The most common material used by Manton is 8620. A basic material used to manufacture gears. This material, when heat treated correctly, exhibits excellent wear properties and is very impact resistant. This 8620 material is used in most pushrod tip applications and has a surface hardness of approximately 62 Rockwell “C”. It can be used in conjunction with almost all rockerarm adjusting screws on the market today, of similar hardness.When using rockerarm adjusting screws made from harder and stronger materials such as H-13 tool steel or other grades of tool steel it is very common for the surface hardness to be in excess of 70+ Rockwell “C” after heat treating. In these applications we usually recommend using our H-13 tool steel pushrod tips. We are very particular about the heat treat characteristics of our tool steel pushrod tips and adjusting screws. Different material core values will produce slight hardness changes to the surface. The rule of thumb is that you always want the ball surface to be as hard or harder than the cup surface.
In some applications the use of proprietary hybrid copper alloy insert is utilized. This insert is pressed into a tool steel body. This copper alloy cup is used in conjunction with a tool steel ball adjusting screw. The reason we use this copper alloy material is because of its excellent coefficient of friction and superior lubricity characteristic. In the past few years the chemical makeup of engine oils has changed. This combined with the use of low viscosity oil has increased the issue of premature wear in applications such as Pro Stock, Super Stock, Comp Eliminator, Sprint Car, Etc. The copper alloy cup combination is extremely durable and reliable in this type of environment.