Cylinder Bore Measurement
Inspection
Measure cylinder bore diameter at three positions; top, middle, and bottom. At these three positions, measure in both directions; along crankshaft center line and direction of crankshaft rotation.
All Models Cylinder Roundness and Taper
→NOTE:
If engine has had a previous major overhaul, oversize pistons and rings
may have been installed.
– If cylinder bore exceeds wear limit, replace cylinder block or have cylinder rebored. (See Rebore Cylinder in this Group.)
– If cylinder is rebored, oversize pistons and rings must be installed. Pistons and rings are available in 0.25 mm (0.010 in.) oversize.
– If clearance (cylinder bore ID minus piston OD) exceeds specification, replace cylinder block, piston or both; or rebore cylinder and install oversize piston and rings.
Deglazing
IMPORTANT:
If cylinder bores are deglazed with crankshaft installed in engine, put clean shop towels over crankshaft to protect journal and bearing surfaces from any abrasives.
– Deglaze cylinder bores using a flex-hone with 180 grit stones.
– Use flex-hone as instructed by manufacturer to obtain a 30—40° crosshatch pattern as shown.
IMPORTANT:
Do not use gasoline, kerosene, or commercial solvents to clean cylinder bores. Solvents do not remove all abrasives from cylinder walls.
Remove excess abrasive residue from cylinder walls using a clean dry rag. Clean cylinder walls using clean white rags and warm soapy water. Continue to clean cylinder until white rags show no discoloration.
