Removal and Replacement

Piston and Connecting Rod, Assembly Overview

• Oil injector jet for piston cooling => [ Oil spray jet for piston cooling ]





1 Connecting rod bolt - 30 Nm + 90° (1/4 turn) additional turn

• Replace

• Lubricate threads and contact surface

• use old bolt to measure radial play

• tighten to 30 Nm to measure radial play, do not turn further

2 Connecting rod bearing cap

• Do not interchange

• Mark allocation to cylinder using a color marker - B - => [ Mark connecting rod ]

• When installing bearing cap, observe: Tabs on contact surfaces on front side of connecting rod must align - A -

• Installation position of connecting rod pairs => [ Connecting rod, installed location ]

3 Bearing shell

• Note installation position

• do not interchange used bearings (mark)

• Radial clearance, measuring => [ Radial Clearance of Connecting Rod, Checking ] Radial Clearance of Connecting Rod, Checking

• When measuring radial clearance, tighten bolts => [ (Item 1) Connecting rod bolt - 30 Nm + 90° (/ turn)
additional turn ] to 30 Nm but do not turn further

4 Connecting rod

• only replace as set

• Mark allocation to cylinder using a color marker - B - => [ Mark connecting rod ]

• When installing bearing cap, observe: Tabs on contact surfaces on front side of connecting rod must align - A -

• Installation position of connecting rod pairs => [ Connecting rod, installed location ]

5 Circlip

6 Piston pin

• If difficult to move, heat piston to approx. 60 °C

• removing and installing using a Pilot Drift (VW222A )

7 Piston

• checking => [ Checking piston ]

• Installation position and allocation, piston/cylinder => [ Installation position of piston and piston/cylinder
allocation ]

• Arrow on piston face points toward belt pulley side

• Install using piston ring compressor

• Piston and cylinder dimensions => [ Piston and Cylinder Dimensions ] Piston and Cylinder Dimensions

• Cylinder bore, checking => [ Checking cylinder bores ]

8 Piston rings

• Offset gaps by 120°

• use piston ring pliers for removal and installation

• Mark "TOP" must face toward piston head

• Checking ring gap => [ Checking piston ring gap ]

• Check piston ring groove clearance => [ Checking ring to groove clearance ]

Checking piston ring gap





- Push ring squarely from above down to approx. 15 mm from bottom end of cylinder. To do this use a piston without rings.





Checking ring to groove clearance





- Clean the ring groove of piston before checking.





Checking piston





- Measure pistons approx. 10 mm from bottom edge and at points offset by 90° to piston pin axis.

• Maximum deviations from nominal dimension: 0.04 mm.

Nominal dimension => [ Piston and Cylinder Dimensions ] Piston and Cylinder Dimensions.

Checking cylinder bores





- Using an internal dial gauge 50... 100 mm, measure at 3 points in diagonal sequence horizontally - A - and vertically - B -.

• Maximum deviations from nominal dimension: 0.08 mm.

Nominal dimension => [ Piston and Cylinder Dimensions ] Piston and Cylinder Dimensions.

Installation position of piston and piston/cylinder allocation





- Identify installation location and allocation to cylinder with paint on piston crown.

• Do not use a center punch or scribe, since the piston head coating will be damaged.

• Installed location: Arrow on piston face points toward belt pulley side

Mark connecting rod





• Only replace connecting rod as a set.

• Do not interchange connecting rod bearings.

- Mark connecting rod and connecting rod bearing cap to each other and to cylinder - arrow - with paint before removal.

Connecting rod, installed location





• The molded tabs - arrows - at the beveled surfaces of the connecting rod pairs 1 and 2, 3 and 4, and 5 and 6 must point toward each other.

Oil spray jet for piston cooling





1. Bolt -10 Nm

2. Oil spray jet for piston cooling