Pistons and Connecting Rods, Disassembling and Assembling

Pistons and connecting rods, disassembling and assembling

Pistons And Connecting Rods, Disassembling And Assembling:

1 - 30 Nm + 1/4 turn (90 °) further
^ Oil threads and contact surface
^ To measure radial clearance, tighten to 30 Nm but not further

2 - Pressure relief valve, 27 Nm
^ Opens at: 2.5...3.2 bar

3 - Oil spray jet
^ For piston cooling

4 - Connecting rod bearing cap
^ Mark cylinder number - B -
^ Installed position: Marking - A - must face toward pulley end

5 - Bearing shell
^ Note installed position
^ Do not interchange used bearing shells (mark)
^ Make sure that bearing shell is seated correctly in retaining lugs
^ Axial clearance, New: 0.10...0.35 mm; Wear limit: 0.40 mm
^ Check radial clearance with Plastigage (TM), New: 0.01...0.05 mm; Wear limit: 0.12 mm
^ Do not rotate crankshaft when checking radial clearance

6 - Cylinder block
^ Checking cylinder bore
^ Piston and cylinder dimensions Piston and cylinder dimensions

7 - Bearing shell
^ With oil drilling for piston pin lubrication
^ Note installed position
^ Do not interchange used bearing shells (mark)
^ Axial clearance, New 0.10...0.35 mm; Wear limit: 0.40 mm
^ Check radial clearance with Plastigage (TM), New: 0.01...0.05 mm; Wear limit: 0.12 mm
^ Do not rotate crankshaft when checking radial clearance

8 - Connecting rod
^ Only replace as set
^ Mark cylinder number - B -
^ Installed position: Marking - A - must face toward pulley end
^ With oil drilling for piston pin lubrication

9 - Circlip

10 - Piston pin
^ If difficult to move, heat piston to approx. 60 ° C
^ Remove and install with VW222a

11 - Piston rings
^ Offset gaps by 120 °
^ Remove and install with piston ring pliers
^ "TOP" must face toward piston crown
^ Checking ring gap
^ Checking ring to groove clearance

12 - Piston
^ Checking
^ Mark installed position and cylinder number
^ Arrow on piston crown must point to pulley end
^ Install using piston ring clamp

13 - Connecting rod bolt
^ Replace





Checking piston ring gap
- Push ring squarely from above down to lower cylinder bore, approx. 15 mm from cylinder edge. To do this use a piston without rings.








Checking ring to groove clearance
- Clean groove before checking clearance.








Checking piston
- 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 bore

Special tools, testers and auxiliary items required
^ Internal dial gauge 50...100 mm

- Take measurements at 3 positions in both lateral - A - and longitudinal - B - directions.

^ Deviation from nominal dimension: max. 0.08 mm