Cylinder Bore Repair
STANDARD PROCEDURE - CYLINDER BORE REPAIRCylinder bore(s) can be repaired by one of two methods:
^ Method 1:-Over boring and using oversize pistons and rings.
^ Method 2:-Boring and installing a repair sleeve to return the bore to standard dimensions.
METHOD 1-OVERSIZE BORE
Cylinder bore(s) can be repaired by one of two methods:
Oversize pistons and rings are available in two sizes - 0.50 mm (0.0197 inch) and 1.00 mm (0.0393 inch).
Any combination of standard, 0.50 mm (0.0197 inch) or 1.00 mm (0.0393 inch) overbore may be used in the same engine.
If more than 1.00 mm (0.0393 inch) overbore is needed, a repair sleeve can be installed (refer to Method 2-Repair Sleeve).
Cylinder block bores may be bored twice before use of a repair sleeve is required. The first bore is 0.50 mm (0.0197 inch) oversize. The second bore is 1.00 mm (0.0393 inch) oversize.
After boring to size, use a honing stone to chamfer the edge of the bore.
CYLINDER BORE DIMENSION CHART
A correctly honed surface will have a crosshatch appearance with the lines at 15° to 25° angles with the top of the cylinder block. For the rough hone, use 80 grit honing stones. To finish hone, use 280 grit honing stones.
A maximum of 1.2 micrometer (48 microinch) surface finish must be obtained.
After finish honing is complete, immediately clean the cylinder bores with a strong solution of laundry detergent and hot water.
After rinsing, blow the block dry.
Check the bore cleanliness by wiping with a white, lint-free, lightly- oiled cloth. There should be no grit residue present.
If the block is not to be used right away, coat it with a rust- preventing compound.
METHOD 2-REPAIR SLEEVE
REPAIR SLEEVE BLOCK REBORE DIMENSIONS CHART
If more than a 1.00 mm (0.03937 inch) diameter oversize bore is required, the block must be bored and a repair sleeve installed.
Bore the block cylinder bore to 104.500 - 104.515 mm (4.1142 - 4.1148 inch).
Repair sleeves can be replaced by using a boring bar to bore out the old sleeve. DO NOT cut the cylinder bore beyond the oversize limit.
After machining the block for the new repair sleeve, thoroughly clean the bore of all metal chips, debris and oil residue before installing the sleeve.
Cool the repair sleeve(s) to a temperature of -12°C (10°F) or below for a minimum of one hour. Be ready to install the sleeve immediately after removing it from the freezer.
Apply a coat of Loctite 620, or equivalent to the bore that is to be sleeved.
Wear protective gloves to push the cold sleeve into the bore as far as possible.
Using a sleeve driver (1), drive the sleeve (2) downward until it contacts the step at the bottom of the bore.
SLEEVE DRIVER CONSTRUCTION SPECIFICATION CHART
A sleeve driver can be constructed as shown.
SLEEVE MACHINING DIMENSIONS CHART
Set up a boring bar and machine the sleeve to 101.956 mm (4.014 inch).
After removing the boring bar, use a honing stone to chamfer the corner of the repair sleeve(s).
A correctly honed surface will have a crosshatch appearance with the lines at 15° to 25° angles with the top of the cylinder block. For the rough hone, use 80 grit honing stones. To finish hone, use 280 grit honing stones.
Finished bore inside dimension is 102.020 ±0.020 mm (4.0165 ±0.0008 inch).
A maximum of 1.2 micrometer (48 microinch) surface finish must be obtained.
After finish honing is complete, immediately clean the cylinder bores with a strong solution of laundry detergent and hot water.
After rinsing, blow the block dry with compressed air.
Wipe the bore with a white, lint-free, lightly oiled cloth. Make sure there is no grit residue present. Apply a rust-preventing compound if the block will not be used immediately.
A standard diameter piston and a piston ring set must be used with a sleeved cylinder bore.