Procedures

Pistons and connecting rods, disassembling and assembling





1- Piston rings
^ Shift by 120°
^ Use piston ring pliers to remove and install
^ Marking "TOP" faces piston head
^ Check end play see Fig. 1
^ Check height play see Fig. 2
^ 2 part or 3 part oil scraper ring, mixed construction is permitted
2- Pistons
^ Checking see Fig. 3
^ Mark installation position and matching cylinder
^ Arrow on piston head points to belt pulley side
^ Install with piston ring tension strip
3- Piston pins
^ In case of difficulty of movement, warm piston To 60°C.
^ When removing and installing, use VW222a Pilot drift
4- Snap ring
5- Connecting rod
^ Replace only as a set
^ Mark to indicate which cylinder corresponds to each cover -B
^ Installation position: Markings -A point to belt pulley side
6- Bearing shell
^ Note installed position see Fig. 4
^ Do not interchange used bearing shells
^ Axial play when new: 0.05 to 0.31 mm wear limit: 0.37 mm
^ Measure radial play with Plastigage: New: 0.01 to 0.06 mm wear limit: 0.12 mm Do not turn crankshaft when measuring radial play.
7- Cylinder block
^ Checking cylinder bore hole see Fig 5
^ Piston and cylinder dimensions at end of Article.
8- Connecting rod cover
^ Note installed position
9- Oil injection jet
^ to cool pistons
10- Pressure release valve, 27 Nm
^ Opening pressure: 1.3 to 1.6 bar positive pressure
11- Connecting rod bolt, 30 Nm + 1/4 turns (90°) turn
^ Always replace
^ Grease thread and contact surface
^ Use old bolt for radial play measurement.

Special tools and equipment
^ Feeler gauge
^ Inner bore gauge 50 - 100 mm
^ External micrometer 75 - 100 mm





Part 1 of 2





Part 2 of 2

Fig. 1 Checking piston ring end gap
^ Insert ring into lower cylinder opening at a right angle from above, approximately 15 mm from cylinder edge.





Fig. 2 Checking piston ring side clearance





Clean ring groove before checking.





Fig. 3 Checking pistons
Measure pistons approximately 10 mm (3/8 inch) from bottom edge at points offset by 90° to piston pin axis.
Deviation from specified size: maximum 0.04 mm





Fig. 4 Bearing shells - installation position
Bearing shell -1- with oil bore (arrow) for connecting rod.
Bearing shell -2- without oil bore for connecting rod cover.
- Insert bearing shells into connecting rod and connecting rod cover in centered manner.
Dimension -a- must be the same at left and right. maximum deviation: 0.2 mm

Fig. 5 Check bore
^ Measure diagonally at 3 positions horizontally -A- and lengthwise -B-.
^ Use inner bore gauge 50 - 100 mm.
^ Deviation from specified size: maximum 0.08 mm

Note: Cylinder bore must not be measured if cylinder block is secured to engine stand with VW540 holding fixture, or else results will be incorrect.





Piston and cylinder measurements





1) Dimensions exclude graphite coating (thickness 0.02 mm). The graphite coating wears off.