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MAN Energy Solutions
7S65MC-C8
The MAN 7S65MC-C8 is a low‑speed, 2‑stroke main propulsion engine delivering up to 49 MW at 95 rpm, distinguished by its camshaft‑controlled fuel injection and exhaust valve system with built‑in Variable Injection Timing.
49000.0 kW
Power
Engine Specifications
7
Cylinders
650 mm
Bore
2730 mm
Stroke
49,000 kW
MCR Power
95.0 rpm
MCR RPM
2-stroke
Stroke Type
Family: MAN B&W MC/MC-C
· Tier: Tier II
· Fuel: HFO, VLSFO, MDO
Inspector Detail
✓ verified
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Designation decoded
7 stands for 7 cylinders, S for Super-Long-Stroke, 65 for 650 mm bore, MC-C for the MAN B&W MC Compact series, 8 for Mark 8.
Background
The S65MC-C8 is part of the MC/MC-C platform from MAN Energy Solutions and is positioned as the Super-Long-Stroke variant with a 650 mm bore. Typical propulsion for medium-sized bulkers and tankers. As the Mark 8 version, the final conventional evolutionary stage before the ME-C electronic generation.
Calculated metrics
Stroke To Bore Ratio
4.2
Inspector checklist
Running gear & tribology
- Cylinder liners: with the high S/B ratio of 4.2, pay particular attention to thrust-side wear — the increased lateral force leads to greater liner wear on the thrust side
- Measure piston ring butt clearance and compare against service letter limits, especially the top ring
- Cylinder lubrication: check feed rate and distribution of the lubrication points (quills) — even wetting is critical at the 650 mm bore
Crosshead & stuffing box
- Crosshead bearing: the long 2,730 mm stroke causes high load cycling — track the bearing temperature trend carefully
- Check stuffing box sealing rings for wear, document drainage quantities
- Check piston rod surface for scoring and corrosion
Control & hydraulics
- Camshaft chain drive: measure chain elongation, check chain tensioner function
- Exhaust valve hydraulics: check actuating cylinders for leakage, measure valve lift
- Injection pumps: check plunger tightness and nozzle opening pressure
Scavenge air & exhaust system
- Inspect scavenge air box for oil deposits — indication of stuffing box condition
- Measure air cooler differential pressure, visually assess fouling level of the fin blocks
- Check exhaust duct and compensators for cracks and leaks
Sealing systems
- Check cylinder cover gaskets for blow-by traces
- Exhaust valve seat: check contact pattern and spindle rotation
- Check scavenge port edges for burrs and carbon deposits
Logbook reference values
| Parameter | Expected | Deviation means |
|---|---|---|
| Exhaust gas temperature after cylinder | 350-430 °C at MCR | Spread >20 °C → injection or compression problem |
| Scavenge air pressure | 2.5-3.5 bar at full load | Drop → check turbocharger fouling or air cooler blockage |
| Pmax (firing pressure) | Cylinder balance ±3 bar | Deviation → check timing or nozzle condition |
| Cooling water outlet temperature | 80-85 °C | Single-cylinder deviation >5 °C → scale buildup or thermostat |
| Cylinder oil feed rate | 0.6-1.0 g/kWh | Over-/under-lubrication directly affects liner wear |
Common Failure Modes
Cylinder liner cold wear
Symptoms: Increased liner wear rate, rough surface on inspection, accelerated piston ring wear
Causes: Cylinder oil feed rate too low, Cooling water temperature below dew point, BN number not matched to fuel
Preventive: Adjust feed rate to sulfur content, keep cooling water inlet >65 °C
Exhaust valve corrosion and burning
Symptoms: Rising exhaust gas temperature on the affected cylinder, visible erosion at the valve seat
Causes: Vanadium/sodium attack with HFO, Defective rotocap (valve not rotating), Poor seat geometry
Preventive: Visually check valve rotation, regrind seat every 8,000-12,000 Bh
Crosshead bearing overheating
Symptoms: Temperature rise >5 °C above normal, metallic particles in the oil filter
Causes: Blocked oil bores, Crankshaft misalignment, Overload
Preventive: Measure deflection every six months, check oil supply at inspection
Expert tips
- 💡 With the S65MC-C8's S/B of 4.2, the lateral load on the piston guide is particularly high — during liner inspection always compare the running track side against the thrust side
- 💡 After switching fuel from HFO to VLSFO, wait at least 500 operating hours before completing feed-rate optimization — the tribological balance settles slowly
- 💡 On MC-C engines, open and inspect the chain box every 16,000 Bh, even without an alarm
Related components
Turbocharger (water and dry wash intervals)
Scavenge air cooler (water side for corrosion)
Fuel separators and pre-heater
Foundation bolts and chocking
Classification & regulatory
IMO Tier I compliant. For Tier II, turbocharger upgrade and injection timing adjustment may be needed. Observe MARPOL Annex VI for ECA areas — sulfur limit of 0.1% requires VLSFO or scrubber.
Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.
Other Cylinder Configurations 50
5L35MC-C8
5 cyl
· 6,450 kW
5L42MC-C8
5 cyl
· 10,100 kW
5L60MC-C8
5 cyl
· 21,000 kW
5L70MC-C8
5 cyl
· 31,150 kW
5L80MC-C8
5 cyl
· 42,000 kW
5S26MC-C8
5 cyl
· 3,700 kW
5S35MC-C8
5 cyl
· 7,650 kW
5S42MC-C8
5 cyl
· 12,950 kW
5S46MC-C8
5 cyl
· 15,500 kW
5S50MC-C8
5 cyl
· 18,650 kW
5S60MC-C8
5 cyl
· 28,250 kW
5S65MC-C8
5 cyl
· 35,000 kW
5S70MC-C8
5 cyl
· 40,400 kW
5S80MC-C8
5 cyl
· 51,000 kW
5S90MC-C8
5 cyl
· 64,350 kW
6K80MC-C8
6 cyl
· 43,500 kW
6K90MC-C6
6 cyl
· 30,780 kW
6K90MC-C8
6 cyl
· 56,700 kW
6K98MC-C8
6 cyl
· 85,020 kW
6L35MC-C8
6 cyl
· 7,740 kW
6L42MC-C8
6 cyl
· 12,120 kW
6L60MC-C8
6 cyl
· 25,200 kW
6L70MC-C8
6 cyl
· 37,380 kW
6L80MC-C8
6 cyl
· 50,400 kW
6S26MC-C8
6 cyl
· 4,440 kW
6S35MC-C8
6 cyl
· 9,180 kW
6S42MC-C8
6 cyl
· 15,540 kW
6S46MC-C8
6 cyl
· 18,600 kW
6S50MC-C8
6 cyl
· 22,380 kW
6S50MC-C8.2
6 cyl
· 9,960 kW
6S60MC-C8
6 cyl
· 33,900 kW
6S65MC-C8
6 cyl
· 42,000 kW
6S65MC-C8.2
6 cyl
· 16,440 kW
6S70MC-C8
6 cyl
· 48,480 kW
6S80MC-C8
6 cyl
· 61,200 kW
6S90MC-C8
6 cyl
· 77,220 kW
7K80MC-C6
7 cyl
· 28,980 kW
7K80MC-C8
7 cyl
· 50,750 kW
7K90MC-C8
7 cyl
· 66,150 kW
7K98MC-C7.1
7 cyl
· 40,040 kW
7K98MC-C8
7 cyl
· 99,190 kW
7L35MC-C8
7 cyl
· 9,030 kW
7L42MC-C8
7 cyl
· 14,140 kW
7L60MC-C8
7 cyl
· 29,400 kW
7L70MC-C8
7 cyl
· 43,610 kW
7L80MC-C8
7 cyl
· 58,800 kW
7S35MC-C8
7 cyl
· 10,710 kW
7S42MC-C8
7 cyl
· 18,130 kW
7S46MC-C8
7 cyl
· 21,700 kW
7S50MC-C8
7 cyl
· 26,110 kW
Components & Design
Component data being added…
Technical Data
unified from engine model
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Maritime Network →Manuals
-
operating
MAN B&W MC/MC-C Engine Operating Manual (OM-MC-C)MAN Energy Solutions
-
maintenance
MAN B&W MC/MC-C Maintenance Manual (MM-MC-C)MAN Energy Solutions
-
spare_parts
MAN B&W MC/MC-C Illustrated Parts Catalogue (IPC-MC-C)MAN Energy Solutions
-
project_guide
MAN B&W Project Guide MC/MC-C (PG-MC-C)MAN Energy Solutions
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Equipment Model #38234
· ✓ still in production