How to Adjust Valve Lash On Chevy 350

Adjust valve lash on Chevy 350 – As a proud owner of a Chevy 350, you know that it’s a true workhorse that’s built to last. But to keep it running at its peak performance, you need to roll up your sleeves and get your hands dirty.

One of the most critical maintenance tasks you can perform is a valve lash adjustment on a Chevy 350 adjusting the valve lash, which can have a huge impact on your engine’s power, fuel efficiency, and longevity. Neglecting this vital task could leave you stranded on the side of the road or facing costly repairs down the line. But fear not! In this post, we’ll walk you through the step-by-step process to adjust the valve lash on your Chevy 350 engine, so you can keep your ride running like a dream.

Understanding Valve Lash

Valve lash refers to the gap between the rocker arm and the valve stem when the valve is closed. It’s important to have the correct amount of valve lash because it affects the engine’s performance and can impact the longevity of the valve train components.

The valve train’s purpose is to control the flow of air and fuel into the combustion chamber and exhaust out of the engine. The camshaft opens and closes the valves, and the rocker arm transfers the motion from the camshaft to the valve. When the valve is closed, there needs to be a small gap between the rocker arm and valve stem. If there is no gap, the valve may not fully close, which can cause compression loss and poor performance. On the other hand, if the gap is too large, the valve may not open fully, which can reduce engine power and fuel economy.

To determine if valve lash is out of specification, you can measure the gap between the rocker arm and valve stem using a feeler gauge. Refer to the engine’s service manual to determine the correct valve lash specification for your engine. If the gap is too large or too small, then you will need to adjust the valve lash to bring it back into specification. A common symptom of incorrect valve lash is a loud ticking noise coming from the valve train, which can be caused by the rocker arm hitting the valve stem or the valve not closing completely. By understanding valve lash and how it affects the engine’s performance, you can identify issues early and prevent further damage to the engine.

Related: The Biggest Cam for Chevy 350

Valve Lash Adjustment Tools For Chevy 350

To adjust valve lash on a Chevy 350, you’ll need the following tools and materials:

  1. Feeler gauge – used to measure the gap between the rocker arm and valve stem.
  2. Socket set – to remove the valve covers and adjust the rocker arms.
  3. Torque wrench – used to tighten the rocker arm nut to the correct specification.
  4. Clean rags – to clean the valve cover gasket surfaces and other engine components.
  5. Gasket scraper – to remove old gasket material from the valve cover and engine surfaces.
  6. RTV silicone gasket maker – to seal the valve cover gasket to the engine.

The feeler gauge is the most important tool for adjusting valve lash, as it allows you to accurately measure the gap between the rocker arm and valve stem. The socket set and torque wrench are needed to remove the valve covers, adjust the rocker arms, and ensure that the rocker arm nut is tightened to the correct specification. The clean rags and gasket scraper are necessary to ensure a clean surface for the valve cover gasket to seal properly, and the RTV silicone gasket maker is used to seal the valve cover gasket to the engine. Using the correct tools and materials is essential to ensure that the valve lash adjustment is performed correctly and the engine operates optimally.

Preparing to Adjust Valve Lash in Chevy 350

Before you can adjust the valve lash on a Chevy 350 engine, there are a few steps you need to take to prepare the engine for adjustment. Here’s what you need to do:

  1. Remove the valve covers: The valve covers must be removed to access the rocker arms and adjust the valve lash. Use a socket set to remove the bolts holding the valve covers in place, and carefully lift the covers off the engine. Be sure to keep track of the bolts and store them in a safe place.
  2. Identify the correct cylinder: To adjust the valve lash, you need to work on one cylinder at a time. Use the engine’s firing order to determine which cylinder is up for adjustment. You can find the firing order in the engine’s service manual.
  3. Position the engine: The engine needs to be in the correct position to adjust the valve lash. You can do this by rotating the engine using a socket wrench on the crankshaft bolt. Rotate the engine until the cylinder you’re working on is at top dead center (TDC) on the compression stroke. You can tell if the cylinder is on the compression stroke by checking to see if both the intake and exhaust valves are closed. You can use a screwdriver to feel the valve movement, or use a dial indicator on the rocker arm to see when the valve is fully closed.

By following these steps, you can prepare the engine for valve lash adjustment. This preparation is important to ensure that you’re working on the correct cylinder and that the engine is in the correct position for adjustment.

Detailed Instructions on Adjusting Valve Lash in Chevy 350 

Here are detailed instructions for a valve lash adjustment on a Chevy 350 engine involves adjusting the clearance between the rocker arm and the valve stem. Here are the detailed step-by-step instructions for adjusting valve lash:

  1. Determine the correct valve lash: Consult the engine’s service manual to determine the correct valve lash specification for your engine. The valve lash is different for the intake and exhaust valves, so be sure to consult the correct specification.
  2. Adjust the intake valves: Insert the correct thickness feeler gauge between the rocker arm and valve stem. Tighten the rocker arm nut until you feel slight resistance on the feeler gauge. Hold the rocker arm in place and torque the nut to the specified torque value.
  3. Adjust the exhaust valves: Use the same process as for the intake valves to adjust the exhaust valves. Insert the feeler gauge between the rocker arm and valve stem, and tighten the rocker arm nut until you feel slight resistance on the feeler gauge. Hold the rocker arm in place and torque the nut to the specified torque value.
  4. Check the valve lash: After adjusting the valve lash, check the clearance again with the feeler gauge. If the clearance is within the specified range, the valve lash adjustment is complete. If the clearance is out of specification, readjust the valve lash until it is within the correct range.
  5. Reinstall the valve covers: After you’ve completed the valve lash adjustment, clean the valve cover gasket surfaces and install new gaskets if necessary. Use RTV silicone gasket maker to seal the gasket to the engine, and torque the valve cover bolts to the specified torque value.

