Connecting Rod: Service and Repair

NOTE: This procedure is when the cylinder heads have already been removed.





REMOVAL
1. Scrape away any soot deposits and burrs in the top of the cylinders. Mark the pistons with the cylinder numbers.
2. Raise the car and drain the engine oil.
3. Remove the cover plates and the oil pan.
4. Remove the oil strainer and the anti-slosh baffle. Wipe off dripping oil.
5. Mark the position and remove the appropriate connecting rod cap. Push the piston and the connecting rod out of the cylinder bore. Loosely install the bearing shells and the cap on the connecting rod.
6. Remove the wrist pin locking ring and tap out the wrist pin using a plastic mallet and drift.

NOTE: Pistons are held in stock as a spare part in standard and oversize. In the case of oversize pistons, the cylinder must be bored to achieve correct piston clearance.





INSTALLATION
1. Link pistons and connecting rods by tapping the wrist pins with a plastic mallet and drift. Make sure that the markings on the pistons point towards the transmission end of the engine and that the protuberances on the connecting rods point towards the flywheel end.
2. Install the wrist pin locking ring.

CAUTION: It is very important that the locking ring is installed with the opening upwards.

3. Place the bearing halves in the connecting rods.
4. Lubricate the piston rings, the bearings and the cylinders.
5. Install the pistons using fitting ring 83 95 113, or equivalent.
6. Install the bearing cap with upper bearing half and tighten bolts to 35 Nm (26 ft. lbs.) + 45°.

NOTE: The connecting rod and bearing cap contact surfaces must be clean and free from imperfection. If any contact surfaces are damaged, the connecting rod must be replaced as good fit can no longer be guaranteed. Clean contact surfaces with compressed air.





7. Check that there are no impurities in the oil pan and clean sealing surfaces. Use washing gasoline.
8. Seal all partition joints with (10) 81 52 381, or equivalent.
9. Install a new gasket and install the baffle plates, the oil strainer and the oil pan, using (10) 74 96 268, or equivalent on the bolts. See illustration for order. Tighten the following bolts to appropriate torque:
^ Baffle Plate: 8 Nm (6 ft. lbs.)
^ Oil Strainer: 8 Nm (6 ft. lbs.)
^ Oil Pan: 15 Nm (11 ft. lbs.)
10. Screw on the drain plug and tighten to 55 Nm (41 ft. lbs.).
11. Install the cover plate and tighten to 8 Nm (6 ft. lbs.). Lower the car.