Piston: Service and Repair

Piston and Connecting Rod, Engine Set, Renew

- Remove the engine and transmission unit from the vehicle.

- Remove the transmission unit from the engine and fit the engine to a stand.

- Remove the cylinder head.

- Remove the oil pan.

- Remove the oil pump.




- Remove the windage trays securing bolts. Remove the windage trays (6 Fig. 1).




- Remove the connecting rod nuts (1 Fig. 2) in connecting rod pairs (1 & 6, 2 & 5, 3 & 4 cylinders) and remove the connecting rod bearing caps (2 Fig. 2). Note the position of the cap to connecting rod. Discard the connecting rod bearing nuts.

- Push the pistons up and through the top of the cylinder block.




- Remove the piston pin snap-rings (1 Fig. 3) from each piston, remove the piston pin (2 Fig. 3) and separate the piston (3 Fig. 3) from the connecting rod (4 Fig. 3).

- Check the connecting rods for balance, twisting and bending. If any connecting rod is bent, twisted or out of balance with the other five, then the complete set must be renewed. Renew the connecting rod bearing bolts.




- Insert each new piston ring into the cylinder bore (1 Fig. 1) ensuring they are square in the cylinders and check the gap using a strip gauge (2 Fig.1).

- If the gap is insufficient, then a small flat file or carborundum stone can be used on the butting ends of the ring. Ensure that after filing no burrs remain.

Note: Ensure that the rings are not inter-mixed after they have been gapped and that each piston/ring assembly is matched to its respective bore. If new piston rings are being fitted without reboring, deglaze the cylinder bores using a hone or glaze buster. This operation will not increase the size of the bores and will give the bores a cross-hatched finish

- Lubricate the small end bush and slide the piston pin through the new piston and connecting rod. Secure with new snap-rings. NEVER re-use old snap-rings.




- Fit the rings to the pistons ensuring that gaps are positioned as in (Fig. 2).




- Lubricate and compress the rings using Service Tool 18G 55A (Fig. 3).

Note: Ensure that each piston I ring assembly is matched to its respective bore.

- Insert the piston skirt into the bore and using a suitable implement, i.e. a wooden hammer shaft, gently tap the piston into the cylinder bore.


- Ensure that the connecting rod does not foul either the cylinder block or crankshaft.

Note: Ensure that each connecting rod and connecting rod bearing cap are correctly `paired' for assembly.

- Lubricate and fit the connecting rod bearing shells to the connecting rod and the connecting rod bearing cap. Pull the connecting rod and bearing carefully onto the crankshaft and fit the connecting rod bearing cap to the rod.

- Fit and torque tighten the new connecting rod bearing nuts.

CAUTION: The connecting rod nuts and bolts MUST be renewed during assembly and torque tightened as described under Engine, Service and Repair, Service Procedures, SPS Joint Control System.

- Repeat the operation for the remaining five piston assemblies.

- Clean and fit the crankshaft windage trays and torque tighten the securing bolts.

- Refit the oil pump.

- Refit the oil pan.

- Refit the cylinder head.

- Remove the engine from the stand.

- Attach the transmission unit to the engine.

- Fit the engine / transmission unit to the vehicle.