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Caterpillar MaK

9L M552C

MaK M551 / M552 (Legacy 450mm) — Viertakt-Marinediesel, Bohrung 450 x Hub 550 (M551) / 520 (M552) mm, M551: 300-450 rpm (typical 425 rpm rated); M552: 500 rpm rated rpm, 3,490-7,469 kW depending on configuration (6M551 to 12M552). Brennstoff: Heavy Fuel Oil (HFO), Marine Diesel, up to 7,000 sec Redwood I viscosity. Status: Legacy / Obsolete (Production: ~1980s, Caterpillar acquired division 1997, engine now discontinued but still operational in field). Verifiziert, Datenblatt verlinkt.

8280.0 kW
Power

Engine Specifications

9
Cylinders
552 mm
Bore
720 mm
Stroke

Components & Design

Component data being added…

Technical Data

Bore 450 mm
Stroke M551 550 mm
Stroke M552 520 mm
Output per cylinder 780 bhp (M551 @ 425 rpm) / 835 bhp (M552 @ 500 rpm)
SFOC (8-cyl economy) 130 g/bhp-h
Lubrication oil inlet 50-55 °C
Oil pressure 4.0-5.0 bar
Valve guide clearance limit 0.40 mm (inlet & exhaust)
Fuel capability up to 7,000 sec Redwood I @ 100 °F
configuration L
rpm 400
fuel type HFO
technology Mechanical Heavy-Duty Trunk Piston
displacement l per cyl 172.3

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Common failures & inspection points

Valve guide wear and excessive clearance (>0.40 mm) leading to hot gas leakage and loss of compression

Measure valve guide clearance in cross-direction; check for elevated crankcase pressure

Piston crown erosion/burning from fuel injection system degradation or premature injection timing

Borescope inspection for crown material loss; check fuel injection pressure & timing

Turbocharger bearing wear and oil starvation (legacy medium-speed engines prone to lube oil management issues)

Check turbo shaft play; inspect oil feed/drain lines for blockage

Connecting rod bearing clearance drift and main bearing wear (long-stroke design, 50+ year old engines)

Measure bearing clearance with Plastigage; inspect crankshaft for ovality

Type-general inspection and maintenance points for this equipment category — not model-specific.

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Equipment Model #66559 · discontinued