Getting to Know Your Engine: Rocker Arms

How Rocker Arms Work in Semi-Truck Diesel Engines

Next up in our series on diesel engines, we'll be discussing rocker arms and how the function to help your engine move your vehicle. To help you learn more about commercial truck diesel engines, our team of experts have put together the following article on rocker arms. Read on to learn more about rocker arms.

What Does a Rocker Arm Do?

The rocker arm in a diesel engine is the component that transmits the movement of the camshaft towards the engine's intake and exhaust valves. This process happens through the direct contact of these parts with the tappets and the movement of the shaft.

The rocker arms have direct contact with the tappet at one end. At the other end, the intake and exhaust valves are coupled. When triggered by the camshaft cam, the rocker arm lowers one side, which opens the valve. This allows the mix of air and fuel to enter the combustion chamber. The displacement is held by a spring which forces the valves back to their original position.

What Holds a Rocker Arm in Place?

Rocker arms use a trunnion pivot with a nut that has a rounded bottom to hold position. This gives support to the rocker arm while allowing it to move up and down smoothly.

What Moves the Rocker Arm?

In a typical pushrod engine, the camshaft pushes the pushrod upwards. The top of the pushrod then presses upwards on one side of the rocker arm which is located at the top of the engine. This process causes the rocker arm to rotate.

How Do I Know If My Rocker Arm Is Worn Out?

There are several symptoms you can watch out for to determine whether you have bad rocker arms. Here are a few things to look out for:

1. Clicking noises: If you are hearing a clicking or ticking sound when you turn on the engine, it could mean that the rocker arm is stuck and isn't opening and closing the valves properly.

2. Weak engine performance: For an engine to function properly the vales have to open and close with precision timing. If your rocker arm is bad, the valves will not open correctly, and you will notice that the performance of the engine suffers.

3. Engine light: Today's diesel engines can find the weak spot in performance with their AI systems. These systems diagnose the engine and warn the driver with a light.

With broken or loose rocker arms, the exhaust valves and intake valves will not operate properly. The cylinder with the faulty rocker arm will no longer open and close the way it's supposed to. IN turn this will decrease the performance of your engine and your ability to drive your truck in way that is comfortable and safe.

Read More About Heavy-Duty Diesel Engines

Have you been researching diesel engines and the components that help make sure your vehicle runs smoothly? If so, then you have arrived at the perfect place! For those that have been looking up diesel engines, our team of experts have written the following articles. Click on any of the links below to read more about engine parts!

· Getting To Know Your Engine

· Getting To Know Your Engine: Camshafts

· Getting To Know Your Engine: Turbochargers

· Getting To Know Your Engine: Pumps

· Getting To Know Your Engine: Fuel Injectors

· Getting To Know Your Engine: Surge Tanks

· Getting To Know Your Engine: Flywheels

Shop Now For Heavy-Duty Diesel Engine Parts

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