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Yanmar 2TNE68 Engine

The Yanmar 2TNE68 is a four-stroke vertical two-cylinder indirect injection naturally aspirated liqiud-cooled diesel engine from TNE series. A 47.8 cubic inches (0.8 L) engine has a cylinder bore of 2.69" (68 mm), piston stroke of 2.85" (72 mm), and rated power of 11.5 Hp (8.5 kW) at 3000 rpm. The compression ratio rating is 23:1. The Yanmar 2TNE68 engine is equipped with a mechanical fuel injection pump, air cleaner with dry element, forced lubrication with trochoid pump, and starting system with electric starter. The operating weight is 143 lbs (65 kg).

General Technical Data

Engine Specifications

Engine Model ........... Yanmar 2TNE68
Engine Type ........... 4-cycle vertical 2-cylinder liquid-cooled diesel
Number of Cylinders ........... Two
Displacement, cu.in (L) ........... 47.8 (0.784)
Cylinder Bore, in (mm) ........... 2.69 (68.0)
Piston Stroke, in (mm) ........... 2.85 (72.0)
Maximum Engine Power, hp (kW) ........... 11.5 (8.5)
Maximum Engine Speed, rpm ........... 3000
Idling Speed, rpm ........... 2200
Aspiration Type ........... Naturally aspirated
Compression Ratio ........... 23:1
Firing Order ........... 1-2
Air Cleaner Type ........... Dry element
Lubrication System ........... Forced lubrication with trochoid pump
Oil Filter Type ........... Full Flow, replaceable
Cooling System ........... Liquid-cooled with radiator
Starting System ........... Electric Starter
Electrical System Rating, Volts ........... 12
Charging System ........... Alternator

Fuel System

Fuel System ........... Indirect injection
Fuel Pump Type ........... Mechanical
Governor Type ........... Mechanical, centrifugal
Fuel Filter Type ........... Replaceable element
Fuel Type ........... Diesel Fuel

Dimensions and Weight

Overall Width, in (mm) .......... 15.2 (385)
Overall Height, in (mm) .......... 16.4 (415)
Overall Depth, in (mm) .......... 19.7 (500)
Net Weight, lbs (kg) .......... 143 (65)

Maintenance Data

Engine Oil

Engine Oil Type (Summer) .......... SAE 10W-30
Engine Oil Type (Winter) .......... SAE 5W-20
API Service Classifications .......... CC or higher
Engine Oil Capacity, qts (L) .......... 2.6 (2.5)

Cylinder and Valves

Cylinder Compression, psi (MPa) .......... 470 (3.24)
Intake Valve Clearance, mm (in) .......... 0.20 (0.008)
Exhaust Valve Clearance, mm (in) .......... 0.20 (0.008)

Fuel System and Coolant Capacity

Injection Pump Timing, deg .......... 14±1, BTDC
Fuel Injection Nozzle Pressure, MPa (psi) .......... 11.8 (1710)
Fuel Supply Pump Pressure, kPa (psi) .......... 29 (4.3)
Coolant Capacity (Engine), qts (L) .......... 3.7 (3.5)

Service Specifications

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)
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 to bushing oil clearance, mm (in) .......... 0.033-0.059 (0.0013-0.0023)
Crankshaft journal bend, mm (in) .......... 0.020 (0.0008)
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)
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)
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)
Piston to cylinder clearance, mm (in) .......... 0.03-0.06 (0.0010-0.0022)
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 to piston pin clearance, mm (in) .......... 0.02 (0.0007)
Top ring width, mm (in) .......... 1.470-1.490 (0.0581-0.0589)
Top ring side clearance, mm (in) .......... 0.060-0.100 (0.0024-0.0040)
Top ring end gap, mm (in) .......... 0.100-0.250 (0.0040-0.0099)
Second ring width, mm (in) .......... 1.430-1.450 (0.0565-0.0573)
Second ring side clearance, mm (in) .......... 0.090-0.125 (0.0036-0.0049)
Second ring end gap, mm (in) .......... 0.150-0.350 (0.0059-0.0138)
Oil ring width, mm (in) .......... 2.970-2.990 (0.1174-0.1182)
Oil ring side clearance, mm (in) .......... 0.020-0.055 (0.0008-0.0022)
Oil ring end gap, mm (in) .......... 0.150-0.350 (0.0059-0.0138)

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 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 stem to valve guide 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 stem to valve guide clearance, mm (in) .......... 0.04-0.07 (0.0016-0.0028)
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)
Valve spring free length, mm (in) .......... 28.00 (1.1067)
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)
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)
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)

Tightening Torque Specs

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

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