A4 Mk2
Pistons and conrods - exploded view |
Note
Oil spray jet for piston cooling → Fig.. |
1 - | Conrod bolt, 30 Nm + 90° (1/4 turn) further |
q | Renew |
q | Lubricate threads and contact surface |
q | Use old bolts when measuring radial clearance |
q | To measure radial clearance, tighten to 30 Nm but do not turn further |
2 - | Conrod bearing cap |
q | Do not interchange |
q | Mark cylinder allocation with a coloured pen -B- → Fig. |
q | When installing the bearing cap, the projections on the side of the conrod must be on the same side -A- |
q | Installation position of conrod pairs → Fig. |
3 - | Bearing shell |
q | Note installation position |
q | Do not interchange used bearing shells (mark positions) |
q | Measuring radial clearance → Chapter |
q | To measure radial clearance, tighten bolts → Item to 30 Nm but do not turn further |
4 - | Conrod |
q | Only renew as a complete set |
q | Mark cylinder allocation with a coloured pen -B- → Fig. |
q | When installing the bearing cap, the projections on the side of the conrod must be on the same side -A- |
q | Installation position of conrod pairs → Fig. |
5 - | Circlip |
6 - | Piston pin |
q | If difficult to move, heat piston to approx. 60 °C |
q | Remove and install using drift -VW 222 A- |
7 - | Piston |
q | Checking → Fig. |
q | Installation position and allocation of piston/cylinder → Fig. |
q | Arrow on piston crown points to pulley end |
q | Install using piston ring clamp |
q | Piston and cylinder dimensions → Chapter |
q | Checking cylinder bore → Fig. |
8 - | Piston rings |
q | Offset gaps by 120° |
q | Use piston ring pliers to remove and install |
q | “TOP” must face towards piston crown |
q | Checking ring gap → Fig. |
q | Checking ring-to-groove clearance → Fig. |
Piston ring Dimensions in mm | New | Wear limit |
1st compression ring | 0.35 … 0.50 | 0.8 |
2nd compression ring | 0.60 … 0.80 | 1.0 |
Oil scraper ring | 0.25 … 0.50 | 0.8 |
|
Piston ring Dimensions in mm | New | Wear limit |
Compression rings | 0.02 … 0.08 | 0.20 |
Oil scraper ring | 0.02 … 0.08 | 0.15 |
|
|
Note
|
Note
|
|
|