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Yanmar 2TR16 Engine

The Yanmar 2TR16 is a vertical, two-cylinder, liquid-cooled, four-stroke diesel engine produced by Yanmar for agricultural and compact utility applications. It serves as the primary powerplant for the Yanmar YM1600 compact utility tractor. Characterized by its cast-iron overhead-valve cylinder block design, this engine is engineered for low-speed torque stability, fuel efficiency, and heavy-duty operation in demanding agricultural environments. Bore: 85 mm (3.35 inches). Stroke: 90 mm (3.54 inches). Total Displacement: 1.0 Liter (62.3 cubic inches).

The engine uses an overhead valve (OHV) arrangement driven by a gear-propelled camshaft located within the cylinder block. A standard pushrod and rocker arm assembly actuates two valves per cylinder (one intake and one exhaust). Access for valve lash adjustment and cylinder head servicing is provided via a removable top rocker cover. A mechanical decompression lever is integrated into the rocker mechanism to assist with manual crank rotation or cold-weather starting.

Fuel delivery is managed via a mechanical indirect injection system utilizing a pre-combustion chamber design. Diesel fuel is drawn from the fuel storage tank by a mechanical fuel feed pump and passes through a primary inline fuel filter assembly to remove moisture and particulate contaminants. The filtered fuel is then supplied to a dedicated multi-plunger mechanical fuel injection pump, which times and pressurizes the fuel. This high-pressure fuel is distributed through rigid steel lines to the individual fuel injection valves (nozzles) mounted in the cylinder head. Engine speed control is managed via a mechanical governor linkage coupled directly to the fuel injection limiter and the operator-controlled throttle speed lever.

Lubrication is managed by a forced-pressure feed system driven by a trochoid-type oil pump. The pump draws lubricating oil from the bottom oil pan through an internal screen assembly and delivers it to the main bearings, connecting rod journals, and overhead valve train components. System pressure is regulated by an integrated spring-loaded relief valve. Structural maintenance components include a spin-on full-flow oil filter element, a crankcase dipstick for oil level verification, and a dedicated oil pressure sender unit for system monitoring.

The engine utilizes a thermosiphon or forced liquid-cooling system designed to maintain optimal thermal stability. Coolant is continuously circulated through internal water jackets surrounding the cylinder liners and the cylinder head combustion chambers. System flow is driven by a belt-connected, external cooling water pump mounted to the front housing. Standard maintenance features include an engine-driven cooling fan, an integrated thermostat to regulate operational temperatures, and a block-mounted cooling water drain cock to allow for complete system draining.

General Technical Data

Engine Specifications

Engine Model ............... Yanmar 2TR16
Engine Type ............... 4-cycle inline 2-cylinder direct injection liquid-cooled diesel
Number of Cylinders ............... 2
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 3.35 (85.0)
Engine Stroke, in (mm) ............... 3.54 (90.0)
Displacement, cu.in (L) ............... 62.3 (1.021)
Rated Engine Power, hp (kW) ............... 15.8 (11.8)
Rated Engine Speed, rpm ............... 2300
Peak Torque ............... 39.1 Nm (28.8 lb-ft) at 1600 rpm
Idle Speed ............... 700-800 rpm
Aspiration Type ............... Naturally Aspirated
Operating Speed ............... 2300 rpm
Compression Ratio ............... 20.0:1
Firing Order ............... 1-2
Combustion System ............... Direct injection spherical chamber
Piston Material ............... Aluminum alloy silicon impregnated
Connecting Rod Material ............... Forged carbon steel
Crankshaft Material ............... Forged alloy steel fully counterweighted
Valve Mechanism ............... Overhead valve pushrod driven
Intake Valves Per Cylinder ............... 1
Exhaust Valves Per Cylinder ............... 1
Cylinder Block Type ............... Cast iron
Cylinder Head Type ............... Cast iron
Lubrication System ............... Full-pressure trochoid pump
Oil Pump Type ............... Gear-driven trochoid pump
Oil Filter Type ............... Full-flow, spin-on
Cooling System ............... Liquid-cooled Thermo-Siphon
Air Cleaner Type ............... Dry dual-stage element
Starting System ............... Electric Starter
Electrical System ............... 12V
Alternator Capacity ............... 12V 15A

