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Sulzer
6RTA52
The Sulzer 6RTA52 is a low‑speed, two‑stroke marine diesel engine delivering about 8 820 kW at 136 rpm, known for its conventional camshaft design and constant‑pressure turbocharging.
8820.0 kW
Power
Engine Specifications
6
Cylinders
520 mm
Bore
1850 mm
Stroke
8,820 kW
MCR Power
136.0 rpm
MCR RPM
2-stroke
Stroke Type
Family: Sulzer RTA
· Tier: IMO Tier I
· Fuel: HFO, MDO
Inspector Detail
▸
Designation decoded
6RTA52: Sulzer reversible turbocharged Typ A, 520 mm Bohrung, 6 Zylinder, Standardausführung ohne Suffix (weder Tanker noch Ultra-Langhub). Zweitakt-Kreuzkopfmotor mit konventionellem Zahnrad-Nockenwellenantrieb.
Background
The 6RTA52 is a standard engine of the Sulzer RTA series with 520 mm bore and 1850 mm stroke. The basic version without suffix provides a balanced ratio between output and height. The 6-cylinder configuration ensures good vibration behavior and smooth engine operation across the entire operating range.
Calculated metrics
Stroke To Bore Ratio
3.558
Inspector checklist
Cylinders and cylinder liners (CLU)
- Laufbuchsen-Verschleißmessung an allen 6 Zylindern mittels Innenmikrometer
- Document ovality and conicity of running gear liners
- Measure piston ring end gaps and axial height
- Check scavenge ports for deposits and edge quality
Fuel injection and VIT
- Perform VIT (Variable Injection Timing) functional test and calibration
- Check fuel injection nozzle opening pressure and spray pattern
- Check fuel pump plunger and barrel for wear and leakage
- Inspect high-pressure lines for fatigue cracks and vibration damage
Camshaft and gear drive
- Gear-driven camshaft drive – document flank clearance and contact pattern
- Camshaft bearing inspect for clearance and condition
- Inspect cam profiles for pitting, scoring and surface hardness
Pulse Lubricating System
- Check dosage and distribution of cylinder oil at each cylinder
- Pulse System Verteilerventile auf korrekte Funktion testen
- Document cylinder oil consumption against operating hours
Exhaust System and Turbocharger
- Abgastemperaturen aller Zylinder vergleichen (Soll: 340-420°C)
- Check turbocharger bearings and seals
- Evaluate charge air cooler differential pressure and cleanliness condition
Engine and bearings
- Kurbelwellendurchbiegung an allen Lagerstellen messen
- Document crosshead and connecting rod bearing clearance
- Check main bearing temperatures and oil supply
Logbook reference values
| Parameter | Expected | Deviation means |
|---|---|---|
| Exhaust gas temperature per cylinder | 340-420 °C | Spreizung >15°C zwischen Zylindern deutet auf ungleichmäßige Verbrennung hin |
| Pmax (Zünddruck) | Nennwert ±3 bar | Deviations indicate VIT misalignment, injection problems or compression deficiency |
| Kühlwassertemperatur Zylinder | 80-95 °C Austritt | Elevated temperature can indicate running gear liner crack or cooling jacket fouling |
| Kurbelwellendurchbiegung | Gemäß Sulzer Grenzwerte für RTA52 | Excess indicates foundation deformation or bearing wear |
| Spülluftdruck | Gemäß Betriebsdiagramm | Low pressure indicates turbocharger or charge air cooler problems |
| Schmieröl-Eintrittstemperatur Hauptlager | 40-50 °C | Elevated temperature can indicate insufficient oil cooling or bearing damage |
Common Failure Modes
Piston ring wear and blow-by
Symptoms: Increased cylinder oil consumption, compression pressure loss, smoke development at scavenge air port
Causes: Normal aging at high operating hours, Unzureichende Zylinderschmierung, Betrieb mit abrasiven Brennstoffverunreinigungen
Preventive: Piston ring wear measurement at each piston inspection, timely ring replacement after manufacturer interval, pulse system calibration
Nockenwellen-Pittings
Symptoms: Metallische Geräusche aus dem Steuerungsbereich, verändertes Einspritz-Timing, Metallpartikel im Schmieröl
Causes: Fatigue of cam surface at high operating hours, Unzureichende Schmierölfilterung, Fehlausrichtung im Zahnrad-Nockenwellenantrieb
Preventive: Visually inspect cam surfaces during overhauls, regularly analyse lube oil, check tooth flank clearance
Abgasventilsitz-Erosion
Symptoms: Pmax-Abfall, erhöhte Abgastemperatur am betroffenen Zylinder, Blow-by-Spuren
Causes: Hochvanadiumhaltiger Brennstoff, Ventilspindel-Rotation gestört (Rotocap), Thermal overload during continuous full-load operation
Preventive: Check valve seat condition at every overhaul, ensure Rotocap function, guarantee high-quality fuel treatment
Expert tips
- 💡 Der RTA52 ohne Suffix hat einen S/B von 3,558 – vergleichsweise moderat. Im Vergleich zur U-Variante (RTA52U mit S/B 3,996) sind die spezifischen Langhub-Probleme weniger ausgeprägt, dafür ist die Drehzahl höher.
