Overview - Piston And Connecting Rod

WARNING: This page is about a different car, the 2015 Audi Q7, 2014 Audi Q7, and 2013 Audi Q7. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Piston And Connecting Rod Overview

Courtesy of AUDI OF AMERICA, LLC

Bolts
- 35 Nm +90°
- Replace
- Lubricate the thread and contact surface.
Connecting Rod Bearing Cap
- Due to the separation procedure (cracking) of the connecting rod, the connecting rod bearing cap only fits in one position and only to the corresponding connecting rod.
- Mark allocation to the cylinder and connecting rod with paint -B-. Refer to Fig 4.
- Note when installing: the wide thrust flange -A- must point to the same side on connecting rod and connecting rod bearing cap
Bearing Shells
- Note the installation position
- Replace any worn bearing shells
- Note the version: the upper bearing shell (to piston) is made of wear-resistant material. How to recognize new bearing shells: there is a black line on the contact surface near the separating point.
- Make sure the tabs are tight
Connecting Rod
- With a cracked connecting rod bearing cap
- Mark allocation to the cylinder and connecting rod bearing cap with paint -B-. Refer to Fig 4.
- Installed position. Refer to Fig 5
- Axial play for each new connecting rod pair: 0.20 to 0.44 mm
- Radial play, measuring. Refer to CONNECTING ROD, MEASURING RADIAL CLEARANCE .
- Always replace as a set.
- Note when installing: the wide thrust flange -A- must point to the same side on connecting rod and connecting rod bearing cap
Circlip
- Replace
Piston Pin
- Removing and installing. Refer to PISTONS, REMOVING AND INSTALLING .
Piston
- Mark the installation position and cylinder allocation. Refer to Fig 3
- Replace the piston if there are cracks on the piston head or piston shaft
- Removing and installing. Refer to PISTONS, REMOVING AND INSTALLING .
- Measure the piston projection at "Top Dead Center (TDC)". Refer to PISTON PROJECTION, MEASURING AT "Top Dead Center (TDC)" .
- Check piston and cylinder bore. Refer to PISTONS AND CYLINDER BORE, CHECKING .
Circlip
- Replace
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 Oil Spray Jet For Piston Cooling

Courtesy of AUDI OF AMERICA, LLC

Bolt - 9 Nm
Oil spray jet for cooling the piston and spray jet valve

CAUTION:

The oil spray jets could get damaged.

Do not bend the oil injector jets.
Check that the oil spray jet is accessible after reinstalling the pins.
Bent oil injector jets must be replaced.

Fig 3: Identifying Piston, Installed Position

Courtesy of AUDI OF AMERICA, LLC

CAUTION:

There is a risk of damaging the piston crowns.

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, scratch, notch or something similar.

Installation position: arrow -1- on the piston head toward the pulley side

Fig 4: Connecting Rod, Marking

Courtesy of AUDI OF AMERICA, LLC

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

NOTE:

Only replace the connecting rods as a set.

Do not interchange the connecting rod bearing.

Fig 5: Connecting Rod, Installed Position

Courtesy of AUDI OF AMERICA, LLC

The larger thrust flange on the connecting rod -arrow- faces the adjacent crankshaft bearing.

NOTE:

The front connecting rod pair is pictured here.