The camshaft is one of the key parts of the engine. The hardness of the tip of the camshaft and the depth of the white layer are the key technical indicators that determine the service life of the camshaft and the efficiency of the engine. Under the premise of ensuring that the cam has a sufficiently high hardness and a relatively deep white layer, it should also be considered that the journal does not have a high carbide, so that it has better cutting performance.
The main methods for producing camshafts at home and abroad are: the process of forming a martensite layer by high-frequency quenching of a cam tip portion after cutting by a steel forged blank. In the late 1970s, Germany and France successively developed a new process of camshaft argon arc remelting; another US-based hardenable cast iron camshaft; chilled cast iron camshafts based on Japan and France; and cams. The production process of casting the surface of the casting by Cr-Mn-Mo alloy coating.
In order to improve the engine's power, some modification shops have modified the camshaft of the engine. The replacement of the high-angle camshaft (Hi-CAM) is a common modification method. This modification operation is not complicated, but due to the lack of understanding of the working angle and working principle of the cam on the camshaft by some of the refitting personnel, the effect after the modification is not obvious or even deteriorates the performance of the engine.
The high-angle camshaft is relative to the cam operating angle of about 240° of the ordinary camshaft, and the cam working angle of the high-angle camshaft can usually reach 280° or more. The large angle camshaft can extend the valve opening time, increase the valve lift, and make the intake and exhaust valves open early and late, allowing more air to enter the cylinder to improve the engine's medium and high speed power. Output. For civil vehicles, the camshaft with cam working angle below 278° should be selected for modification, because the camshaft with working angle greater than 278° will greatly increase the valve overlap angle, which will increase the power of the engine at high speed, but the engine At low speeds, the idling speed is severely shaken or even extinguished due to poor cylinder sealing performance. Such a vehicle cannot be adapted to daily use and can only be used for competition purposes.