When are the final valve adjustments made?

Final valve adjustments are best made when the engine reaches normal operating temperature because this is when the engine components have expanded to their operating size. Metal expands when heated, and this expansion can affect the clearance between the valve and the rocker arm. Making adjustments at this temperature ensures that the clearances are set correctly for optimal engine performance during operation.

If adjustments were made while the engine is cold, the clearances might be too tight once the engine heats up, leading to potential valve damage or inefficient engine operation. Therefore, conducting the adjustments at normal operating temperature allows for the most accurate and effective valve clearances, ensuring the engine runs smoothly and efficiently.