Connecting Rod: Service and Repair

NOTE:
- During service procedures, refer to the illustration above and the information below.
- Engine is dismantled.
- The numbers in the above illustration refer to the steps below.

Determine Type Of Knurled Ring Bolt
To determine if a 3-ring knurled bolt (connecting rod bolt) or a 4-ring knurled bolt has been installed with the bolt installed, measure the groove diameter.

1. Using suitable calipers, measure the diameter of groove one
- Former 3-ring knurled bolt diameter: 7.95 to 8.20 mm
- New 4-ring knurled bolt diameter: 7.75 to 7.85 mm

2. Difference between both types of knurled ring bolts
- The visable difference between the two types of bolt is only detectable with the bolts removed

3. Determine elongation of knurled ring bolts
- Before reassembling the connecting rods, make sure the elongation of the knurled ring bolts is checked.
- If dimension x (38.3 mm) is exceeded the knurled bolts must be replaced.

NOTE:
- Connecting rods with the 3-ring knurled bolt must be replaced as an assembly
- 4-ring knurled bolts are available as replacement parts.

4. Press out 4-ring knurled bolt.
- Clamp connecting rod in a machine vise, with suitable soft jaw inserts, then press out both 4-ring knurled bolts simultaneously.

5. Press in 4-ring knurled bolt
- Insert a new 4-ring knurled bolt onto former (old) splines

NOTE: To avoid damage to the parting face use an aluminum sleeve e.g. from special tool set P140 (cylinder retaining sleeves) or equivalent

- Press in 4-ring knurled bolt until it is seated at the stop

6. Assemble connecting rod.
- Always use new connecting rod nuts
- When assembling the connecting rod always make sure the matching numbers are located on the same side.
- Tighten as follows:
Apply a thin coating of motor oil to threads and seating surfaces.
initial tightening: 30 Nm (22 ft lb)
Final tightening: turn an additional 90°
- Check as follows:
Scribe a mark on connecting rod and connecting rod nut
Tighten to 60 Nm (44 ft lb) to check the press fit of the knurled bolt.
If the knurled bolt starts to turn or if the specified torque cannot be reached, the entire connecting rod assembly must be replaced.