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OS Giken - Behind The Scenes

The Inner Workings Of One Of Japan's Most Well-Respected Tuning Companies

Dino Dalle Carbonare
Jan 22, 2010

In order to finish first, you must first finish the race." This is a motto Okazaki-san of OS Giken has built his successful company around. Back in the 1970s preparing your car for racing in Japan was close to impossible because quality parts were so hard to find. People thought that extracting more power from their engines was synonymous with success, but failures to drivetrain components-not driver skill-were the determining factor in deciding who would win and who would lose the race. Okazaki-san saw an opportunity and took it, dedicating his life to developing and producing some of the most sought-after components in Japan. To find out more about OS Giken, we met up with Okazaki-san and his staff at the company's HQ outside Okayama City in the south of Japan.

Modp_1002_01_o+os_giken_tour+store_front Photo 2/17   |   OS Giken - Behind The Scenes

Talking to the brains behind such a respected name in the automotive world is always intimidating, but this meeting with the Shacho (boss) couldn't have been better. As soon as we arrived, we got down to business, and it was obvious that even after so many years in the game Okazaki-san still has an outstanding passion for the products he creates. He talks with an assertiveness that commands respect from the people around him, but at the same time manages to create a family-type atmosphere within his workforce, something that is rarely seen within the extremely formal (most of the time) setting of a Japanese company.

Modp_1002_02_o+os_giken_tour+limited_slip_differential_clutch Photo 3/17   |   OS Giken - Behind The Scenes

The enthusiasm as he explains the general theories behind components like limited-slip differentials and sequential gearboxes is awe-inspiring, and I'm convinced that given enough time he would go on all day long. OS Giken values reliability as a top priority when creating its products, and some of the things we were first shown were the internal parts of a clutch and LSD that had been tested for more than 100,000 miles. Comparing them to equivalent products from other manufacturers also subjected to the same test, it was obvious that OS Giken parts were superior, showing a fraction of the wear and tear as their competition. Okazaki-san is especially proud of the Super Lock LSD (developed in three specific specs), the top-of-the-line item being impressively smooth and silent during operation thanks to specially grooved and drilled plates that provide optimal lubrication. He runs one in his Nissan Fuga (Infiniti M45) and even takes us out to feel for ourselves just how quiet it is!

Modp_1002_03_o+os_giken_tour+sequential_transmission_gears Photo 7/17   |   OS Giken - Behind The Scenes

Okazaki-san is always open to new challenges, which is why the company dedicates a lot of its time to one-off custom projects. These span from motorsport teams requiring tough components to deal with the rigors of racing, all the way to private customers trying to improve their import cars. One of the last custom LSDs the company created was for a Mercedes Benz C63 AMG.

Next up was a tour of the factory where some OS Giken components are built. On one side of the main factory floor, components arrive from the foundry ready to be machined like the forged ring billets, which will be turned into precise cogs for its gearbox kits. We were shown the full R33 Skyline GT-R close-ratio transmission upgrade, as well as the lightweight clutch fork for a JZA80 gearbox.

Modp_1002_09_o+os_giken_tour+nissan_kouki_s14 Photo 8/17   |   Much like every shop in Japan, space is at a premium, so it's common to have a workshop and office in one area.

Most of the downstairs of the building houses the vast parts warehouse, where everything from replacement clutch plates and gear sets to camshafts and pistons are organized by car type on the tightly stacked shelves. We were taken to the special projects workshop where an R34 GT-R sequential transmission had just been put together ready to be dropped into the OS Giken branded aluminum housing.

We spotted an old classic Alfa Romeo GT in a dark corner of the garage, its engine in pieces on the workbench ready to be fitted with custom internals created by OS Giken. Despite specializing in drivetrain parts, OS Giken also produces a variety of engine components, the most well-known being the 3.0-liter stroker kit for the RB26. We were shown the specially counterweighted and treated crankshaft, connecting rods and pistons that make up the kit as well as the prepped block. The RB26 cast block is fitted with a top plate that extends the cylinder bore to increase the stroke, this brand-new kit now increasing capacity to an incredible 3.15-liter from the stock 2.6-liter.

Modp_1002_14_o+os_giken_tour+grinding Photo 12/17   |   You won't find many manufacturers using skilled tradespeople or taking this much care into their products.

The tour ended in the machine shop, where parts like clutch discs and gearbox housings were finely modified before being assembled. We walked past one machine, which was busy grinding an RB26 camshaft into shape, programmed with the preset settings for the specific cam lobe design. This is also the place where OS Giken pistons are created, and again there are stacks of custom orders being processed-even motorcycle pistons.

Okazaki-san has created countless one-off pistons for applications in racing as well as street use, like the twin-turbo Ferrari 550 Maranello Garage Saurus built a few years ago. With OS Giken offering unparalleled quality and thoroughly tested components, it's no surprise that when you want top-of-the-line products, Okazaki-san is the man you need to speak to. We would like to thank all the crew at OS Giken for being such a great bunch during our tour and showing us why OS Giken products are the best around.

Modp_1002_07_o+os_giken_tour+transmission Photo 15/17   |   OS Giken - Behind The Scenes
By Dino Dalle Carbonare
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