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Volvo Penta D6-350 Engine

The Volvo Penta D6-350 is a heavy-duty, marine straight-six diesel engine with a displacement of 5.5 liters (336 cubic inches), engineered for high-speed planning commercial and recreational vessels. Developed using modern diesel technology, this model features a robust cast-iron cylinder block reinforced with a structural ladder frame at the base to minimize operating noise and internal vibrations. Power delivery is optimized through dual-stage forced induction: combining a belt-driven mechanical compressor (supercharger) for powerful torque at low RPMs and a freshwater-cooled turbocharger with an aftercooler for high-speed efficiency. The entire assembly is fully managed and monitored by the proprietary Volvo Penta Electronic Vessel Control (EVC)
architecture.

The D6-350 is globally recognized for delivering exceptional, car-like performance within marine drivelines, primarily paired with the high-strength DPH Duoprop sterndrive or inboard configurations. By utilizing a mechanical supercharger to eliminate traditional turbo lag, the engine generates massive low-end torque, facilitating rapid acceleration and swift hull planning. The integration of common-rail injection eliminates characteristic diesel knock, resulting in highly refined, quiet operation. Built strictly for durability and high power density, the platform provides extended service intervals and fully complies with global emissions regulations, including EU RCD and US EPA standards.

Cylinder Block and Valve: Inline 6-cylinder layout with a 1-5-3-6-2-4 firing sequence. Camshaft Arrangement: Double overhead camshafts (DOHC). Valves: 4 valves per cylinder (24 valves total) featuring replaceable valve seats. Lash Adjusters: Integrated hydraulic lash adjusters for automatic valve clearance regulation. Cylinder Bore: 103 mm (4.05 inches). Piston Stroke: 110 mm (4.33 inches). Lubrication System: Forced lubrication via oil-cooled pistons equipped with two compression rings and one oil scraper ring. The assembly uses a seawater-cooled tubular oil cooler alongside a dual-filtration package containing separate, easily replaceable full-flow and bypass oil filters.

Fuel System: High-pressure Common-Rail Direct Fuel Injection system. System Control: Reprogrammed Electronic Diesel Control (EDC 7) processing node providing precise injection cycles. Pressure Operating Limits: Managed by an MPROP high-pressure fuel pump and a dedicated rail pressure sensor operating between 0 and 180 MPa, requiring a minimum critical rail pressure of 20 MPa (2900 psi) to initiate engine starting. Filtration Components: High-efficiency fuel delivery lines running through a primary fine fuel filter assembly integrated with a water separator and an electronic water-in-fuel monitor.

Cooling System: Pressurized, thermostatically regulated closed-loop freshwater system. Heat dissipation occurs through a heavy-duty tubular heat exchanger backed by a large-volume expansion tank. Raw seawater is drawn through an integrated intake by an easily accessible, rubber-impeller seawater pump protected by sacrificial zinc anodes. The engine block includes a freshwater-cooled turbocharger housing and dedicated connections prepared for external hot water/cabin heater outlets.

General Technical Data

Engine Specifications

Engine Model ............... Volvo Penta D6-350
Engine Type ............... 4-cycle inline 6-cylinder direct injection liquid-cooled marine diesel
Number of Cylinders ............... 6
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 4.06 (103.0)
Engine Stroke, in (mm) ............... 4.33 (110.0)
Displacement, cu.in (L) ............... 335.6 (5.50)
Rated Engine Power, hp (kW) ............... 350 (257)
Rated Engine Speed, rpm ............... 3500
Peak Torque ............... 875 Nm (645 lb-ft) at 2000 rpm
Idle Speed ............... 600-650 rpm
Aspiration Type ............... Turbocharged, supercharged with aftercooled
Operating Speed ............... 1500-3500 rpm
Compression Ratio ............... 17.5:1
Firing Order ............... 1-5-3-6-2-4
Combustion Chamber ............... Direct injection bowl in piston configuration base profile
Cylinder Block Type ............... Cast iron
Cylinder Head Type ............... Cast iron single-piece multi-valve
Lubrication System ............... Full-pressure force-feed system
Oil Pump Type ............... Gear-driven oil pump
Oil Filter Type ............... Dual full-flow and bypass spin-on filters
Cooling System ............... Liquid-cooled closed freshwater system with heat exchanger
Water Pump Type ............... Belt-driven centrifugal freshwater pump and seawater pump
Air Cleaner Type ............... Washable dry element type
Starting System ............... Electric starter motor
Electrical System ............... 12V or 24V
Alternator Output ............... 115A