Fuel System

Fuel Injection Pump Model ............... Yanmar Deck type inline PFR
Injection Pump Feed Type ............... Gravity feed with mechanical lift option
Plunger Diameter, in (mm) ............... 0.236 (6.0)
Plunger Stroke, in (mm) ............... 0.275 (7.0)
Injection Timing ............... 22 degrees before top dead center
Injection Start Pressure, psi (bar) ............... 2275 (157)
Fuel Delivery Control ............... Mechanical rack and pinion linkage
Fuel Feed Pump Pressure, psi (bar) ............... 2.8-4.2 (0.2-0.3)
Fuel Filter Element Type ............... Paper element spin-on cartridge
Fuel Injection Nozzle Type ............... Throttle multi-hole type
Number of Nozzle Hole ............... 4
Nozzle Hole Diameter, in (mm) ............... 0.0098 (0.25)
Injection Spray Angle ............... 150 degrees
Fuel Return System ............... Over-flow return line to tank
Maximum Fuel System Lift, ft (m) ............... 3.3 (1.0)
Governor Type ............... Mechanical centrifugal
Governor High Speed Limit, rpm ............... 2450
Governor Low Speed Limit, rpm ............... 650
Fuel Specification ............... ASTM D975 No. 2-D diesel

Dimensions and Weight

Overall Length, in (mm) ............... 21.8 (555)
Overall Width, in (mm) ............... 17.6 (445)
Overall Height, in (mm) ............... 23.4 (595)
Dry Weight, lbs (kg) ............... 341 (155)
Operating Weight, lbs (kg) ............... 366 (166)

Maintenance Data

Service Information

Compression Pressure, Minimum, psi (bar) ............... 398 (27.5)
Compression Pressure, Service Limit, psi (bar) ............... 313 (21.6)
Compression Pressure Between Cylinders ............... 28.4 psi (2.0 bar)
Oil Pressure at Low Idle, psi (bar) ............... 14.2 (0.98)
Oil Pressure at Rated Speed, psi (bar) ............... 42.6-56.8 (2.94-3.92)
Pressure Regulating Valve Setting, psi (bar) ............... 56.8 (3.92)
Fan Belt Tension Deflection, in (mm) ............... 0.39-0.55 (10.0-14.0)
Intake Valve Clearance, mm (in) ............... 0.006-0.008 (0.15-0.20)
Exhaust Valve Clearance, mm (in) ............... 0.006-0.008 (0.15-0.20)

Engine Oil and Coolant

Engine Oil Type .................. SAE 30, SAE 10W-30, or SAE 5W-30
API Service Classifications ......................... CD or higher
Engine Oil Capacity, Sump, qt (L) ............... 3.17 (3.0)
Engine Oil Capacity, Total, qt (L) ............... 3.48 (3.3)
Cooling System Capacity, qt (L) ............... 4.75 (4.5)

Service Intervals

Change oil and filter ............... Every 100 hours
Inspect air cleaner ............... Every 50 hours
Replace air cleaner ............... Every 400 hours
Replace fuel filter ............... Every 200 hours
Valve clearance adjustment ............... Every 300 hours
Fuel system inspection ............... Every 500 hours
Change coolant ............... Every 1000 hours
Compression test ............... Every 1000 hours
Clean radiator core ............... Every 200 hours
Inspect belt tension ............... Every 100 hours

