Yanmar 4JH57 Specifications
| Engine Model: Yanmar 4JH57 |
| Engine Type: 4-stroke inline 4-cylinder naturally aspirated water-cooled diesel |
| Total Displacement: 134 cu.in (2.19 L) |
| Rated Engine Power: 57 Hp (41.9 kW) at 3000 rpm |
| Fuel System Type: Common rail direct injection |
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The Yanmar 4JH57 is a 4-cylinder, naturally
aspirated marine diesel engine from the JH-CR series. This power unit
employs a common rail direct injection system, a departure from
mechanically governed predecessors. The engine is designed for silent
operation, low exhaust emissions, and seamless integration with modern
boat electronics through an Electronic Control Unit (ECU) equipped with
NMEA 2000 connectivity.
The Yanmar 4JH57 complies with EPA Tier 3 and RCD Stage II emission
standards, making it suitable for sailboat auxiliary propulsion, small
cruising motor yachts, and commercial displacement vessels. The
naturally aspirated configuration eliminates turbocharger complexity and
lag, providing predictable throttle response at low engine speeds. A
fresh water cooling system with a heat exchanger isolates the engine
block from corrosive seawater. The engine shares its 2.19-liter
displacement with other 4JH-CR variants (4JH45, 4JH57, 4JH80), with
power differentiation achieved through injection mapping rather than
hardware changes.
Engine Type: Vertical, 4-cycle, water-cooled diesel engine, naturally
aspirated
Number of Cylinders: 4 (inline)
Bore x Stroke: 88 mm x 90 mm (3.46 in x 3.54 in)
Displacement: 2.190 L (2190 cc / 134 cu.in)
Compression Ratio: 18.3:1
Combustion System: Direct injection, common rail
Aspiration: Naturally aspirated (no turbocharger)
Valvetrain: OHV (Overhead Valve), 2 valves per cylinder, 8 valves total
Firing Order: 1-3-4-2
Direction of Rotation: Counter-clockwise viewed from the flywheel end
Maximum Output (crankshaft, SAE J1228): 41.9 kW (57 hp) at 3000 rpm
Continuous Rating (ISO 3046): 38.1 kW (51.8 hp) at 2907 rpm
Maximum Torque: 172 Nm (127 lb-ft) at 1900-2100 rpm
Low Idle Speed: 750 rpm
High Idle Speed (no-load, governed): 3150 rpm
Emission Standard: EPA Tier 3, RCD Stage II
The cylinder block is manufactured from cast iron with a closed-deck
design. Four cylinder bores are machined directly into the parent metal
without replaceable wet liners. The block features a siamese bore
configuration where each cylinder shares a common wall with the adjacent
cylinder, reducing overall engine length for installation in sailboat
engine compartments. The crankcase extends below the crankshaft
centerline with a deep skirt design. Five main bearing bulkheads support
the crankshaft, with thrust bearing position at number three main
journal from the flywheel end.
The water jacket surrounds the upper portion of each cylinder bore
fully. Cast oil galleries supply lubricant to the main bearings and
camshaft bearings. A side-mounted spin-on oil filter threads directly
onto the block casting. The block incorporates an integral
seawater-cooled oil cooler mounted on the port side. Corrosion-resistant
sacrificial anodes are threaded into the block cooling passages. The
engine mounting feet are integrated into the block casting at four
positions. Crankshaft: Forged carbon steel with five main journals. Five
counterweights are integrated into the crank web. A rubber torsional
vibration damper is pressed onto the crankshaft nose.
The cylinder head is a single-piece cast iron component with a
cross-flow intake and exhaust port arrangement. Each cylinder features a
centrally located vertical injector nozzle directing fuel into a
re-entrant bowl machined into the piston crown. No pre-combustion
chamber is present. The valve train is an overhead valve (OHV)
configuration with pushrods and roller-type rocker arms. Each cylinder
receives two valves: one intake and one exhaust, arranged in a parallel
valve layout. Valve stem seals are positive-type on both intake and
exhaust valves for marine operation.