Fuel System

Injection System Type ............... Bosch common rail system controlled by electronic vessel control
High Pressure Pump Model ............... Bosch CP3.3 triple piston design
Maximum Rail Pressure, psi (bar) ............... 23200 (1600)
Minimum Starting Rail Pressure, psi (bar) ............... 2900 (200)
Pressure Regulator Type ............... Magnetic proportional valve or fuel flow regulator
Fuel Feed Pump Type ............... Gear driven mechanical pump integrated on high pressure pump
Injector Type ............... Electromagnetic solenoid type multi hole vertical configuration
Fuel Filter Type ............... Single spin on primary cartridge with water separator sensor
Fuel Return Flow Rate, gph (L/h) ............... 18.5 (70.0)
Fuel Temperature Limit, F (C) ............... 122 (50.0)
Feed Pump Delivery Pressure, psi (bar) ............... 58-87 (4.0-6.0)
Fuel Density Standard, lb/gal (g/L) ............... 7.01 (840.0)
Fuel Lower Heating Value, Btu/lb (kJ/kg) ............... 18358 (42700)

Dimensions and Weight

Overall Length, in (mm) ............... 47.6 (1210)
Overall Width, in (mm) ............... 31.9 (810)
Overall Engine Height, in (mm) ............... 34.6 (880)
Dry Weight, lbs (kg) ............... 1279 (580)
Total Weight with DP Drive, lbs (kg) ............... 1664 (755)

Maintenance Data

Service Information

Engine Compression Pressure, psi (bar) ............... 348-406 (24.0-28.0)
Minimum Oil Pressure at Idle, psi (kPa) ............... 18.1 (125.0)
Normal Operating Oil Pressure, psi (kPa) ............... 63.8 (440.0)
Maximum Boost Air Pressure, psi (kPa) ............... 31.9 (220.0)
Maximum Manifold Temperature, F (C) ............... 140 (60.0)
Maximum Oil Temperature, F (C) ............... 257 (125.0)
Thermostat Opening Temperature, F (C) ............... 180 (82.0)
Thermostat Full Open Temperature, F (C) ............... 198 (92.0)
Intake Valve Clearance, Cold, in (mm) ............... 0.0138 (0.35)
Exhaust Valve Clearance, Cold, in (mm) ............... 0.0217 (0.55)

Engine Oil and Coolant

Engine Oil Type .................. SAE 5W-30, SAE 10W-30, or SAE 15W-40
API Service Classifications ......................... CH-4 or higher
Engine Oil Capacity with Filters, qt (L) ............... 21.1 (20.0)
Cooling System Capacity, qt (L) ............... 16.9 (16.0)
Compressor Oil Capacity, oz (mL) ............... 3.38 (100.0)

Service Intervals

Change oil and filter ............... Every 200 hours
Service air cleaner ............... Every 100 hours
Replace air cleaner ............... Every 400 hours
Replace fuel filter ............... Every 200 hours
Fuel system inspection ............... Every 1200 hours
Change coolant ............... Every 1000 hours
Compression test ............... Every 2000 hours
Replace drive belt ............... Every 400 hours
Replace impeller ............... Every 200 hours
Service heat exchanger ............... Every 400 hours

