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Continental TM20 Engine

The Continental TM20 is an industrial-grade, heavy-duty internal combustion engine developed by the Wisconsin Motors / Continental group. Engineered for longevity and ease of service, this 3-cylinder overhead-valve (OHV) powerplant is designed for heavy-duty applications, commonly found in industrial equipment, skid steer loaders (such as the Case 1835C and New Holland L554), and specialized utility machinery. The engine features solid-state electronic ignition, heavy cast-iron blocks with full-surrounding water jackets, and individual cylinder porting to optimize thermal management and overall output efficiency under prolonged, variable loads.

The engine employs an overhead valve (OHV) arrangement actuated via a classic pushrod system from a single gear-driven camshaft. There are two valves per cylinder (one intake and one exhaust). Valve clearances must be adjusted periodically when cold to maintain peak volumetric efficiency. The engine architecture uses a standard square-leaning geometry optimized for high low-end torque profiles. The cylinder barrel bore diameter is 91.0 mm (3.583 inches). The piston travel distance or stroke length is 103.2 mm (4.063 inches).

Fuel System: The TM20 configuration supports dedicated low-pressure gasoline or liquefied petroleum gas (LPG) delivery configurations. Fuel delivery is handled either by a low-pressure mechanical pull pump or an auxiliary electric transfer pump supplying constant flow to a heavy-duty single-barrel down-draft carburetor (typically Zenith or CK models). These industrial carburetors utilize a fixed high-speed main metering jet for consistent fuel mixture profiles at governor-regulated RPMs, paired with an adjustable low-speed idle mixture screw and mechanical butterfly valve linked directly to a centrifugal cam-gear governor system.

Lubrication is managed through a full-pressure system driven by a internal Gerotor-style oil pump. Oil is pulled through an inlet screen and directed through a spin-on full-flow filtration system. Standard operating oil pressure must be maintained between 2.8 to 4.1 Bar (40 to 60 PSI) at operational speeds. At warm idle, oil pressure should not drop below a critical minimum threshold of 0.5 Bar (7 PSI). Regular oil and filter replacements are mandatory every 50 to 100 operating hours depending heavily on dust and dirt levels in the operating environment.

Thermal regulation uses a force-circulated liquid coolant system driven by a belt-powered water pump assembly. The cooling passages feature complete, surrounding water jackets cast directly around the cylinder walls. System flow is regulated by a pellet-type thermostat designed to begin opening at 81C (178F) and achieve maximum wide-open flow state at 94C (201F). System pressure is contained by a radiator pressure cap rated between 0.3 to 1.0 Bar depending on application specifications.

General Technical Data

Engine Specifications

Engine Model ............... Continental TM20
Engine Type ............... 4-cycle inline 3-cylinder OHV liquid-cooled gasoline/LPG
Number of Cylinders ............... 3
Cylinder Arrangement ............... In-line vertical
Engine Bore, in (mm) ............... 3.583 (91.00)
Engine Stroke, in (mm) ............... 4.063 (103.20)
Displacement, cu.in (L) ............... 123 (2.0)
Rated Engine Power, hp (kW) ............... 45-52 (33.5-38.8)
Rated Engine Speed, rpm ............... 2000-2500
Peak Torque ............... 105-115 Nm (77-85 lb-ft) at 1400-1600 rpm
Idle Speed, rpm ............... 750-850
Governed High Idle Speed, rpm ............... 2400-2600
Compression Ratio ............... 8.2:1
Firing Order ............... 1-3-2
Camshaft Drive Type ............... Helical gear train system direct mesh
Number of Main Bearings ............... 4
Crankshaft Material Type ............... Forged steel
Valve Configuration ............... Overhead valve pushrod actuated 2 per cylinder
Cylinder Block Type ............... Cast iron alloy heavy duty Monoblock
Cylinder Head Type ............... Cast iron alloy cross-flow design single piece
Lubrication System Type ............... Full-pressure circulation type
Oil Pump Type ............... Gear-driven internal rotor pump assembly
Oil Filter Type ............... Full-flow spin-on disposable canister element
Cooling System Type ............... Forced liquid circulation
Water Pump Type ............... Belt-driven centrifugal impeller
Air Cleaner Type ............... Heavy duty dry dual-stage element
Ignition System ............... Solid state electronic distributor ignition
Starting System Type ............... Electric starter motor
Electrical System, V ............... 12
Alternator Charging, A ............... 37-55

