Question 433Motor Plants - Assistant Engineer

The correct answer is B) earlier and remain open longer. Decreasing the exhaust valve clearance of a diesel engine causes the exhaust valve to open earlier in the engine cycle. This is because the reduced clearance allows the valve to open sooner, as the cam lobe can push the valve open with less piston movement. Additionally, the reduced clearance means the valve will remain open for a longer duration, as it takes longer for the valve spring to close the valve against the reduced clearance. The other options are incorrect because: A) the valve would open earlier but not necessarily remain open longer, C) the valve would open later and have greater lift, and D) the valve would open later and have less duration, which is the opposite of the correct answer.