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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2001 🢒 Regal (China) 🢒 Engine 🢒 Engine Mechanical - 2.5L (LE8) 🢒 Cylinder Boring and Honing

Cylinder Boring

    Caution: Refer to Safety Glasses Caution in the Preface section.


    Object Number: 188016 Size: SH
  1. Before starting the honing or reboring operation, measure all the new pistons with the micrometer contacting at points exactly 90 degrees from the piston pin centerline.
  2. File the top of the cylinder block in order to remove any dirt or burrs before using any type of boring bar.
  3. Follow the instructions furnished by the manufacturer regarding use of the boring equipment.
  4. When reboring the cylinders, make sure the lower crankcase is installed. Tighten the lower crankcase to the proper torque specifications in order to avoid distortion of the cylinder and bearing bores during final assembly.
  5. When making the final cut with the boring bar, leave 0.02 mm (0.0008 in) on the cylinder bore diameter for finish honing. This gives the required position to the cylinder clearance specifications. Carefully perform the boring and honing operation in order to maintain the specified clearances between the pistons, the piston rings, and the cylinder bores.

Cylinder Honing

    Caution: Refer to Safety Glasses Caution in the Preface section.


    Object Number: 186747 Size: SH
  1. When honing the cylinder bores, follow the manufacturer's recommendations for equipment use, cleaning, and lubrication.
    2. • Use only clean sharp stones of the proper grade for the amount of material to be removed.
    • Dull, dirty stones cut unevenly and generate excessive heat.
    • DO NOT hone to a final grade with a coarse or medium-grade stone.
    • Leave sufficient metal so that all the stone marks will be removed with the fine grade stones.
    • Perform the final honing with a fine-grade stone and hone the cylinder bore in a cross hatch pattern at 45-65 degrees to obtain the proper clearance.
  2. During the honing operation, thoroughly check the cylinder bore.
    3. • Repeatedly check the cylinder bore fit with the selected piston.
    • All measurements of the piston or cylinder bore should be made with the components at normal room temperature.
  3. When honing to eliminate taper in the cylinder bore, use full strokes the complete length of the cylinder bore.

    4. Repeatedly check the measurement at the top, the middle, and the bottom of the cylinder bore.

    • The finish marks should be clean but not sharp.
    • The finish marks should be free from imbedded particles or torn or folded metal.
  4. By measuring the selected piston at the sizing point and then by adding the average of the clearance specification, the final cylinder bore honing dimension required can be determined.
  5. When finished, the reconditioned cylinder bores should have less than or meet the specified out-of-round and taper requirements.
  6. After the final honing and before the piston is checked for fit, clean the cylinder bore with hot water and detergent.
    7. 6.1. Scrub the cylinder bores with a stiff bristle brush.
    6.2. Rinse the cylinder bores thoroughly with clean hot water.
    6.3. Dry the cylinder bores with a clean, lint-free cloth.
    6.4.  Do not allow any abrasive material to remain in the cylinder bores.
       • Abrasive material may cause premature wear of the new piston rings and the cylinder bores.
       • Abrasive material will contaminate the engine oil and may cause premature wear of the bearings.
  7. Perform final measurements of the piston and the cylinder bore.
  8. Permanently mark the top of the piston for the specified cylinder to which it has been fitted.
  9. Apply clean engine oil to each cylinder bore in order to prevent rusting.