Overview - Piston And Connecting Rod

Fig 1: Identifying Assembly Overview: Pistons And Connecting Rod

Courtesy of AUDI OF AMERICA, LLC

1. Connecting Rod Bolts
   • 45 Nm + 90° turn
   • Replacing
   • Lubricate the thread and contact surface.
   • Use old bolts to measure radial play.
2. Connecting Rod Bearing Cap
   • Pay attention to the installed position.
   • 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 affiliation to cylinder -A-
   • Installed position: the markings -B- face the belt pulley side
   • Disconnect the new connecting rod, refer to NEW CONNECTING ROD, SEPARATING .
3. Bearing Shells
   • Installed position, refer to Fig 2
   • Replace any worn bearing shells
   • Axial play new: 0.10 to 0.35 mm, wear limit: 0.40 mm
   • Radial play, measuring, refer to CONNECTING RODS, CHECKING RADIAL CLEARANCE .
4. Relief Valve
   • 27 Nm
5. Oil Spray Jet
   • For piston cooling
6. Locking Ring
   • Replacing
7. Piston Pin
8. Piston
   • Removing and installing, refer to PISTONS, REMOVING AND INSTALLING .
   • Mark installed position and cylinder allocation
   • Arrow on piston face points toward belt pulley side
   • Check piston and cylinder bore, refer to PISTON AND CYLINDER BORE, CHECKING .
9. Compression Rings
   • Use piston ring pliers (commercially available) for removing and installing
   • Offset gaps by 120°
   • Installed position: "TOP" marking or side with writing faces the piston crown.
   • Checking the ring gap, refer to Figure.
   • Checking the piston ring groove clearance, refer to Figure.
10. Oil Scraping Ring
    • Two-part
    • Install offset gaps by 120° to the neighboring compression ring
    • The "TOP" or "R" marking must face toward the piston crown.
    • Checking the ring gap, refer to Figure.
    • Side clearance cannot be measured.
11. Connecting Rod
    • Always replace as a set.
    • Mark affiliation to cylinder -A-
    • Installed position: the markings -B- face the belt pulley side
    • Disconnect the new connecting rod, refer to NEW CONNECTING ROD, SEPARATING .
    • Radial play, measuring, refer to CONNECTING RODS, CHECKING RADIAL CLEARANCE .

Fig 2: Identifying Installed Position of Bearing Shell

Courtesy of AUDI OF AMERICA, LLC

-- Place bearing shells centrally into connecting rod and connecting rod bearing cap.

Dimension -a- must be the same at left and right.