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ............... 4.0551-4.0559 (103.000-103.020)
Cylinder Bore Ovality, Maximum Wear, in (mm) ............... 0.0008 (0.020)
Cylinder Bore Taper, Maximum Wear, in (mm) ............... 0.0012 (0.030)
Main Bearing Journal Diameter, in (mm) ............... 3.3461-3.3468 (84.992-85.012)
Main Bearing Clearance, in (mm) ............... 0.0015-0.0035 (0.040-0.090)
Connecting Rod Bearing Journal Diameter, in (mm) ............... 2.5587-2.5594 (64.992-65.010)
Connecting Rod Bearing Clearance, in (mm) ............... 0.0015-0.0033 (0.038-0.084)
Crankshaft Axial End Play, in (mm) ............... 0.0031-0.0118 (0.080-0.300)
Thrust Bearing Journal Width, in (mm) ............... 1.4567-1.4583 (37.000-37.040)
Connecting Rod Total Side Play, in (mm) ............... 0.0059-0.0138 (0.150-0.350)
Piston Skirt Outside Diameter, in (mm) ............... 4.0511-4.0523 (102.900-102.930)
Piston to Cylinder Bore Clearance, in (mm) ............... 0.0027-0.0047 (0.070-0.120)
Piston Pin Diameter, in (mm) ............... 1.5746-1.5748 (39.994-40.000)
Piston Pin to Con Rod Bushing Clearance, in (mm) ............... 0.0006-0.0014 (0.015-0.035)
Top Ring Groove Side Clearance, in (mm) ............... 0.0024-0.0043 (0.060-0.110)
Second Ring Groove Side Clearance, in (mm) ............... 0.0019-0.0037 (0.050-0.095)
Oil Ring Groove Side Clearance, in (mm) ............... 0.0011-0.0029 (0.030-0.075)
Top Ring End Gap, in (mm) ............... 0.0118-0.0197 (0.300-0.500)
Second Ring End Gap, in (mm) ............... 0.0197-0.0295 (0.500-0.750)
Oil Ring End Gap, in (mm) ............... 0.0098-0.0197 (0.250-0.500)
Cylinder Head Flatness Distortion, in (mm) ............... 0.0039 (0.10)
Cylinder Block Deck Flatness, in (mm) ............... 0.0020 (0.05)
Intake Valve Stem Outside Diameter, in (mm) ............... 0.2736-0.2742 (6.950-6.965)
Exhaust Valve Stem Outside Diameter, in (mm) ............... 0.2724-0.2732 (6.920-6.940)
Intake Valve Guide Inside Diameter, in (mm) ............... 0.2756-0.2764 (7.000-7.020)
Exhaust Valve Guide Inside Diameter, in (mm) ............... 0.2756-0.2764 (7.000-7.020)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0014-0.0027 (0.035-0.070)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0024-0.0039 (0.060-0.100)
Valve Seat Angle ............... 45 degrees
Valve Face Angle ............... 44.5 degrees
Camshaft Journal Diameter, in (mm) ............... 1.9681-1.9693 (49.990-50.020)
Camshaft Bearing Clearance, in (mm) ............... 0.0019-0.0039 (0.050-0.100)
Cam Lobe Height (Intake), in (mm) ............... 0.3346 (8.50)
Cam Lobe Height (Exhaust), in (mm) ............... 0.3543 (9.00)
Camshaft Axial End Play, in (mm) ............... 0.0039-0.0098 (0.100-0.250)

