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Wärtsilä

Wärtsilä 31SG marine spark gas engine

The Wärtsilä 31SG is available in 8 to 16 cylinder configurations and has a power output ranging from 4.2 to 8.8 MW, at 720 and 750 rpm. The launch of the Wärtsilä 31SG introduces a 4-stroke engine having the best fuel economy of any engine in its class. At the same time, it maintains outstanding performance across the complete operating range. Its modular design enables a significant reduction in maintenance time and costs, thereby improving power availability and reducing the need for spare parts.

Components & Design

Component data being added…

Technical Data

Cylinder power 610 kW/cyl (diesel)
Mean effective pressure (BMEP) 30 bar
SFOC (diesel) 167.7 g/kWh (optimal point)
Weight (8V31) ~57.1 tonnes (dry, diesel)
Weight (16V31) ~89–92.5 tonnes (dry, diesel)
Piston speed 10.75 m/s
Turbocharging Two-stage turbocharging with intercooling
Fuel injection Common rail direct injection
Valve layout 2 inlet, 2 exhaust valves per cylinder

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Common failures & inspection points

Low-load operation: Poor combustion, carbon deposit accumulation in cylinders, turbocharger fouling, economizer fouling. Wärtsilä offers Slow Steaming Upgrade K
Cylinder liner wear and scuffing (general 4-stroke diesel pattern, not W31-specific): Exacerbated by inadequate lubrication oil film, excessive cylinder tempera
Fuel injection system: Common rail system generally robust; however, HP fuel pump overhaul intervals are extended to 24,000 hrs (vs. 12,000 in prior-gen engines
Scavenge space deposit accumulation and fire risk (class-wide diesel phenomenon): Carbonized lube oil and unburnt fuel residues accumulate in scavenge space. Ex

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

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Equipment Model #64368 · ✓ still in production