Cam (for cam shaft)

Descripción del producto

• NEPs products are produced by Powder metallurgy manufacturing process.
• Powder metallurgy manufacturing process: Process of filling metal powder of which average particle size is **0㎕ in a mold having a shape of desired part, molding with a press, and sintering at the metal melting point or less.

The camshaft "lift" is the resultant net rise of the valve from its seat. The farther the valve rises from its seat the more airflow can be provided, which is generally more beneficial. Greater lift has some limitations. Firstly, lift is limited by the increased proximity of the valve head to the piston crown and secondly, greater effort is required to move the valve springs to a higher state of compression. Increased lift can also be limited by lobe clearance in the cylinder head casting. Higher valve lift can have the same effect as increased duration where valve overlap is less desirable.

Higher lift allows greater airflow; although even by allowing a larger volume of air to pass thru the larger opening, the brevity of the typical duration with a higher lift cam results in less airflow than with a cam with lower lift but more duration, all else being equal. On forced induction motors this higher lift could yield better results than longer duration, particularly on the intake side. Notably though, higher lift has more potential problems than increased duration, in particular as valve train rpm rises which can result in less efficient running or loss of torque.

Cams that have excessive valve lift, running at high rpm, can cause what is called "valve float", where the valve spring tension is insufficient to keep the valve following the cam at its apex. This could also be a result of a very steep rise of the lobe, where the valve is effectively shot off the end of the cam rather than following the cams profile. This is typically what happens when a motor over revs. This is where the engine rpm exceeds the maximum design rpm. The valve train is typically the limiting factor in determining the maximum rpm the engine can maintain either for a prolonged period or temporarily. Sometimes an over rev can cause engine failure when the valves become bent as a result of colliding with the piston crowns.