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Engine Inspection, Disassembly, and Cylinder Reconditioning
By: Ronald J. Oakley
Presentation Outline
• • • • • • • • Removal of engine from implement Inspection Pre Cleaning Disassembly Organization of Parts Assessment of Internal Parts Measurement of Internals Reconditioning of Surfaces
Engine Removal Steps
• 1. Locate mounting bolts for engine • 2. Detach implements (ie. Blades, clutches) • 3. Detach fuel lines if separate tank system • 4. Remove all necessary bolts. • 5. Pull engine
Engine Inspection
• Observe overall condition. • Check for :
– Loose or broken engine mounts – Major oil leaks – Disconnected wires – Cracks in engine case – Any other obvious sign of breakage
External Part Disassembly
• Remove grass, and other debris from accessible areas. • Remove:
– Starter assembly first – *gas tank and carburetor assembly ( be sure to remove gasoline; take note of linkage set-ups) – flywheel, and magneto – muffler, and any remaining brackets
Cleaning and Organizing
• Larger items can be placed aside in a cardboard box, or plastic pail. • Place all loose nuts and bolts into a seal able container. (ie. Ziplock bags)
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• Remove excess debris from the engine. • Clean engine with a safe solvent.
External Engine Disassembly
• Remove: • Head bolts and head. • Crankcase breather assembly. • Side cover
Internal Disassembly
• Remove rod nuts, and cap. • Push piston through top of cylinder
Crankshaft Removal
• Remove crankshaft from open area of case.
Cylinder Assessment
• Check cylinder for scoring. • Observe ring condition and placement, and piston condition.
Cylinder Measurement
• Take readings below ring travel area first. • Use a telescoping gauge to measure cylinder diameter. • Then take readings below the ridge.
Measurement
• *Be sure to turn gauge 90 degrees after each measurement. • Record findings for accuracy. • Check cylinder findings against manufacturer’s specifications.
Cylinder Reconditioning
• Three main Areas:
– Boring, and boring equipment. – Honing, equipment, and techniques. – Cylinder sleeves.
Boring a cylinder
• Reasons
– Returns cylinder to round, straight bore. – Produces a correct cylinder finish. – Performance!!!!!
Boring
• Cylinders bored or cut in increments. • Oversized from .010 up to .060 in some instances. • Restores lost compression. • Raises horsepower.
Boring Equipment
• Fits in milling machine. • Cutters
Cylinder sleeves
• Primarily used in aluminum engine blocks. • Constructed of cast iron. • Fully replaceable, and machine able.
Cylinder Honing
• Required after boring. • Finish made in cross-hatch pattern created by the motion of the hone. • Allows proper break-in of rings.
Summary
• Engine is removed from implement, or vehicle. • Thorough inspection. • External parts removed. • Head and other final parts removed • Piston, rod and crankshaft is removed.
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• Inside of cylinder is inspected for damage. • Cylinder is measured twice, at two locations. • Specifications are checked. • Engine is bored if necessary.
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