Overview - Pistons And Connecting Rod: Notes

Fig 1: Pistons And Connecting Rod Exploded View

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1. Bolts
   • Replace after removing.
   • Lubricate the threads and contact surface.
   • Use the old bolts for radial clearance measurement
   • Tightening Specifications:
     • M8 Bolt: 30 Nm +90°
     • M9 Bolt: 45 Nm +90°
2. Connecting Rod Bearing Cap
   • Note the installation 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.
   • Use a color to mark the cylinder and connecting rod to which it belongs -A-
   • Installation position: the marks -B- face the belt pulley side
   • Separating the new connecting rod. Refer to NEW CONNECTING ROD, SEPARATING .
3. Bearing shells
   • Installation position. Refer to appropriate service information. .
   • Replace any worn bearing shells
   • Coat with engine oil before installing
   • Axial clearance
     • New: 0.10 to 0.35 mm
     • Wear limit: 0.40 mm.
   • Radial play, measuring. Refer to CONNECTING RODS, CHECKING RADIAL CLEARANCE .
4. Connecting Rod
   • Always replace as a set
   • Identify the cylinder and connecting rod bearing cap to which it belongs
   • Installation position: the marks -B- face the belt pulley side
   • Separating the new connecting rod. Refer to NEW CONNECTING ROD, SEPARATING .
   • Radial play, measuring. Refer to CONNECTING RODS, CHECKING RADIAL CLEARANCE .
5. Relief Valve
   • 27 Nm
6. Oil Spray Jet
   • For piston cooling
   • Removing and Installing. Refer to OIL SPRAY JETS, REMOVING AND INSTALLING .
7. Circlip
   • Replace after removing.
8. Piston Pin
   • Coat with engine oil before installing
9. Piston
   • Removing and Installing. Refer to PISTONS, REMOVING AND INSTALLING .
   • Mark the installation position and cylinder allocation
   • Arrow on piston crown points toward belt pulley side
   • Check piston and cylinder bore. Refer to PISTON AND CYLINDER BORE, CHECKING .
10. Compression rings
    • Install with Piston Ring Pliers :VAS211 003  . Refer to appropriate service information. .
    • Offset gaps by 120°
    • Installation position in connection with two-piece oil scraping ring: installation position "TOP" "R" must point to the piston crown
    • Allocation and installation position in connection with three part oil scraping ring. Refer to appropriate service information .
    • Checking the piston ring gap. Refer to the appropriate Service Information .
    • Checking the groove clearance. Refer to the appropriate Service Information .
11. Oil Scraping Ring
    • Depending on the version two or three part. Refer to the Parts information for the allocation.
    • Two-Piece Oil Scraping Ring: 
      • Install offset gaps by 120° to the neighboring compression ring
      • The "TOP" or "R" marking must face toward the piston crown.
      • Checking the piston ring gap. Refer to the appropriate Service Information .
      • Height clearance cannot be measured
    • Three Part Oil Scraping Ring: 
      • Remove and install carefully by hand
      • Installation position. Refer to appropriate service information. .
      • Allocation. Refer to appropriate service information. .
      • Piston ring gap is not measurable
      • Height clearance cannot be measured

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1. Compression ring with bevel -arrow A- on the upper side inside. >>TOP<< marking or lettering points upward
2. Compression ring offset -arrow B- on the bottom outside. >>TOP<< marking or lettering points upward
3. Three Part Oil Scraping Ring

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• >>TOP<< marking or lettering points upward.
• Only open the compression ring -2- using the Piston Ring Pliers :VAS211 003  only until it can be pushed over the pistons -1-.

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-- Pay attention to the spring installation position:

• The plunger of the plates -2 and 3- and the spring -1- must be offset 90° to each other.

-- Install by hand.