Pistons and Connecting Rod Overview

Pistons and Connecting Rod Overview






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 ] Procedures

3 Bearing Shells

• Installed position, refer to => [ Installed Position of Bearing Shell ]

• 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 ] 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 ] Testing and Inspection

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 => [ Piston Ring Gap, Checking ] Testing and Inspection

• Check piston ring groove clearance, refer to => [ Piston Ring Groove Clearance, Checking ] Testing and Inspection

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 => [ Piston Ring Gap, Checking ] Testing and Inspection

• 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 ] Procedures

• Radial clearance, measuring, refer to => [ Connecting Rod Radial Clearance, Measuring ] Testing and Inspection

Installed Position of Bearing Shell





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

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