The Oval Piston Engine / 1979

The Challenge of Engineering: To Find the Very Best Technology

The Oval Piston Engine / 1979

A 4-stroke Engine: The Natural Choice for a Comeback

Honda returned to the 500 cc class of the World Motorcycle Grand Prix series in 1979, following a twelve-year hiatus. The machine they had developed for their comeback - an entry in the World Grand Prix's most prominent class - was the NR500, powered by a four-stroke, DOHC V-four engine. With its oval piston engine incorporating eight valves and two connecting rods per cylinder, plus an aluminum semi-monococque frame complete with an inverted front fork, the machine surprised everyone with its daringly innovative technologies.

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The oval piston engine (0X engine, developed in 1979) was a product of Honda's drive to conquer technical challenges.

"When I look back at it, I'm not sure if we were experimenting with cutting-edge technologies or obsessed with foolish ideas," recalled Toshimitsu Yoshimura, an engineer involved in the development of the NR500's oval piston engine.

"At least we were doing something that was beyond the realm of conventional thinking. I'm not just talking about us, who were designing the engine, but also those who were creating the body.

"The emphasis was to create a difference-not just any difference but the difference that would work to our definite advantage. That's why we decided that Honda should go with four-stroke engines. We wanted to achieve our target through innovative technology, and in so doing have the edge over our competition."

Road-racing circuits were in those days dominated by bikes with two-stroke engines. Despite this trend Honda went with its NR500 machines equipped with a four-stroke engine. That decision, however, wasn't so much a bold move as it was a natural choice.

During its first years in motorcycle racing - dating back to a memorable entry in the Isle of Man TT Race - Honda won event after event with four-cycle engines. They achieved so much success, in fact, that four-cycle engines came to be thought of as a Honda specialty. Though two-stroke engines had the benefit of relatively higher output, nobody could stop Honda from wanting to develop four-stroke engines capable of producing even greater power. In that regard, the conventional thinking proved somewhat contrary at Honda. In fact, competing in the TT race was in every perspective an extraordinary decision.

Adding to the Honda preoccupation with four-stroke engines was the fact that many in top management, who had decided to make a comeback in the World Grand Prix series, and those involved in the development, were imbued with the philosophies of Soichiro Honda, who had criticized two-stroke engines as being little more than "bamboo tubes." To them, it was simply out of the question to reclaim their victory with anything less than a four-cycle engine.

Yoshimura, who had actually designed the engine, was from the very beginning a staunch advocate of the four-cycle approach. "Four-stroke engines," he said, "have distinctive mechanical processes. The (intake) valve closes tight, combustion occurs, the exhaust valve opens, and the exhaust is released. It's a sequence of independent processes, each with a different function, working together to facilitate the engine's entire operation. This is really fascinating, from an engineering standpoint. I believe this mechanism will be the basis of further advancement in engine technology."

Afterall there is no point in participating in a race if one isn't confident of victory. However, that confidence must come from hard work and the determination to stay the course through thick and thin. No matter how difficult the journey, one must continue as long as there is the slightest possibility of a positive outcome. It is in this very struggle that the value of one's endeavor exists. Honda engineers recognized how difficult the process could be, but ultimately they also knew success would be gratifying. Thus, the development team's decision to return to glory with four-stroke engines was most appropriate.

