Tools You'll Need:
* Service Manual: Absolutely essential for specific clearances and procedures.
* Valve Adjusting Wrenches: The correct size for your engine's rocker arm nuts (usually 7/16" or 9/16"). Feeler gauges are also critical.
* Feeler Gauges: A set covering the range of valve lash clearances specified in your service manual.
* Socket Set: For removing the valve covers.
* Wrench for distributor hold-down (if applicable): To prevent rotating the distributor during adjustment
* Torque Wrench (optional but recommended): To properly torque the rocker arm nuts after adjustment.
* Gloves: To keep your hands clean and protect them from engine oil.
* Rags or Shop Towels: To clean up spills.
Steps:
1. Preparation:
* Disconnect the negative battery cable. Safety first!
* Warm up the engine: Run the engine until it reaches operating temperature (this helps stabilize the engine parts for accurate measurements). Let it cool slightly, but don't let it get completely cold.
* Locate the valve adjustment points. Consult your service manual for the location of the rocker arms and their corresponding cylinders.
* Remove the valve covers: Carefully remove the valve covers, being mindful of any gaskets or seals. Clean the valve cover gasket surfaces before reinstalling them.
2. Identify Intake and Exhaust Valves: Typically, the intake valves are on the side closest to the front of the engine (radiator). Exhaust valves are on the opposite side.
3. Valve Lash Clearance: Consult your service manual for the *precise* valve lash clearance specifications (measured in inches or millimeters) for your specific 350 engine. These clearances vary depending on the camshaft. Common specs are around 0.016" for intake and 0.020" for exhaust, but this is just a generic example.
4. Adjusting the Valves: This process involves one cylinder at a time:
* Rotate the Engine: Using a wrench on the crankshaft pulley or a socket on the harmonic balancer, slowly rotate the engine until the rocker arm for the valve you want to adjust is loose (no pressure on the pushrod). This is the point where you can easily feel movement on the pushrod.
* Insert Feeler Gauge: Insert the appropriate feeler gauge between the rocker arm and the valve stem.
* Adjust the Rocker Arm Nut: Loosen the rocker arm nut. Adjust the nut until you have the correct feeler gauge measurement. The feeler gauge should slide with slight resistance.
* Tighten the Rocker Arm Nut: Once you have the correct clearance, tighten the rocker arm nut to the specification in your service manual. This usually requires a torque wrench. Improper torque can damage the rocker arm.
* Repeat: Repeat steps 4a through 4d for all valves, making sure to rotate the crankshaft to the correct position for each valve. Pay close attention to your service manual for the firing order of the engine, to ensure you are correctly adjusting each valve.
5. Reassembly:
* Reinstall the valve covers: Ensure the valve cover gaskets are properly seated.
* Reconnect the negative battery cable.
* Start the Engine: Check for unusual noises, leaks, or other problems.
Important Considerations:
* Hydraulic vs. Solid Lifters: The procedure may vary slightly depending on whether your 350 uses hydraulic or solid lifters. Hydraulic lifters self-adjust, while solid lifters require manual adjustment. Your service manual will tell you which type you have.
* Cam Timing: If the camshaft is not correctly timed, the valve adjustments will be inaccurate and could cause engine damage.
* Professional Help: If you are uncomfortable performing this procedure, it's best to seek professional help from a qualified mechanic. Incorrect valve adjustment can lead to engine damage.
This is a complex task that requires careful attention to detail. Using a service manual is absolutely crucial. If you don't have one, get one specific to your engine before attempting this repair. Improperly adjusted valves can lead to serious engine damage.
