Motor Plants & Auxiliary Boilers USCG Question #629 (Set 14)

Decreasing the exhaust valve clearance of a diesel engine will cause the exhaust valve to open __________.

Official USCG Answer & Rule Citation

Correct Answer: Option B — earlier and remain open longer

Decreasing valve clearance reduces the lash in the train, causing the cam profile to actuate the valve earlier in the cycle and hold it open longer, altering engine timing, scavenging efficiency, and thermal loading.

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