Piston: Service and Repair

Pistons and Connecting Rod Assembly Overview

• Oil injector jet for piston cooling, refer to --> [ Oil Spray Jet for Piston Cooling ]





1 Connecting rod bolt - 60 Nm + 90° (1/4 turn)

• Replace

• Lubricate threads and contact surface.

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

2 Connecting rod bearing cap

• Do not interchange.

• Mark affiliation to cylinder with paint, refer to --> [ Mark Connecting Rod ]

• Installation position of connecting rod pairs, refer to --> [ Connecting Rod, Installed Location ]

3 Bearing shells

• Check that retaining tabs are secured.

• Do not interchange used bearing shells (mark, but not on the running surface).

• Measuring radial clearance, refer to --> [ Connecting Rod Radial Clearance, Measuring ] Testing and Inspection.

• To measure radial play, tighten bolts - item 1 - to 60 Nm but no further.

• Oversized bearings are available for reworked crankshaft connecting rod journals.

4 Connecting rod

• Only replace as set.

• Mark affiliation to cylinder with paint, refer to --> [ Mark Connecting Rod ]

• Installation position of connecting rod pairs, refer to --> [ 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.

• Measuring radial clearance, refer to --> [ Connecting Rod Radial Clearance, Measuring ] Testing and Inspection.

5 Piston pin

• If tight, heat piston to 60 °C.

• Remove and install using a drift (VW 222 A).

6 Circlip

7 Piston

• Installation position of pistons, refer to --> [ Piston Installation Position ]

• Piston and cylinder dimension, piston allocation to cylinder bore, refer to --> [ Piston and Cylinder Dimensions ] Piston and Cylinder Dimensions.

• Checking, refer to --> [ Piston, Checking ] Testing and Inspection.

• Install with piston ring compressor.

• Measuring cylinder bore, refer to --> [ Cylinder Bore Checking ] Testing and Inspection.

8 Piston rings

• Offset gaps by 120 degrees.

• Use piston ring pliers for removal and installation.

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

• Gap measuring, refer to --> [ Piston Ring Gap, Checking ] Piston Ring Gap, Checking.

• Measuring side clearance, refer to --> [ Piston Ring Groove Clearance, Checking ] Piston Ring Groove Clearance, Checking.

Piston Installation Position





- Identify allocation to cylinder with paint on piston crown.

• 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





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

• Only replace connecting rod as a set.

• Do not interchange connecting rod bearings.

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.