Connecting Rod: Service and Repair

Pistons and connecting rods, disassembling and assembling
1 - Nut for connecting rod bolt
^ 30 Nm (22 ft. lbs.) + additional 1/4 turn (90°)
^ Always replace connecting rod bolt -13-
^ Grease thread and contact surface
^ To measure radial play, tighten to 30 Nm (22 ft. lbs.) but not any further
2 - Pressure relief valve
^ Tightening torque: 27 Nm (20 ft. lbs.)
^ Opening pressure: 2.5 - 3.2 bar (36.25 - 46.4 psi)
3 - Oil spray nozzle For piston cooling
4 - Connecting rod bearing cap
^ Mark -13- to indicate which cylinder each cap belongs to
Installed position:
^ Marks -A- point toward belt pulley side
5 - Bearing shell
^ Verify correct installation position
^ Do not interchange used connecting rod bearing shells (mark accordingly)
^ Check for proper securing in retaining tabs
Axial play:
^ New: 0.10 - 0.35 mm (0.004 - 0.014 inch)
^ Wear limit: 0.40 mm (0.016 inch)
Measure radial play using Plastigage:
^ New: 0.01 - 0.05 mm (0.0004 - 0.0020 inch)
^ Wear limit: 0.12 mm (0.0047 inch)
^ Do not turn crankshaft when measuring radial play with Plastigage in place
- To measure radial play, tighten nut -1- to 30 Nm (22 ft. lbs.) but not any further
6 - Cylinder block
^ Check bore, Refer to Fig. 4
^ Piston and cylinder bore dimensions, Refer to Piston, Specifications
7 - Bearing shell
^ With oil bore for piston pin lubrication
^ Verify correct installation position
^ Do not interchange used connecting rod bearing shells (mark accordingly)
Axial play:
^ New: 0.10 - 0.35 mm (0.004 - 0.014 inch)
^ Wear limit: 0.40 mm (0.016 inch)
Measure radial play using Plastigage:
^ New: 0.01 - 0.05 mm (0.0004 - 0.0020 inch)
^ Wear limit: 0.12 mm (0.0047 inch)
^ Do not turn crankshaft when measuring radial play with Plastigage in place
^ To measure radial play, tighten nut -1to 30 Nm (22 ft. lbs.) but not any further
8 - Connecting rod
^ Replace only as a set
^ Markings -B- indicate which cylinder each rod belongs to
Installed position:
Marks -A- point toward belt pulley side
^ With oil bore for piston pin lubrication
9 - Circlip
10 - Piston pin
^ If stiff, warm pistons to approximately 60°C (140°F)
^ When removing and installing, use VW222a pilot drift
11 - Piston rings
^ Offset by 120°
^ Use piston ring pliers to remove and install
^ Marking "TOP" must point to piston head
^ Checking piston ring end gap, Refer to Fig. 1
^ Checking piston ring side clearance, Refer to Fig. 2
12 - Pistons
^ Checking
^ Mark installation position and matching cylinder
^ Arrow on piston head points toward belt pulley side
^ Install using piston ring compressor
13 - Connecting rod bolt Always replace





Fig. 1 Checking piston ring end gap





^ Insert ring at right angle from top and slide down until approximately 15 mm (19/32 inch) from lower edge of cylinder. To insert, use piston without rings.





Fig. 2 Checking piston ring side clearance





^ Before checking, clean ring groove.





Fig. 3 Checking piston diameter
^ Measure approximately 10 mm (3/8 inch) from bottom edge, at points offset by 90 from piston pin axis.
Deviation from nominal size: maximum 0.04 mm (0.0016 inch)





Fig. 4 Checking cylinder bore
Special tools and equipment
^ Inner bore gauge 50-100 mm (2-4 inch)

CAUTION: DO NOT have the cylinder block mounted to the assembly stand while measuring the cylinder bores. The block is deformed by its own weight under these conditions and this stress will result in false measurements that are not accurate after the tension has been relieved.

^ Measure at three locations diagonally in crosswise direction -A- and lengthwise direction -B-.
Deviation from nominal size: maximum 0.08 mm (0.0031 inch)