volkswagen Workshop Repair Guides

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Dismantling and assembling pistons and conrods
   
Dismantling and assembling pistons and conrods
1 - Piston rings
q   Offset gaps by 120°.
q   Use piston ring pliers to remove and install
q   “TOP” faces towards piston crown.
q   Checking piston ring gap → Fig..
q   Checking ring-to-groove clearance → Fig..
q   2 or 3 part oil scraper ring, mixed installation permissible
2 - Piston
q   Check → Fig..
q   Mark installation position and cylinder number.
q   Arrow on piston crown points to belt pulley end.
q   Install using piston ring clamp.
q   Characteristics → Fig.
3 - Conrod
q   Renew as set only.
q   Mark cylinder number -B-.
q   Installation position: Markings -A- face towards belt pulley end.
q   For 85 kW engines with oil drilling for piston pin lubrication
4 - Conrod bearing cap
q   Note installation position.
5 - 30 Nm + 1/4 turn (90 °) further
q   Oil threads and contact surface
q   To measure radial clearance, tighten to 30 Nm but do not turn further.
6 - Pressure relief valve, 27 Nm
q   For 85 kW engines
q   Opening pressure: 2.5…3.2 bar
7 - Oil spray jet
q   For 85 kW engines
q   For piston cooling.
8 - Bearing shell
q   Note installation position.
q   Do not interchange used bearing shells
q   Ensure secure seating in retaining lugs
q   Axial clearance new: 0.05…0.31 mm , wear limit: 0.37 mm
q   Check radial clearance with Plastigage: new = 0.01…0.06 mm; wear limit = 0.12 mm. Do not rotate crankshaft when checking radial clearance.
9 - Cylinder block
q   Checking cylinder bore → Fig..
q   Piston and cylinder dimensions → Chapter.
10 - Conrod bolt
11 - Circlip
12 - Piston pin
q   If difficult to remove, heat piston to 60 °C.
q   Remove and install using drift -VW 222 A-

   
Checking piston ring gap
–  Insert ring at right angles from above and push down into cylinder approx. 15 mm from bottom end of cylinder.
  V13-0016
Piston ring Ring gap
  NewWear limit
Compression ringsmm0.20…0.401.0
Oil scraper ringmm0.25…0.501.0

   
Checking ring-to-groove clearance
Clean annular groove before check.
  V13-0687
Piston ring Clearance
  NewWear limit
Compression ringsmm0.02…0.050.15
Oil scraper ringmm0.02…0.050.15

   
Checking piston
Measure piston approx. 10 mm from lower edge of skirt, at 90° to piston pin axis.
Deviation from nominal dimension max. 0.04 mm
  V13-0010
Piston characteristics
  V13-1130
Engine codesAAM and ANNABSADZ and ANP
Dimension “a”mm22.222.222.2
Dimension “b”mm8.14.44.4
Recess Ø “c”mm56.856.056.0
Piston pin Ø “d”mm20.020.020.0

   
Engine codes2EADYAGG and AKR
Dimension “a”mm20.420.420.4
Dimension “b”mm5.05.05.7
Recess Ø “c”mm64.064.064.0
Piston pin Ø “d”mm21.021.021.0

When performing repairs, only pistons and piston rings of the same type and pistons in the same weight class must be installed in the engine.
   
Checking cylinder bores
t  Take measurements at 3 positions in both lateral direction -A- and longitudinal direction -B-.
t  Use cylinder gauge 50…100 mm.
t  Deviation from nominal dimension max. 0.08 mm
  Note
Cylinder bores must not be measured when cylinder block is mounted on a repair stand with engine and gearbox support -VW 540-, as measurements may then be incorrect.
  V13-0280

Power unit > 4-cylinder injection engine (2-valve), mechanics > Enginecrankshaft group, pistons > Dismantling and assembling pistons and conrods

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