What is the method for checking ignition timing?
3 Answers
Here is the method for checking ignition timing: 1. Remove the valve cover and locate the top and bottom dead center marks on the circumference of the crankshaft pulley. Slowly rotate the crankshaft until the piston is exactly at the top dead center position. Install the dial indicator bracket and head, ensuring the dial indicator's contact point vertically touches the exhaust valve spring seat with appropriate pressure (the small pointer on the dial indicator should read between 1-2). Simultaneously, rotate the dial to set the large pointer of the dial indicator to "0". 2. Install an angle disk on the flywheel. Slowly rotate the flywheel while observing the movement of the dial indicator pointer. When it moves away from "0", this indicates the exhaust valve opening time. At this moment, set the angle disk pointer to "0". Continue rotating the flywheel until its bottom dead center mark aligns with the radiator mark. The angle value indicated by the angle meter pointer at this position represents the exhaust valve opening angle before bottom dead center. 3. Continue rotating the flywheel. When the dial indicator pointer returns to "0", this marks the exhaust valve closing time. The angle value indicated by the angle meter pointer at this moment represents the exhaust valve opening duration angle. Using the same method, you can check the opening/closing times and duration angles of the intake valve. Then you can adjust the distributor to achieve optimal ignition timing.
The method to check ignition timing is to first use a timing light tool, start the engine and let it warm up to normal operating temperature, disconnect the vacuum hose to prevent interference, connect the timing light clip to the spark plug wire of the first cylinder, maintain a stable engine speed such as 1500 RPM after starting the engine, use the timing light to flash and illuminate the timing marks on the crankshaft pulley, and check if the mark position aligns with the standard value such as 10 degrees; if it doesn't match, loosen the distributor mounting screw, slowly adjust the angle by rotating it until the mark is accurate, then tighten the screw and test again to ensure correctness. The entire process requires careful operation to avoid accidental contact with the fan, and the tools are not expensive to buy at auto parts stores. Remember, stable RPM is the key to accuracy.
Checking the ignition timing yourself is quite simple: Buy a timing light, park on a level surface, start the engine and let it warm up for five minutes before shutting it off. Attach the light's clamp to the spark plug wire of cylinder number one, then start the engine again and maintain the throttle at 1500 RPM. Use the flashing light to illuminate the large wheel dial at the front of the engine and observe the degree mark indicated. The standard value can be found in the owner's manual, usually between 8 to 12 degrees. If the deviation is significant, use a wrench to loosen the alternator bolt and slightly adjust the wheel angle. After adjustment, tighten it and test again. Ensure safety by wearing gloves before starting. The timing light is affordable, costing just a few dozen dollars, and with a bit of practice, you'll get the hang of it quickly.
