* GM Small Block 350 (likely a carbureted engine in a classic car or truck): This requires a timing light and is a mechanical process. The procedure varies slightly depending on the ignition system but generally involves:
1. Finding the timing mark: Locate the timing marks on the harmonic balancer and the timing tab on the engine block.
2. Setting the engine to Top Dead Center (TDC) on the #1 cylinder: This is crucial. The engine must be at the exact TDC on the compression stroke of #1. Use a compression gauge or carefully observe the movement of the piston to ensure this.
3. Connecting the timing light: Hook up the timing light to the #1 spark plug wire and power source.
4. Adjusting the distributor: With the engine idling, point the timing light at the timing marks. The mark on the balancer should align with the timing tab according to the specifications found in your engine's repair manual. Adjust the distributor slightly to achieve the correct timing. This is usually specified in degrees BTDC (Before Top Dead Center).
5. Checking and refining: Check the timing at different RPMs (if needed) and make fine adjustments as necessary.
* GM LS1 or similar (e.g., in a Corvette, Camaro, Truck): These engines are almost entirely computer-controlled. You cannot adjust the timing directly with a distributor. The timing is controlled by the Engine Control Module (ECM). To adjust the timing, you'd need:
1. Diagnostic scan tool: A professional-grade scan tool is needed to access the ECM parameters and adjust the timing.
2. Tuning software (potentially): Depending on the desired level of control, tuning software might be necessary.
3. Knowledge of ECM parameters: Incorrectly adjusting timing parameters can severely damage the engine.
* Other manufacturers: If the 350 engine is from a different manufacturer (e.g., Ford, Chrysler), the timing adjustment procedure will vary significantly.
Crucially: You need a repair manual specific to the *exact* year, make, and model of your vehicle and engine. The repair manual will provide the correct timing specifications and the step-by-step procedure. Improper timing adjustment can lead to severe engine damage.
Recommendation: If you're not comfortable working with car engines, especially ignition systems, it's strongly recommended to take your vehicle to a qualified mechanic to have the timing checked and adjusted. The consequences of incorrect timing can be expensive to repair.
