Pistons and Connecting Rods

Removal

1. Drain the cooling system. Refer to Section 03-03. Drain the crankcase. Remove the intake manifold (9424), cylinder heads (6049), oil pan (6675) and oil pump (6600) as outlined.

2. Remove any ridges and/or deposits from the upper end of the cylinder bores as follows.

   Turn the crankshaft (6303) until the piston (6108) to be removed is at the bottom of its travel, then place a cloth on the piston head to collect the cuttings. Remove the cylinder ridge with a ridge cutter. Follow the instructions furnished by the tool manufacturers. Never cut into the ring travel area in excess of 0.794mm (1/32 inch) when removing ridges.

3.  CAUTION: Connecting rod caps must be installed in their original locations.

   Make sure all connecting rod caps are marked so that they can be installed in their original positions.

4. Turn the crankshaft until the connecting rod being removed is down.

5. Remove the connecting rod nuts and cap.

6. Push the connecting rod and piston assembly out the top of the cylinder with the handle end of a hammer. Avoid damage to the crankshaft journal or the cylinder wall when removing the piston and rod assembly.

7. Remove the bearing inserts from the connecting rods and caps.

Installation

1. If new piston rings are to be installed, remove the cylinder wall glaze. Refer to Section 03-00. The small depression on the ring designates the top.

2. Install rings using a piston ring installation tool of the proper size.

3. NOTE: Be sure to install the pistons in the same cylinders from which they were fitted.

   Oil the piston rings, pistons and cylinder walls with recommended quality engine oil. The connecting rod and bearing caps are numbered from 1 to 4 in the right bank and from 5 to 8 in the left bank, beginning at the front of the engine (6007). The numbers on the connecting rod and bearing cap must be on the same side when installed in the cylinder bore. If a connecting rod is ever transferred from one cylinder block (6010) or cylinder to another, new connecting rod bearings (6211) should be fitted and the connecting rod should be numbered to correspond with the new cylinder number. When installing the piston and connecting rod assembly, the largest chamfer at the bearing end of the rod should be positioned toward the crank pin thrust face of the crankshaft.

4. Make sure the ring gaps (oil ring spacer-A, oil ring-B, compression ring-C) are properly spaced around the circumference of the piston.

   

5. NOTE: Replacement pistons are slightly lighter in weight. Pistons must be replaced as a complete set to avoid the introduction of torsional vibration to the engine.

   Install Piston Ring Compressor D81L-6002-C or equivalent on the piston and push the piston in with a hammer handle until it is slightly below the top of the cylinder. Be sure to guide the connecting rods to avoid damaging the crankshaft journals. Install the piston with the indentation notch in the piston head toward the front of the engine.

6. Install connecting bearings and check the clearance of each connecting rod bearing. Refer to Section 03-00.

7. After the connecting rod bearings have been fitted, apply a light coat of recommended engine oil to the journals and connecting rod bearings.

8. Turn the crankshaft throw to the bottom of its stroke. Push the piston all the way down until the connecting rod bearing seats on the crankshaft journal.

9. Install the connecting rod cap. Tighten the nuts on 5.0L engines to 26-33 Nm (19-24 lb-ft); on 5.8L engines to 54-61 Nm (40-45 lb-ft).

10. After the piston and connecting rod assemblies have been installed, use a feeler gauge to check the side clearance between the connecting rods on each shaft journal.

    

11. Disassemble, clean, and assemble the oil pump. Clean the oil pump screen cover and tube (6622) and the oil pan and block gasket surfaces.

12. Prime the oil pump by filling the inlet port with engine oil of the quality recommended in the Owner Guide and rotating the oil pump intermediate shaft (6A618) to distribute the oil within the housing. Install the oil pump and the oil pan.

13. Install the cylinder heads following the steps under Cylinder Head in the In-Vehicle Service portion of this section.

14. Install accessory drive brackets with generator (GEN) (10300), secondary air injection pump (AIR pump) (9A486), air conditioning compressor, and power steering pump (3A674) and connect hoses and electrical connections.

15. Install the intake manifold.

16.  CAUTION: To prevent oil from entering the PCV system during air-powered oil fills, the closure hose should be disconnected from the oil fill pipe (6A868) and positioned away from the oil source. Cover the hose port with a shop towel to prevent oil from spilling onto the engine during oil fill. Reconnect the closure hose after the oil has been filled to the proper level.

    Fill and bleed the cooling system. Refer to Section 03-03. Fill the crankcase with the proper quality and quantity of engine oil as recommended in the Owner Guide.

17. Start the engine, then check and adjust the ignition timing.

18. Operate the engine at fast idle and check for oil and coolant leaks. Operate the engine until engine temperatures have stabilized.

19. Install the engine air cleaner (ACL) (9600) and air cleaner outlet tube (9B659) assembly, including the crankcase ventilation tube (6758).