Removal and Replacement
Pistons and Connecting Rod Assembly Overview
1 Connecting Rod Bolt
• Use the old bolt to measure the radial play.
• For measuring the radial play, do NOT turn an additional 1 /4 turn (90°).
• Always replace.
• Lubricate the threads and contact surface.
M8 bolts:
• 30 Nm + 1/4 turn (90°).
M9 bolts:
• 45 Nm + 1/4 turn (90°).
2 Connecting Rod Bearing Cap
• Note the installed position.
• Mark the affiliation to the cylinder - A -.
• Installed position: Markings - B - point to the belt pulley side.
• Due to the way the separated connecting rod breaks (cracks), the cap fits only in one position and only on to the respective connecting rod.
• separating new connecting rods, refer to --> [ New Connecting Rod, Separating ] Procedures.
3 Bearing Shells
• Note the installed position. Refer to --> [ Bearing Shell Installed Position ] Bearing Shell Installed Position.
• Do not interchange used bearing shells (mark).
• Axial play new: 0.10 to 0.35 mm, wear limit: 0.40 mm.
• Check the radial play with Plastigage: New: 0.02 to 0.06 mm, wear limit: 0.09 mm; do not rotate the crankshaft when measuring the radial play.
4 Pressure Relief Valve, 27 Nm
• Opening pressure 1.6 to 1.9 bar.
5 Oil Spray Jet
• For piston cooling.
• See the notes --> [ If metal shavings or a large quantity of small metal particles are found when repairing an engine, this could indicate that the crankshaft and/or connecting rod bearings are damaged. To prevent further damage, perform the following steps after the repair: ] Description and Operation.
6 Circlip
7 Piston Pin
• If difficult to move, heat the piston to approximately 60 °C.
• Remove and install using the pilot drift (VW 222A).
8 Piston
• Mark the installed position and cylinder allocation.
• Arrow on the piston face points toward the belt pulley side.
• Install with a piston ring compressor.
• Checking, refer to --> [ Piston, Checking ] Testing and Inspection.
• 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.
9 Compression Rings
• Offset the gaps by 120 degrees.
• Use piston ring pliers for removal and installation.
• "TOP" mark must face up toward the piston crown.
• Checking ring gap, refer to --> [ Piston Ring Gap, Checking ] Piston Ring Gap, Checking.
• Checking piston ring groove clearance, refer to --> [ Piston Ring Groove Clearance, Checking ] Piston Ring Groove Clearance, Checking.
10 Oil Scraping Ring
• 2 pieces.
• Install the upper steel ring so the gap is offset by 120 degrees to the neighboring compression ring.
• Offset all oil scraping ring gaps to each other.
• Checking ring gap, refer to --> [ Piston Ring Gap, Checking ] Piston Ring Gap, Checking.
• Side clearance cannot be measured.
11 Connecting Rod
• Only replace as a set.
• Mark affiliation to the cylinder - A -.
• Installed position: Markings - B - point to the belt pulley side.
• Separating new connecting rod, refer to --> [ New Connecting Rod, Separating ] Procedures.