Service Specifications

Cylinder Bore Inside Diameter Standard, in (mm) ............... 3.3464-3.3476 (85.000-85.030)
Cylinder Bore I.D Wear Limit, in (mm) ............... 3.3543 (85.200)
Crankshaft Main Journal Outside Diameter, in (mm) ............... 2.1236-2.1242 (53.940-53.955)
Crankshaft Main Bearing Clearance, in (mm) ............... 0.0015-0.0035 (0.038-0.090)
Crankshaft Main Bearing Clearance Limit, in (mm) ............... 0.0059 (0.150)
Crankpin Journal Outside Diameter, in (mm) ............... 1.7692-1.7698 (44.940-44.955)
Crankpin Bearing Clearance, in (mm) ............... 0.0014-0.0033 (0.035-0.085)
Crankshaft Thrust Play, in (mm) ............... 0.0043-0.0090 (0.110-0.230)
Connecting Rod Big End ID, in (mm) ............... 1.8897-1.8904 (48.000-48.016)
Connecting Rod Big End Side Clearance, in (mm) ............... 0.0059-0.0118 (0.150-0.300)
Piston Skirt Outside Diameter, in (mm) ............... 3.3429-3.3441 (84.910-84.940)
Piston Skirt O.D Wear Limit, in (mm) ............... 3.3366 (84.750)
Piston to Cylinder Bore Clearance, in (mm) ............... 0.0035-0.0047 (0.090-0.120)
Piston Pin Outside Diameter, in (mm) ............... 1.0233-1.0236 (25.993-26.000)
Piston Pin O.D Wear Limit, in (mm) ............... 1.0212 (25.940)
Piston Pin Boss Inside Diameter, in (mm) ............... 1.0237-1.0241 (26.002-26.011)
Piston Pin to Small End Bushing Clearance, in (mm) ............... 0.0005-0.0013 (0.012-0.033)
Top Ring Groove Width, in (mm) ............... 0.0807-0.0815 (2.050-2.070)
Second Ring Groove Width, in (mm) ............... 0.0807-0.0815 (2.050-2.070)
Oil Ring Groove Width, in (mm) ............... 0.1582-0.1590 (4.020-4.040)
Top Ring Side Clearance, in (mm) ............... 0.0027-0.0041 (0.070-0.105)
Second Ring Side Clearance, in (mm) ............... 0.0017-0.0031 (0.045-0.080)
Oil Ring Side Clearance, in (mm) ............... 0.0011-0.0027 (0.030-0.070)
Top Ring End Gap, in (mm) ............... 0.0098-0.0157 (0.250-0.400)
Second Ring End Gap, in (mm) ............... 0.0098-0.0157 (0.250-0.400)
Oil Ring End Gap, in (mm) ............... 0.0078-0.0157 (0.200-0.400)
Intake Valve Stem Outside Diameter, in (mm) ............... 0.3130-0.3135 (7.950-7.965)
Exhaust Valve Stem Outside Diameter, in (mm) ............... 0.3110-0.3116 (7.900-7.915)
Valve Guide Inside Diameter, in (mm) ............... 0.3149-0.3155 (8.000-8.015)
Intake Valve Stem to Guide Clearance Standard, in (mm) ............... 0.0013-0.0025 (0.035-0.065)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0033-0.0045 (0.085-0.115)
Intake Valve Recess Depth, in (mm) ............... 0.027-0.039 (0.7-1.0)
Exhaust Valve Recess Depth, in (mm) ............... 0.027-0.039 (0.7-1.0)
Intake Valve Seat Width, in (mm) ............... 0.047-0.059 (1.20-1.50)
Exhaust Valve Seat Width, in (mm) ............... 0.047-0.059 (1.20-1.50)
Valve Seat Angle ............... 45 degrees
Valve Spring Free Length, in (mm) ............... 1.653 (42.0)
Camshaft Journal O.D (Front), in (mm) ............... 1.6511-1.6519 (41.940-41.960)
Camshaft Journal O.D (Middle), in (mm) ............... 1.6118-1.6125 (40.940-40.960)
Camshaft Journal O.D (Rear), in (mm) ............... 1.5724-1.5732 (39.940-39.960)
Camshaft Bearing Clearance, in (mm) ............... 0.0015-0.0039 (0.040-0.100)
Cam Lobe Height (Intake), in (mm) ............... 1.3523-1.3555 (34.350-34.430)
Cam Lobe Height (Exhaust), in (mm) ............... 1.3523-1.3555 (34.350-34.430)
Camshaft Thrust Play, in (mm) ............... 0.0019-0.0059 (0.050-0.150)
Tappet Outside Diameter, in (mm) ............... 0.4704-0.4712 (11.950-11.970)
Tappet Guide Hole Inside Diameter, in (mm) ............... 0.4724-0.4731 (12.000-12.018)
Tappet to Guide Clearance, in (mm) ............... 0.0011-0.0026 (0.030-0.068)
Rocker Arm Bushing Inside Diameter, in (mm) ............... 0.5511-0.5519 (14.000-14.018)
Rocker Arm Shaft Outside Diameter, in (mm) ............... 0.5496-0.5503 (13.960-13.980)
Rocker Arm Bushing to Shaft Clearance, in (mm) ............... 0.0007-0.0022 (0.020-0.058)