When adjusting valve lash, it’s important to take precautions to avoid damaging the engine. Always use the correct torque value when tightening the rocker arm nut, and be sure to hold the rocker arm in place to prevent it from turning as you tighten the nut. Additionally, use caution when rotating the engine and working around hot components to avoid injury. By following these instructions and taking the necessary precautions, you can adjust the valve lash on your Chevy 350 engine with confidence.

Valve Adjustment Methods

There are  two core methods for adjusting valve lash on a Chevy 350 engine: 

  • Adjusting valves with the engine running 
  • Adjusting valves with the engine not running. 

When adjusting valves with the engine running, there are certain precautions that need to be taken to ensure safety, and valve lash can be checked by listening to the sound of the engine. On the other hand, adjusting valves with the engine not running may be a simpler method, but it requires removing the valve covers to access the valves.

Adjusting valves in Chevy 350 with the engine running

Adjusting valves with the engine running is a method that has certain advantages over adjusting valves with the engine not running. One of the main advantages is that it allows you to hear the engine while making adjustments, which can be helpful in achieving the optimal valve lash. Here are the steps to adjust valves with the engine running:

  1. Start the engine and let it warm up to operating temperature.
  2. Using a mechanics stethoscope, listen to each valve in turn and adjust the lash as necessary.
  3. Loosen the rocker arm nut on the valve you are adjusting with a wrench or socket.
  4. Use a feeler gauge to determine the current valve lash and adjust it as necessary by turning the adjusting screw on the rocker arm.
  5. Tighten the rocker arm nut to the appropriate torque specification.
  6. Move on to the next valve and repeat the process until all valves have been adjusted.

However, there are certain precautions that need to be taken when adjusting valves with the engine running. First and foremost, safety should always be a top priority, as moving engine parts can be dangerous. In addition, the engine should be kept at a safe operating temperature and the proper safety gear should be worn.

Finally, checking valve lash with the engine running is done by listening to the engine and using the stethoscope to identify any issues. If the engine sounds smooth and there are no unusual noises, the valve adjustment is likely correct. However, if there are any unusual sounds or vibrations, adjustments may need to be made. By following these steps and taking the necessary precautions, adjusting valves with the engine running can be a safe and effective method for achieving optimal valve lash.

Adjusting Valves in Chevy 350 with the Engine Not Running

Adjusting valves with the engine not running is a method that has certain advantages over adjusting valves with the engine running. One of the main advantages is that it allows you to work on the engine in a safer environment, without the risks associated with a running engine. Here are the steps to adjust valves with the engine not running:

  1. Remove the valve covers and rotate the engine to Top Dead Center (TDC) on the compression stroke for the cylinder you are adjusting.
  2. Using a feeler gauge, determine the current valve lash and adjust it as necessary by turning the adjusting screw on the rocker arm.
  3. Tighten the rocker arm nut to the appropriate torque specification.
  4. Move on to the next valve and repeat the process until all valves have been adjusted.

However, there are certain precautions that need to be taken when adjusting valves with the engine not running. First and foremost, the engine should be allowed to cool down before beginning work to avoid the risk of burns. In addition, it’s important to take care when rotating the engine to TDC and to use the correct tools to avoid damaging the engine.

Finally, checking valve lash with the engine not running is done by using the feeler gauge to measure the gap between the valve stem and rocker arm. If the gap is too small or too large, adjustments may need to be made. By following these steps and taking the necessary precautions, adjusting valves with the engine not running can be a safe and effective method for achieving optimal valve lash.

Testing and Reassembling Valve Lash

Once you’ve adjusted the valve lash on your Chevy 350 engine, it’s important to test the lash to ensure that it’s within specification. Here’s how to do it:

  1. Reinstall the valve covers: After adjusting the valve lash, clean the valve cover gasket surfaces and install new gaskets if necessary. Use RTV silicone gasket maker to seal the gasket to the engine, and torque the valve cover bolts to the specified torque value.
  2. Start the engine: Start the engine and let it idle for a few minutes to warm up. This will help to ensure that the valves and lifters are properly seated.
  3. Use a feeler gauge to check the valve lash: With the engine running, use a feeler gauge to check the valve lash on each cylinder. Insert the feeler gauge between the rocker arm and valve stem, and check the clearance. If the clearance is within the specified range, the valve lash adjustment is complete. If the clearance is out of specification, readjust the valve lash until it is within the correct range.
  4. Shut off the engine: Once you’ve checked the valve lash on each cylinder, shut off the engine and allow it to cool down before reassembling any other components.
  5. Reassemble any other components: Replace any other components that were removed during the valve lash adjustment, such as the air cleaner assembly or any other hoses or lines that were disconnected.

By following these steps, you can test the valve lash to ensure that it’s within specification and reassemble the engine with confidence. Regular valve lash adjustments can help to ensure optimal engine performance, fuel economy, and longevity. By taking the time to adjust the valve lash on your Chevy 350 engine, you can keep it running smoothly for years to come.

Conclusion

In conclusion, adjusting valve lash on your Chevy 350 engine is a critical maintenance task that can have a significant impact on engine performance, fuel economy, and longevity. By following the steps outlined in this article, you can prepare the engine, adjust the valve lash, and test the results to ensure that your engine is running smoothly. Regular valve lash adjustments are essential to maintaining optimal engine operation and prolonging the life of your engine. Don’t overlook this important maintenance task – take the time to adjust your valve lash regularly, and your engine will thank you with years of reliable performance.

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