Fuel System

Carburetor Manufacturer Type ............... Zenith model series updraft side-draft choice
LPG Regulator Converter ............... Impco model series secondary pressure reduction system
Fuel Transfer Pump Type ............... Mechanical diaphragm type camshaft lobe actuated
Fuel Transfer Pump Pressure, psi (bar) ............... 3.5-5.0 (0.24-0.34)
LPG Fuel Lock-Off Valve ............... 12V electronic solenoid valve unit assembly
Main Metering Jet Diameter, in (mm) ............... 0.047 (1.20)
Idle Metering Jet Size, in (mm) ............... 0.028 (0.71)
Governor Type ............... Mechanical centrifugal
Choke Valve Control Mechanism ............... Manual cable setup or automatic thermal element
Throttle Bore Diameter, in (mm) ............... 1.25 (31.75)
Fuel Inlet Connection Size, in ............... 0.25
Air Horn Diameter Size, in (mm) ............... 2.062 (52.37)
Fuel Filter Housing Rating, microns ............... 10-15 standard filtering efficiency
Fuel Economy Optimum Range, lb hp-hr (g kW-hr) ............... 0.52 (316)
LPG Vaporizer Operating Temperature, F (C) ............... 160-185 (71-85)
Carburetor Float Level Setting, in (mm) ............... 1.22 (31.00)
Idle Mixture Screw Adjustment ............... 1.25-1.50 turns
Fuel Tank Vent System ............... Atmospheric open loop style filtered design

Dimensions and Weight

Overall Length, in (mm) ............... 24.12 (615)
Overall Width, in (mm) ............... 19.85 (505)
Overall Height, in (mm) ............... 26.54 (675)
Dry Weight, lbs (kg) ............... 385 (175)
Operating Weight, lbs (kg) ............... 415 (188)

Maintenance Data

Service Information

Compression Pressure, Minimum, psi (bar) ............... 120 (8.3)
Maximum Allowed Cylinder Variance, psi (bar) ............... 15 (1.0)
Standard Crankcase Oil Pressure, psi (bar) ............... 30-50 (2.1-3.4)
Minimum Idle Oil Pressure, psi (bar) ............... 10 (0.69)
Thermostat Opening Temperature, F (C) ............... 180 (82.2)
Thermostat Full Open Temperature, F (C) ............... 202 (94.4)
Cooling System Cap Pressure Rating, psi (bar) ............... 7.0-9.0 (0.48-0.62)
Fan Belt Deflection Tension, in (mm) ............... 0.50 (12.7)
Spark Plug Gap, in (mm) ............... 0.025 (0.64)
Breaker Points Gap, in (mm) ............... 0.020 (0.51)
Ignition Timing, deg BTDC ............... 4-24
Intake Valve Clearance, Cold, in (mm) ............... 0.012 (0.30)
Exhaust Valve Clearance, Cold, in (mm) ............... 0.014 (0.35)

Engine Oil and Coolant

Engine Oil Type ............... SAE 30, SAE 10W-30, or 20W-20
API Service Classifications ................. SE, SF, SE/CD
Engine Oil Capacity with Filter, qt (L) ............... 5.0 (4.7)
Engine Oil Capacity without Filter, qt (L) ............... 4.5 (4.3)
Cooling System Fluid Capacity, qt (L) ............... 7.5 (7.1)

Service Intervals

Change oil and filter ............... Every 100 hours
Replace/clean fuel filters ............... Every 250 hours
Inspect air cleaner ............... Every 50 hours
Change air filter ............... Every 250 hours
Change coolant ............... Every 1000 hours
Valve-lash adjustment ............... Every 500 hours
Distributor point inspection ............... Every 300 hours
Spark plug replacement ............... Every 500 hours
Compression test evaluation ............... Every 300 hours
Belt tension verification ............... Every 300 hours
Check ignition timing ............... Every 300 hours

