how to adjust chevy 350 valves? [8 steps to follow]

Are you ready to tune up your Chevy 350 engine? Adjusting the valves on a classic Chevy 350 engine is a relatively simple process that can be done in an afternoon. The key to getting it right is taking the time to understand the steps and following them meticulously.

To adjust Chevy 350 valves, start with a cold engine. Rotate the crankshaft to Top Dead Center (TDC) on the compression stroke for the cylinder you’re adjusting. Loosen the rocker arm nut, set the valve lash to the recommended spec, and tighten the nut. Repeat for all valves.

Whether you’re a newbie mechanic or a veteran DIYer, we provide detailed instructions on how to adjust chevy 350 valves so your engine runs as good as new! So get ready for some elbow grease and let’s begin tuning up

Key Takeaways

• Always check valve clearance before beginning the adjustment process.
• Check and adjust rocker arms to ensure proper fitment and operation.
• Use a feeler gauge to accurately measure valve lash consistency, if needed.
• Clean all components before assembly to avoid any dirt or debris entering the engine.

How to Check and Adjust the Valves on a Chevy 350 Engine?

Checking and adjusting the valves on a Chevy 350 engine is an important part of regular maintenance to ensure proper engine performance and longevity. Here’s a step-by-step guide on how to do it:

Tools and Materials You’ll Need:

1. Ratchet and socket set
2. Feeler gauges
3. Valve cover gaskets (if needed)
4. Torque wrench
5. A small hand mirror (optional)

Step 1: Prepare the Engine

• Park your vehicle on a flat and level surface.
• Allow the engine to cool down to prevent burns or injuries.

Step 2: Remove Valve Covers

• Locate the valve covers on the top of the engine, typically one on each side.
• Use a ratchet and socket set to remove the bolts holding the valve covers in place.
• Gently lift the valve covers off to access the valvetrain components.

Step 3: Identify TDC (Top Dead Center)

• You’ll need to identify the top dead center for the cylinder whose valves you want to adjust.
• Rotate the engine using a socket and ratchet on the harmonic balancer bolt. You may need to remove a spark plug and use a tool to turn the engine manually if necessary.
• Use a piston stop tool or a small hand mirror to determine when the piston in the cylinder you’re working on is at TDC. The piston should be at its highest point.

Step 4: Adjust Intake Valves

• For the cylinder at TDC, you can adjust the intake valves.
• Using a feeler gauge, find the specified valve clearance for your engine. This information can usually be found in your vehicle’s repair manual.
• Loosen the lock nut on the rocker arm and use the feeler gauge to check the valve clearance. Insert the feeler gauge between the valve stem and the rocker arm until it is snug but not too tight.
• Turn the adjusting screw to achieve the correct clearance.
• Tighten the lock nut while holding the adjusting screw in place.

Step 5: Adjust Exhaust Valves

• After adjusting the intake valves, you can adjust the exhaust valves for the same cylinder.
• Follow the same process as with the intake valves, using the specified clearance values for your engine.

Step 6: Reinstall Valve Covers

• Once you’ve adjusted the valves for the cylinder at TDC, carefully place the valve cover back onto the cylinder head.
• Tighten the valve cover bolts to the specified torque value using a torque wrench.

Step 7: Repeat for Other Cylinders

• Rotate the engine to TDC for the next cylinder you want to adjust and repeat the intake and exhaust valve adjustment process.
• Continue this process for all the cylinders in the engine.

Step 8: Reassemble and Test

• Reinstall any components you removed to access the valve covers, such as air filters, hoses, and spark plug wires.
• Start the engine and listen for any abnormal sounds. If you hear tapping or other noises, recheck your valve adjustments.

Always refer to your vehicle’s specific repair manual for precise specifications and instructions, as valve clearance and torque values can vary between different Chevy 350 engines. It’s also a good idea to consult a professional mechanic if you’re unsure about any aspect of this process or if you encounter difficulties.

Tips for Getting the Best Results When Adjusting Chevy 350 Valves

Adjusting the valves on a Chevy 350 engine is an essential maintenance task that helps ensure proper engine performance and longevity. Here are some tips for getting the best results when adjusting Chevy 350 valves:

Safety First

Always work on the engine in a well-ventilated area with appropriate safety equipment, such as safety glasses and gloves.

