Connecting Rod: Service and Repair

Pistons and Connecting Rods, Disassembling and Assembling

Vehicles with engine code AWP, AWV

Note:
Secure engine to engine bracket VW540 on assembly stand when disassembling/assembling engine.

1. Piston ring
^ Offset gaps by 120°
^ Remove and install with piston ring pliers
^ "TOP" faces toward piston crown
^ Checking ring gap, Refer to Fig. 1
^ ^Checking ring to groove clearance, Refer to Fig. 2
2. Piston
^ Checking, Refer to Fig. 3
^ Mark installation position and cylinder number
^ Arrow on piston crown points to pulley end
^ Install using piston ring clamp
3. Piston pin
^ If difficult to remove, heat piston to 60°C
^ Remove and install with VW222a
4. Circlip
5. Connecting rod
^ Only replace as a set
^ Mark cylinder number -B
^ Installation position:Marking-A-faces toward pulley end
6. Bearing shell
^ Note installation position
^ Do not interchange used bearing shells
^ Axial clearance
New: 0.05 to 0.31 mm
Wear limit: 0.37 mm
^ Check radial clearance with Plastigage:
New: 0.01 to 0.06mm
Wear limit: 0.09 mm
^ Do not rotate crankshaft when checking radial clearance
7. Cylinder block
^ Checking cylinder bores, Refer to Fig. 4
8. Connecting rod bearing cap
^ Note installation position
9. Oil spray jet
^ For piston cooling
10. Pressure relief valve, 27 Nm
^ Opening pressure: 1.3 to 1.6 bar
11. Connecting rod bolt, 30 Nm +1/4turn (90°) further
^ Always replace
^ Oil threads and contact surface
^ To measure radial clearance use old bolts
^ To measure radial clearance tighten to 30 Nm but not further





Fig. 1 Checking piston ring gap

Special tools and equipment
^ Feeler gauges





- Push ring squarely from above down to approximately 15 mm from bottom end of cylinder.





Fig. 2 Checking ring to groove clearance

Special tools and equipment
^ Feeler gauges





Clean groove before check.





Fig. 3 Checking piston

Special tools and equipment
^ Micrometer 75 to 100 mm

- Measure pistons approximately 10 mm from lower edge of skirt, at 90° to piston pin axis.
Deviation from nominal dimension: max. 0.04 mm





Fig. 4 Bearing shells - Mount
Bearing shell -1- for connecting rod (with hole -arrow- for oil channel).
Bearing shell -2- for connecting rod (without hole for oil channel).
- Place bearing shells on the middle of connecting rod and connecting rod bearing cap.
Measure -a- must be the same at right and left.
max. deviation: 0.2 mm





Fig. 5 Checking cylinder bores

Special tools and equipment
^ Internal dial gauge 50 to 100 mm

- Measure bores at 3 locations in both directions -A- across the engine and -B- in line with crankshaft.
Deviation from nominal dimension: max. 0.08 mm

Note: Measuring the cylinder bores must not be done when the cylinder block is mounted on a repair stand with adapter bracket VW540, as incorrect measurements would then be possible.





Piston and cylinder dimensions (engine codes: AWP, AWV)
1) Dimension without graphite coating (thickness 0 02 mm). The graphite coating wears away.