Cylinder Honing
Caution: Wear safety glasses in order to avoid eye damage.
- When honing
the cylinder bores, 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 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. |
- During the honing operation, thoroughly check the cylinder bore.
• | 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. |
- When honing to eliminate taper in the cylinder bore, use full
strokes the complete length of the cylinder bore.
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. |
- 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.
- When finished, the reconditioned cylinder bores should have less
than or meet the specified out-of-round and taper requirements.
- After the final honing and before the piston is checked for fit,
clean the cylinder bore with hot water and detergent.
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 rag. |
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. |
- Perform final measurements of the piston and the cylinder bore.
- Permanently mark the top of the piston for the specified cylinder
to which it has been fitted.
- Apply clean engine oil to each cylinder bore in order to prevent
rusting.
Boring Procedure
Caution: Wear safety glasses in order to avoid eye damage.
- 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.
- File the top of the cylinder block in order to remove any dirt
or burrs before using any type of boring bar.
- Follow the instructions furnished by the manufacturer regarding
use of the boring equipment.
- When reboring the cylinders, make sure all the crankshaft bearing
caps are installed in the original position and direction.
- Tighten the crankshaft bearing caps to the proper torque specifications
in order to avoid distortion of the cylinder bores in the final assembly.
- When making the final cut with the boring bar, leave 0.03 mm
(0.001 in) on the cylinder bore diameter for finish honing. This gives
the required position to the cylinder clearance specifications. (Carefully
perform the honing and boring operation in order to maintain the specified
clearances between the pistons, the piston rings, and the cylinder bores).