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Yanmar 3TNE68 Engine

General Technical Data

Yanmar 3TNE68 Engine Specifications

Engine Model ........... Yanmar 3TNE68
Engine Type ........... Vertical, 4-cycle water-cooled diesel
Combustion System ........... Special swirl pre-combustion chamber
Number of Cylinders ........... 3
Engine Bore, in (mm) ........... 2.69 (68.0)
Engine Stroke, in (mm) ........... 2.85 (72.0)
Displacement, (L) ........... 0.784
Maximum Engine Power, hp (kW) ........... 20.2 (15.1)
Maximum Engine Speed, rpm ........... 3600
Fast Idle, rpm ........... 3225
Slow Idle, rpm ........... 1450
Firing Order ........... 1-3-2
Direction of Rotation ........... Counterclockwise (viewed from flywheel)
Compression Ratio ........... 23:1
Compression Pressure, MPa ........... 3.24±0.1
Air Cleaner ........... Primary and Secondary Filters
Intake Valve Clearance, in (mm) ........... 0.008 (0.02)
Exhaust Valve Clearance, in (mm) ........... 0.008 (0.02)
Electrical System Rating, Volts ........... 12
Starting system ........... Electric Starter

Fuel System

Fuel Type ........... Diesel Fuel
Fuel Filter ........... Replaceable Element
Fuel Injection Timing (FlD, B.T.D.C.) deg ........... 14±1
Fuel injection Pressure, MPa ........... 11.8
Governor ........... Mechanical centrifugal

Lubrication System

Lubrication System Type ........... Forced lubrication with trochoid pump
Oil Filter ........... Full Flow, Replaceable
Lubricating Oil Capacity, qt (L) ........... 2.5 (2.4)

Cooling System

Cooling System Type ........... Liquid cooling / Radiator
Cooling System Capacity, qt (L) ........... 3.7 (3.5)
Cooling Fan Type ........... Pusher
Cooling Fan Number of Blade ........... 5
Cooling Fan Diameter, in (mm) ........... 12.3 (310)

Dimensions

Width, in (mm) .......... 15.9 (401)
Height, in (mm) .......... 19.6 (496)
Depth, in (mm) .......... 18.7 (474)
Weight, lbs (kg) .......... 178 (81)

Yanmar 3TNE68 Maintenance Data

Engine oil type .......... SAE 10W-40/5W-30
Engine oil capacity, qt (L) .......... 2.5 (2.4)
Coolant capacity, qt (L) .......... 3.7 (3.5)
Oil filter change interval .......... Every 200 hours
Oil change interval .......... Every 200 hours
Fuel filter change interval .......... Every 500 hours

Yanmar 3TNE68 Service Specifications

Cylinder head and valves

Cylinder head combustion surface distortion, mm (in) .......... 0,05 (0,0020)
Intake valve seat angle, degrees .......... 120
Exhaust valve seat angle, degrees .......... 90
Intake valve seat width, mm (in) .......... 1,15 (0,0455)
Exhaust valve seat width, mm (in) .......... 1,41 (0,0557)
Intake valve alve stem outside diameter, mm (in) .......... 5,46-5,48 (0,2158-0,2164)
Intake valve guide inside diameter, mm (in) .......... 5,50-5,52 (0,2174-0,2180)
Intake valve oil clearance, mm (in) .......... 0,03-0,06 (0,0010-0,0022)
Exhaust valve stem outside diameter, mm (in) .......... 5,45-5,46 (0,2152-0,2158)
Exhaust valve guide inside diameter, mm (in) .......... 5,50-5,52 (0,2174-0,2180)
Exhaust valve oil clearance, mm (in) .......... 0,04-0,07 (0,0016-0,0028)
Valve guide projection, mm (in) .......... 7,00 (0,2767)
Intake valve sinking depth, mm (in) .......... 0,30-0,50 (0,0119-0,0198)
Exhaust valve sinking depth, mm (in) .......... 0,75-0,95 (0,0296-0,0375)
Thickness of intake valve head, mm (in) .......... 0,85-1,15 (0,0336-0,0455)
Thickness of exhaust valve head, mm (in) .......... 0,95-1,25 (0,0375-0,0494)
Intake valve timing (Open), degrees .......... 50-15
Intake valve timing (Close), degrees .......... 37-47
Exhaust valve timing (Open), degrees .......... 37-47
Exhaust valve timing (Close), degrees .......... 5-15
Valve spring free length, mm (in) .......... 28,00 (1,1067)
Intake and exhaust valve clearance, mm (in) .......... 0,15-0,25 (0,0059-0,0099)
Rocker arm shaft outside diameter, mm (in) .......... 9,97-9,99 (0,3942-0,3947)
Rocker arm bushing inside diameter, mm (in) .......... 10,00-10,02 (0,3953-0,3960)
Rocker arm clearance, mm (in) .......... 0,01-0,05 (0,0005-0,0019)
Pushrod bending, mm (in) .......... 0,03 (0,0012)
Tappet stem outside diameter, mm (in) .......... 17,95-17,97 (0,7095-0,7102)
Tappet guide hole inside diameter, mm (in) .......... 18,00-18,02 (0,7115-0,7122)
Tappet clearance, mm (in) .......... 0,03-0,07 (0,0013-0,0027)

