What Causes A Push Rod To Bend- Learn & Make Your Engine Safe!

By: James Diaz | September 3, 2022

What Causes A Push Rod To Bend

A bent push rod is a serious engine problem that can cause significant damage. It’s important to understand the factors contributing to pushrod bending so you can take steps to prevent it.

In this article, I’ll discuss all the causes of why a push rod bends and some tips for making your engine safe. Stay tuned!

What’s A Pushrod?

A pushrod is a simple but essential mechanical component in many engines, particularly older ones. Its job is to act as a link between the camshaft and the valves. 

The camshaft is a shaft with cams (lobes) that opens and closes the engine’s valves. The pushrod sits at the end of the camshaft and transfers the motion to the valves via the rocker’s arms.

How Do Pushrods Work?

Pushrods are simple, effective, and relatively inexpensive, making them a popular choice for many engines. It is the effective mechanism to transfer motion from the cam to the rockers, which open the valves.

Here’s a quick rundown of how pushrods work:

  • The cam is mounted on the engine block and has lobes that open and close the valves.
  • The pushrod sits in a guide sleeve and is connected to the rocker’s arm.
  • As the cam lobe rotates, it pushes on the pushrod, opening the valve.
  • The pushrod is also responsible for returning the valve to its closed position.
  • When the engine runs, the pushrods constantly move up and down, opening and closing the valves hundreds or thousands of times per minute.

How Does A Pushrod Get Bent?

There are a few ways, but the most common is from an engine valve spring that has too much preload.

Overloaded Engine Valve Spring

The most common way is from an engine valve spring with too much preload. The preload is the tension on the spring when it is at rest. When an engine is running, the valves are constantly opening and closing, which puts a lot of stress on the valve springs. If the preload is too high, it can cause the pushrod to bend.

When Pushrod Hits Something Hard

Another way that a pushrod can get bent is from an impact. If the pushrod hits something hard, it can bend. This is usually caused by a rock or piece of debris hitting the pushrod while the engine is running.

Bent From Fatigue

Finally, a pushrod can get bent from fatigue. This is when the metal of the pushrod wears out from being used too much. Fatigue can happen over time or from a sudden shock, like an impact.

Also Read: Duramax Reduced Engine Power Reset

6 Symptoms Of The Bent Pushrod 

The purpose of the pushrod in an internal combustion engine is to actuate the valves. The pushrod is a relatively simple component, but it’s essential to the engine’s proper functioning.

There are a few different ways that a bent pushrod can occur. It can be caused by something as simple as an errant rock hitting the pushrod, or more serious engine issues can cause it.

6 Symptoms Of The Bent Pushrod

1. Engine Misfires

When a pushrod is bent, it might cause the engine to misfire. The pushrod’s ability to operate the valves is crucial to the efficient air and fuel intake into the cylinders. The engine will start to misfire as a result of this.

2. Rough Idle

A harsh idle is another sign that your pushrod is bent. The engine won’t be able to maintain a steady idling temperature if the pushrod isn’t opening and closing the valves properly. The car’s engine might stall as a result.

3. Poor Fuel Economy

Your fuel efficiency may suffer if the engine cannot perform as well as it should. This is because, without a properly working pushrod, the engine cannot burn gasoline as effectively as it might.

4. Engine Knocking

Another symptom of a bent pushrod is engine knocking. This is caused by the valves not opening and closing as they should. If the valves cannot seal properly, the air/fuel mixture will escape and cause the engine to knock.

5. Reduced Engine Power

If the pushrod has been twisted in any way, it will not be able to operate the valves as efficiently as it should be. Because of this, the power output of the engine will be diminished. Additionally, the engine can have a choppier performance than typical.

6. Excessive Engine Noise

When the pushrod is bent, it might create excessive noise from the engine. This is because the valves are not correctly sealed, which allows exhaust gases to leak out of the vehicle.

