Checking, Replacement and Tightening of Big-End Clamp Bolts

Self-made tool
Steel plate refer to image below

Connecting rod bolts made by Fontana (secondary supplier) are installed since September 1984.
Identification: chrome-colored (previously brass colored)







Installation: September 1984

Checking







1 Measure minimum necked-down dia. prior to re-use.







NOTE: When the minimum necked-down dia. of 8.0 mm has been attained or is less than 7.2 mm, renew connecting rod bolt.


Knock-out connecting rod bolt only for replacement.

Shop Made Tool:

Hole spacing a = 67 mm
Bore b = 11 mm

Replacement
2 Knock-out connecting rod bolts.
3 Press new connecting rod bolts into connecting rod at approx. 45000 N or knock-in with a hammer and mandrel.

When knocking-in or pressing-in connecting rod bolts, place connecting rod on a ground steel plate.







Tightening
4 Lubricate nuts and threaded support.
5 Tighten connecting rod nuts to 40 - 50 Nm initial torque and 90-100° angle of rotation torque.


Attention!
Tighten connecting rod bolts knocked in with a hammer for the first time at 60 - 70 Nm initial torque and 90-100° angle of rotation torque.

This specification must be strictly observed since otherwise the connecting rod nuts may become loose.


NOTE: If no angle of rotation tool is available, the connecting rod nuts can also be tightened by means of a normal socket wrench with tommy bar in one step by an angle of 90-100°. This angle should be estimated as accurately as possible. To eliminate angle of rotation errors, do not use torque wrench for tightening according to angles of rotation.