Cylinder block

Cylinder bore (Std), mm (in) .......... 68,00-68,03 (2,6877-2,6889)
Cylinder bore (Wear limit), mm (in) .......... 68,20 (2,6957)
Piston outside diameter (Std), mm (in) .......... 67,96-67,99 (2,6862-2,6874)
Piston outside diameter (Wear limit), mm (in) .......... 67,90 (2,6838)
Min. clearance between piston and cylinder, mm (in) .......... 0,03-0,06 (0,0010-0,0022)
Top clearance, mm (in) .......... 0,61-0,73 (0,0241-0,0289)
Piston pin outside diameter, mm (in) .......... 19,99-20,00 (0,7902-0,7905)
Piston pin hole diameter, mm (in) .......... 20,00-20,01 (0,7905-0,7908)
Piston pin clearance, mm (in) .......... 0,00-0,02 (0,0000-0,0007)
Top ring groove width, mm (in) .......... 1,550-1,570 (0,0613-0,0621)
Top ring width, mm (in) .......... 1,470-1,490 (0,0581-0,0589)
Top ring minimum side clearance, mm (in) .......... 0,060-0,100 (0,0024-0,0040)
Top ring end clearance, mm (in) .......... 0,100-0,250 (0,0040-0,0099)
Second ring groove width, mm (in) .......... 1,540-1,555 (0,0609-0,0615)
Second ring width, mm (in) .......... 1,430-1,450 (0,0565-0,0573)
Second ring minimum side clearance, mm (in) .......... 0,090-0,125 (0,0036-0,0049)
Second ring end clearance, mm (in) .......... 0,150-0,350 (0,0059-0,0138)
Oil ring groove width, mm (in) .......... 3,010-3,025 (0,1190-0,1196)
Oil ring width, mm (in) .......... 2,970-2,990 (0,1174-0,1182)
Oil ring minimum side clearance, mm (in) .......... 0,020-0,055 (0,0008-0,0022)
Oil ring end clearance, mm (in) .......... 0,150-0,350 (0,0059-0,0138)
Crankpin bushing inside diameter, mm (in) .......... 39,000-39,016 (1,5415-1,5421)
Crankpin metal thickness, mm (in) .......... 1,487-1,500 (0,0588-0,0593)
Crankpin outside diameter, mm (in) .......... 35,970-35,980 (1,4217-1,4221)
Oil clearance, mm (in) .......... 0,033-0,059 (0,0013-0,0023)
Piston pin bushing inside diameter, mm (in) .......... 20,025-20,038 (0,7915-0,7920)
Piston pin outside diameter, mm (in) .......... 19,991-20,000 (0,7902-0,7905)
Oil clearance, mm (in) .......... 0,025-0,047 (0,0010-0,0019)

Camshaft and crankshaft

Camshaft journal outside diameter (Gear side), mm (in) .......... 35,940-35,960 (1,4206-1,4213)
Camshaft oil clearance (Gear side), mm (in) .......... 0,040-0,085 (0,0016-0,0034)
Camshaft journal outside diameter (Intermediate), mm (in) .......... 35,910-35,935 (1,4194-1,4204)
Camshaft oil clearance (Intermediate), mm (in) .......... 0,065-0,115 (0,0026-0,0045)
Camshaft journal outside diameter (Flywheel side), mm (in) .......... 35,940-35,960 (1,4206-1,4213)
Camshaft oil clearance (Flywheel side), mm (in) .......... 0,040-0,125 (0,0016-0,0049)
Crankshaft journal outside diameter, mm (in) .......... 39,970-39,980 (1,5798-1,5802)
Crankshaft Bearing metal thickness, mm (in) .......... 1,487-1,500 (0,0588-0,0593)
Crank journal and bushing oil clearance, mm (in) .......... 0,033-0,059 (0,0013-0,0023)
Crankshaft journal bend, mm (in) .......... 0,020 (0,0008)

Yanmar 3TNE68 Tightening Torque Specs

Cylinder head bolt (M8x1,25), Nm (lb-ft) ........... 37-41 (28-30)
Connecting rod bolt (M7x1,0), Nm (lb-ft) ........... 23-28 (17-20)
Flywheel clamping bolt (M10x1,25), Nm (lb-ft) ........... 80-86 (59-64)
Metal cap clamping bolt (M9x1,25), Nm (lb-ft) ........... 52-56 (38-41)
Crankshaft V-pulley clamping bolt (M12x1,5), Nm (lb-ft) ........... 113-123 (83-90)
Fuel injection nozzle nut (M20x1,5), Nm (lb-ft) ........... 49-53 (36-39)
Glow plug (M10x1,25), Nm (lb-ft) ........... 15-20 (11-15)
Stub shaft bolt (M10x1,5), Nm (lb-ft) ........... 54-64 (40-47)
Governor weight support nut (M12x1,25), Nm (lb-ft) ........... 69-74 (51-54)
High pressure pipe sleeve clamping nut (M12x1,5), Nm (lb-ft) ........... 29-34 (22-25)