Tools Required

1. Remove the cylinder head from the cylinder block. Refer to Cylinder Head Replacement in this section.
2. Remove the three right-side engine mount-to-engine bracket bolts and the right-side engine mount from the engine.
3. Remove the three left-side engine mount-to-engine bracket bolts and the left-side engine mount from the engine.
4. Remove the following from the engine:

•	The generator mounting bolts

•

The nuts

•	The generator with the generator/coolant pump drive belt




5. Remove the one bolt and the guide tube (1) from the cylinder block.
6. Remove the guide tube seal from the oil pump body (2).
7. Remove the one bolt and the coolant inlet pipe from the cylinder block.
8. Remove the five bolts and the coolant pump from the cylinder block.
9. Remove the oil pressure switch from the cylinder block.
10. Remove the generator mounting bracket.
11. Place a drain pan beneath the engine oil pan to catch the escaping oil.



12. Remove the engine oil drain plug (2) and gasket, allowing the engine oil to drain.



13. Remove the following from the cylinder block (1):

•	The sixteen bolts

•

Two nuts

•	The engine oil pan (2)

14. Remove the two bolts and the oil pump strainer (3) from the cylinder block (1).



15. Remove the crankshaft timing gear bolt (1).
16. Remove the crankshaft timing gear (2).



17. Remove the following from the cylinder block:

•	The seven bolts

•	The oil pump assembly (1)

•	The gasket

•	The rubber oil pump-to-coolant pump seals

•	Two guide pins

18. Remove the carbon from the top of the cylinder bores.
19. Remove the following components:

•	The connecting rod bearing cap bolts

•	The connecting rod bearing caps

•	The connecting rod bearings

20. Place a small piece of the hose over the threads of the connecting rod to protect the following during removal and installation:

•	The threads

•	The journal

•	The cylinder bore

21. Remove the pistons and the connecting rods from the cylinder block through the top of the cylinder bores.
22. Remove the following components:

•	The main bearing cap bolts

•	The bearing cap supports

•	The main bearing cap

•	The main bearings

23. Remove the crankshaft from the cylinder block.
24. Clean the ceiling material from the mating surfaces.

Notice: Caustic cleaning solution destroys the bearing material. All bearings left in block must be replaced after cleaning with a caustic solution. Do not clean bearing material or aluminum parts with caustic solution.

25. Boil the cylinder block in a caustic solution. Flush with clean water or steam.
26. Clean the engine oil passages.
27. Clean all of the blind holes.
28. Spray or wipe the cylinder bores and the machined surfaces with clean engine oil.
29. Inspect the cylinder block for cracks in the following areas:

•	The cylinder walls

•	The coolant jacket

•	The main bearing webs

•	Replace if any cracks are found.

30. Use a straightedge and a feeler gage in order to measure the cylinder block-to-cylinder head gasket surface for distortion and flatness . If specification is exceeded, correction is necessary. Minor irregularities can be carefully machined.

•	The standard distortion is 0.03 mm (0.0012 in).

•	Replace the cylinder block if distortion after any correction exceeds 0.06 mm (0.0024 in).

Measure

1. Use a straightedge and a feeler gage in order to measure the cylinder block-to-cylinder head gasket surface for distortion and flatness. If specification is exceeded, correction is necessary. Minor irregularities can be carefully machined.

•	The standard distortion is 0.03 mm (0.0012 in).

•	Replace the cylinder block if distortion after any correction exceeds 0.06 mm (0.0024 in).

•	When any one cylinder needs reboring, then all other cylinders must be rebored at the same time.

•	Select oversize pistons according to the amount of cylinder wear.

•	Oversized piston of 0.25 has a diameter of 75.220-75.230 mm (2.9614-2.0618 in).

•	Oversized piston of 0.50 has a diameter of 75.470-75.480 mm (2.9712-2.9716 in).

2. Use a J 26900-2 in order to measure the piston diameter.

Calculate the cylinder bore diameter to be rebored. D = A+B-C when:

•	D = Cylinder bore diameter is to be rebored.

•	A = Piston diameter as measured.

•	B = Piston Clearance = 0.02-0.04 mm (0.0008 in).

•	C = Allowance for honing = 0.02 mm (0.0008 in).

Notice: Before reboring, install all main bearing caps and tighten to specification to avoid distortion of bearing bores.

3. Rebore and hone cylinders to the calculated dimension.
4. Measure the piston clearance after the honing is completed.

Notice: To prevent damage to the cylinder block or parts installed:

•	All parts to be installed must be perfectly clean.

•	Be sure to apply engine oil to the crankshaft journals, journal bearings, thrust bearings, crankpins, connecting rod bearings, pistons, piston rings and cylinder bores.

•	Journal bearings, bearing caps, connecting rod, rod bearings, rod bearing caps, pistons and piston rings are in combination sets. Do not disturb the combinations and check to ensure that each part goes back to where it came from when installing.

