Note:
^ Only replace connecting rod as a set.
^ Do not interchange connecting rod bearings.

- Before removing, mark allocation of connecting rod and connecting rod bearing caps to each other and to cylinder with paint - arrow -.





Connecting rod, installed location
^ The molded tabs - arrows - at beveled surfaces of connecting rod pairs 1 and 2, 3 and 4, and 5 and 6 must point toward each other.





Oil spray jet for piston cooling
1. Insert bolt (9 Nm) using locking compound
2. Oil spray jet with spray nozzle valve