Piston: Service and Repair

Pistons and Connecting Rod Overview





1 Bolt

• 30 Nm + 90° (1/4) additional turn.

• Replace

• Lubricate the threads and contact surface.

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

2 Bolt with Pressure Relief Valve

• 27 Nm

• Opening pressure: 1.3 to 1.6 bar pressure.

3 Oil Spray Jet

• For piston cooling.

4 Connecting Rod Bearing Cap

• Note the installed position.

• Due to the separation procedure (cracking) of the connecting rod, the cap only fits in one position and only to the corresponding connecting rod.

• Affiliation to the cylinder mark - B -.

• Installed position: marks - A - face the pulley side.

5 Bearing Shell

• Note the installed position, refer to=> [ Bearing Shell Installed Location ] Bearing Shell Installed Location.

• Do not interchange used bearing shells.

• Axial play new: 0.10 to 0.35 mm, wear limit: 0.4 mm

• Check radial clearance with Plastigage, new: 0.02 to 00.06 mm, wear limit: 0.09 mm. Do not turn crankshaft when checking the radial clearance.

6 Connecting Rod

• With cracked bearing cap.

• Only replace as a set.

• Affiliation to the cylinder mark - B -.

• Installed position: marks - A - face the pulley side.

7 Circlip

8 Piston Pin

• If difficult to move, heat piston to 60 °C (140 °F).

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

9 Piston

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

• Mark the installed position and cylinder allocation.

• Arrow on piston face points toward the belt pulley side.

• Install with a piston ring compressor.

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

• Piston and cylinder dimensions, refer to => [ Piston and Cylinder Dimensions ] Piston and Cylinder Dimensions.

10 Piston Rings

• Offset ring gaps by 120°

• Use piston ring pliers for removal and installation.

• Marks face toward the piston crown.

• Checking ring gap, refer to => [ Piston Ring Gap, Checking ] Testing and Inspection.

• Checking piston ring groove clearance, refer to => [ Piston Ring Groove
Clearance, Checking ] Testing and Inspection.