Overhaul

Pistons and connecting rods, Assembly overview

Pistons and connecting rods, Assembly overview:

1 - Piston rings
^ Offset gaps by 120°
^ Position oil scraper ring gap in tight winded spring area
^ Remove and install using piston ring pliers
^ "TOP" faces piston crown

2 - Piston
^ With combustion chamber
^ Mark installation position and cylinder number
^ Mark installation position and allocation of piston/cylinder
^ Arrow on piston crown points to belt pulley end
^ Install using piston ring clamp
^ Cracks on piston skirt, replace piston

3 - Piston pin
^ If difficult to remove, heat piston to 60 °C.
^ Remove and install with drift VW 222 A

4 - Retaining ring
5 - Connecting rod
^ Mark cylinder number - A - with colored pen
^ Installation position: Marking - B - faces pulley end
^ With industrially cracked bearing caps

6 - Bearing shell
^ Note installation position.
^ Note versions:
- Upper bearing shell (toward piston) is made of material which is more resistant to wear. Identification characteristics: black line on running surface in separating area
^ Do not interchange used bearing shells
^ Insert bearing shells centrally
^ Check for secure seating
^ Measuring axial clearance
- Wear limit: 0.37 mm
^ Check radial clearance with Plastigage:
- Wear limit: 0.08 mm (Do not rotate crankshaft when checking radial clearance)

7 - Cylinder block

8 - Connecting rod bearing cap
^ Note installation position
^ Caps only fit in one position and only on appropriate connecting rod due to breaking procedure (industrial cracking) separating cap from connecting rod

9 - Oil spray jet
^ For piston cooling

10 - 25 Nm
^ Insert without sealant

11 - Connecting rod bolt, 30 Nm plus 1/4 turn (90°)
^ Replace
^ Oil threads and contact surfaces
^ To measure radial clearance use old bolts





Checking piston ring gap
Special tools, testers and auxiliary items required
^ Feeler gauge (commercial type)
- Push ring squarely from above down to approximately 15 mm from bottom end of cylinder.
- Determine ring gap with feeler gauge.








Checking ring-to-groove clearance

Special tools, testers and auxiliary items required
^ Feeler gauge (commercial type)
- Clean ring groove before checking.
- Determine clearance with feeler gauge.








Checking cylinder bores

Special tools, testers and auxiliary items required
^ Internal dial gauge 50 to 100 mm (commercial type)

- Take measurements at 3 positions in both lateral - A - and longitudinal - B - planes, as illustrated.
- Deviation from nominal dimension: maximum 0.10 mm

Note:
^ Measuring the cylinder bores must not be done when the cylinder block is mounted on a repair stand with holding fixture VW 540 as incorrect measurements would then be possible.





Piston installation and piston/cylinder allocation
Piston in cylinders 1 and 2:

Larger intake valve chamber toward flywheel - arrows -

Piston in cylinders 3 and 4:

Larger intake valve chamber toward belt pulley side - arrows -.

Note:
^ New piston allocation to cylinder is shown by a colored marking on piston crown.
^ Piston for cylinder 1 and 2: marked 1/2
^ Piston for cylinder 3 and 4: marked 3/4





Installation position of bearing shells
Insert bearing shells centralized in connecting rod and connecting rod bearing cap.

Dimension - a - must be same on left and right sides; maximum deviation: 0.2 mm