5S26MC-C8
The MAN 5S26MC-C8 is a low‑speed, crosshead, 5‑cylinder two‑stroke main engine delivering about 3 700 kW at 250 rpm, noted for its long‑standing reliability and flexible fuel capability.
Engine Specifications
Inspector Detail
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Designation decoded
5 for 5 cylinders, S for Super-Long-Stroke, 26 for 260 mm bore, MC-C for a mechanically controlled engine with compact C design, 8 for Mark version 8. Specs: stroke 980 mm, S/B 3.77.
Background
The 5S26MC-C8 is the smallest MAN B&W two-stroke engine — with only a 260 mm bore but an impressive S/B ratio of 3.77, a true slow-speed engine. The MC-C line uses conventional camshaft control (not electronic like the ME). Used on very small merchant ships, coastal freighters and feeder vessels. Mark 8 is a well-proven design generation.
Calculated metrics
Inspector checklist
- Cylinder liner: 260 mm bore, 980 mm stroke, S/B 3.77 — despite the small bore, a true slow-speed engine with high side forces
- Piston rings: high specific ring loading at S/B 3.77 and 260 mm bore
- Crosshead bearing: disproportionate side forces from the high S/B despite the small bore
- Camshaft: MC-C = camshaft control for injection AND exhaust valve
- Fuel pumps: plunger/barrel — compact pumps
- Valve clearance: manual measurement and adjustment
- Injection timing: check camshaft timing
- Injection nozzles: very small nozzle bores — sensitive to particulates
- Fuel: often MGO at 260 mm; separator required with HFO
- Fuel filter: condition
- Stuffing box: relatively high stress at 980 mm stroke despite the small bore
- Exhaust valve: mechanical — seat and sealing ring
- Cylinder head: blow-by
- Turbocharger: 1× — no redundancy, condition critical
- Scavenge air cooler
- Auxiliary Blower
Logbook reference values
| Parameter | Expected | Deviation means |
|---|---|---|
| Exhaust gas temperature after cylinder | 340-420 °C at 85% MCR | Spread >20 °C → fuel pump or nozzle |
| Scavenge Air Pressure | 1.5-2.0 bar abs at MCR | Turbocharger (no redundancy) |
| Valve clearance | Per MAN manual | Drift → timing |
| Cylinder oil feed rate | 0.8-1.2 g/kWh (mechanical lubricator) | Check dosing |
Common Failure Modes
Expert tips
- 💡 Smallest MAN two-stroke: S/B 3.77 at a 260 mm bore — the engine behaves like a slow-speed engine despite its compact size
- 💡 MC-C control: mechanical camshaft — no electronic optimization, efficiency lower than the ME variant
- 💡 For newbuilds: the ME variant (S26ME-B) is available and offers better efficiency — MC-C for existing engines
Related components
Classification & regulatory
IMO Tier II (Mark 8). EEXI: MC-C has worse efficiency than ME — EPL possibly required. Retrofit to ME control as an option.
Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.
Other Cylinder Configurations 50
Components & Design
Component data being added…
Technical Data
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Maritime Network →Manuals
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operating
MAN B&W MC/MC-C Engine Operating Manual (OM-MC-C)MAN Energy Solutions
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maintenance
MAN B&W MC/MC-C Maintenance Manual (MM-MC-C)MAN Energy Solutions
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spare_parts
MAN B&W MC/MC-C Illustrated Parts Catalogue (IPC-MC-C)MAN Energy Solutions
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project_guide
MAN B&W Project Guide MC/MC-C (PG-MC-C)MAN Energy Solutions