Piston and Connecting Rod, Assembly Overview
Piston and connecting rod, assembly overview
Gradual introduction of industrially fractured connecting rods
Piston with conventional connecting rod
Piston with industrially fractured connecting rod
Gradual introduction of industrially fractured connecting rods
Identifying characteristics:
A - Conventional connecting rods with polished contact surfaces
B - Industrially cracked connecting rods with rough contact surfaces.
Piston with conventional connecting rod
Piston with industrially fractured connecting rod
Piston with conventional connecting rod
Note:
^ When working on the engine, it should be secured to the holding fixture VW 540 with spacers VW 540/1 B to the assembly stand.
1 - Piston rings
^ Offset gaps by 120
^ Remove and install using piston ring pliers
^ "TOP" faces piston crown
2 - Piston
^ Mark installation position and cylinder number
^ Arrow on piston crown points to belt pulley end
^ Install using piston ring clamp
3 - Connecting rod
^ Replace as set only
^ Mark cylinder number - B -
^ Installation position: Marking - A - faces belt pulley end
4 - Connecting rod bearing cap
^ Mark cylinder number - B -
^ Installation position: Marking - A - faces belt pulley end
5 - 30 Nm plus 1/4 turn (90°)
^ Replace
^ Oil threads and contact surfaces
^ To measure radial clearance, tighten to 30 Nm, but do not turn further
6 - Pressure relieve valve, 27 Nm
^ Opening pressure: 2.53.2 bar
7 - Oil spray jet
^ For piston cooling
8 - Bearing shell
^ Note installed position.
^ Do not interchange used bearing shells
^ Ensure retaining lugs fit tightly in recesses
^ Axial clearance:
- New: 0.100.31 mm
- Wear limit: 0.40 mm
^ Check radial clearance with Plastigage:
- New: 0.010.05 mm
- Wear limit: 0.12 mm
^ Do not rotate crankshaft when checking radial clearance
9 - Cylinder block
10 - Connecting rod bolt
^ Replace
11 - Retaining ring
12 - Piston pin
^ If difficult to remove, heat piston to 60° C
^ Remove and install with VW 222 A
Checking piston ring gap
Special tools, testers and auxiliary items required
^ Feeler gauges
Work sequence
- Push ring squarely from above down to approx. 15 mm from bottom end of cylinder
Checking piston ring-to-groove clearance
Special tools, testers and auxiliary items required
^ Feeler gauges
- Clean groove before check.
Checking piston
Special tools, testers and auxiliary items required
^ External micrometer 75...100 mm
- Measure pistons approx. 10 mm from lower edge of skirt, at 90° to piston pin axis.
- Deviation from nominal dimension: max. 0.04 mm
Checking cylinder bores
Special tools, testers and auxiliary items required
^ Internal dial gauge 50100 mm
- Take measurements at 3 positions in both lateral - A - and longitudinal - B - planes, as illustrated.
- Deviation from nominal dimension: max. 0.10 mm.
Note:
^ Measurement of the cylinder bores must not be done when the cylinder block is mounted on a repair stand with holding fixture VW 540 and spacers VW 540/1 B.
Piston with industrially fractured connecting rod
Note:
^ When working on the engine, it should be secured to the holding fixture VW 540 with spacers VW 540/1 B to the assembly stand.
1 - Piston rings
^ Offset gaps by 120°
^ Remove and install using piston ring pliers
^ "TOP" faces piston crown
2 - Piston
^ Mark installation position and cylinder number
^ Arrow on piston crown points to belt pulley end
^ Install using piston ring clamp
3 - Piston pin
^ If difficult to remove, heat piston to 60°C
^ Remove and install with VW 222 A
4 - Retaining ring
5 - Connecting rod
^ Replace as set only
^ Mark cylinder number - B -
^ Installation position: Marking - A - faces belt pulley end
6 - Bearing shell
^ Note installed position.
^ Do not interchange used bearing shells
^ Insert bearing shells centrally
^ Axial clearance:
- New: 0.050.31 mm
- Wear limit: 0.37 mm
^ Check radial clearance with Plastigage:
- New: 0.010.06 mm
- Wear limit: 0.09 mm
^ Do not rotate crankshaft when checking radial clearance
7 - Cylinder block
8 - Connecting rod bearing cap
^ Note installed position
9 - Oil spray jet
^ For piston cooling
10 - Pressure relieve valve, 27 Nm
^ Opening pressure: 1.31.6 bar
11 - 30 Nm plus 1/4 turn (90°)
^ Replace
^ Oil threads and contact surfaces
^ To measure radial clearance, tighten to 30 Nm, but do not turn further
Checking piston ring gap
Special tools, testers and auxiliary items required
^ Feeler gauges
Work sequence
- Push ring squarely from above down to approx. 15 mm from bottom end of cylinder
Checking piston ring-to-groove clearance
Special tools, testers and auxiliary items required
^ Feeler gauges
- Clean groove before check.
Checking piston
Special tools, testers and auxiliary items required
^ External micrometer 75...100 mm
- Measure pistons approx. 10 mm from lower edge of skirt, at 90° to piston pin axis.
- Deviation from nominal dimension: max. 0.04 mm
Installation position of bearing shells
Bearing shell - 1 - with oil drilling - arrow - for connecting rod
Bearing shell - 2 - with no oil drilling for connecting rod bearing cap
- Insert bearing shells centralized in connecting rod and connecting rod bearing cap.
- Dimension - a - must be same on left and right sides, max. deviation: 0.2 mm.
Checking cylinder bores
Special tools, testers and auxiliary items required
^ Internal dial gauge 50100 mm
- Take measurements at 3 positions in both lateral - A - and longitudinal - B - planes, as illustrated.
- Deviation from nominal dimension max. 0.10 mm.
Note:
^ Measurement of the cylinder bores must not be done when the cylinder block is mounted on a repair stand with holding fixture VW 540 and spacers VW 540/1 B.