Cylinder Boring and Honing

Tools Required 

J 8087  Cylinder Bore Gauge

1. Measure the cylinder bore for out-of-round and taper.
2. Measure dimension (1) at 13 mm (0.5 in) below the head gasket surface. Measure dimension (2) at 100 mm (4 in) below the head gasket surface.
   Fig 1: Measuring Cylinder Bore For Out-Of-Round And Taper

   Courtesy of GENERAL MOTORS CORP.
3. Measure the cylinder bores by setting the J 8087  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. If dimension (1) is larger than dimension (2) by 0.013 mm (0.0005 in), bore the cylinder for oversize piston and rings.
   • If relatively few bores require correction, do not rebore all the cylinders to the same oversize in order to maintain engine balance.
   • All oversize service pistons are held to the same weights as the standard size pistons.
5. 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.
   Fig 2: Measuring Cylinder Bores

   Courtesy of GENERAL MOTORS CORP.
6. If the bore is glazed but otherwise serviceable, lightly break the glaze with a hone. Replace the piston rings. Refer to Piston and Connecting Rod Installation.
   1. 6.1. Ensure that the hone stones are clean, sharp, and straight.
   2. 6.2. Move the hone slowly up and down to produce a 45 degree cross hatch pattern.
   3. 6.3. Clean the bore thoroughly with soap and water.
   4. 6.4. Dry the bore.
   5. 6.5. Rub clean engine oil in the bore.
   6. 6.6. Remeasure the bore.
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.