Hardened steel valve seat inserts on both intake and exhaust sides
resist wear under continuous load. The camshaft is located in the
cylinder block on the starboard side. Valve clearance adjustment uses a
screw-and-locknut arrangement on the rocker arms. The cold clearance
specification for both intake and exhaust valves is 0.20 mm (0.008 in).
The rocker shaft is supported by four pedestals bolted directly to the
cylinder head. Glow plugs are installed in the intake ports for cold
start assistance. Camshaft: Cast iron, located in the cylinder block on
the starboard side. Driven by a gear from the crankshaft. Camshaft
bearings are plain-type machined directly into the block.
The fuel system is a high-pressure common rail (CR) design with full
electronic control. A gear-type lift pump draws fuel from the marine
fuel tank and delivers it at 2-3 bar (29-44 psi) to the high-pressure
pump. The high-pressure pump is a radial piston design with two pumping
elements, generating rail pressure up to 1600 bar (23,200 psi). The
common rail accumulator distributes pressurized fuel to four
electronically controlled solenoid injectors.
The engine control unit (ECU) governs injection timing, duration, and
pressure based on sensors monitoring crankshaft position, camshaft
position, boost pressure (ambient in naturally aspirated configuration),
coolant temperature, and rail pressure. Each injection event may include
up to three separate discharges per combustion cycle: pilot, main, and
post injections. The ECU also manages engine speed governing, torque
limiting, and diagnostic functions. A seawater-cooled fuel cooler
prevents vapor lock in tropical conditions. The system is self-bleeding
with an automatic air purge routine activated when the ignition is
turned on.
The lubrication system uses a trochoid-type oil pump driven directly
from the crankshaft gear. The trochoid pump consists of an inner rotor
with four lobes and an outer rotor with five lobes, producing smooth
flow with minimal pulsation. The pump draws oil through a wire mesh
suction strainer positioned at the bottom of the deep marine oil pan.
Oil passes through a spin-on full-flow filter mounted on the port side
of the cylinder block. A seawater-cooled oil cooler, integrated into the
block casting, maintains oil temperature during sustained high-speed
operation.
The oil cooler is a shell-and-tube design with seawater on the tube
side. A pressure relief valve in the oil pump opens at 0.50-0.56 MPa
(73-81 psi) to prevent over-pressurization during cold starts. Piston
cooling jets are absent due to the naturally aspirated configuration
generating moderate thermal loads. Oil pressure at rated speed measures
0.28-0.40 MPa (41-58 psi). A low oil pressure switch triggers an audible
alarm at 0.06 MPa (9 psi). Standard oil pan capacity is 5.8 L (6.1 qt)
including the filter.
The cooling system comprises two separate circuits: a high-temperature
fresh water circuit and a low-temperature seawater circuit. The fresh
water circuit cools the engine block, cylinder head, and exhaust
manifold. A belt-driven centrifugal fresh water pump circulates coolant
through the engine. A copper-nickel heat exchanger integrates the two
circuits. Seawater, drawn through a hull strainer, passes through the
heat exchanger shell side, absorbing heat from the fresh water before
discharging through the exhaust mixing elbow.
A wax-pellet thermostat begins opening at 71°C (160°F) and reaches full
opening at 85°C (185°F). A bypass circuit permits fresh water
circulation within the engine when the thermostat remains closed.
Coolant capacity (fresh water circuit, including heat exchanger) is 5.8
L (6.1 qt). A seawater pressure switch activates a warning device if
flow drops below 0.7 bar (10 psi). A sacrificial zinc anode in the heat
exchanger prevents galvanic corrosion. The fresh water system requires a
40% ethylene glycol antifreeze concentration for corrosion inhibition
and freeze protection.