The Challenging Spirit of Honda

A System that Fosters Expertise
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  2. The R&D Center Goes Independent / 1960The R&D Center Goes Independent / 1960
  3. Employing the "My Record" Project and Expert Certification  / 1960Employing the "My Record" Project and Expert Certification / 1960
A Dream Come True: Car Builder for the World
  1. A Dream Come True: Car Builder for the WorldA Dream Come True: Car Builder for the World
  2. Launching the S360 and T360 / 1962Launching the S360 and T360 / 1962
  3. Entering the Auto Market at Last / 1966Entering the Auto Market at Last / 1966
  4. Introducing N360 / 1967Introducing N360 / 1967
  5. Launching the Honda 1300 / 1968Launching the Honda 1300 / 1968
  6. Introducing the CVCC / 1972Introducing the CVCC / 1972
  7. Announcing the Civic / 1972Announcing the Civic / 1972
  8. Introducing the Accord / 1976Introducing the Accord / 1976
Marketing Globally, Producing Lacally
  1. Marketing Globally, Producing LocallyMarketing Globally, Producing Locally
  2. Establishing American Honda Motor Co. / 1959Establishing American Honda Motor Co. / 1959
  3. Establishing Belgium Honda / 1963Establishing Belgium Honda / 1963
  4. Establishing Honda of America Manufacturing / 1980Establishing Honda of America Manufacturing / 1980
A Refreshing New Development
  1. A Refreshing New DevelopmentA Refreshing New Development
Products Emerging From Technology and Innovation
  1. Products Emerging From Technology and InnovationProducts Emerging From Technology and Innovation
  2. The Oval Piston Engine / 1979The Oval Piston Engine / 1979
  3. The Hondamatic Transmission / 1968The Hondamatic Transmission / 1968
  4. The Car Navigation System / 1981The Car Navigation System / 1981
  5. The Airbag System / 1987The Airbag System / 1987
  6. Four-Wheel Steering System (4WS) / 1987Four-Wheel Steering System (4WS) / 1987
  7. The VTEC Engine / 1989The VTEC Engine / 1989
  8. The ME Engine (G100 / 150 / 200 / 300 / 400 Series) / 1977The ME Engine (G100 / 150 / 200 / 300 / 400 Series) / 1977
  9. The ZE Engine (GX110 / 140 / 240 / 270 / 340 Series) / 1983The ZE Engine (GX110 / 140 / 240 / 270 / 340 Series) / 1983
  10. The Dream CB750 FOUR / 1969The Dream CB750 FOUR / 1969
  11. CG125 / 1975CG125 / 1975
  12. Road Pal / 1976Road Pal / 1976
  13. City / 1981City / 1981
  14. The NSX / 1990The NSX / 1990
  15. Odyssey / 1994Odyssey / 1994
  16. Honda EV Plus: The Dream of an Electric Vehicle / 1988Honda EV Plus: The Dream of an Electric Vehicle / 1988
  17. The E300 Portable Generator / 1965The E300 Portable Generator / 1965
  18. The HR21 Lawn Mower / 1978The HR21 Lawn Mower / 1978
  19. The F200 "Komame" Mini-Tiller / 1980The F200 "Komame" Mini-Tiller / 1980
Production Technology: The Essence of Creative Manufacturing
  1. Production Technology: The Essence of Creative ManufaturingProduction Technology: The Essence of Creative Manufaturing
  2. Establishment of Honda Engineering / 1974Establishment of Honda Engineering / 1974
  3. The World's Smallest Welding Line / 1982The World's Smallest Welding Line / 1982
  4. Transfer Lines for Modular Components / 1981Transfer Lines for Modular Components / 1981
  5. An Automated Line for Painting and Coating / 1988An Automated Line for Painting and Coating / 1988
A Neverending Passion for Racing
  1. A Neverending Passion for RacingA Neverending Passion for Racing
  2. Completion of Suzuka Circuit / 1962Completion of Suzuka Circuit / 1962
  3. Returning to the World Motorcycle Grand Prix / 1979Returning to the World Motorcycle Grand Prix / 1979
  4. Formula One Entry: The Initial Phase / 1964Formula One Entry: The Initial Phase / 1964
  5. Formula One Entry: The Second Phase / 1983Formula One Entry: The Second Phase / 1983
  6. Entry to Champ Car Racing / 1994Entry to Champ Car Racing / 1994
  7. The Birth of Twin Ring Motegi / 1997The Birth of Twin Ring Motegi / 1997
Creativity - The Way to Work Harder, Play Harder
  1. Creativity – The Way to Work Harder, Play Harder Creativity – The Way to Work Harder, Play Harder
  2. Holding All Honda Idea Contests / 1970Holding All Honda Idea Contests / 1970
People and Society Coexisting in Harmony with Nature
  1. People and Society Coexisting in Harmony with NaturePeople and Society Coexisting in Harmony with Nature
  2. Establishment of Honda Taiyo, Kibo-no-Sato Honda and Honda R&D Taiyo / 1992Establishment of Honda Taiyo, Kibo-no-Sato Honda and Honda R&D Taiyo / 1992
  3. Creating Hometown Forests / 1977Creating Hometown Forests / 1977
  4. Hosting "Orei-no-kai" / 1991Hosting "Orei-no-kai" / 1991

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