What Is The Rocker Arm Ratio?

The Rocker arm ratio is the length of the valve divided by the length of the Pushrod side of the rocker arm to the centre. Since the valve side is usually longer than the pushrod or the Rocker Ratio generates cam side, the Rocker Arm’s motion.

How Rockers Add Power To Engine

The cam’s lobe lift is mechanically multiplied by the rocker arm. The valve stem tip is moved closer to the fulcrum pivot point than the pushrod. When the ratio is increased to 1.6, the valve or rocker arm stud cannot be moved, and the pushrod cup must be moved closer to the pivot centerline.

3 Ways To Increase Engine Power

Rocker arms are one of the most stressed and vital components in your engine. They are responsible for conveying movement from the camshaft lobes to the valves, making them an essential component in the power generation of your engine. To get more horsepower, you may make three essential adjustments or enhancements to your rocker arms.

  • Increase Rocker Arm Ratio

You may efficiently boost valve lift without replacing your camshaft by raising the rocker arm ratio in this calculation. The amount of power-building airflow entering the engine is determined by valve lift, which informs us how much the valves are opening. Follow rocker arm manufacturers in India‘s recommendations when picking a rocker arm ratio to minimise any clearance concerns and guarantee your other valvetrain components are appropriate to your desired valve lift.

  • Make The Rocker Arms Stiffer

Flexing at the rocker arm’s installation point might result in power loss. The energy is transmitted to the valves slower due to Deflection or undesired movement inside the rocker arm. Steel is less prone to flex and is usually more robust than aluminium; nevertheless, it is heavier, so there is a trade-off. Changing the installation location is another technique to strengthen up your rocker arms. Most rocker arms are placed on studs, and bigger diameter screw-in type studs may enhance stiffness.

  • Decrease The Moment Of Inertia

The more valve spring pressure it takes to operate the rocker arm instead of the valves, the greater the moment of inertia measurement. As a result, rpm and potential horsepower are lost. You may reduce the moment of inertia by reducing the weight of the rocker arm, especially in locations away from the trunnion. This may be accomplished by decreasing bulk from less crucial rocker locations or by employing a lighter material.

Installation Issues


  • Frequent Change Of Pushrod Length

Adjusting rocker arms frequently necessitates changing pushrod lengths, depending on the design of the rockers. The geometry of the valvetrain is determined by the position of the rocker arm on the stud with stud-mounted rockers.

  • Increased Friction

The tip of the rocker arm will be centred on the tip of the valve stem when the pushrod is the suitable length for the application. The tip of the rocker will be displaced towards the outside or inside of the valve stem if the pushrod is excessively long or short rather than centred over it. This might result in side stresses on the valve stem, which increases friction and wear on the stem and guides.

Many rocker arm manufacturers in India now provide Chromoly steel rocker arms to bridge the gap between the advantages of steel and aluminium. The Chromoly steel material is more vital than standard stamped steel rockers while also weighing less—then it is the best of both worlds.


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