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Caterpillar MaK
9M43C
The MaK M43C 9M43C is a 9‑cylinder, medium‑speed (500 rpm) 4‑stroke diesel main engine delivering up to 7.2 MW, designed for direct‑drive propulsion and robust operation on heavy fuel oil.
7200.0 kW
Power
Engine Specifications
9
Cylinders
430 mm
Bore
610 mm
Stroke
7,200 kW
MCR Power
500.0 rpm
MCR RPM
183.0 g/kWh
SFC
4-stroke
Stroke Type
Family: Caterpillar/MaK MaK M43C
· Tier: IMO Tier II
· Fuel: HFO, MDO
Inspector Detail
▸
Common issues
- Fuel injector wear and coking, particularly on heavy fuel oil operation
- Piston ring and liner wear with bore polishing from combustion residues
- Turbocharger fouling reducing charge air pressure and raising exhaust temperatures
- Charge air cooler fouling
- Exhaust valve burning or seat recession
- Camshaft and roller wear
- Crankcase oil contamination from catalyst fines or water when running on heavy fuel oil
- Cylinder head gasket or O-ring leakage
Inspection checklist
- Exhaust temperature spread monitoring per cylinder
- Borescope inspection of piston crown and liner via indicator valve
- Fuel injector spray pattern and condition check
- Turbocharger fouling and bearing clearance check
- Charge air cooler pressure drop and fouling inspection
- Lube oil analysis for catalyst fines, TBN depletion and water content if HFO-fuelled
- Cylinder liner wear measurement
- Valve clearance and rotator function check
- Crankshaft deflection readings
Service intervals
| Fuel injector overhaul or exchange | medium-speed engines running on heavy fuel oil commonly need injector service every 2,000-4,000 running hours - confirm against maker's schedule and actual fuel quality |
| Piston, ring and liner overhaul | typically in the 12,000-20,000 running hour range for this engine class - confirm against the maker's manual |
| Turbocharger overhaul | typically 16,000-24,000 running hours |
| Lube oil analysis | monthly or per maker's condition monitoring schedule |
| Cylinder head overhaul | per running hours per maker's schedule |
Typical wear limits
| Cylinder liner bore wear | typically renewal is considered around 0.3-0.5% increase over nominal bore diameter for medium-speed engines of this bore class - confirm against the maker's manual |
| Main bearing clearance | commonly in the 0.20-0.45 mm range depending on maker tolerance - confirm against the maker's manual |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Fuel injectors
- Piston ring set
- Cylinder liner
- Main and big-end bearing shells
- Cylinder head gasket set
- Turbocharger repair kit
- Exhaust valve and seat insert
Safety
- Crankcase explosion risk - oil mist detector integrity must be verified regularly
- Heavy fuel oil handling - heated fuel lines present burn and leak-onto-hot-surface fire risk
- High-pressure fuel injection system retains residual pressure after shutdown
- Hot exhaust manifold and turbocharger surfaces
- Starting air system pressure hazards
Class survey
Typically eligible for Continuous Survey Machinery with rotating examination of cylinder units and turbochargers plus periodic crankshaft deflection checks; running-hours log and oil analysis records are commonly requested at survey.
Estimated lifetime:
Medium-speed four-stroke engines of this class are commonly designed for major overhaul cycles around 20,000-30,000 running hours and total service life well beyond 100,000 hours with proper maintenance, subject to duty cycle.
Other Cylinder Configurations 2
Components & Design
Cylinder Head Body
Caterpillar/MaK
M43C Cylinder Head Assembly
4-valve design (2 intake, 2 exhaust). Overhaul at 16,000-24,000 hrs. Pressure test cooling passages at overhaul.
Lead time: 14 wk
680.0 kg
Fuel Pump (Jerk-Type / Common Rail)
Caterpillar/MaK / Bosch
M43C Fuel Injection Pump (Jerk-Type)
Mechanical jerk-type pump per cylinder. Overhaul at 8,000-12,000 hrs. Check plunger clearance with micrometer.
Lead time: 8 wk
85.0 kg
Turbocharger Unit (ABB/MHI/Napier)
ABB Turbocharging / MHI
M43C Turbocharger (ABB TPL / MHI MET)
Single-stage turbocharger. Water washing every 100-500 hrs depending on fuel. Major overhaul at 12,000-16,000 hrs.
Lead time: 12 wk
2200.0 kg
Technical Data
SFOC (Specific Fuel Oil Consumption)
175–178 g/kWh (HFO optimized)
Lube Oil Consumption
0.6 g/kWh standard; 0.3 g/kWh optional
Engine Type
4-stroke turbocharged intercooled non-reversible with direct injection
Cylinder Block Material
Nodular cast iron (Kugelgraphitguss)
Turbocharger Maintenance Interval
15,000 operating hours (inspection/cleaning)
Per-Cylinder Power Output
~700–760 kW/cylinder
Engine Centre Distance
3400 mm
Charge Air Cooler
Cast casing with 40% increased base area for turbocharger mounting
unified from engine model
True
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Common failures & inspection points
Heavy fuel oil corrosion of cylinder liners and piston rings due to high sulfur content; nodular cast iron offers improved wear resistance vs. gray iron but req
Turbocharger bearing wear and seizure from contaminated or degraded lube oil; tight clearances vulnerable to sluggish operation or complete seizure if oil break
Fuel injector nozzle carbon deposits and stiction (sticking) from poor fuel quality (high viscosity, low volatility); coke accumulation at nozzle holes can caus
Intake and exhaust rocker arm bearing wear requiring clearance checks every 30,000 hours; bearing surfaces (ball pin, adjusting screw) subject to friction and w
Main running gear (crankshaft, bearings, piston skirts, liners) susceptible to seizure and discoloration from inadequate lube oil separation/filtration; long-st
Type-general inspection and maintenance points for this equipment category — not model-specific.
Suppliers & Spare Parts
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Equipment Model #38091
· ✓ still in production