1. Install the main bearings lower half to the crankshaft: Install the half with the oil groove (upper half) to the cylinder block.
2. Install the thrust bearings to the cylinder block between the number 2 and number 3 cylinders. Face the oil groove sides to the counterweights.
3. Install the crankshaft to the cylinder block.

Important: On each main bearing cap, the arrow mark and number are embossed. When installing each main bearing cap to the cylinder block, point the arrow mark toward the crankshaft pulley side and install each cap from the crankshaft pulley end to the flywheel in order 1, 2, 3, 4 and 5.

4. Install the five main bearing caps and two bearing cap supports.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Important: 

•	Gradual and uniform tightening is important for main bearing cap bolts.

•	After tightening the main bearing bolts, check to ensure that the crankshaft rotates smoothly when turned by hand.

5. Secure with the ten main bearing cap bolts.

Tighten
Tighten the main bearing cap bolts to 54 N·m (40 lb ft).

6. Apply a light coat of clean engine oil to the following:

•	The pistons

•

The rings

•	The cylinder walls

•	The connecting rod bearings

•	The crank pins




7. Install the guide hoses over the connecting rod bolts in order to prevent damage to the bearing journal and the connecting rod bolt threads when installing the connecting rods.
8. Use a J 8037 in order to install the piston and the connecting rod into the connecting bore. Ensure that the arrow mark on top of the piston points to the crankshaft pulley end.



9. Use a hammer handle in order to tap the piston head and install the piston into the cylinder bore. Keep the J 8037 pressed securely against the top of the cylinder block (1) until all of the piston rings have entered the cylinder bore.
10. Remove the hose pieces from the connecting rod bolts.

Important: Be sure to point the arrow mark on the cap toward the crankshaft pulley side.

11. Install the connecting rod bearing cap to the connecting rod.
12. Secure the connecting rod bearing cap with two nuts.

Tighten
Tighten the connecting rod bearing nuts to 35 N·m (26 lb ft).

Important: After the rear main housing bolts are tightened, the gasket may extend past the rear main seal housing. Trim the excess with a sharp knife so the gasket is flush with the cylinder block.

13. Install the rear main seal housing and new gasket to the engine. Secure the housing and gasket with five rear main seal housing bolts. There are two different bolt lengths. Ensure correct placement.

Tighten
Tighten the rear main seal housing bolts to 12 N·m (106 lb in).

14. Apply a thin coat of oil to the J 34853 .
15. Use the J 34853 in order to install the oil seal to the crankshaft.



16. Use the J 34853 in order to install the two guide pins and the oil pump assembly with a new gasket and rubber oil pump-to-coolant pump seals (1) to the crankshaft .



17. Secure the two guide pins and the oil pump assembly with seven bolts.

Tighten
Tighten all of the oil pump bolts to 11 N·m (97 lb in).

18. Ensure that the oil seal lip is not upturned. Remove the J 34853 .
19. Inspect the edge of the oil pump gasket.

•	Trim the edge with a sharp knife if it protrudes out into the engine oil pan mating surface.

•	Make the edge smooth and flush with the mating surface of the engine oil pan.




20. Apply gasket paste GM P/N 1050026, or the equivalent, to the engine oil pan mating surface (1) in a continuous bead.
21. Install the oil pump strainer to the engine oil pan.



22. Install the oil pump strainer (3) to the cylinder block. Secure the strainer with two bolts.

Tighten
Tighten the oil pump strainer bolts to 11 N·m (97 lb in).

23. Install the engine oil pan (2) to the cylinder block. Secure the engine oil pan with sixteen and two nuts.

Tighten
Tighten the engine oil pan nuts and bolts to 11 N·m (97 lb in).

24. Install the engine oil pan drain plug and gasket to the engine oil pan.

Tighten
Tighten the engine oil drain plug to 35 N·m (26 lb ft).

25. Install the new O-ring seal to the coolant intake pipe.
26. Install the coolant intake pipe to the cylinder block. Secure the pipe with one bolt.

Tighten
Tighten the coolant intake pipe bolt to 11 N·m (97 lb in).

27. Install the coolant pump with the new gasket to the engine. Secure the coolant pump with five bolts.

Tighten
Tighten the coolant pump bolts to 12 N·m (106 lb in).

28. Install the rubber seals between the coolant pump and the oil pump and between the coolant pump and the cylinder head.
29. Install the engine oil level indicator tube with a new O-ring to the cylinder block. Secure the tube with a mounting bolt. Do not fully tighten.

Tighten
Tighten the mounting bolt to 11 N·m (97 lb in).

30. Install the right-side engine mount to the engine. Secure the engine mount with three right-side engine mount-to-engine bracket bolts.

Tighten
Tighten the three right-side engine mount-to-engine bracket bolts to 55 N·m (40 lb ft).

31. Install the left-side engine mount to the engine. Secure the mount with three left-side engine mount-to-engine bracket bolts.

Tighten
Tighten the three mount-to-engine bracket bolts to 55 N·m (40 lb ft).

32. Install the cylinder head onto the cylinder block. Refer to Camshaft Replacement in this section.