Connecting Rod: Service and Repair

Piston and Connecting Rod Component Overview

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





1 Connecting rod bolt - 30 Nm plus an additional 90° ( 1/4 turn)

• Replace

• Lubricate threads and contact surface

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

2 Connecting rod bearing cap

• Do not interchange

• Mark allocation to cylinder using a color marker - B - => [ Mark connecting rod ]

• When installing bearing cap, observe: The wide thrust flange - A - must point to the same side on connecting rod and connecting rod bearing cap

• Installation position of connecting rod pairs => [ 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)

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

• When measuring radial clearance, tighten bolts => [ (Item 1) Connecting rod bolt - 30 Nm plus an additional 90° (/ turn) ] to 30 Nm but do not turn further

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

4 Connecting rod

• Only replace as set

• Mark allocation to cylinder with paint - B - => [ Mark connecting rod ]

• When installing bearing cap, observe: The wide thrust flange - A - must point to the same side on connecting rod and connecting rod bearing cap

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

• Axial play for each new connecting rod pair: 0.20 to 0.38 mm

• Axial play wear limit: 0.60 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 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 => [ Pistons, Checking ] Testing and Inspection

• Install with piston ring compressor

• Measuring cylinder bore => [ 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

• Measuring end cap => [ Piston Ring Gap, Measuring ] Piston Ring Gap, Measuring

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

Piston installation position





- Mark allocation to cylinder on piston head using chalk or water-proof felt pen.

• 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.

• Valve recesses - 1 - point toward center of engine.

Mark connecting rod





• Only replace connecting rod as a set.

• Do not interchange connecting rod bearings.

- Before removing, mark allocation of connecting rod and connecting rod bearing caps to each other and to cylinder with paint - arrow -.

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 (opening pressure 2 to 2.4 bar)

2. Bolts - 9 Nm. Insert using locking compound; locking compound.