The result is an even better product that can withstand higher spring pressures and rpms.
High lift rocker arms also reduce the amount of lifter travel needed to open the valves, which reduces friction and the inertia of the lifters and pushrods that must be overcome by the valve springs to close the valves.īy analyzing the stresses and loads on rocker arms with fancy computer programs (finite element analysis), manufacturers are finding new ways to CNC machine out even more weight without sacrificing strength or durability. By opening and closing the valves at a faster rate, the engine flows more air for the same number of degrees of valve duration. Increasing the lift ratio adds horsepower with little or no loss in low rpm torque, idle quality or vacuum. If a higher lift ratio is used, even more power can be squeezed from the engine by increasing the effective lift of the camshaft. When the stock steel rockers are replaced with aluminum rockers, the same lift ratio will often add an extra 15 to 40 horsepower due to friction reduction alone. Most have needle bearing fulcrums and roller tips to minimize friction and wear. These include forged or billet aluminum rocker arms, titanium valve spring retainers, titanium valves, even titanium springs.Īluminum rocker arms typically provide some reduction in weight over stock stamped steel rocker arms, and increased durability. One way to trim weight is to replace steel valvetrain components with ones made from lighter materials such as aluminum or titanium. Consequently, you want the lightest possible parts that are still strong enough to handle the valve spring pressures and rpms the engine will generate. Yet if valvetrain components are lightened too much, it increases the risk of bending or breaking something.
So a weight reduction of 10 grams could theoretically add 350 to 400 more rpm to the engine with no other changes to the valvetrain (same springs, etc.). Less weight is almost always better because it lessens the load on the valve springs, and allows the engine to turn more rpms for more top end power.Įvery gram of weight reduction in the valvetrain adds 35 to 40 rpm potential to the engine. Weight is always a major factor to consider when choosing individual valvetrain components.
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