Engine Mechanical - 4.3L: Overhaul Chevrolet Silverado Classic 2500 HD

Piston and Connecting Rod Disassemble

1. Remove the piston rings from the pistons.
2. Press the piston pin from the connecting rod using the J 24086-C . See «Special Tools»(ref-277938-S12463979202008012100000) . The piston pin has an interference fit into the connecting rod, and is full floating in the piston.
3. Mark, separate, and organize the parts for assembly.

Piston and Connecting Rod Assemble

1. Install the new piston pin and connecting rod assembly. Lubricate the piston pin bores with clean engine oil. Use a torch and apply MILD heat to the piston pin end of the connecting rod. Use the J 24086-C in order to press the new piston pin into the piston and connecting rod assembly. See «Special Tools»(ref-277938-S12463979202008012100000) . Inspect for the proper installation of the piston and piston pin. The piston must move freely on the new piston pin with no binding or interference.
2. Install the piston rings onto the piston. Install the oil control piston ring spacer. Install the lower oil control piston ring. Install the upper oil control piston ring. Install the lower compression piston ring. The mark on the side of the piston ring should face the top of the piston. Install the upper compression piston ring. The mark on the side of the piston ring should face the top of the piston.
3. Space the compression piston ring end gaps 120 degrees apart.
4. Space the oil control piston ring end gaps a minimum of 90 degrees apart.

Cylinder Head Disassemble

1. Use the J 8062 in order to compress the valve springs. See «Special Tools»(ref-277938-S12463979202008012100000) .
2. Remove the valve stem keys (1).
3. Remove the J 8062 from the cylinder head. See «Special Tools»(ref-277938-S12463979202008012100000) .
4. Remove the valve spring cap (2).
5. Remove the valve spring (3).
6. Remove the valve stem oil seal (4).
7. Discard the valve stem oil seal.
8. Remove the valve.

Cylinder Head Assemble

Tools Required

1. J 8062 Valve Spring Compressor. See «Special Tools»(ref-277938-S12463979202008012100000) .
2. J 42073 Valve Stem Seal Installer. See «Special Tools»(ref-277938-S12463979202008012100000) .

1. Assemble the valve into the proper valve guide.
2. Select the proper valve stem oil seal for the specific valve guide.
3. Lubricate the valve stem oil seal and the outside diameter of the valve guide with clean engine oil.
4. Assemble the valve stem oil seal onto the valve stem.
5. Using the J 42073 , install the valve stem oil seal onto the valve guide. See «Special Tools»(ref-277938-S12463979202008012100000) . Tap the valve stem oil seal onto the valve guide until the J 42073 bottoms against the valve spring seat. See «Special Tools»(ref-277938-S12463979202008012100000) . Inspect the valve stem oil seal. The valve stem oil seal should not be bottomed against the valve guide. There should be a 1-2 mm (0.03937-0.07874 in) gap between the bottom edge of the valve stem oil seal and the valve guide.
6. Install the valve spring (3).
7. Install the valve spring cap (2) onto the valve spring (3), over the valve stem.
8. Use the J 8062 to compress the valve spring. See «Special Tools»(ref-277938-S12463979202008012100000) .
9. Install the valve stem O-ring seal.
10. Install the valve stem keys. Use grease to hold the valve stem keys in place while disconnecting the J 8062 . See «Special Tools»(ref-277938-S12463979202008012100000) . Tap the end of the valve stem with a plastic-faced hammer to seat the valve stem keys. Inspect the valve stem keys to ensure that they are seated in the upper groove of the valve stem.

Oil Pump Disassemble

1. Remove the oil pump driveshaft and oil pump driveshaft retainer.
2. Remove the oil pump pipe, if necessary. The oil pump pipe has a press fit into the oil pump cover.
3. Remove the oil pump cover bolts.
4. Remove the oil pump cover.
5. Remove the oil pump drive gear and the oil pump driven gear.
6. Matchmark the gear teeth for assembly.
7. Remove the following items: The oil pump pressure relief valve spring straight pin The oil pump pressure relief spring The oil pump pressure relief valve

