Refinishing Cylinder Walls

Honing is recommended for reboring cylinder walls only when no crosshatch pattern is visible on the cylinder walls, or for fitting pistons to the specified clearance. The grade of hone to be used is determined by the amount of metal to be removed. Follow the instructions of the hone manufacturer. If coarse stones are used to start the honing operation, leave enough material so that all hone marks can be removed with the finishing hone which is used to obtain the proper piston clearance. After honing, thoroughly clean the cylinder bores with a detergent and water solution.





If the cylinder walls have minor surface imperfections but the out-of-round and taper are within limits, it may be possible to remove the imperfections by honing the cylinder walls and installing new service piston rings. However, piston clearance must be within specification for this procedure to be done.

When honing the cylinder bores, use a lubricant mixture of equal parts kerosene and SAE No. 20 motor oil. Operate the hone so that it will produce a crosshatch finish on the cylinder bore.

Use a motor-driven, spring pressure-type cylinder hone set such as the Engine Cylinder Hone Set T73L-6011-A.

Cylinder walls that are severely marred and/or worn beyond the specified limits should be rebored.

Hone only the cylinder or cylinders that require refinishing. Both standard and oversize pistons are the same weight. Therefore, various sizes of pistons can be used without upsetting engine balance.

NOTE: Only experienced personnel should perform cylinder wall reboring procedures. Before any cylinder is rebored, all main bearing caps must be in place and tightened to the proper torque so that the crankshaft bearing bores will not become distorted from the reboring operation.

Rebore the cylinder with the most wear first to determine the maximum oversize. If the cylinder will not clean up when it has been rebored for the maximum oversize piston recommended, replace the cylinder block.

Rebore the cylinder to within approximately 0.038 mm (0.0015 inch) of the required oversize diameter. This will allow enough stock for the final step of honing so that the correct surface finish and pattern are obtained. For proper use of the refinishing equipment, follow the instructions of the manufacturer.

Mark the pistons to correspond to the cylinders in which they are to be installed. After the necessary cylinders have been rebored and the pistons fitted, thoroughly clean the entire cylinder block and oil the cylinder walls.