Tightening Torques

Cylinder Head Bolts (1-Stage), lb-ft (Nm) ............... 36.9 (50.0)
Cylinder Head Bolts (2-Stage), lb-ft (Nm) ............... 73.8 (100.0)
Cylinder Head Bolts (3-Stage), lb-ft (Nm) ............... 110.6 (150.0)
Main Bearing Cap Bolts (1-Stage), lb-ft (Nm) ............... 44.3 (60.0)
Main Bearing Cap Bolts (2-Stage), lb-ft (Nm) ............... 95.9 (130.0)
Connecting Rod Cap Bolts (1-Stage), lb-ft (Nm) ............... 22.1 (30.0)
Connecting Rod Cap Bolts (2-Stage), lb-ft (Nm) ............... 47.9 (65.0)
Flywheel Fixing Bolts (1-Stage), lb-ft (Nm) ............... 36.9 (50.0)
Flywheel Fixing Bolts (2-Stage), lb-ft (Nm) ............... 73.8 (100.0)
Vibration Damper Crankshaft Pulley Bolts, lb-ft (Nm) ............... 62.7 (85.0)
Camshaft Gear Center Retaining Bolt, lb-ft (Nm) ............... 55.3 (75.0)
Camshaft Bearing Cap, lb-ft (Nm) ............... 17.7 (24.0)
Crankcase Oil Pan Mounting Bolts, lb-ft (Nm) ............... 17.7 (24.0)
Oil Pan Drain Plug, lb-ft (Nm) ............... 33.2 (45.0)
Valve Rocker Arm Shaft Support Bolts, lb-ft (Nm) ............... 22.1 (30.0)
Engine Valve Cover Top Screws, lb-ft (Nm) ............... 8.1 (11.0)
Exhaust Manifold Flange Nuts, lb-ft (Nm) ............... 35.4 (48.0)
Turbocharger Mounting Flange Nut, lb-ft (Nm) ............... 35.4 (48.0)
Common Rail High Pressure Fuel Line Nuts, lb-ft (Nm) ............... 20.7 (28.0)
Fuel Injector Clamping Bracket Fasteners, lb-ft (Nm) ............... 15.5 (21.0)
High Pressure Fuel Pump Drive Gear Bolt, lb-ft (Nm) ............... 66.4 (90.0)
Fuel Injector Feed Pipe Connection Joints, lb-ft (Nm) ............... 19.9 (27.0)
Alternator Bracket Base Pivot Bolts, lb-ft (Nm) ............... 35.4 (48.0)
Starter Motor Frame Mounting Fasteners, lb-ft (Nm) ............... 35.4 (48.0)
Seawater Pump Housing Screws, lb-ft (Nm) ............... 15.5 (21.0)
Oil Cooler Housing Core Clamping Screws, lb-ft (Nm) ............... 17.7 (24.0)
Freshwater Thermostat Housing Cover Bolts, lb-ft (Nm) ............... 17.7 (24.0)
Flywheel Housing to Engine Block (M12), lb-ft (Nm) ............... 62.7 (85.0)
Flywheel Housing to Engine Block (M10), lb-ft (Nm) ............... 35.4 (48.0)
Crankcase Breather Element Cover Screws, lb-ft (Nm) ............... 8.1 (11.0)
Supercharger Compressor Sump Drain Plug, lb-ft (Nm) ............... 14.8 (20.0)
Supercharger Assembly Main Bracket Bolts, lb-ft (Nm) ............... 35.4 (48.0)
Intake Manifold Air Inlet Plenum Bolts, lb-ft (Nm) ............... 17.7 (24.0)
Glow Plug Cylindrical Heating Elements, lb-ft (Nm) ............... 11.1 (15.0)
Oil Pump Internal Delivery Pipe Flange, lb-ft (Nm) ............... 8.1 (11.0)
Piston Oil Cooling Jet Nozzle Bolt, lb-ft (Nm) ............... 11.1 (15.0)
Timing Gear Case Backplate M8 Bolts, lb-ft (Nm) ............... 17.7 (24.0)
Timing Gear Case Outer Cover M6 Screws, lb-ft (Nm) ............... 7.4 (10.0)
Engine Oil Filter Bypass Valve Assembly, lb-ft (Nm) ............... 25.8 (35.0)
Coolant Heat Exchanger Drain Cock Valve, lb-ft (Nm) ............... 18.4 (25.0)
Raw Water Sacrificial Anode Brass Plug, lb-ft (Nm) ............... 22.1 (30.0)
Engine Support Foot Marine Mount Bolts, lb-ft (Nm) ............... 103.3 (140.0)
Exhaust Riser Discharge Elbow Band Clamp, lb-ft (Nm) ............... 8.9 (12.0)
Engine Control Unit Heat Sink Bolts, lb-ft (Nm) ............... 6.6 (9.0)
Rail Pressure Sensor Threaded Interface, lb-ft (Nm) ............... 51.6 (70.0)
Fuel Temperature Sensor Brass Housing, lb-ft (Nm) ............... 14.8 (20.0)
Coolant Temperature Sensor Element, lb-ft (Nm) ............... 16.2 (22.0)
Manifold Boost Air Pressure Sensor Bolt, lb-ft (Nm) ............... 6.6 (9.0)
Lube Oil Pressure Sensor, lb-ft (Nm) ............... 22.1 (30.0)
Crankshaft Position Sensor Pickup Bracket, lb-ft (Nm) ............... 7.4 (10.0)
Camshaft Position Reference Indicator Bolt, lb-ft (Nm) ............... 7.4 (10.0)
Water In Fuel Contamination Bottom Sensor, lb-ft (Nm) ............... 2.2 (3.0)
Sea Water Circuit Impeller End Cover Screws, lb-ft (Nm) ............... 4.4 (6.0)
Air Intake Silencer Filter Housing Clamps, lb-ft (Nm) ............... 5.2 (7.0)
Compressor Drive Electromagnetic Clutch Bolt, lb-ft (Nm) ............... 44.3 (60.0)

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• Volvo Penta Engines Specs
  
• Volvo Penta D6-310 Specs
  
• Volvo Penta D6-370 Specs
  
• Volvo Penta D6-380 Specs
  
• Volvo Penta D6-400 Specs
  
• Volvo Penta D6-440 Specs
  
• Volvo Penta D6-480 Specs
  

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