For 1990-2009 cars only
Boring Procedure
- Before you start the honing or reboring operation, measure all new pistons with the micrometer contacting at points exactly 90 degrees from the piston pin centerline. Refer to Piston and Connecting Rod Disassemble and Assemble . Select the smallest piston for the piston fitting. Slightly varied pistons in a set may provide correction, in case the first piston is too loosely fitted.
- Before you use any type of boring bar, file the top of the cylinder block in order to remove any dirt or burrs. If you do not check the cylinder block, the boring bar may be tilted, this could result in the rebored cylinder wall being at incorrect right angles to the crankshaft.
- Carefully follow the instructions furnished by the manufacturer regarding use of equipment.
- When you rebore cylinders, make sure all crankshaft bearing caps are in place. Tighten the bearing caps to the proper torque in order to avoid distortion of the bores in the final assembly. The crankshaft must be clear of the boring cutter when you bore each cylinder. Cover or tape the crankshaft bearings and other internal parts to protect these parts during the boring or honing operation.
- When you take the final cut with a boring bar, leave 0.03 mm (0.001 in) on the diameter for finish honing. This gives the required position to the cylinder clearance specifications.
Important: Carefully perform the honing and boring operation in order to maintain the specified clearances between pistons, rings, and cylinder bores.
Honing Procedure
- When honing the cylinders, follow the manufacturer's recommendations for 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. When using coarse or medium-grade stones, leave sufficient metal so that all stone marks may be removed with the fine stones you use for finishing in order to provide for proper clearance.
- During the honing operation, thoroughly clean the cylinder bore. Check for a correct fit the piston you select for the individual cylinder.
- When honing to eliminate taper in the cylinder, make full strokes of the hone in the cylinder. Repeatedly check the measurement at the top, the middle, and the bottom of the bore.
- When finished honing a cylinder bore to fit a piston, move the hone up and down at a sufficient speed to obtain very fine, uniform surface finish marks in a cross hatch pattern at 45°.
- The finish marks should be clean but not sharp. The finish marks should be free from imbedded particles and torn or folded metal.
- By measuring the piston to be installed at the sizing point specified, and by adding the average of the clearance specification, you can determine the finish hone cylinder measurement. Refer to Engine Mechanical Specifications . Measure the block and the piston at normal room temperature.
- True up the refinished cylinder bores to have less than the specified out-of-round or taper. You must final hone each bore in order to remove all stone or cutter marks and in order to provide a smooth surface.
- For piston-to-bore tolerance specifications, refer to Engine Mechanical Specifications .
- After final honing and before the piston is checked for fit, clean the 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 will wear the new rings, the cylinder bores, and the bearings lubricated by the contaminated oil. After you wash the bore, brush the dry bore clean with a power-driven fiber brush.
- Permanently mark the piston for the cylinder to which the piston has been fitted.
- Apply clean engine oil to each bore in order to prevent rusting.
Notice: Handle the pistons with care. Do not force the pistons through the cylinder until you hone the cylinder to the correct size. The piston can be distorted through careless handling.
