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Measuring radial clearance of conrods > < Pistons and conrods

A1

Pistons and conrods - exploded view
   
Pistons and conrods - exploded view
1 - Bolt
q   Renew
q   Lubricate threads and contact surface
q   30 Nm + 90° further
2 - Conrod bearing cap
q   Due to the cracking method used to separate the bearing cap from the conrod in manufacture, the caps only fit in one position and only on the appropriate conrod
q   Mark cylinder and conrod allocation in colour -B-
q   Installation position: Markings -A- face towards pulley end
3 - Bearing shell
q   Installation position → Fig.
q   Renew used bearing shells
q   Note version: Upper bearing shell (closest to piston) is constructed from a more wear-resistant material. Distinguishing feature on new bearing shells: black marking on bearing surface near joint
q   Check that it is securely seated
4 - Conrod
q   Only renew as a complete set
q   With industrially cracked conrod bearing cap
q   Separating parts of new conrod → Fig.
q   Mark cylinder and conrod bearing cap allocation in colour -B-
q   Installation position: Markings -A- face towards pulley end
q   Axial clearance: wear limit: 0.37 mm
q   Measuring radial clearance → Chapter
5 - Circlip
q   2x
q   Renew
6 - Piston pin
q   Removing and installing → Chapter „Removing and installing pistons“
7 - Piston
q   With combustion chamber
q   Version fitted in vehicle may differ from illustration
q   Mark installation position and cylinder number → Fig.
q   Removing and installing → Chapter
q   Measuring piston projection at „TDC“ → Chapter
q   Checking pistons and cylinder bores → Chapter
8 - Piston rings
q   Compression rings
q   Measuring ring gap → Fig.
q   Measuring ring-to-groove clearance → Fig.
q   Use piston ring pliers (commercially available) to remove and install
q   Installation position: marking „TOP“ or side with lettering faces towards piston crown
q   Offset gaps by 120°
9 - Piston ring
q   Oil scraper ring
q   Measuring ring gap → Fig.
q   Measuring ring-to-groove clearance → Fig.
q   Use piston ring pliers to remove and install
q   Installation position: marking „TOP“ or side with lettering faces towards piston crown
q   Offset gap 120° from bottom compression ring

   
Installation position of pistons and allocation of piston/cylinder
  N13-10005
Installation position of bearing shells in conrods
–  Insert bearing shells centrally in conrod and conrod bearing cap.
l  Distance -a- = 2.5 mm.
  A13-0360
Separating parts of new conrod
It is possible that the two parts of a new conrod are not completely separated as intended. If it is not possible to take off the conrod bearing cap by hand, proceed as follows:
–  To avoid any risk of damage, the conrod should only be clamped lightly in a vice using jaw covers as shown in illustration.
l  The conrod is clamped in position below the dotted line.
–  Unscrew bolts -arrows- approx. 5 turns.
  N13-10285
–  Using a plastic hammer, carefully knock conrod bearing cap loose -arrow-.
  N13-10286
Oil spray jet and pressure relief valve
1 - Bolt with pressure relief valve, 27 Nm
2 - Oil spray jet (for cooling of pistons)
l  Installation position: align locating edge of oil spray jet with machined surface of cylinder block.
  Note
t  Take care not to bend oil spray jets.
t  Always renew bent oil spray jets.
  A13-0687

Measuring radial clearance of conrods > < Pistons and conrods