Cylinder Block Assembly: Service and Repair

Piston and Connecting Rod, Component Overview

Note:
^ Oil injector jet for piston cooling





1 - Connecting rod bolt - 30 Nm plus an additional 90 degree (1/4 turn)

^ 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 the same side on connecting rod and connecting rod bearing cap
^ Installation position of connecting rod pairs

3 - Bearing shell

The version depends on construction:

^ Lower bearing shell (for bearing cap), identified by a dark-colored bearing. Upper bearing shell (for connecting rod) made of wear resistant material, identified by a light-colored bearing

or

^ The same bearing, no allocation
^ Check that retaining tabs are secured
^ Do not interchange used bearing shells (mark)
^ Radial clearance, measuring

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 the 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 degree C
^ Removing and installing using a drift VW 222 A

6 - Circlip

^ Replace

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
^ Cylinder bore, checking

8 - Piston rings

^ Offset gaps by 120 degree
^ 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





Piston Ring Gap, Checking

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








Ring to Groove Clearance, Checking

- Clean ring groove of piston before checking.








Pistons, Checking

- Measure approximately 10 mm from the lower edge at a 90 degree angle to the piston pin axis using an external micrometer 75 to 100 mm.

^ Maximum deviation from nominal dimension: 0.04 mm.

Nominal dimension.





Cylinder Bore, Checking

- 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.





Installed position of piston and piston/cylinder allocation

- 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 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 the beveled surfaces of the 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. Install bolt - 9 Nm - using a locking compound

2. Oil spray jet with spray nozzle valve