Audi Workshop Service and Repair Manuals

Note:

Oil spray jet and oil pressure relief valve

=> Fig. 13-85

• Conrod bolt, 30 Nm + 1/4 turn (90 °) further
• ◆ Renew
• ◆ Oil threads and contact surface
• ◆ To measure radial clearance use old bolts
• ◆ To measure radial clearance tighten to 30 Nm but not further

• Conrod bearing cap
• ◆ Mark cylinder number -B-
• ◆ Installation position:
  Marking -A- faces towards pulley end
• Bearing shells
• ◆ Upper bearing shell with oil drilling for piston pin lubrication
• ◆ Note installation position
  =>Fig.13-85
• ◆ Do not interchange used bearing shells (mark)
• ◆ 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

• 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
• Circlip
• Piston pin
• ◆ If difficult to move, heat piston to approx. 60 °C
• ◆ Remove and install with VW 222a

• Piston
• ◆ Checking => Fig. 13-84
• ◆ Mark installation position and cylinder number
• ◆ Arrow on piston crown points to pulley end
• ◆ Install using piston ring clamp
• ◆ Piston and cylinder dimensions
  =>Page 13-86
• Piston rings
• ◆ Offset gaps by 120 °
• ◆ Remove and install with piston ring pliers
• ◆ "TOP" must face towards piston crown
• ◆ Checking ring gap
  => Fig. 13-83
• ◆ Checking ring to groove clearance
  => Fig. 13-83

→ 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° to the piston pin axis.
• ‒ Deviation from nominal dimension
  not more than 0.04 mm

→ Fig. 4    Checking cylinder bores

Special tools and workshop equipment required

• ◆ Internal dial gauge 50...100 mm

• ‒ Take measurements at 3 positions in both lateral -A- and longitudinal -B- directions.
• ‒ Deviation from nominal dimension
  not more than 0.08 mm

→ Fig.5    Bearing shell installation position with cracked-steel conrods

• ‒ Insert bearing shell centrally in conrod or conrod bearing cap.
• ‒ Dimension a = 3.0 mm

→ Fig.6    Oil spray jet and pressure relief valve

•     1 -    Oil spray jet (for piston cooling)
•     2 -    Bolt with pressure relief valve - 27 Nm
• ‒ Engines with sawn conrods:
  Opening pressure 2.5 ... 3.2 bar
• ‒ Engines with cracked-steel conrods:
  Opening pressure 1.3 ... 1.6 bar