The technology of valve has made great progress in the past few years, the main change is the progress of materials and the improvement of precision.
High efficiency of intake, exhaust, environmental regulations, the requirements of the valve, are well-made. The principle of valve modification is to reduce the weight of the valve as much as possible without affecting the strength. Action-accurate valve is the basic elementof of high-performance engine, professional modification plant usually provides different valve combinations for consumers to choose from, the more engine installation items valve mechanism accuracy requirements are more critical, so the valve must be set up with the camshaft and valve rocker arm.
The original valves usually have the right material and size, but can be moderately replaced with larger or smaller sizes if necessary. The material of the valve is very important, the current modification of the valve is usually used titanium alloy as a material for the strength of the promotion and lightweight requirements, but a set of titanium alloy valve price is not low.
Some are the back of the valve cutting or the design of hollow to achieve the purpose of lightweight, and sometimes the valve surface into a vortex shape, in order to benefit the valve when the flow of gas. The heat of the valve can be transmitted through the valve seat when in contact with the valve seat to achieve the purpose of heat dissipation, is the most important cooling way of the valve. Therefore, the configuration of the valve holder must be very careful, if too close to the edge of the valve or the edge of the valve too thin may result in poor tightness. In addition, the precision and surface smoothness between the valve sleeve and the valve, the surface accuracy between the valve rocker arm and the valve holder (Keeper) must be strictly required or serious damage will be caused at high speed. The strength setting of the valve spring must be just right, to take into account the tightness of the valve and can not cause difficulties when opening, if the spring strength is too large so that the camshaft open valve when the load is too heavy for the horsepower output is very unfavorable.
The valve's fixing seat is also a potential problem, and the device is a clamp that holds the spring to the valve rod, which can cause distortion or break on engines with rapid acceleration and high head, and therefore must also be made with changes. The original valve rocker arm in the engine speed limit increase and valve timing change will become inadequate demand, for the modified engine for the reinforced valve rocker arm is necessary, the lift too large camshaft will cause the valve rocker arm distortion, so the strength of the increase and lightweight are necessary. For the general valve, the drum-type rocker arm reduces the pressure on the surface in contact with the valve seat and can also withstand higher pressure from the pushrod. Usually if the valve rocker arm has a sleek surface and rolling bearings, it will cause the friction resistance to be less when running, the smaller the friction altimed, the less power consumed.