« 1992 Aerostar/Ranger/Explorer Table of Contents»
«Group 03: ENGINE»
«Section 03-00: Engine Service, Gasoline»
«OVERHAUL»
Cylinder Walls, Refinishing
Honing is recommended for refinishing cylinder walls only when no cross-hatch pattern is visible on 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 cylinder bores with a
detergent and water solution.
Cylinder walls that are severely marred and/or worn beyond the specified limits should be refinished. Before
any cylinder is refinished, 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 refinishing operation. Hone
only the cylinder or cylinders that require refinishing. All pistons are the same weight, both standard and
oversize; therefore, various sizes of pistons can be used without upsetting engine balance. Refinish the
cylinder with the most wear first to determine the maximum oversize. If the cylinder will not clean up when
refinished for the maximum oversize piston recommended, replace the block.
Refinish the cylinder to within approximately 0.038mm (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 the proper use of the refinishing equipment, follow the instructions of the manufacturer. Only
experienced personnel should be allowed to perform this work.
Use a motor-driven, spring pressure-type Cylinder Hone Set T73L-6011-A or equivalent, hone at a speed of
300-500 rpm. Hones of grit sizes 180-220 will normally provide the desired bore surface finish of 18-38 AA.
When honing the cylinder bores, use a lubricant mixture of equal parts of kerosene and SAE No. 20 motor oil.
Operate the hone in such a way as to produce a cross-hatch finish on the cylinder bore. The cross-hatch
pattern should be at an angle of approximately 30 degrees to the cylinder bore. After the final operation in
either of the two refinishing methods described and prior to checking the piston fit, thoroughly clean
with a detergent and water solution and then oil the cylinder walls. Mark the pistons to correspond to the
cylinders in which they are to be installed. When the refinishing of all cylinders that require it has been
completed and all pistons are fitted, thoroughly clean the entire block and oil the cylinder walls.
Refinish cylinders that are deeply scored, out-of-round, and/or taper exceeds specification. 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, providing the
piston clearance is within specification. For Specifications, refer to «Section 03-01A» (3.0L), «Section 03-01B»
(2.3L), «Section 03-01C» (2.9L), or «Section 03-01D» (4.0L).
Cleaning
After any cylinder bore service operation, such as honing or deglazing, clean the bore(s) with soap or
detergent and water. Then, thoroughly rinse the bore(s) with clean water to remove the soap or detergent, and
wipe the bore(s) dry with a clean, lint-free cloth. Finally, wipe the bore(s) with a clean cloth dipped in engine
oil. If these procedures are not followed, rusting of the cylinder bore(s) may occur.
If the engine is disassembled, thoroughly clean the block with solvent. Remove old gasket material from all
machined surfaces. Remove all pipe plugs that seal oil passages, clean out all the passages. Blow out all
passages, then bolt holes, etc., with compressed air. Make sure threads in the cylinder head bolt holes are
clean. Dirt in the threads may cause binding and result in a false torque reading. Use a tap to true-up threads
and to remove all deposits. Thoroughly clean the grooves in the crankshaft bearings and bearing retainers.
Inspection
After the block has been thoroughly cleaned, check it for cracks. Tiny cracks not visible to the naked eye may
be detected by coating the suspected area with a mixture of 25 percent kerosene and 75 percent light engine
oil. Wipe the part dry and immediately apply a coating of zinc oxide dissolved in wood alcohol. Do not use
rubbing alcohol as a substitute. If cracks are present, the coating will become discolored at the damaged area.
Replace the block if it is cracked.
Check all machined surfaces for burrs, nicks, scratches and scores. Remove minor imperfections with an oil
stone.
Check the cylinder block for flatness of the cylinder head gasket surface following the procedure and
specifications recommended for the cylinder head. The cylinder block can be machined to bring the cylinder
head gasket surface within the flatness specifications listed in the specific engine section, but not to exceed
0.254mm (0.010 inch) stock removal from the original gasket surface.
Replace all plugs that show evidence of leakage. Inspect the cylinder walls for scoring, roughness or other
signs of wear. Check the cylinder bore for out-of-round and taper. Measure the bore with an accurate bore
gauge following the instructions of the manufacturer. Measure the diameter of each cylinder bore at the top,
middle and bottom with the gauge placed at right angles and parallel to the centerline of the engine.Use only
the measurements obtained at 90 degrees to the engine centerline when calculating the
piston-to-cylinder bore clearance.
Inspect the main and connecting rod journals for cracks, scratches, grooves, scores or rough finish. Inspect
the crankshaft oil seal surface for nicks, sharp edges, or burrs that might damage the oil seal during
installation or cause premature seal wear.
