Overview - Piston And Connecting Rod

NOTE:

Lubricate all bearings and running surfaces.

Oil injector jet for piston cooling. Refer to Fig 5.

Fig 1: Identifying Pistons And Connecting Rod Overview

Courtesy of AUDI OF AMERICA, LLC

Bolts
- 50 Nm + 90° turn
- Replace
- Lubricate the thread and contact surface.
- Use old bolts to measure radial play.
Connecting Rod Bearing Cap
- Mark for installation later
- Use color to identify the cylinder and connecting rod to which it belongs. Refer to Fig 3
- Installation position of connecting rod pairs Fig 4
Bearing Shells
- Make sure the tabs are tight
- Replace any worn bearing shells
- Oversized bearings are available for reworked crankshaft connecting rod journals.
- The connecting rod tabs are above each other
Connecting Rod
- Always replace as a set.
- Use color to identify the cylinder and connecting rod bearing cap to which it belongs. Refer to Fig 3
- Installation position of connecting rod pairs. Refer to Fig 4
- Axial play for each new connecting rod pair: 0.20 to 0.45 mm
- Radial play, measuring. Refer to CONNECTING RODS, CHECKING RADIAL CLEARANCE .
Circlip
- Replace
Piston Pin
- Removing and installing. Refer to PISTONS, REMOVING AND INSTALLING .
Piston
- Mark the installation position and cylinder allocation. Refer to Fig 2
- Removing and installing. Refer to PISTONS, REMOVING AND INSTALLING .
- Replace the piston if there are cracks on the piston head or piston shaft
- Check piston and cylinder bore. Refer to PISTONS AND CYLINDER BORE, CHECKING .
Piston Rings
- Measuring the gap. Refer to Figure
- Measuring side clearance. Refer to Figure
- Use piston ring pliers (commercially available) for removing and installing
- Installed position: "TOP" marking or side with writing faces the piston crown.
- Offset gaps by 120°

Fig 2: Identifying Installed Position Of Piston And Piston/Cylinder Allocation

Courtesy of AUDI OF AMERICA, LLC

CAUTION:

The coating on the piston crown could be destroyed.

Mark the allocation to the cylinder on the piston crown with paint to install used pistons. Do not mark the piston head with a punch, notch or something similar.

Installed position:

The arrows on the piston heads point to the belt pulley side.

Fig 3: Arrows On Piston Heads Point To Belt Pulley Side

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Only replace the connecting rods as a set.

-- Mark the connecting rod and connector rod bearing caps to each other and to the cylinder -arrow- with paint for installation.

Fig 4: Connecting Rod Installed Location

Courtesy of AUDI OF AMERICA, LLC

The molded tabs -arrows- on the beveled surfaces of the connecting rod pairs "1 and 2", "3 and 4" and "5 and 6" must face each other.

Fig 5: Identifying Oil Spray Jet And Bolt

Courtesy of AUDI OF AMERICA, LLC

Insert the bolt with locking compound and tighten to 9 Nm.
Oil spray jet with spray nozzle valve (opening pressure 2.0 to 4.0 bar (29 to 43 psi))

CAUTION:

The oil spray jets could get damaged.

Do not bend the oil injector jets.
Bent oil injector jets must be replaced.