How do you set Opel Astra timing?

To set the timing on an Opel Astra, first, ensure the engine is at top dead center (TDC) for the first cylinder by aligning the timing marks on the crankshaft and camshaft pulleys. Remove the timing belt or chain cover, then loosen the tensioner to adjust the timing belt or chain, ensuring it aligns with the timing marks. After adjustment, re-tension the belt or chain, recheck alignment, and finally, reassemble the timing cover. Always consult the specific service manual for your model for detailed instructions and torque specifications.