Tightening Torques

Cylinder Head M10 Bolts ............... 54.2-65.0 Nm (40.0-47.9 lb-ft)
Cylinder Head M12 Bolts ............... 86.8-93.9 Nm (64.0-69.2 lb-ft)
Connecting Rod Cap Bolts ............... 39.7-43.3 Nm (29.3-31.9 lb-ft)
Main Bearing Cap M10 Bolts ............... 54.2-61.4 Nm (40.0-45.3 lb-ft)
Main Bearing Cap M12 Bolts ............... 86.8-93.9 Nm (64.0-69.2 lb-ft)
Flywheel Retaining Bolts ............... 68.6-75.7 Nm (50.6-55.8 lb-ft)
Crankshaft Pulley Center Nut ............... 115.6-122.8 Nm (85.2-90.5 lb-ft)
Camshaft Thrust Plate Retaining Bolts ............... 22.5-28.9 Nm (16.6-21.3 lb-ft)
Camshaft Timing Gear Center Bolt ............... 57.8-65.0 Nm (42.6-47.9 lb-ft)
Rocker Arm Shaft Support Bracket Nut ............... 22.5-28.9 Nm (16.6-21.3 lb-ft)
Valve Cover Retaining Cap Nuts ............... 7.2-9.6 Nm (5.3-7.0 lb-ft)
Oil Pan Drain Plug ............... 54.2-61.4 Nm (40.0-45.3 lb-ft)
Oil Pan Perimeter Securing Bolts ............... 8.4-11.6 Nm (6.2-8.5 lb-ft)
Fuel Injection Pump Delivery Valve Holder ............... 39.2-44.1 Nm (28.9-32.5 lb-ft)
Fuel Injection Pump Securing Nuts ............... 22.5-28.9 Nm (16.6-21.3 lb-ft)
Fuel Injector Assembly Clamp Bolt ............... 24.5-29.4 Nm (18.0-21.6 lb-ft)
Fuel Injector Case Nozzle Retaining Nut ............... 39.2-49.0 Nm (28.9-36.1 lb-ft)
Fuel High Pressure Line Union Nuts ............... 24.5-29.4 Nm (18.0-21.6 lb-ft)
Fuel Return Line Overflow Joint Bolt ............... 9.8-12.7 Nm (7.2-9.3 lb-ft)
Exhaust Manifold Securing Nuts ............... 24.5-29.4 Nm (18.0-21.6 lb-ft)
Intake Manifold Securing Bolts ............... 22.5-28.9 Nm (16.6-21.3 lb-ft)
Oil Pump Assembly Securing Screws ............... 22.5-28.9 Nm (16.6-21.3 lb-ft)
Oil Pressure Switch Sensor ............... 14.7-19.6 Nm (10.8-14.4 lb-ft)
Thermostart Glow Plug ............... 19.6-24.5 Nm (14.4-18.0 lb-ft)
Starter Motor Securing Flange Bolts ............... 42.6-49.0 Nm (31.4-36.1 lb-ft)
Alternator Pivot Mount Bolt ............... 42.6-49.0 Nm (31.4-36.1 lb-ft)
Alternator Tension Link Lock Bolt ............... 19.6-24.5 Nm (14.4-18.0 lb-ft)
Flywheel Housing Adaptor Mounting Bolts ............... 42.6-49.0 Nm (31.4-36.1 lb-ft)
Timing Gear Case Outer Shield Fasteners ............... 22.5-28.9 Nm (16.6-21.3 lb-ft)
Idler Gear Shaft Retaining Hex Head Bolt ............... 24.5-29.4 Nm (18.0-21.6 lb-ft)
Oil Filter Housing Adapter Plate Studs ............... 19.6-24.5 Nm (14.4-18.0 lb-ft)
Water Drain Cock Assembly Side Block Port ............... 14.7-19.6 Nm (10.8-14.4 lb-ft)

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• Yanmar 2TR20A Specs
  

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