Manton Pushrod Tips are precision CNC machined in-house, guaranteeing quality control and versatility. Our most common tip material is 8620 bearing steal and is used because of its wear resistance. We carefully heat-treat, and temper our tips to maximize their wear properties and impact resistance. This makes the 8620 material suitable for use with nearly all rocker arm adjusting screws, excluding those made of tool steel (like the ones we offer).
For applications requiring even greater durability, we offer H-13 tool steel pushrod tips. These are meticulously heat-treated, triple tempered, and salt bath nitrided, ensuring extreme surface hardness. Such tips are typically paired with tool steel rocker arm adjusting screws due to their compatibility in hardness.
We meticulously monitor the heat treat characteristics of our tool steel pushrod tips and adjusting screws, as different core values can slightly alter surface hardness. The general principle is to maintain the ball surface as hard or harder than the cup surface for optimal wear and performance.
Additionally, we provide two designs of our unique copper alloy inserted tip for .281, 5/16 and 3/8 ball adjusting screws: a radius cup and a v cup. These hybrid copper alloy inserts, pressed into a tool steel body, offer outstanding lubricity and a low coefficient of friction. This is particularly beneficial in high-wear environments like Pro Stock, Super Stock, Comp Eliminator, and Sprint Car racing, being especially advantageous with recent changes in engine oil compositions and the use of low viscosity oils.
When considering pushrod column strength there are two main things we want to ask. First how strong does my pushrod need to be? And second, What factors can we change to make the pushrod column stronger.
This first question is a hard one to answer as their isn’t a clear marker to know when your pushrod is “strong enough”. There are however a few major factors that increase the need for a stronger pushrod, being: spring pressure, rocker arm ratio, the aggressiveness of the camshaft, and the pushrod angle. The spring pressure refers to the force exerted by the valve springs. Higher spring pressure demands more strength from the pushrod to resist the forces trying to compress it. This is amplified by the rocker arm as its ratio multiplies the spring force being channeled through it. Furthermore, the aggressiveness of the camshaft, in conjunction with the RPM increase the dynamic loads on the pushrod. lastly and often not considered, the pushrod angle. Increasing the angle of the pushrod increases the amount of load that the pushrod has to support. This is because the pushrod can only push along its axis so if the lifter isn’t in line with the pushrod it also has to add a sideways force to make it so that it pushes directly up the pushrod.
To address the second question regarding enhancing pushrod column strength, several factors can be modified, including diameter, wall thickness, heat treatment, and taper. When narrowing down which factors to use, you will generally want to first select the largest diameter pushrod that fits. Then, increase the wall thickness until you believe the pushrod has adequate strength. If you still do not think the pushrod is strong enough with the thickest wall, we can perform an additional heat treatment on the tube to increase its strength. If more strength is needed and the diameter of your pushrod is limited at one or both ends, we can taper the pushrod, reducing the outer diameter only where necessary. As a last resort, and if you do not require through-oiling in your pushrod, we can upgrade the material of the pushrod to S-7 tool steel, providing ultimate rigidity and impact resistance.
V-CUP DESIGN
The V-Cup design was the original answer to a major fit problem that started to become an issue as the rockerarm ratios approached 2 to 1. The lack of working room between the rockerarm body and the pushrod had been reduced to the point where it became necessary to decrease the adjusting screw ball diameter and the problem was solved. Several other problems then appeared mainly because of the very small contact ring in the pushrod end. We have made a few small changes that have shown excellent results.
Copper Radius Cup Advantages
The increased surface area in the Copper Radius Cup provides several advantages:
- Reduced heat generation = Improved reliability.
- Reduced surface loading = Resulting in extended service life.
- Depth of engagement = Reduces the possibility of damage during valve train surge.
- Overall design = Durability and cost effective.
- Longer hydrodynamic wedge = Cooler running temperature.
This style Pushrod end is most commonly used in the following applications:
- Pro Stock, Competition Eliminator, Pro Mod, Super Stock.
- Pulling Trucks and Tractors.
- Sprint Cars.