- 💡 For the gear-driven camshaft drive (Sulzer-typical, not chain-driven like MAN), pay attention to correct tooth flank bearing pattern – uneven bearing pattern indicates foundation deformation.
- 💡 Standard design without tanker compactification – the cylinder spacing is generous, which improves accessibility during inspections.
Related components
VIT-Stellantrieb
Pulse Lubricating System
Zahnrad-Nockenwellenantrieb
Fuel injection nozzles and fuel pumps
Exhaust valves and Rotocap
Turbocharger and charge air cooler
Crosshead and connecting rod bearings
Crankshaft and main bearing
Classification & regulatory
NOx emissions must comply with MARPOL Annex VI and NOx Technical Code. VIT parameters must correspond to the EIAPP certificate. Crankshaft deflections must be documented according to class requirements. Cylinder oil TBN must be adapted to applicable sulphur limits (SECA/Global Cap).
Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.
Other Cylinder Configurations 50
5RTA48T
5 cyl
· 6,600 kW
5RTA48T-B
5 cyl
· 7,150 kW
5RTA52
5 cyl
· 7,350 kW
5RTA52U
5 cyl
· 7,850 kW
5RTA58T
5 cyl
· 10,150 kW
5RTA58T-B
5 cyl
· 10,800 kW
5RTA62
5 cyl
· 10,100 kW
5RTA62U
5 cyl
· 11,000 kW
5RTA62U-B
5 cyl
· 12,000 kW
5RTA72
5 cyl
· 16,000 kW
5RTA72U
5 cyl
· 17,000 kW
5RTA72U-B
5 cyl
· 18,000 kW
5RTA82T
5 cyl
· 16,600 kW
5RTA84T
5 cyl
· 19,100 kW
5RTA84T-D
5 cyl
· 22,600 kW
6RTA48T
6 cyl
· 7,920 kW
6RTA48T-B
6 cyl
· 7,920 kW
6RTA52U
6 cyl
· 9,420 kW
6RTA58T
6 cyl
· 12,180 kW
6RTA58T-B
6 cyl
· 12,960 kW
6RTA62
6 cyl
· 12,120 kW
6RTA62U
6 cyl
· 13,200 kW
6RTA62U-B
6 cyl
· 14,400 kW
6RTA72
6 cyl
· 19,200 kW
6RTA72U
6 cyl
· 20,400 kW
6RTA72U-B
6 cyl
· 21,600 kW
6RTA82T
6 cyl
· 19,920 kW
6RTA84C
6 cyl
· 22,920 kW
6RTA84T
6 cyl
· 22,920 kW
6RTA84T-D
6 cyl
· 27,120 kW
6RTA96C
6 cyl
· 32,940 kW
6RTA96C-B
6 cyl
· 34,320 kW
7RTA48T
7 cyl
· 9,240 kW
7RTA48T-B
7 cyl
· 10,010 kW
7RTA52
7 cyl
· 10,290 kW
7RTA52U
7 cyl
· 10,990 kW
7RTA58T
7 cyl
· 14,210 kW
7RTA58T-B
7 cyl
· 15,120 kW
7RTA62
7 cyl
· 14,140 kW
7RTA62U
7 cyl
· 15,400 kW
7RTA62U-B
7 cyl
· 16,800 kW
7RTA72
7 cyl
· 22,890 kW
7RTA72U
7 cyl
· 23,800 kW
7RTA72U-B
7 cyl
· 25,200 kW
7RTA82T
7 cyl
· 23,240 kW
7RTA84C
7 cyl
· 26,740 kW
7RTA84T
7 cyl
· 26,740 kW
7RTA84T-D
7 cyl
· 31,640 kW
7RTA96C
7 cyl
· 38,430 kW
7RTA96C-B
7 cyl
· 40,040 kW
Components & Design
Component data being added…
Technical Data
unified from engine model
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Maritime Network →Manuals
-
operating
Sulzer RTA Operating ManualWärtsilä Switzerland (historical Sulzer)
-
maintenance
Sulzer RTA Maintenance ManualWärtsilä Switzerland (historical Sulzer)
-
spare_parts
Sulzer RTA Spare Parts CatalogueWärtsilä Switzerland (historical Sulzer)
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Equipment Model #38639
· ✓ still in production