Starting in the early 1960’s, Osamu Okazaki set out on a mission to build high-performance Japanese race engines to compete with the championship-winning European offerings of the time. Armed only with a pure passion for motorsports and an innate ability to absorb information, he basically took things apart in his garage, figured out how they work, and designed improvements to increase performance. A self-educated man, he originally began working on motorcycles and eventually moved on to parts development for 4-wheel automobiles. Mr. Okazaki founded his company, OS Giken, in the early 1970’s with strength, durability, and the pursuit of high performance in mind; these goals for parts development remain true today and OS Giken has established itself in the upper-echelon for designing and manufacturing high quality, high performance, and supremely durable parts.
The TC16-MA2 twin cam head for Datsun L-series was designed in 1974 and successfully campaigned on the international rally and circuit racing scene; on the streets of Japan it ruled as king and was virtually untouchable. Producing 230+hp naturally aspirated (quite a feat for 4-cylinder engines in Japan during that time), a very limited number of units were produced to supply various Datsun race teams. The 6-cylinder version (TC24-B1) followed shortly thereafter, with a specific target of outperforming the fastest production car of the time, the Porsche 930 turbo. Featuring twin cams, pent-roof combustion chambers, and 24-valves., power output was in the 320+hp range (about double the power output of the OEM L28 motor).
With the amount of power the OS built motors were generating, no clutches available at the time were able to sufficiently transfer power down the driveline, so Mr. Okazaki took the initiative to analyze what was available and redesign something to improve performance and durability. The end result was the Racing Line of OS Giken clutches: smaller disk diameter, lighter assembly weight, increased durability/power capacity with decreased pedal pressure. OS clutches have since become a major part of the product lineup, with new improvements being developed and tested continually.
The next weak link for high performance applications proved to be the transmission, so once again OS set out to improve on components already available in the market. OS gear kits are designed to optimize the gear ratios for sports/race driving, but with the knowledge and experience garnered from years of manufacturing, power capacity also increased immensely, furthering OS’ reputation for producing extremely durable components.
As time passed and technology progressed, the need for a better limited-slip differential presented itself and once again OS set out on a mission to “build a better mousetrap”. The clutch-type LSD’s popular at the time served their purpose, but were commonly known to require regular maintenance/service, performed inconsistently, were noisy, and not comfortable for normal street driving. Just as he had done with engine, clutch, and gear development, Mr. Okazaki came up with a completely new design with the purpose of eliminating all the shortfalls of parts available at the time. The end result of his efforts resulted in the Lock Timing Control System and Spline-Through Side Gear designs, which were patented and implemented into the all-new Superlock LSD, a revolution in limited-slip technology that could offer all the benefits of a limited-slip differential without the shortfalls inherent with other products offered from competitors.
From Mr. Okazaki’s humble beginnings tinkering with motorcycle parts at home, OS Giken has evolved and grown over the years, building and cementing a reputation as one of the best racing drivetrain parts manufacturers in the world. Officially founded in 1973, the company headquarters and factory are located in Okayama, Japan. All OS Giken parts are 100% man
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