How To Adjust Valves On Small Block Chevy

How to Adjust Valves on a Small Block Chevy: A Comprehensive Guide

Adjusting valves on your small block Chevy engine is a crucial maintenance task that ensures optimal engine performance and longevity. While it might seem daunting, with the right tools and a methodical approach, it's a manageable job for even intermediate DIY mechanics. This guide will walk you through the process, providing step-by-step instructions and valuable tips.

Tools You'll Need

Before you begin, gather the necessary tools. Having everything ready beforehand will streamline the process significantly:

• Valve Adjusting Wrenches: These are specialized wrenches, usually in feeler gauge sizes, designed for precise valve adjustment. Make sure you have the correct sizes for your engine.
• Feeler Gauges: Essential for accurately measuring the valve lash. A set covering a range of thicknesses is recommended.
• Socket Set and Wrenches: For removing rocker arm covers and other components.
• Torque Wrench: To ensure proper tightening of bolts and nuts, preventing damage.
• Mechanic's Gloves: To protect your hands from grease and oil.
• Shop Rags: For cleaning and wiping.
• Chilton's or Haynes Repair Manual: This is incredibly helpful for specific details relating to your particular small block Chevy engine (e.g., 350, 283, etc.) Different years and models might have slight variations.
• Jack Stands and Safety Stands: For securing your vehicle and preventing accidental injury.

Preparing Your Engine

Proper preparation is key to a successful valve adjustment. Neglecting these steps can lead to mistakes and frustration:

• Safety First: Disconnect the negative battery terminal. Always prioritize safety! Support the vehicle securely on jack stands.
• Engine Cool Down: Ensure the engine is completely cool before starting any work. Hot engine parts can cause severe burns.
• Locate the Rocker Arm Covers: These covers protect the valve train. You'll need to remove them to access the valves.
• Consult Your Manual: Your repair manual will provide detailed diagrams and specifications for your specific engine, indicating the correct valve lash clearances (measured in inches or millimeters).

The Valve Adjustment Process

This is where the precision comes in. Follow these steps carefully:

1. Identifying Valve Lash

• Locate the pushrods: These connect the rocker arms to the lifters.
• Determine the correct valve lash: Use your manual to find the correct cold lash specifications for your engine. This is typically measured in thousands of an inch.

2. Setting the Lash

• Rotate the Engine: Carefully rotate the engine crankshaft using a wrench on the crankshaft bolt until you find a cylinder where both valves are closed (exhaust and intake). You can use a helper to turn the engine and verify the valve position.
• Adjust the Intake Valve: Insert the appropriate feeler gauge between the rocker arm and the valve stem. Adjust the rocker arm nut until you achieve the correct feeler gauge thickness. Then tighten the nut to the specifications outlined in your manual.
• Adjust the Exhaust Valve: Repeat the process for the exhaust valve in the same cylinder.
• Repeat for All Cylinders: Continue rotating the engine and adjusting valves one cylinder at a time until all valves are adjusted. Always refer to your repair manual for the proper firing order to ensure you don't miss any cylinders.

3. Reassembly

• Replace Rocker Arm Covers: Carefully reinstall the rocker arm covers and tighten the bolts to the specified torque.
• Reconnecting the Battery: Reconnect the negative battery terminal.

Troubleshooting

• Incorrect Valve Lash: If you've adjusted valves and the engine still has issues (rough idle, ticking noises), double-check your work. Ensure you've used the correct feeler gauges and followed the specifications in your manual.
• Bent Pushrods or Other Issues: A persistent issue could point towards a more serious problem requiring professional attention.

Remember, precision and patience are crucial when adjusting valves. Take your time, refer to your repair manual frequently, and don't hesitate to seek professional assistance if you encounter unexpected problems. Proper valve adjustment will significantly improve your engine's performance and longevity.