How do you set the timing on a 160IE Opel Astra without touching the timing belt?

To set the timing on a 160IE Opel Astra without touching the timing belt, first, ensure the engine is at TDC (top dead center) for the first cylinder. Then, align the timing marks on the crankshaft pulley and the timing cover. Use a timing light to check the ignition timing by connecting it to the number one spark plug wire and adjusting the distributor as needed to achieve the correct timing specification indicated in the service manual. Finally, double-check all connections and secure the distributor once the timing is set.