Pistons and connecting rods, disassembling and assembling: Notes

The following list pertains to Fig 1.

1. Piston ring 
   • Offset gaps by 120
   • Remove and install with piston ring pliers
   • "TOP" marking faces toward piston crown
   • Checking ring gap, see Checking Piston Ring Gap 
   • Ring to groove side clearance, checking, see Checking Ring To Groove Clearance 
2. Piston 
   • Checking, See Checking Piston Diameter 
   • Mark installation position and relationship to cylinder and connecting rod
   • High point of piston crown faces to center of cylinder block
   • Install with special piston installing tool 3278, See Installing Pistons With Special Tool 3278 
3. Connecting rod 
   • Replace as a set only
   • Mark cylinder number -B
   • Installation position: marks - A- must be above one another on same side
4. Connecting rod bearing cap 
   • Note installation position
5. 30 Nm (22 ft lb) plus additional 1/4 turn (90 °) 
   • Always replace
   • Oil threads and bolt contact surfaces
   • To measure radial clearance tighten to 30 Nm (22 ft lb) but not further
6. Connecting rod bearing shell 
   • Note installation position
   • Do not interchange used bearing shells
   • Holding tabs must fit tightly in recesses in connecting rod and connecting rod bearing caps

     Axial clearance

   • New: 0.05 -0.31 mm (0.0020 -0.0122 in.)
   • Wear limit: 0.40 mm (0.0157 in.)

     Check radial clearance with Plastigage®:

   • New: 0.01 -0.06 mm (0.0004 - 0.0024 in.)
   • Wear limit: 0.10 mm (0.0039 in.)
   CAUTION: DO NOT rotate crankshaft when checking radial clearance.
7. Cylinder block 
   • Checking cylinder bores, See Checking Cylinder Bores 
   • Piston and cylinder dimensions, see PISTON AND CYLINDER DIMENSIONS 
8. Piston pin 
   • If difficult to remove, heat piston to 60 °C (140°)
   • Remove and install with tool VW 222a
9. Circlip 
   • Always replace
     Fig 1: Exploded View Of Pistons And Connecting Rods