Here's a general outline of the process. Specifics may vary slightly depending on the brand of your roller rockers and any modifications to your engine:
1. Preparation:
* Consult your rocker arm manufacturer's instructions: These are crucial and will supersede any general advice. Pay close attention to the specific instructions for your rockers.
* Gather your tools: You'll need a torque wrench, a dial indicator (highly recommended), feeler gauges, a pushrod length checker (highly recommended for accurate pushrod length), and possibly a valve spring compressor (depending on your rocker arm design). Also, have a shop manual for your specific 1979 350 V8.
* Remove valve covers: Provides access to the rocker arms.
* Check pushrod length: This is absolutely vital. Incorrect pushrod length will render all your rocker adjustment attempts pointless and potentially damaging. Use a pushrod length checker to ensure your pushrods are the correct length for your camshaft and lifter setup.
* Rotate the engine: Using the crankshaft pulley or a wrench on the harmonic balancer, rotate the engine to find Top Dead Center (TDC) on the compression stroke for each cylinder. You'll need to do this for each cylinder individually during adjustment.
2. Pre-load Adjustment (This is the most crucial step):
* Zero lash: This is where you set the initial rocker arm preload or "zero lash." The method varies slightly depending on your rocker type:
* Screws/Nuts: For rockers adjusted via screws or nuts, you'll typically use feeler gauges to set a precise amount of clearance. The recommended pre-load is usually specified in the manufacturer's instructions (often around 0.000"-.005"). You'll need to rotate the engine and check each cylinder. This is NOT a simple turn the adjuster to snug-type thing.
* Nut and adjusting screw: Some designs have an adjusting screw on top of the rocker that sits in a nut. Similar feeler gauge method as above.
* Dial Indicator (Highly Recommended): Use a dial indicator mounted to the rocker arm to accurately measure rocker arm movement. This is far more accurate than feeler gauges alone. Set it to zero with the valve closed, then gently rotate the engine to open the valve. The dial indicator will show how much the rocker arm is lifting the valve, and you can adjust the pre-load accordingly. This method avoids potential for incorrect pre-load caused by feeler gauge inaccuracies.
3. Torque Adjustment (If applicable):
* Some roller rocker arms require torque specification once the pre-load is set, which would be found in your manufacturer's instructions. Use a torque wrench to ensure proper tightening.
4. Checking the Adjustment:
* Recheck: After adjusting the pre-load on each rocker, re-check the adjustment with the dial indicator or feeler gauges. If you see any change, readjust as needed.
5. Reinstall Valve Covers:
Once all rockers are adjusted, reinstall the valve covers.
Important Considerations:
* Hydraulic vs. Solid Lifters: The process is different for hydraulic and solid roller lifters. Hydraulic lifters self-adjust, generally requiring only a zero-lash check, while solid lifters require precise pre-load adjustment. This instruction is geared towards solid lifters. Hydraulic roller lifters would require less adjustment.
* Cam Break-in: After installation of a new camshaft, a break-in period is crucial. This requires following specific instructions and techniques to seat the cam lobes correctly. Improper break-in can damage the cam and lifters.
* Professional Help: If you're uncomfortable with any part of this process, consult a professional mechanic. Incorrect adjustment can cause serious engine damage.
This is a general overview. Always consult your specific rocker arm manufacturer's instructions and a shop manual for your 1979 350 V8 for precise details and torque specifications. Remember, safety first!