Combustion System: Direct injection with bowl-in-piston. The piston bowl
has a re-entrant lip geometry promoting air-fuel mixing. The injector
nozzle has 6 holes (0.12 mm diameter each) arranged symmetrically.
Cold Start System: Glow plugs in each intake port, rated at 12 V. The
ECU controls a glow timer relay providing pre-heat from 2 to 15 seconds
dependent on coolant temperature. Glow plug indicator lamp signals when
pre-heat is active.
Electrical System: 12 V negative ground. Starter motor power rating is
1.4 kW, fitted with a marine-grade corrosion-resistant housing.
Alternator output is 125 A standard, providing capacity for house
battery charging. The alternator is a water-cooled unit with a sealed
regulator.
Engine Control Unit (ECU): Production-optimized controller mounted
directly on the engine. The ECU supports NMEA 2000 protocol for
communication with vessel displays and navigation systems. Parameters
accessible include engine speed, coolant temperature, oil pressure, fuel
rate, and cumulative hours. Diagnostic fault codes are retrievable via a
compatible marine display.
Exhaust System: Water-injected mixing elbow of nickel-aluminum-bronze
construction. Seawater injects at the bend, reducing exhaust gas
temperature from 500°C (932°F) to below 60°C (140°F) at the outlet.
Length (front pulley to flywheel housing face): 740 mm (29.1 in)
Width (overall, exhaust elbow to injection pump): 580 mm (22.8 in)
Height (oil pan rail to rocker cover peak): 700 mm (27.6 in)
Dry Weight (engine without gearbox, without fluids): 220 kg (485 lb)
Dry Weight (with KM4P1 marine gearbox): 235 kg (518 lb)
Dry Weight (with KM4A1 marine gearbox, hydraulic clutch): 245 kg (540
lb)
Engine Oil Change Interval: 250 hours or 12 months under normal marine
duty.
Engine Oil Capacity (including filter, standard oil pan): 5.8 L (6.1 qt)
Engine Oil Grade (ambient above 0°C / 32°F): SAE 15W-40, API CF-4 or
higher.
Engine Oil Grade (cold ambient -15°C to 0°C / 5°F to 32°F): SAE 10W-30.
Engine Oil Pressure Relief Valve Setting: 0.50-0.56 MPa (73-81 psi)
Engine Oil Pressure at Rated Speed: 0.28-0.40 MPa (41-58 psi)
Engine Oil Pressure at Low Idle (minimum, hot engine): 0.08 MPa (12 psi)
Coolant Capacity (fresh water circuit, engine + heat exchanger): 5.8 L
(6.1 qt)
Coolant Specification: Ethylene glycol base marine antifreeze.
Thermostat Opening Temperature: 71°C (160°F) start; fully open at 85°C
(185°F)
Seawater Pump Impeller Replacement Interval: 500 hours or 12 months.
Heat Exchanger Zinc Anode: Replace every 250 hours or 6 months in
saltwater operation.
Fuel Filter: Replace every 250 hours. Water sediment bowl drain daily
before first start.
Air Filter Service Interval: Replace every 250 hours. Clean foam
pre-cleaner every 50 hours.
Valve Clearance (Cold Engine, Intake and Exhaust): 0.20 mm (0.008 in).
Valve Clearance Inspection Interval: 500 hours.
Injector Replacement Interval: 2000 hours or as indicated by ECU fault
code.
Glow Plug Inspection: Check resistance every 500 hours.
Compression Pressure (std): 3.5-3.9 MPa (508-566 psi) at cranking speed
with injectors removed.
Compression Pressure Variation Between Cylinders: Max 0.2 MPa (29 psi)
difference.
Drive Belt (fresh water pump) Tension: Replace belt every 1000 hours.
Idle Speed Adjustment (low, ECU controlled): 750 rpm.
