That said, here's a general outline of the process. Specific clearances will be found in your Pontiac 301's repair manual; this is crucial information you MUST obtain. This procedure varies slightly depending on the specific engine configuration, so using a factory service manual is essential.
Tools you'll need:
* Factory service manual: Absolutely essential for torque specs, valve clearances, and procedure.
* Valve adjustment tool: This allows you to precisely measure and adjust valve clearances. The type depends on the engine (feeler gauges are usually used).
* Socket set: Various sizes for removing and installing rocker arms and other components.
* Wrench set: For various fasteners.
* Torque wrench: To properly tighten fasteners to specified torque.
* Breaker bar (optional): May be needed to loosen stubborn bolts.
* Jack and jack stands: To safely lift and support the vehicle.
* Wheel chocks: For safety.
* Clean rags: To keep things clean.
* Safety glasses and gloves: To protect yourself.
General Procedure (Adapt to your service manual's specifics):
1. Preparation: Disconnect the negative battery terminal. Consult your service manual for any other specific disconnections needed (like the coil wire, etc.)
2. Access: Remove components necessary to access the valve covers (air cleaner, etc.). Remove the valve covers. Clean the area thoroughly.
3. Identify: Familiarize yourself with the cylinder firing order (found in your service manual). This is crucial for knowing which valves are open and closed at any given time.
4. Rotate Engine: Using the crankshaft bolt (usually found on the front of the engine), carefully rotate the engine using a wrench or breaker bar. The engine must be rotated to position each piston at Top Dead Center (TDC) on the compression stroke for each cylinder. Your service manual will show you how to identify this. Use a piston stop or a degree wheel for precise TDC if possible. This is extremely important!
5. Check and Adjust Valve Lash (Clearance): Once a piston is at TDC on the compression stroke for a cylinder, check the intake and exhaust valve clearances for that cylinder using your feeler gauges. The service manual will specify the correct clearance (usually measured in thousandths of an inch). If the clearance is incorrect, adjust it using the valve adjusting tool. There are different types of rocker arm adjustments (some have adjusting screws, others use shims). Again, consult your manual for the specific procedure.
6. Repeat: Repeat steps 4 and 5 for each cylinder. Remember that the order is crucial.
7. Reassembly: Reinstall the valve covers and any components that were removed. Torque all fasteners to the specifications in your service manual.
8. Check: Recheck the valve adjustments after running the engine for a short period and allowing it to cool down.
Important Considerations:
* Hydraulic Lifters: Pontiac 301s usually have hydraulic lifters, which automatically adjust valve lash. However, some wear and tear could still make manual adjustment necessary, depending on the condition of the engine. Your manual will specify.
* Safety: Always use jack stands when working under a vehicle. Never work on a vehicle supported only by a jack.
* Accuracy: Precise measurements and torquing are critical. Using incorrect torque values can damage the engine.
Again, I strongly advise consulting a factory service manual for your 1981 Pontiac 301 engine. This is a complex procedure with the potential for significant engine damage if done incorrectly. The information above is a general guideline only and may not apply precisely to your specific engine. Don't attempt this unless you are experienced with automotive repair.
