HIGH-OUTPUT SMALL-DISPLACEMENT TWO-STROKE ENGINES

Approaches taken by manufacturers and independent engine developers over the past 20 years are reviewed in converting lightweight, air-cooled, reed-valved, chain-saw type, two-stroke engines into high-output competition motors for powering small vehicles for recreation, sports, and organized racing. Increasing small two-stroke engine output has entailed solving problems associated with their high rpm potentials, reed and rotary-valve induction systems, cylinder and piston ports, crankcase induction, anti-friction bearing cranktrains, air cooling, and fuel-lubricant combustion. Developing modification routines for the small two-stroke engines has involved techniques differing considerably from those used in boosting output of small four-stroke engines. Manufacturers and competition engine developers have used high-strength, anti-fatigue, and anti-corrosive aerospace type alloys, and advanced metallurgical treatment techniques. They have also investigated induction-exhaust acoustic tuning effects, novel carburetor designs, new type spark plugs, ring and rod innovations, radical high-rpm anti-friction bearing designs, new synthetic lubricants, special alcohol racing fuels, improved engine cooling methods, ultra-high-strength fastener designs, and crankcase tolerances in thousandths of an inch. Some of these approaches are applicable to four-stroke engines. Appended are a list of SAE paper numbers on two-stroke engines and illustrations of engines and components.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/01487191
• Supplemental Notes:
  • Presented at SAE Off-Highway Vehicle Meeting and Exposition, Milwaukee, Wisconsin, 11-14 September 1978.
• Corporate Authors:

  Society of Automotive Engineers (SAE)

  400 Commonwealth Drive
  Warrendale, PA  United States  15096
• Authors:
  • POWELL, T
• Publication Date: 1978

Media Info

• Features: References;
• Pagination: 23 p.
• Serial:
  • SAE Technical Paper
  • Publisher: Society of Automotive Engineers (SAE)
  • ISSN: 0148-7191
  • EISSN: 2688-3627
  • Serial URL: http://papers.sae.org/

Subject/Index Terms

• TRT Terms: Alcohol fuels; Alloys; Design; Synthetic crude oil; Two stroke cycle engines
• Old TRIS Terms: Synthetic oils
• Subject Areas: Design; Energy; Safety and Human Factors;

Filing Info

• Accession Number: 00399001
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: SAE 780737, HS-025 569U
• Files: HSL, USDOT
• Created Date: Aug 31 1985 12:00AM