Cylinder Head Bolts (Stage 1): 30 Nm (22 lb-ft)
Cylinder Head Bolts (Stage 2): 70 Nm (52 lb-ft)
Connecting Rod Cap Nuts: 55 Nm (41 lb-ft)
Main Bearing Cap Bolts: 75 Nm (55 lb-ft)
Flywheel Bolts (to crankshaft flange): 85 Nm (63 lb-ft)
Flywheel Housing Bolts (to block, M10): 45 Nm (33 lb-ft)
Camshaft Drive Gear Nut: 100 Nm (74 lb-ft)
Camshaft Thrust Plate Bolts: 22 Nm (16 lb-ft)
Rocker Arm Shaft Bracket Bolts: 30 Nm (22 lb-ft)
Rocker Arm Adjusting Lock Nut: 15 Nm (11 lb-ft)
Valve Cover Nuts (with rubber gasket): 10 Nm (7 lb-ft)
High-Pressure Fuel Pump Mounting Bolts: 30 Nm (22 lb-ft)
Common Rail Mounting Bolts: 25 Nm (18 lb-ft)
Injector Clamp Bolts: 25 Nm (18 lb-ft)
High-Pressure Fuel Line Nuts (pump to rail): 35 Nm (26 lb-ft)
High-Pressure Fuel Line Nuts (rail to injector): 30 Nm (22 lb-ft)
Crankshaft Pulley Bolt (center): 150 Nm (111 lb-ft)
Oil Pan Bolts (M8): 14 Nm (10 lb-ft)
Oil Pan Drain Plug (magnetic): 45 Nm (33 lb-ft)
Oil Filter (spin-on canister): Hand tighten plus 3/4 turn, or 15 Nm (11
lb-ft)
Oil Cooler Mounting Bolts (to block): 35 Nm (26 lb-ft)
Fresh Water Pump Mounting Bolts: 25 Nm (18 lb-ft)
Heat Exchanger Mounting Bolts (to block): 30 Nm (22 lb-ft)
Seawater Pump Mounting Bolts: 25 Nm (18 lb-ft)
Seawater Pump Cover Bolts (impeller access): 12 Nm (9 lb-ft)
Thermostat Housing Bolts: 18 Nm (13 lb-ft)
Exhaust Manifold Bolts (to cylinder head): 30 Nm (22 lb-ft)
Exhaust Mixing Elbow Bolts (to manifold): 35 Nm (26 lb-ft)
Starter Motor Mounting Bolts (M10): 50 Nm (37 lb-ft)
Alternator Mounting Bolts: 45 Nm (33 lb-ft)
Alternator B+ Terminal Nut: 8 Nm (71 lb-in)
Glow Plug (in cylinder head): 22 Nm (16 lb-ft)
Engine Mount Bracket Bolts (to block, inline mounts): 65 Nm (48 lb-ft)
ECU Mounting Bolts (to engine bracket): 12 Nm (9 lb-ft)
Zinc Anode Plug (in heat exchanger): 18 Nm (13 lb-ft)
Fuel Cooler Mounting Bolts (seawater side): 15 Nm (11 lb-ft)
Sailboats: Auxiliary propulsion for cruising yachts from 40 ft to 50 ft
length overall (LOA). Displacement hulls requiring 50-60 hp class
engines. Catamarans with twin 4JH57 installations. Models include
Beneteau Oceanis 45, Jeanneau Sun Odyssey 44, Dufour 45, Hanse 455.
Motor Yachts: Small trawler yachts up to 42 ft (12.8 m).
Semi-displacement hull cruising vessels. Canal boats and river cruisers
in European markets. Downeast-style lobsterman yachts.
Small Commercial Vessels: Harbour taxis and water taxis up to 10 m
length. Patrol craft for port authorities. Fish farm workboats and
aquaculture support vessels. Dive boats operating coastal routes.
Sail Training Vessels: School boats requiring simple, reliable auxiliary
power. Sail training organizations operating yachts up to 50 ft.
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