Oil Pump Assemble

1. Apply clean engine oil GM P/N 12345610 (Canadian P/N 9931930) or equivalent, to the oil pump pressure relief valve, oil pump pressure relief valve spring, and oil pump body.
2. Install the following items: The oil pump pressure relief valve The oil pump pressure relief valve spring The oil pump pressure relief valve spring straight pin
3. Apply clean engine oil GM P/N 12345610 (Canadian P/N 993193) or equivalent, to the oil pump drive gear, the oil pump driven gear, and the oil pump body internal surfaces.
4. Install the oil pump drive gear and the oil pump driven gear into the oil pump body. Align the matchmarks on the oil pump drive and driven gears. Install the smooth side of the oil pump drive and driven gears toward the oil pump cover.
5. Install the oil pump cover.
6. Install the oil pump cover bolts. Tighten: Tighten the bolts to 12 N.m (106 lb in).
7. Inspect the oil pump for smoothness of operation by turning the oil pump driveshaft by hand.
8. Install the oil pump screen. If removed, replace the oil pump screen. The oil pump screen must have a good press fit into the oil pump body. Mount the oil pump in a soft jawed vise. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the end of the oil pump screen pipe. Use the J 21882 and a soft-faced hammer in order to tap the oil pump screen into the pump body. See «Special Tools»(ref-277938-S12463979202008012100000) . The oil pump screen must align parallel with the bottom of the oil pan when the oil pan is installed.
9. Install the oil pump driveshaft and the NEW oil pump driveshaft retainer.

Intake Manifold Disassemble

1. Remove the nuts, the studs, and the accelerator control cable bracket.
2. Remove the throttle body attaching studs.
3. Remove the throttle body.
4. Remove the throttle body to upper intake manifold gasket.
5. Discard the throttle body to upper intake manifold gasket.
6. Remove the water outlet studs.
7. Remove the water outlet (309).
8. Remove the engine coolant thermostat.
9. Remove the engine coolant temperature (ECT) sensor plug (1) or the ECT sensor (2) from the front of the lower intake manifold, if equipped.
10. Remove the studs and the ignition coil.
11. Remove the manifold absolute pressure (MAP) sensor.
12. Remove the MAP sensor seal from the MAP sensor.
13. Discard the MAP sensor seal.
14. Remove the fuel pipe bolt (509).
15. Remove the fuel service port cap (751) and schrader valve (752), if required.
16. Remove the fuel pipe retainer nuts (510).
17. Remove the fuel pipe retainer (753).
18. Remove the fuel pipe (749).
19. Remove the fuel pipe plug (750), if required.
20. Remove and discard the fuel seal retainers (511).
21. Remove and discard the fuel seals (512), yellow O-rings.
22. Remove and discard the spacer rings (513), flat washers.
23. Remove and discard the fuel seals (514), black O-rings.
24. Remove the studs and the evaporative emission (EVAP) canister purge solenoid valve.
25. Remove the nut and the engine wiring harness bracket.
26. Remove the upper intake manifold attaching studs.
27. Remove the upper intake manifold.
28. Remove the upper intake manifold to lower intake manifold gasket.
29. Discard the upper intake manifold to lower intake manifold gasket.
30. Remove the fuel meter body seal and discard.
31. Remove the 6 injectors from the lower intake manifold bores.
32. Remove the fuel meter body.
33. Remove the bolt and the fuel meter body bracket.

