Volkswagen Workshop Service and Repair Manuals

• Circlip
• Piston pin
• ◆ If difficult to remove, heat piston to 60 °C
• ◆ Remove and install with drift 10-14
• Piston
• ◆ Checking => Fig. 3
• ◆ Mark installation position and cylinder number
• ◆ Arrow on piston crown points to pulley end
• ◆ Install using piston ring clamp

• Compression rings
• ◆ Offset gaps by 120 °
• ◆ Remove and install compression rings with piston ring pliers
• ◆ "TOP" faces towards piston crown
• ◆ Checking ring gap=> Fig. 1
• ◆ Checking ring to groove clearance
  => Fig. 2
• Oil scraper rings
• ◆ Carefully remove and install 3-part oil scraper rings by hand
• ◆ Checking ring gap=> Fig. 1
• ◆ Checking ring to groove clearance
  => Fig. 2
• Conrod
• ◆ Only renew as a set
• ◆ Mark cylinder number -A-
• ◆ Installation position:
  Marking -B- faces towards pulley end
• ◆ Guided axially via piston

• Conrod bearing cap
• ◆ The caps only fit in one position and only on the appropriate con-rod, this is due to the breaking procedure (cracking) separating the cap from the con-rod
• Conrod bolt, 20 Nm + 1/4 turn (90 °) further
• ◆ Renew
• ◆ Oil threads and contact surface
• ◆ To measure radial clearance tighten to 20 Nm but not further
• Cylinder block
• ◆ Checking cylinder bores
  =>Fig. 4
• ◆ Piston and cylinder dimensions
  

• Bearing shell
• ◆ Do not interchange used bearing shells
• ◆ Measure pretension
  => Fig. 5
• ◆ Insert bearing shells centrally
• ◆ Check radial clearance with Plastigage:
  New: 0.020...0.061 mm
  Wear limit: 0.091 mm
  Do not rotate crankshaft when checking radial clearance

→ Fig. 1     Checking piston ring gap

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

     1)     No wear limit details

→ Fig. 2     Checking ring to groove clearance

Clean groove before check.

→ Fig. 3     Checking piston

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ 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, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ 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 13-64 ; 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.

→ Fig. 5     Measuring bearing shell pretension

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ Vernier caliper

The bearing shell pretension is calculated as follows:

     Bearing shell dimension -a-
-     Conrod diameter -b-
=     Pretension

Minimum dimension: 1.5 mm

If the pretension is not achieved:

• ‒ Renew bearing shells.