The Yamaha OX66 is a four-stroke, naturally-aspirated, 30-valve (five-valves per cylinder), V6 racing engine, designed, developed and built by Japanese manufacturer Yamaha, in 1984. Development history and background Yamaha Motor started development around 1980 as an engine development that leads to high performance. As a design concept, 1. High performance 2. Easy maintenance 3. Lightweight and compact 4. Wide power band And so on. In order to realize the above design concept, if F2 is a high-speed, high-performance engine, it was implemented as a project because it can be used in actual battles in domestic development. At the time of development, both BMW (in-line 4-cylinder) and Honda (V-type 6-cylinder) provided engines for F2, but Honda has achieved good results with high output with the V6 engine ( Honda RA264E ) despite limited supply. Therefore, the development proceeded to have an advantage over Honda. Participation in the race was carried out in partnership with Ken Matsuura Racing Service. The Fédération Internationale de l'Automobile (FIA) changed the category directly under F1 to Formula 3000 (F3000) in 1985, but the Japan Automobile Federation (JAF) announced that it will continue F2 for four years, so Yamaha announced the development of OX66. Then I decided to supply it to the market. Performance / technical specifications V6 engine, DOHC, 5 valve, naturally-aspirated, Bank angle: 75 degrees Inner diameter X stroke: x Maximum output: 330ps / 11000rpm Maximum torque: @ 9000rpm Weight: Fuel injection device: Electronically controlled fuel injection Engine overview Cylinder block In the racing engine V6 engine, compactness is prioritized over torque fluctuations in non-equidistant explosions. Yamaha emphasized compactness rather than Honda, and set the bank angle to the angle bank angle (75 degrees). In order to reduce the weight at the same time as making it compact, the cylinder block is cast from aluminum and the cam drive is made into a belt to thoroughly reduce the weight. A cast-iron wet liner is inserted into the aluminum block to prevent the deformation of the block from being directly transmitted to the inner surface of the cylinder. In addition, by using a wet liner, if the cylinder wears, only the wet liner needs to be replaced, achieving the goal of easy maintenance. Belt drive A belt drive is also used to drive the cam, achieving weight reduction, compactness, and easy maintenance. In the engine, a gasket is sandwiched between the cylinder block and the head,