Intake Manifold Assemble

1. If reusing the fastener, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the fuel meter body bracket bolt.
2. Install the fuel meter body bracket and bolt. Tighten: Tighten the fuel meter bracket bolt to 10 N.m (89 lb in).
3. Install the fuel meter body into the fuel meter body bracket.
4. Install the 6 injectors into the proper lower intake manifold bores in proper sequence (3, 5, 1, 2, 4, 6).
5. Inspect the injectors in order to ensure that they are firmly seated and locked in the lower intake manifold bores.
6. Ensure that the electrical connections of the injectors are positioned so that they do not interfere with each other, and are pointing towards the center of the intake manifold. Rotate the electrical connector inboard if necessary. Also, ensure there is no tension on the injector wires.
7. Install a NEW upper intake manifold to lower intake manifold gasket into the groove of the upper intake manifold.
8. Install the upper intake manifold onto the lower intake manifold.
9. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the upper intake manifold attaching studs.
10. Install the upper intake manifold attaching studs. Tighten: Tighten the upper intake manifold attaching studs on the first pass to 5 N.m (44 lb in). Tighten the upper intake manifold attaching studs on the final pass to 9 N.m (80 lb in).
11. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the evaporative emission (EVAP) canister purge solenoid valve studs.
12. Install the EVAP canister purge solenoid valve and studs. Tighten: Tighten the EVAP canister purge solenoid valve studs to 10 N.m (89 lb in).
13. Install the engine wiring harness bracket and nut. Tighten: Tighten the engine wiring harness bracket nut to 12 N.m (106 lb in).
14. Install the NEW fuel seals (514), black O-rings, into the fuel meter body.
15. Install the NEW spacer rings (513), flat washers, into the fuel meter body.
16. Install the NEW fuel seals (512), yellow O-rings, into the fuel meter body.
17. Install the NEW fuel seal retainers (511) into the fuel meter body.
18. Install the fuel pipe plug (750), if required.
19. Install the fuel pipe (749) into the fuel meter body.
20. Install the fuel pipe retainer bracket (753) onto the fuel pipe.
21. Install the fuel pipe retainer bracket nuts (510).
22. If reusing the fastener, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the fuel pipe bolt.
23. Install the fuel service port cap (751) and schrader valve (752), if required.
24. Install the fuel pipe bolt (509). Tighten: Tighten the fuel pipe bracket nuts to 3 N.m (27 lb in). Tighten the fuel pipe bolt to 6 N.m (53 lb in).
25. Install a NEW manifold absolute pressure (MAP) sensor seal onto the MAP sensor.
26. Apply a small amount, approximately 1 drop, of clean engine oil to the MAP sensor seal.
27. Install the MAP sensor into the upper intake manifold.
28. Install the ignition coil and studs. Tighten: Tighten the ignition coil studs to 12 N.m (106 lb in).
29. If reusing the engine coolant temperature (ECT) sensor plug (1) or the ECT sensor (2), if equipped, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the ECT sensor plug (1) or the ECT sensor (2).
30. Install the ECT sensor or plug, if equipped, into the front of the lower intake manifold. Tighten: Tighten the ECT sensor or plug to 20 N.m (15 lb ft).
31. Install the engine coolant thermostat.
32. Install the water outlet (309).
33. Install the water outlet studs. Tighten: Tighten the water outlet studs to 25 N.m (18 lb ft).
34. Install a NEW throttle body gasket into the groove in the upper intake manifold.
35. Install the throttle body onto the upper intake manifold.
36. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the throttle body attaching studs.
37. Install the throttle body attaching studs. Tighten: Tighten the throttle body attaching studs to 9 N.m (80 lb in).
38. Install the accelerator control cable bracket, the studs, and the nuts. Tighten: Tighten the accelerator control cable bracket stud to the intake manifold to 6 N.m (53 lb in). Tighten the accelerator control cable bracket nuts to 12 N.m (106 lb in). Tighten the accelerator control cable bracket stud to the throttle body to 12 N.m (106 lb in).

Service Prior to Assembly

1. Dirt will cause premature wear of the rebuilt engine. Clean all the components.
2. Use the proper tools to measure the components when checking for excessive wear. Components not within the manufacturer's specification must be repaired or replaced.
3. When the components are re-installed into an engine, return the components to the original location, position, and direction.
4. During assembly, lubricate all the moving parts with clean engine oil, unless otherwise specified. The engine oil will provide the initial lubrication when the engine is first started.

Piston and Connecting Rod Assemblies

The cast aluminum pistons use two compression rings and one oil control assembly. The piston is a low friction, lightweight design with a flat top and barrel shaped skirt. The piston pins are offset 0.9 mm (0.0354 in) toward the major thrust side, right side, to reduce piston slap as the connecting rod travels from one side of the piston to the other side after a stroke. The piston pins have a floating fit in the piston and are retained by a press fit in the connecting rod. Powdered metal connecting rods were introduced into production in late 2006. Powdered metal connecting rods and rod bearing caps are NOT interchangeable. They must be assembled with the mating surfaces properly oriented and aligned, and the piston, piston pin, and connecting rod are to be serviced as an assembly.

Disassembly and Assembly Procedure Revisions

Instructions added specific to powdered metal connecting rod service.

Assembling Components

1. Assemble components using only the sealant (or equivalent) that is specified in the service procedure.
2. Sealing surfaces must be clean and free of debris or oil.
3. Specific components such as crankshaft oil seals or valve stem oil seals may require lubrication during assembly.
4. Components requiring lubrication will be identified in the service procedure.
5. Apply only the amount of sealant specified in the service procedure to a component.
6. Do not allow the sealant to enter into any blind threaded holes, as the sealant may prevent the fastener from clamping properly or cause component damage when tightened.
7. Tighten the fasteners to the proper specifications.