Cylinder Block Assembly: Service and Repair

Pistons and connecting rods, disassembling and assembling

Note:
When working on the engine it should be secured to engine stand with engine bracket VW 540.





1 - Piston ring

^ Offset gaps by 120 degrees
^ Remove and install with piston ring pliers
^ "TOP" faces toward piston crown
^ Checking ring gap Go to Fig. 1
^ Checking ring to groove clearance Go to Fig. 2

2 - Piston

^ Checking Go to Fig. 3
^ Mark installation position in relation to connecting rod and cylinder number with a permanent felt marker.
^ Arrow on piston crown points to pulley end
^ Install using piston ring clamp
^ Piston and cylinder dimensions

3 - Connecting rod

^ Only replace as a set
^ Mark cylinder number -B-.
^ Installation position: Marks -A- must be aligned and facing belt pulley side
^ With hole for lubricating piston pin

4 - Connecting rod bearing cap

^ Mark cylinder number -B-.
^ Installation position: Marks -A- must be aligned and facing belt pulley side

5 - 30 Nm + 1/4 turn (90 degrees) further

^ Replace
^ Oil threads and contact surface
^ To measure radial clearance tighten to 30 Nm, but not further

6 - Pressure relief valve, 27 Nm

^ Opens at 2.5-3.2 bar
^ Do not apply sealant when installing

7 - Oil spray jet

^ For piston cooling

8 - Bearing shell

^ Note installation position
^ Do not interchange used bearing shells (mark)
^ Ensure retaining lugs fit tightly in recesses
^ Axial clearance, New: 0.10 - 0.35 mm; Wear limit: 0.40 mm
^ Check radial clearance with Plastigage, New: 0.01 - 0.05 mm; Wear limit: 0.12 mm
^ Do not rotate crankshaft when checking radial clearance
^ With hole for lubricating piston pin

9 - Cylinder block

^ Checking cylinder bores Go to Fig. 4

10 - Connecting rod bolt

^ Replace together with item -5-

11 - Circlip

12 - Piston pin

^ If difficult to move, heat piston to approx. 60 degrees C.
^ Remove and install with drift VW 222a





Fig. 1 Checking piston ring gap

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








Fig. 2 Checking ring to groove clearance

- Clean groove before checking clearance.








Fig. 3 Checking piston

- Measure pistons approx. 10 mm from lower edge of skirt, at 90 degrees to piston pin axis.

Permissible deviation from nominal dimension: max. 0.04 mm





Fig. 4 Checking cylinder bores

Use internal dial indicator (50-100 mm).

- Take measurements at 3 positions in both lateral direction -A- and longitudinal direction -B-.

Permissible deviation from nominal dimension: max. 0.10 mm

Note:
Measuring the cylinder bores must not be done when the cylinder block is mounted on a repair stand with adapter bracket VW 540, as incorrect measurements would then be possible.