Volkswagen Workshop Service and Repair Manuals

• Piston ring
• ◆ Offset gaps by 120 °
• ◆ Remove and install with piston ring pliers
• ◆ "TOP" faces towards piston crown
• ◆ Checking ring gap=> Fig. 1
• ◆ Checking ring to groove clearance
  => Fig. 2
• Piston
• ◆ Checking => Fig. 3
• ◆ Mark installation position and cylinder number
• ◆ Arrow on piston crown points to pulley end
• ◆ Install using piston ring clamp

• Conrod
• ◆ Only renew as a set
• ◆ Mark cylinder number -B-
• ◆ Installation position:
  Marking -A- faces towards pulley end
• ◆ With oil drilling for piston pin lubrication
• Conrod bearing cap
• ◆ Note installation position
• 30 Nm + 1/4 turn (90 °) further
• ◆ Oil threads and contact surface
• ◆ To measure radial clearance tighten to 30 Nm but not further
• Pressure relief valve, 27 Nm
• ◆ Opening pressure: 2.5...3.2 bar

• Oil spray jet
• ◆ For piston cooling
• Bearing shell
• ◆ Note installation position
• ◆ Do not interchange used bearing shells
• ◆ Ensure retaining lugs fit tightly in recesses
• ◆ Axial clearance
  New: 0.05...0.31 mm
  Wear limit: 0.37 mm
• ◆ Check radial clearance with Plastigage:
  New: 0.01...0.06 mm
  Wear limit: 0.12 mm
  Do not rotate crankshaft when checking radial clearance
• ◆ With oil drilling for piston pin lubrication
• Cylinder block
• ◆ Checking cylinder bores
  =>Fig. 4
• ◆ Piston and cylinder dimensions
  

• Conrod bolt
• Circlip
• Piston pin
• ◆ If difficult to remove, heat piston to 60 °C
• ◆ Remove and install with VW 222a

→ Fig. 1     Checking piston ring gap

• ‒ Push ring squarely from above down to approx. 15 mm from bottom end of cylinder.

→ Fig. 2     Checking ring to groove clearance

Clean groove before check.

→ Fig. 3     Checking piston

Special tools, testers and auxiliary items

• ◆ Micrometer 75...100 mm

• ‒ Approx. 10 mm from lower edge and offset 90 ° to piston pin axis. Deviations from nominal dimensions
       max. 0.04 mm

• Nominal dimension ; Piston and cylinder dimensions

→ Fig. 4     Checking cylinder bores

Special tools, testers and auxiliary items

• ◆ Internal dial gauge 50...100 mm

• ‒ Take measurements at 3 positions in both lateral -A- and longitudinal -B- directions, as illustrated. Deviation from nominal dimension
       max. 0.08 mm

• Nominal dimension => Page 13-34 ; Piston and cylinder dimensions

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.