Audi Workshop Service and Repair Manuals

Note:

All bearing and running surfaces must be oiled before assembling.

• Piston
• ◆ Checking => Fig. 3
• ◆ Mark installation position and cylinder number
• ◆ Arrow on piston crown points to pulley end
• ◆ Install using piston ring clamp
• Piston pin
• ◆ If difficult to remove, heat piston to 60 °C
• ◆ Remove and install with10-206
• Circlip

• Conrod
• ◆ Only renew as a set
• ◆ Mark cylinder number -A-
• ◆ Installation position:
  Marking -B- faces towards pulley end
• ◆ Guided axially via piston
• Bearing shell
• ◆ Note installation position
• ◆ Do not interchange used bearing shells
• ◆ 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
• Cylinder block
• ◆ Checking cylinder bores
  =>Fig. 4
• ◆ Piston and cylinder dimensions
  

• Conrod bearing cap
• ◆ Note installation position
• ◆ 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, 30 Nm +1/4turn (90°) further
• ◆ Renew
• ◆ Oil threads and contact surface
• ◆ To measure radial clearance tighten to 30 Nm but not further
• Oil scraper rings
• ◆ Carefully remove and install 3-part oil scraper rings by hand
• ◆ "TOP" faces towards piston crown
• ◆ Checking ring gap=> Fig. 1
• ◆ Checking ring to groove clearance
  => Fig. 2

• 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

→ 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, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ External micrometer 60...90 mm

• ‒ Measure approx. 10 mm from lower edge and offset 90°from piston pin axis. Deviation from nominal dimension
      max. 0.07 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 13-47; 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.