If you suspect a bent pushrod, it’s important to have the problem fixed as soon as possible. A bent pushrod can cause serious engine damage if it’s not fixed.

When Should You Replace A Pushrod?

Pushrods are one of the most important components in your engine, and they need to be replaced from time to time. But how often should you replace them?

Classification of Engine

The frequency with which your pushrods require replacing depends on several variables. The first factor is the powertrain of your vehicle. Pushrods should be replaced more often in high-performance engines than in standard ones.

When Should You Replace A Pushrod

The Mechanical Age

The frequency with which you use your engine is a second consideration. You will need to change your pushrods more often if you use your engine for racing or other high-performance applications than if you merely use it for daily driving.

Condition of your engine

Your engine’s condition is the third consideration. Pushrods wear out more quickly and require replacing more often in older engines than in modern ones.

Finally, When To Replace it?

Pushrods should be replaced every 20,000 to 30,000 miles for a high-performance engine and every 50,000 to 60,000 miles for a stock engine.

However, if you use your engine for racing or other high-performance applications, you should replace your pushrods every 10,000 to 15,000 miles. If you have an older engine, you should replace pushrods every 5,000 to 10,000 miles.

Finally, When To Replace it?

Can I Prevent Pushrods From Being Bent?

Yes, there are ways that you can prevent your pushrods from being bent. Some of these methods include:

  1. Inspect your pushrods regularly.
  2. Be careful when handling your pushrods.
  3. Store your pushrods in a safe place.
  4. Use pushrod covers or guards when necessary.
  5. Replace your pushrods if they become damaged.
  6. Do not use damaged pushrods.
  7. Do not use bent pushrods.
  8. Follow the manufacturer’s instructions when using pushrods.

If you take these precautions, you can help to prevent your pushrods from being bent.

Can I Prevent Pushrods From Being Bent?

How Can I Fix A Bent Pushrod?

Do you have a car with a bent pushrod? Here are 4 ways how you can fix it!

1. Check The Pushrod Length

The first thing you need to do is to check the pushrod length. If the pushrod is too long, it will cause the rocker arm to bind. This will eventually lead to a bent pushrod. To fix this, you need to shorten the pushrod by about 1/8 inch.

2. Check The Rocker Arm Geometry

The next thing you need to check is the rocker arm geometry. If the geometry is off, it will cause the pushrod to bind. This will eventually lead to a bent pushrod. To fix this, you need to adjust the rocker arm geometry.

3. Check The Valve Clearance

Another thing you need to check is valve clearance. If the clearance is too small, it will cause the pushrod to bind. This will eventually lead to a bent pushrod. To fix this, you need to increase the valve clearance.

4. Check The Lash Adjuster Height

The last thing you need to check is the lash adjuster height. If the height is too low, it will cause the pushrod to bind. This will eventually lead to a bent pushrod. To fix this, you need to raise the lash adjuster height.

These are the most common ways how to fix a bent pushrod.

Can You Replace A Bent Rod?

If your fishing rod has a bent tip, you may wonder if it can be replaced. The answer is yes, but the process is a bit more complicated than buying a new rod.

Here are the steps you’ll need to take to replace a bent rod:

  1. Find a replacement rod of the same length and weight as your old one.
  2. Cut the old rod to the point where it is bent.
  3. Remove the guides from the old rod.
  4. Install the guides on the new rod.
  5. Attach the new rod to your reel.

Now you’re ready to fish with your new rod! Just remember to be careful not to bend it again.

Cost Of Replacing A Pushrod?

The cost of replacing a pushrod will vary depending on the make and model of your vehicle. Generally speaking, replacing a pushrod will cost between $200 and $400. 

However, the cost could be much higher if you have a luxury vehicle or one that is very difficult to work on. Always consult with a certified mechanic before attempting to replace a pushrod on your own.


Video Ref:

  1. https://www.youtube.com/watch?v=n6Y44K_HMjM
  2. https://www.youtube.com/watch?v=VagLgQVKGKs