Main Engine 2-Stroke · Main Engines (2-Stroke)
The Wärtsilä 7RT-flex50‑B is a low‑speed, 2‑stroke marine main engine delivering up to 12 320 kW at 124 rpm, featuring common‑rail fuel injection and electronic exhaust valve control for improved efficiency and emissions.
| Piston overhaul (crown/rings) | typically 12,000-18,000 hours - condition-based per maker's guidance |
|---|---|
| Cylinder liner inspection | typically every 8,000-12,000 hours |
| Exhaust valve overhaul | typically 8,000-16,000 hours depending on fuel and load profile |
| Servo oil filter/system check | typically every 500-1,000 hours |
| Turbocharger overhaul | typically 16,000-20,000 hours or condition-based |
| Scavenge space cleaning | typically every 2,000-4,000 hours |
| Piston ring gap | typically 0.8-1.6 mm for this bore class - confirm against the engine's own manual |
|---|---|
| Cylinder liner wear (bore increase) | condition-based, commonly assessed against a per-diameter wear-rate limit - confirm against maker's limit table |
| Crosshead/main bearing clearance | check against the maker's stated range in the engine's own instruction manual |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Typically surveyed under Continuous Survey Machinery (CSM) with condition-based extension subject to trending of cylinder pressures, exhaust temperature spread, servo oil condition and turbocharger performance; RT-flex control system alarm/event logs are commonly requested by surveyors as supporting evidence.
Estimated lifetime: Low-speed 2-stroke main engines of this class are typically designed for a service life well beyond 100,000 hours with scheduled piston, liner and valve overhauls; specific overhaul intervals are condition and load-profile dependent - confirm against the maker's maintenance system
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