Connecting Rod: Service and Repair

Piston and connecting rod, disassembling and assembling

Note: Oil spray jet and pressure relief valve





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

2. Connecting rod bearing cap
^ Affiliation to cylinder mark - B -
^ Installed location: Markings - A - point to belt pulley side

3. Bearing shells
^ Upper bearing shell with oil hole for piston pin lubrication
^ Installed location
^ Do not interchange used bearings (mark)
^ Axial play new: 0.10 to 0.35 mm Wear limit: 0.40 mm
^ Measure radial clearance with Plastigage: New: 0.01 to 0.05 mm Wear limit: 0.12 mm. Do not turn crankshaft when checking radial clearance

4. Connecting rod
^ Only replace as set
^ Affiliation to cylinder mark - B -
^ Installed location: Markings - A - point to belt pulley side
^ With oil hole for piston pin lubrication

5. Circlip
6. Piston pin
^ If difficult to move, heat piston to approximately 60° C
^ Removing and installing using a drift VW 222 A

7. Piston
^ Checking
^ Mark installed position and cylinder allocation
^ Arrow on piston face points toward belt pulley side
^ 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
^ Mark TOP must face toward 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 pistons approximately 10 mm from bottom edge and at points offset by 90° to piston pin axis.
^ Deviation from nominal dimension: max. 0.04 mm





Checking cylinder bores

Special tools, testers and auxiliary items required
^ Internal dial gauge 50 to 100 mm
- Measure bores at 3 locations in both directions - A - across engine and - B - in line with crankshaft.
^ Deviation from nominal dimension: max. 0.08 mm





Installed position of bearing shell
- Insert bearing shells centrally into connecting rod and into connecting rod cap.
^ Dimension a = 3.0 mm





Oil spray jet and pressure relief valve
1 - Oil spray jet (for piston cooling)
2 - Bolt with pressure relief valve - 7 Nm
^ Opening pressure 1.3 to 1.6 bar