Chevrolet Silverado / GMC Sierra. Service manual — part 344

Fig. 393: View Of Honing Of Cylinders
Courtesy of GENERAL MOTORS CORP.

1. When honing the cylinders, follow the manufacturer's recommendations for equipment use,

cleaning, and lubrication. Use only clean, sharp stones of the proper grade for the amount of
material you remove. Dull, dirty stones cut unevenly and generate excessive heat. Do not
hone to final clearance with a coarse or medium-grade stone. Leave sufficient metal so that
all stone marks may be removed with fine-grade stones. Perform final honing with a fine-
grade stone, honing the cylinder to the proper clearance.

2. During the honing operation, thoroughly clean the cylinder bore. Repeatedly check the

cylinder bore for fit with the selected piston.

All measurements of the piston or the cylinder bore should be made with the components at
normal room temperature.

3. When honing a cylinder for fit to an oversize piston, first perform the preliminary honing

with a 100-grit stone.

4. Perform final cylinder honing with a 240-grit stone and obtain a 45 degree cross hatch

pattern.

A 240-grit stone is preferred for final honing. If a 240-grit stone is not available, a 220-grit

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

stone may be used as a substitute.

5. The finish marks should be clean but not sharp. The finish marks should also be free from

imbedded particles and torn or folded metal.

6. By measuring the selected piston at the sizing point and by adding the average of the

clearance specification, you can determine the final cylinder honing dimension required.

7. After final honing and before the piston is checked for fit, clean the cylinder bores with hot

water and detergent. Scrub the bores with a stiff bristle brush and rinse the bores thoroughly
with hot water. Do not allow any abrasive material to remain in the cylinder bores. This
abrasive material may cause premature wear of the new piston rings and the cylinder bores.
Abrasive material will also contaminate the engine oil and may cause premature wear of the
bearings. After washing the cylinder bore, dry the bore with a clean rag.

8. Perform final measurements of the piston and the cylinder bore.

9. Permanently mark the top of the piston for the specific cylinder to which it has been fitted.

10. Apply clean engine oil to each cylinder bore in order to prevent rusting.

Deglazing Procedure

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

Fig. 394: Illustrating Deglazing Cylinder Bore
Courtesy of GENERAL MOTORS CORP.

Using a ball type or self centering honing tool, deglaze the cylinder bore lightly. Deglazing
should be done only to remove any deposits that may have formed. Use a 240-grit stone of
silicone carbide, or equivalent, material when preforming the deglazing procedure.

A 240-grit stone is preferred for final honing. If a 240-grit stone is not available, a 220-grit stone
may be used as a substitute.

CRANKSHAFT AND BEARING CLEANING AND INSPECTION

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

Tools Required

J 7872 Magnetic Base Dial Indicator Set

J 43690 Rod Bearing Checking Tool. See Special Tools.

J 43690-100 Rod Bearing Checking Tool - Adapter Kit. See Special Tools.

Cleaning Procedure

Fig. 395: Oil Passages & CKP Reluctor Ring Teeth
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: Use care when handling the crankshaft. Avoid damage to the

bearing surfaces or the lobes of the crankshaft position
(CKP) reluctor ring. Damage to the teeth of the CKP reluctor
ring may affect on-board diagnostics (OBD) II system
performance.

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2