Pistons and Connecting Rod Overview

Pistons and Connecting Rod Overview






1 Connecting Rod Bolt

• Replace

• 45 Nm + 90° turn further

• Lubricate the 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

• Note installation 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.

• Mark affiliation to cylinder - A -

• Installed position: the markings - B - face the belt pulley side

• Separate new connecting rod, refer to => [ New Connecting Rod, Separating ] New Connecting Rod, Separating

3 Bearing Shells

• Installed location => [ Installed Position of Bearing Shell ]

• Do not interchange used bearing shells (mark)

• Axial play new: 0.10 to 0.35 mm, wear limit: 0.40 mm

• Check radial clearance with plastigage, new: 0.02 to 0.06 mm, wear limit: 0.09 mm. Do not turn crankshaft when checking radial clearance.

4 Pressure Relief Valve

• 27 Nm

5 Oil Spray Jet

• For piston cooling

6 Circlip

7 Piston Pin

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

• Removing and installing with the pilot drift (VW 222 A)

8 Piston

• Checking => [ Pistons, Checking ]

• Mark installed position and cylinder allocation

• Arrow on piston face points toward belt pulley side

• Install with piston ring compressor

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

• Cylinder bore, checking => [ Cylinder Bore, Checking ]

9 Compression Rings

• Offset gaps by 120°

• Use piston ring pliers for removal and installation

• The "TOP" or "R" marking must face toward the piston crown.

• Checking ring gap => [ Piston Ring Gap, Checking ]

• Check piston ring groove clearance => [ Piston Ring Groove Clearance, Checking ]

10 Oil Scraping Ring

• 2-part

• Install upper steel ring so gap is offset by 120° to neighboring compression ring

• The "TOP" or "R" marking must face toward the piston crown.

• Offset all oil scraping ring component gaps to each other.

• Checking ring gap => [ Piston Ring Gap, Checking ]

• Side clearance cannot be measured.

11 Connecting Rod

• Only replace as set

• Mark affiliation to cylinder - A -

• Installed position: the markings - B - face the belt pulley side

• Separate new connecting rod, refer to => [ New Connecting Rod, Separating ] New Connecting Rod, Separating

Piston Ring Gap, Checking





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






Piston Ring Groove Clearance, Checking





- Clean the ring groove of piston before checking.






Pistons, Checking





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

• Deviation from nominal size: max. 0.04 mm.

Cylinder Bore, Checking





Special tools, testers and auxiliary items required

• Internal dial gauge 50 - 100 mm


Do not bore, hone, grind or rework the cylinder bores with workshop tools. Reworking damages the surface of the cylinder bore.

- Measure diagonally at 3 positions transversely - A - and longitudinally - B -.

• Deviation from nominal size: max. 0.08 mm.

• Measurement of cylinder bore may not be performed when the cylinder block is mounted in engine and transmission holder (VAS 6095) , incorrect measurements are possible.

Installed Position of Bearing Shell





- Place bearing shells centrally into connecting rod and connecting rod bearing cap.

Dimension - a - must be the same at left and right.