The Chevy 350 small block engine is a staple in automotive performance and a favorite among car enthusiasts. One crucial aspect of maintaining its performance is the valve adjustment process. Properly adjusting the valves ensures that the engine runs efficiently, enhances power, and prolongs engine life. In this article, we will explore the valve adjustment sequence for the Chevy 350 small block, discussing its importance, the steps involved, and tips for achieving the best results.
Understanding the Importance of Valve Adjustment
Valve adjustment is essential for maintaining proper engine timing and performance. The valves control the intake of air and fuel into the combustion chamber and the exhaust of combustion gases. When the valves are not adjusted correctly, several issues can arise:
- Loss of Power: Incorrect valve clearance can lead to poor engine performance, resulting in a noticeable loss of power.
- Increased Wear: Improperly adjusted valves can cause excessive wear on engine components, leading to premature failure.
- Poor Fuel Economy: An engine that is not running efficiently can lead to increased fuel consumption.
- Rough Idle: If the valves are out of adjustment, the engine may run roughly or unevenly at idle.
Regular valve adjustments can prevent these problems and keep your Chevy 350 running smoothly.
Tools and Materials Required
Before diving into the valve adjustment sequence, it is essential to gather the necessary tools and materials:
- Socket and Ratchet Set: To remove the valve covers.
- Torque Wrench: For accurate torque settings.
- Feeler Gauge: To measure valve clearance accurately.
- Screwdriver: For adjusting the rocker arms.
- Shop Manual: For specific torque specifications and adjustments.
- Engine Oil: To lubricate the components during assembly.
Preparing for the Adjustment
Before beginning the valve adjustment process, follow these preparatory steps:
1. Ensure Safety: Disconnect the battery to prevent any electrical mishaps.
2. Remove Valve Covers: Use the socket and ratchet to remove the valve covers carefully. Clean the surfaces to prevent debris from entering the engine.
3. Check Engine Condition: Inspect for any signs of wear or damage to the rocker arms, pushrods, and other components.
Valve Adjustment Sequence
The valve adjustment sequence for the Chevy 350 small block is based on the engine's firing order. The firing order for the Chevy 350 is 1-8-4-3-6-5-7-2. This order is crucial for determining which valves to adjust during the process.
Step-by-Step Adjustment Process
Follow these steps for a precise valve adjustment:
1. Rotate the Engine: Use a socket and ratchet on the crankshaft pulley bolt to rotate the engine to the top dead center (TDC) on the compression stroke of cylinder 1. You can determine this by observing the position of the piston and the timing marks on the harmonic balancer.
2. Check Valve Clearance: With cylinder 1 at TDC, check the clearance of the following valves:
- Intake valve for cylinder 1
- Exhaust valve for cylinder 1
3. Adjust Valve Clearance:
- Insert a feeler gauge between the rocker arm and the valve stem.
- Adjust the rocker arm until you achieve the specified clearance (typically between 0.015 and 0.020 inches for intake and 0.018 to 0.022 inches for exhaust, but refer to your shop manual for exact specifications).
- Tighten the lock nut while holding the adjustment screw in place.
4. Continue with the Firing Order: Rotate the engine to the TDC of the next cylinder in the firing order and repeat the process for each cylinder:
- Cylinder 8
- Cylinder 4
- Cylinder 3
- Cylinder 6
- Cylinder 5
- Cylinder 7
- Cylinder 2
5. Final Check: Once all valves are adjusted, rotate the engine through a full cycle (two revolutions) and recheck the adjustments to ensure nothing has shifted.
Post-Adjustment Steps
After completing the valve adjustment process, follow these steps:
- Reinstall Valve Covers: Ensure that the gaskets are in good condition and properly seated to prevent oil leaks. Torque the valve cover bolts to the manufacturer's specifications.
- Reconnect Battery: Reconnect the battery and check for any electrical issues.
- Start the Engine: Start the engine and listen for any unusual noises. A properly adjusted engine should run smoothly without any ticking or knocking sounds.
Common Mistakes to Avoid
While performing a valve adjustment, there are common pitfalls that can lead to complications:
- Not Checking TDC: Ensure you are at TDC on the compression stroke for the cylinder being adjusted. This is critical for accurate clearance.
- Incorrect Clearance Settings: Always double-check your specifications against the engine manual. Incorrect settings can lead to engine damage.
- Failing to Torque Properly: Use a torque wrench to ensure that the rocker arm nuts are tightened to the correct specifications. Over-tightening can lead to component failure.
- Skipping Final Checks: After adjustment, always rotate the engine and recheck clearances to confirm that they have not shifted.
Tips for Successful Valve Adjustments
To achieve the best results from your valve adjustment, keep these tips in mind:
- Work in a Clean Environment: A clean workspace will help prevent dirt and debris from entering the engine.
- Take Your Time: Rushing through the process can lead to mistakes. Take your time to ensure each step is performed correctly.
- Use Quality Tools: Invest in high-quality tools to make the job easier and more accurate.
- Consult the Manual: Always refer to the engine manual for specific torque settings and adjustments unique to your engine.
Conclusion
Regular valve adjustments are essential for maintaining the performance and longevity of your Chevy 350 small block engine. By understanding the adjustment sequence and following the steps outlined in this article, you can ensure that your engine runs smoothly and efficiently. With the right tools and attention to detail, you can keep your classic Chevy performing at its best for years to come. Embrace the process, and take pride in the maintenance of your engine; it's a rewarding experience that pays off on the road.
Frequently Asked Questions
What is the purpose of adjusting the valves on a Chevy 350 small block engine?
Adjusting the valves ensures proper clearance between the rocker arms and the valve stems, which optimizes engine performance and prevents damage.
What tools are needed for a valve adjustment on a Chevy 350?
You will need a feeler gauge, a wrench for the rocker arm nuts, and possibly a socket set to remove any necessary components.
What is the correct valve adjustment sequence for a Chevy 350 small block?
The correct sequence is to adjust the valves in the following order: 1-8-4-3-6-5-7-2, which corresponds to the cylinder firing order.
How do you determine the proper valve clearance for a Chevy 350?
The typical valve clearance for a Chevy 350 is 0.006 inches for intake valves and 0.008 inches for exhaust valves, but you should always refer to the specific engine manual.
Can valve adjustment be done without removing the valve covers on a Chevy 350?
No, the valve covers must be removed to access the rocker arms and adjust the valves properly.
What is the importance of following the firing order during valve adjustment?
Following the firing order ensures that each valve is adjusted when the corresponding piston is at top dead center, allowing for accurate clearance settings.
How do you know when the valves are at the correct position for adjustment?
You can turn the engine by hand to bring the piston of the cylinder being adjusted to top dead center on the compression stroke.
Is it necessary to adjust valves on a Chevy 350 with hydraulic lifters?
Yes, even with hydraulic lifters, periodic adjustments may be needed to maintain optimal engine performance and prevent issues.
What common mistakes should be avoided during valve adjustment on a Chevy 350?
Common mistakes include not allowing the engine to cool down, failing to check for proper piston position, and not using the correct feeler gauge size.
How often should valve adjustments be performed on a Chevy 350?
It's recommended to check valve adjustments every 15,000 to 30,000 miles or as specified in the vehicle's maintenance schedule.
