Cylinder Block Assembly: Service and Repair

Pistons and connecting rods, disassembling and assembling

Note: Mount in engine stand VW 540 before beginning work.





1. Piston ring
^ Offset gaps by 120
^ Remove and install using piston ring pliers
^ "TOP" faces piston crown
^ Ring gap, checking -> Fig. 1
^ Ring to groove clearance checking refer to Fig. 2
^ 2-part oil ring
2. Piston
^ Checking -> Fig. 3 Mark installation position and cylinder number
^ Arrow on piston crown points to pulley end Install using piston ring clamp
3. Connecting rod
^ Only replace as a set
^ Mark cylinder number -B-
^ Installation position: Marking -A- faces towards pulley end
4. Connecting rod bearing cap
^ Mark cylinder number -B-
^ Installation position: Marking -A- faces towards pulley end
5. 30 Nm (22 ft. lbs.) + 1/4 turn (90°)
^ Oil threads and contact surfaces
^ To measure radial clearance tighten to 30 Nm (22 ft. lbs.) but no further
^ 90° additional angle can be measured with torque angle meter i.e., Hazet 6690
6. Pressure relief valve
^ 27 Nm (20 ft. lbs.)
^ Opening pressure: 2.5 - 3.2 bar (36 - 46 psi)
7. Oil spray jet
^ for piston cooling
8. Bearing shell
^ Note installation position
^ Do not interchange used bearing shells
^ Ensure retaining lugs fit tightly in recesses
Axial clearance
^ New: 0.05 to 0.31 mm
^ Wear limit: 0.37 mm
Check radial clearance with Plastigage:
^ New: 0.01 to 0.06 mm
^ Wear limit: 0,12 mm
^ Do not rotate crankshaft when checking radial clearance
9. Engine block
^ Checking cylinder bores
^ Piston and cylinder dimensions
10. Connecting rod bolt
11. Circlip
12. Piston pin
^ If difficult to remove, heat piston to 60°C (140°F) Remove and install using VW 222a

Fig. 1 Piston ring gap, checking
Special Tools








^ Feeler gauges
- Squarely push down on piston ring from above to approximately 15 mm from lower end of cylinder bore.

Fig. 2 Ring to groove clearance, checking
Special Tools








^ Feeler gauges
- Clean groove before check.

Fig. 3 Piston, checking
Special Tools





- Micrometer 75 - 100 mm (2.95 - 3.95 inch)
- Measure pistons approximately 10 mm from the lower edge of skirt, at 90° angle to the piston pin axis.
- Deviation from nominal dimension max. 0.04 mm


Cylinder bores, checking
Special Tools





^ Internal dial gauge 75 - 100 mm (2.95 - 3.95 inch)
- Measure bore 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: Do NOT measure the cylinder bores when the engine block is mounted on a repair stand using the VW540 adapter bracket, inaccurate measurements will result due to the uneven bending of the engine block on the repair stand.






Piston and cylinder dimensions