Q1.
Sketch and show all parts of a two-stroke engine stuffing box. Describe the procedure of overhauling two stroke engine stuffing box, without removing piston. Answer should include all safety precautions and necessary tools used for stuffing box overhaul.(16)
Reference Answer
### Function of a Two-Stroke Engine Stuffing Box The stuffing box in a two-stroke crosshead marine diesel engine serves a critical dual function by creating a seal around the piston rod. It is mounted on the diaphragm plate, which separates the scavenge air space below the cylinder from the crankcase. 1. **Prevents Scavenge Air Leakage:** It stops high-pressure scavenge air from leaking down the piston rod into the crankcase. Such leakage would pressurize the crankcase, creating a hazardous condition, and reduce engine efficiency. 2. **Prevents Crankcase Oil Contamination:** It scrapes crankcase lubricating oil from the piston rod on its upstroke, preventing it from entering the scavenge space. Oil entering the scavenge space can lead to scavenge fires, fouling of ports, and excessive system oil consumption.
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