Engine Warm-Up

It’s generally best to adjust the valves when the engine is warm. This ensures that the valve clearances are at their specified values.

Cylinder Identification

Familiarize yourself with the cylinder numbering and firing order of your specific Chevy 350 engine. This information can usually be found in the service manual for your vehicle.

Use a Feeler Gauge

To accurately measure valve clearances, use a quality feeler gauge. Make sure it’s clean and in good condition.

Remove Valve Covers

To access the rocker arms and adjust the valves, remove the valve covers. This may require disconnecting any associated wiring or hoses.

Common Problems When Adjusting Chevy 350 Valves and What To Do About Them

When adjusting the valves on a Chevy 350 engine, you may encounter common problems. Here are some of these issues and what you can do to address them:

Problem: Incorrect Valve Clearance

• Symptoms: If the valve clearance is too tight or too loose, it can lead to poor engine performance, excessive valve noise, or even engine damage.
• Solution: Double-check and re-adjust the valve clearances to match the manufacturer’s specifications. Use a feeler gauge to ensure accuracy.

Problem: Valves That Won’t Adjust

• Symptoms: Sometimes, the adjustment screw may be seized or difficult to turn, preventing proper valve adjustment.
• Solution: Apply a penetrating oil to the adjustment screw and let it sit for a while. Gently work the screw back and forth to break free any corrosion or debris. If it still won’t adjust, you may need to replace the valve components.

Problem: Leaking Valve Covers

• Symptoms: Leaking valve covers can lead to oil spills and engine bay mess.
• Solution: Ensure that the valve cover gaskets are in good condition and properly seated. If they are damaged or worn, replace them. When reinstalling the valve covers, use the recommended torque specifications to prevent over-tightening and deformation.

Problem: Uneven Valve Adjustment

• Symptoms: Some valves may be properly adjusted while others aren’t, leading to an imbalanced engine.
• Solution: Recheck the order and sequence of adjustment. Make sure you are following the correct firing order for your engine. Also, verify that each rocker arm is properly seated and not damaged.

Problem: Valve Train Noise

• Symptoms: Excessive valve train noise can indicate poor adjustment or worn components.
• Solution: If the valves are properly adjusted, but you still have noise, it might be time to inspect the valve train components, such as lifters and pushrods. Worn or damaged components should be replaced.

Problem: Lost Valve Adjustment Over Time

• Symptoms: Sometimes, valve adjustments seem to drift out of spec over time.
• Solution: Regularly check and re-adjust the valves as part of your maintenance routine. The valve clearances can change as the engine wears, and readjusting them helps maintain proper performance.

Problem: Inaccurate Specifications

• Symptoms: Using incorrect valve clearance specifications can lead to improper adjustments.
• Solution: Always refer to the manufacturer’s specifications for your specific engine. These values can differ between Chevy 350 variants, so ensure you have the correct information.

Problem: Damaged Threads

• Symptoms: Stripped or damaged threads on adjustment screws or locknuts can make it challenging to adjust the valves.
• Solution: Carefully inspect the threads, and if they are damaged, replace the affected parts. Be sure to use the right tools and techniques to prevent further damage.

In all cases, having a service manual for your specific Chevy 350 engine can be incredibly helpful. It provides detailed instructions and specifications to guide you through the valve adjustment process and help troubleshoot common issues. If you encounter persistent problems, consider seeking assistance from a qualified mechanic or engine specialist.

FAQs

How do I determine the correct valve lash for my Chevy 350?

The correct valve lash setting for a Chevy 350 engine is typically 0.020 inch (0.51mm) for both intake and exhaust valves, though this can vary depending on the specific model and year of your engine. It’s important to refer to your vehicle’s manufacturer specifications or service manual when adjusting the valve lash of any engine.

What tools are necessary to adjust valves on a Chevy 350?

To adjust valves on a Chevy 350, you will need an adjustable wrench or socket set, feeler gauges, a torque wrench, and a vacuum gauge. Additionally, if the spark plug wires are attached directly to each cylinder head bolt, you’ll need special spark plug wire removal pliers or extractors.