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MAN Energy Solutions

8L70MC-C8

Name: MAN Energy Solutions 8L70MC-C8
Brand: MAN Energy Solutions
SKU: OSE-38254

The MAN 8L70MC-C8 is a low‑speed, 2‑stroke marine diesel main engine delivering up to 49 MW at 91 rpm, distinguished by its camshaft‑controlled fuel injection and exhaust valve system.

49840.0 kW

Power

Engine Specifications

Cylinders

700 mm

Bore

2268 mm

Stroke

49,840 kW

MCR Power

91.0 rpm

MCR RPM

2-stroke

Stroke Type

Family: MAN B&W MC/MC-C · Tier: Tier II · Fuel: HFO, VLSFO, MDO

Inspector Detail

▸

Designation decoded

8 stands for 8 cylinders, L for Long-Stroke, 70 for 700 mm bore, MC-C for the MAN B&W MC-Compact series, 8 for Mark 8.

Background

The L70MC-C8 with 8 cylinders is the Long-Stroke variant of the 70 bore class. S/B 3.24 as a balanced compromise. A typical drive for Panamax bulkers and medium-sized container ships. The 8-cylinder version offers higher output and better vibration behavior than the 7-cylinder version.

Calculated metrics

Stroke To Bore Ratio

3.24

Inspector checklist

Running Gear & Tribology

Cylinder liners: S/B 3.24 — moderate lateral forces, wear measurement at 4 positions and several heights
Piston rings: measure butt clearance and height wear, chrome layer for flaking
Cylinder lubrication: check quill distribution and flow at 700 mm bore

Crosshead & Stuffing Box

Crosshead bearing: monitor temperature trend and oil supply
Stuffing box: document drainage trend and sealing ring condition
Piston rod deflection at docking

Control & Hydraulics

Camshaft chain drive: measure chain elongation, inspect guide rails
Exhaust valve hydraulics: pressure, lift, leakage
Fuel injection pumps: timing and nozzle condition

Scavenge Air & Exhaust System

Scavenge air box: accessible via manhole at 700 mm bore — inspect systematically
Turbocharger: 1 or 2 TC — cleanliness
Exhaust temperature distribution across 8 cylinders

Logbook reference values

Parameter	Expected	Deviation means
Exhaust temperature after cylinder	340–410 °C at MCR	Spread >20 °C → injection/compression
Scavenge air pressure	2.8–3.5 bar	Drop → TC/cooler
Pmax	±3 bar cylinder balance	Deviation → timing
Cooling water temperature	80–85 °C	Check individual cylinder deviation
Lube oil pressure	3.5–4.5 bar	Pressure drop → check system

Common Failure Modes

Cold corrosion wear of cylinder liner

Symptoms: Increased wear rate, rough surface, accelerated ring wear

Causes: Cooling water below dew point, Feed rate/BN not matched to fuel

Preventive: Cooling water >65 °C, match feed rate and BN to fuel

Exhaust valve failure

Symptoms: Rising exhaust temperature, blow-by at valve seat

Causes: Hot corrosion from vanadium/sodium, Rotocap defect, Thermal fatigue

Preventive: Check valve rotation, regrind seat regularly

Turbocharger fouling

Symptoms: Falling charge air pressure, generally rising exhaust temperatures

Causes: Insufficient cleaning, Part-load operation, Fuel quality

Preventive: Observe cleaning intervals, periodically run at higher load during slow steaming

Expert tips

💡 L70MC-C8 with 8 cylinders offers very good vibration behavior — the even firing order significantly reduces free 2nd-order inertia forces compared to the 7-cylinder version
💡 At 700 mm bore: check quills at every piston withdrawal — blocked quills are one of the most common preventable causes of damage
💡 Open the MC-C chain case every 16000 running hours, document guide rail wear

Related components

Turbocharger (bearing clearance, balancing) Scavenge air cooler (both sides) Fuel preheater and viscosity controller Crankshaft main bearings

Classification & regulatory

IMO Tier I compliant. Injection system adjustments possible for Tier II. MARPOL Annex VI — VLSFO or scrubber for ECA operation.

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

unified from engine model True

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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 #38254 · ✓ still in production