Motor Plants & Auxiliary Boilers USCG Question #1465 (Set 30)

Which construction detail is apparent in the connecting rod and piston assembly shown in the illustration? Illustration MO-0011

USCG Exam Illustration MO-0011
USCG Examination Diagram: Illustration MO-0011
Official USCG Answer & Rule Citation

Correct Answer: Option A — The piston is designed with a heat dam.

A heat dam in a piston design is an annular groove or restricted section near the crown. It limits the direct flow of heat from the high-temperature combustion zone to the ring belt, protecting ring sticking and lubricant breakdown.

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