Pistons and Connecting Rod Assembly Overview

Pistons and Connecting Rod Assembly Overview

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





1 Bolt

• Replace

• Lubricate threads and contact surface

• 60 Nm plus an additional 90° (1/4) turn.

• Tighten to 60 Nm to measure radial play, do not turn further

2 Connecting rod bearing cap

• Mark for re-installation

• Mark affiliation to cylinder with paint => [ Mark connecting rod ]

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

3 Bearing shells

• Check that retaining tabs are secured

• Mark used bearing shells for reinstallation but not on the running surface

• Radial clearance, measuring, refer to => [ Connecting Rod, Measuring Radial Clearance ] Connecting Rod, Measuring Radial Clearance

• Over-sized bearings are available for reworked crankshaft connecting rod journals.

4 Connecting rod

• Only replace as set

• Mark affiliation to cylinder with paint [ Mark connecting rod ]

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

• Axial play for each new connecting rod pair: 0.20 to 0.27 mm

• Axial play wear limit: 0.30 mm

• Radial clearance, measuring, refer to => [ Connecting Rod, Measuring Radial Clearance ] Connecting Rod, Measuring Radial Clearance

5 Piston pin

• If tight, heat piston to 60 °C

• Removing and installing using a Pilot Drift (VW 222 A)

6 Circlip

7 Piston

• Installation position of pistons => [ Piston installation position ]

• Piston and cylinder dimensions, refer to => [ Piston and Cylinder Dimensions ] [1][2]Piston, Engine

• Checking, refer to => [ Pistons, Checking ] Testing and Inspection

• Install with piston ring compressor

• Measuring cylinder bore, refer to => [ Cylinder Bore, Measuring ] Testing and Inspection

8 Piston rings

• Offset gaps by 120°

• Use piston ring pliers for removal and installation

• "TOP" marking or inscribed side must point to piston head

• Gap, measuring, refer to => [ Piston Ring End Gap, Measuring ] Piston Ring End Gap, Measuring

• Measuring side clearance, refer to => [ Piston Ring Side Clearance, Measuring ] Piston Ring Side Clearance, Measuring

Piston installation position





- Mark allocation to cylinder with pen on piston crown for reinstallation.

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

Installation position:

• Arrows on piston heads point to belt pulley side.

• Large valve recesses - 1 - point toward center of engine.

Mark connecting rod





• Only replace connecting rod as a set.

- Mark connecting rod and connecting rod bearing cap to each other and to cylinder - arrow - with pen for reinstallation.

Connecting rod, installed location





• Molded tabs - arrows - at the beveled surfaces of the connecting rod pairs 1 and 2, 3 and 4, 5 and 6 as well as 7 and 8 must point toward each other.

Oil spray jet for piston cooling





1. Oil spray jet

2. Bolts - 9 Nm. Insert with locking compound.

• Do not bend piston spray nozzles.

• Bend piston spray nozzles must be replaced.