What is the adjustment mnemonic for 4-cylinder 8-valve engines?
1 Answers
The adjustment mnemonic for 4-cylinder 8-valve engines is 'one pair, two intake, three exhaust, four none'. Here are the specific details for adjusting valve clearance in automobiles: 1. Adjustment method: Taking a 4-cylinder engine with a firing order of 1-3-4-2 as an example. First, position cylinder 1 at compression top dead center (TDC) and adjust its valves. Then rotate the engine crankshaft 180 degrees to position cylinder 3 at intake bottom dead center (BDC) and adjust clearance. Next, rotate the crankshaft another 180 degrees to position cylinder 4 at exhaust top dead center and adjust clearance. Finally, position cylinder 2 at power stroke top dead center and adjust clearance. 2. Reason for adjustment: The valve clearance significantly affects engine performance. If the cold clearance is too small or nonexistent, it will cause abnormal engine operation when hot, making proper adjustment essential.