31. By the mid-1990s, the spin valve head using an exchange-bias layer was well on its way to displacing the AMR head. 32. It had a single overhead cam and eight-valve head , and was fitted to Civics in all markets aside from North America. 33. Most road cars used an 8-valve engine, though five Type 13 racers had 16-valve heads , one of the first ever produced. 34. The first idea of using a 2.0-litre engine and then using the 16-valve head from Cosworth simply did not give enough power. 35. A destroked FE at 77mm, the F8 comes in several configurations including a 12-valve head and fuel injection later in its life. 36. The 350X featured a 26-horsepower air and oil cooled 350 cc four-stroke engine with a 4-valve head ; impressive technology for the time. 37. It solved the power dilemma by borrowing superbike technology and giving the YZ a five-valve head , liquid cooling and a 12.5-1 compression ratio. 38. The 3.6 was the first AJ6 engine, debuting in 1983 on the XJ-S . It had DOHC 4-valve heads with a bore and stroke. 39. It was quite advanced in some ways, using hydraulic disc brakes both at the front and back as well as a 6 valve head . 40. Capable of 70 mph, the four-valve head allowed more efficient gas flow and the spark plug could be positioned in the middle for optimum combustion.
