Cylinder Honing

Special Tools 

EN-8087  Cylinder Bore Gauge

For equivalent regional tools, refer to Special Tools (LDK, LHU) .

Fig 1: Measuring Head Gasket Dimensions
Courtesy of GENERAL MOTORS COMPANY
1. Measure the cylinder bore for out-of-round and taper.
2. Measure the dimension (1) at 13 mm (0.5 in) below the head gasket surface. Measure the dimension (2) at 100 mm (4 in) below the head gasket surface.
Fig 2: Measuring Bore Gauge
Courtesy of GENERAL MOTORS COMPANY
3. Measure the cylinder bores by setting the EN-8087  gauge (1) dial at zero in the cylinder at the point of the desired measurement. Lock the dial indicator at zero before removing the dial from the cylinder. Measure across the gauge contact points with an outside micrometer, with the gauge at the same zero setting as when the gauge was removed from the cylinder.
4. Fine vertical scratches made by the ring ends do not, by themselves, cause excessive oil consumption. Do not hone the cylinder in order to remove these scratches.
5. If the bore is glazed but otherwise serviceable, lightly break the glaze with a hone. Replace the piston rings. Refer to Piston, Connecting Rod, and Bearing Installation (LDK, LHU) .
   1. The honing stones must be clean, sharp, and straight.
   2. Move the hone slowly up and down to produce a 45 degree cross-hatch pattern.
   3. Clean the bore thoroughly with soap and water.
   4. Dry the bore.
   5. Rub clean engine oil in the bore.
   6. Measure the bore again.
6. If the cylinder bore is out of specification, replace the engine.
7. If honing is not required, clean the cylinder bores with hot water and detergent. Apply clean engine oil to the bore after washing and drying the bore.