Overview - Piston And Connecting Rod

WARNING: This page is about a different car, the 2015 Audi A7 Quattro and 2014 Audi A7 Quattro. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Lubricate all bearings and running surfaces.

Oil injector jet for piston cooling, refer to Fig 2.

Fig 1: Identifying Piston And Connecting Rod Overview

Courtesy of AUDI OF AMERICA, LLC

Bolts
- 35 Nm +90° turn
- Replace
- Use old bolts to measure radial play.
- 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 for installation later
- Mark allocation to the cylinder with paint -B- 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
- Pay attention to the installed 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 with paint -B- Fig 4.
- Axial play for each new connecting rod pair: 0.20 to 0.44 mm
- Radial play, measuring, refer to CONNECTING RODS, CHECKING RADIAL CLEARANCE .
- Installed position Fig 5
- 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
- Measure the piston projection at "TDC", refer to PISTON PROJECTION, MEASURING AT TOP DEAD CENTER (TDC) .
- Mark the installation position and cylinder allocation Fig 3y
- Replace the piston if there are cracks on the piston head or piston shaft
- Removing and installing, refer to PISTONS, REMOVING AND INSTALLING .
- Check piston and cylinder bore, refer to PISTONS AND CYLINDER BORE, CHECKING .
Circlip
- Replace
Piston rings
- Measuring the gap Figure
- Measuring side clearance 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 against 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.