Pistons And Connecting Rod Overview

Fig 1: Identifying Assembly Overview: Pistons And Connecting Rod

Courtesy of AUDI OF AMERICA, LLC

1. Connecting Rod Bolts
   • 45 Nm plus an additional 90° turn
   • Replace
   • Lubricate the threads and contact surface
   • Use old bolt to measure radial play
   • Tighten to 45 Nm to measure radial play, do not turn further
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: Markings -B- point to belt pulley side
   • Separate new connecting rod, refer to NEW CONNECTING ROD, SEPARATING 
3. Bearing Shells
   • Installed position, refer to Fig 2
   • Do not interchange used bearing shells (mark)
   • Coat with oil before installing
   • Axial play new: 0.10 to 0.35 mm; Wear limit: 0.40 mm
   • Measure radial clearance with Plastigage: New: 0.02 to 0.06 mm; Wear limit: 0.09 mm. Do not turn crankshaft when checking radial clearance
4. Pressure Relief Valve
   • 27 Nm
5. Oil Spray Jet
   • For piston cooling
6. Locking Ring
   • Replace
7. Piston Pin
   • Coat with oil before installing
8. Piston
   • Removing and installing, refer to PISTON 
   • Mark installed position and cylinder allocation
   • Arrow on piston face points toward belt pulley side
   • Piston and cylinder bore, checking, 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" "R" mark must face up toward piston crown
   • Checking ring gap, refer to Figure
   • Check piston ring groove clearance, refer to Figure
10. Oil Scraping Ring
    • 2-part
    • Install offset gaps by 120° to the neighboring compression ring
    • The "TOP" or "R" marking must face toward the piston crown.
    • Checking ring gap, refer to Figure
    • Side clearance cannot be measured.
11. Connecting Rod
    • Only replace as set
    • Mark affiliation to cylinder -A-
    • Installed position: Markings -B- point to the belt pulley side
    • Separate new connecting rod, refer to NEW CONNECTING ROD, SEPARATING 
    • Radial clearance, measuring, refer to CONNECTING ROD RADIAL CLEARANCE, MEASURING 

Fig 2: Dimension -A- Must Be Same At Left And Right

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.