Service Specifications

Cylinder Bore Standard Diameter, in (mm) ............... 3.5825-3.5835 (90.995-91.021)
Cylinder Bore Maximum Out of Round, in (mm) ............... 0.0010 (0.025)
Cylinder Bore Max Taper Allowed, in (mm) ............... 0.0015 (0.038)
Cylinder Liner Sleeve Press Fit Force Block, in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Crankshaft Main Journal Outer Diameter, in (mm) ............... 2.8718-2.8730 (72.943-72.974)
Crankshaft Main Bearing Bore in Block, in (mm) ............... 3.0665-3.0675 (77.889-77.914)
Crankshaft Main Bearing Oil Clearance, in (mm) ............... 0.0015-0.0035 (0.038-0.089)
Crankshaft End Play, in (mm) ............... 0.004-0.008 (0.10-0.20)
Connecting Rod Journal Outer Diameter, in (mm) ............... 1.9365-1.9375 (49.187-49.212)
Connecting Rod Big End Bore Diameter, in (mm) ............... 2.0620-2.0625 (52.374-52.387)
Connecting Rod Bearing Oil Clearance, in (mm) ............... 0.0012-0.0032 (0.030-0.081)
Connecting Rod Bushing Internal Bore, in (mm) ............... 1.1255-1.1260 (28.587-28.600)
Connecting Rod Side Play, in (mm) ............... 0.007-0.013 (0.18-0.33)
Piston Skirt Standard Diameter, in (mm) ............... 3.5795-3.5805 (90.919-90.944)
Piston to Cylinder Wall Clearance, in (mm) ............... 0.0025-0.0035 (0.063-0.089)
Piston Pin Outer Diameter, in (mm) ............... 1.1245-1.1250 (28.562-28.575)
Piston Pin to Piston Bushing Fit, in (mm) ............... 0.0003-0.0007 (0.007-0.017)
Top Ring Groove Width, in (mm) ............... 0.0805-0.0815 (2.044-2.070)
Second Ring Groove Width, in (mm) ............... 0.0805-0.0815 (2.044-2.070)
Oil Ring Groove Width, in (mm) ............... 0.1585-0.1595 (4.025-4.051)
Top Ring End Gap, in (mm) ............... 0.010-0.018 (0.25-0.45)
Second Ring End Gap, in (mm) ............... 0.010-0.018 (0.25-0.45)
Oil Ring End Gap, in (mm) ............... 0.010-0.020 (0.25-0.51)
Intake Valve Stem Outer Diameter, in (mm) ............... 0.3410-0.3415 (8.661-8.674)
Exhaust Valve Stem Outer Diameter, in (mm) ............... 0.3400-0.3405 (8.636-8.648)
Intake Valve Stem to Guide Clearance, in (mm) ............... 0.0015-0.0030 (0.038-0.076)
Exhaust Valve Stem to Guide Clearance, in (mm) ............... 0.0025-0.0040 (0.063-0.101)
Intake Valve Seat Width, in (mm) ............... 0.046-0.062 (1.17-1.57)
Exhaust Valve Seat Width, in (mm) ............... 0.062-0.078 (1.57-1.98)
Valve Guide Internal Bore Diameter, in (mm) ............... 0.3430-0.3440 (8.712-8.737)
Valve Guide Outer Diameter, in (mm) ............... 0.501-0.502 (12.72-12.75)
Valve Seat Angle, deg ............... 45
Valve Face Angle, deg ............... 45
Valve Seat Runout Maximum, in (mm) ............... 0.002 (0.05)
Valve Spring Free Length, in (mm) ............... 1.82 (46.2)
Camshaft Journal Outer Diameter (Front), in (mm) ............... 1.996-1.997 (50.69-50.72)
Camshaft Journal Outer Diameter (Center), in (mm) ............... 1.965-1.966 (49.91-49.93)
Camshaft Journal Outer Diameter (Rear), in (mm) ............... 1.872-1.873 (47.54-47.57)
Camshaft Bearing Bore in Engine Block, in (mm) ............... 2.124-2.126 (53.95-54.00)
Camshaft Bearing Oil Clearance, in (mm) ............... 0.0015-0.0035 (0.038-0.089)
Camshaft End Play, in (mm) ............... 0.003-0.007 (0.07-0.17)
Cam Lobe Height (Intake), in (mm) ............... 0.285 (7.23)
Cam Lobe Height (Exhaust), in (mm) ............... 0.285 (7.23)
Cylinder Head Flatness, Maximum Warp, in (mm) ............... 0.003 (0.076)
Rocker Shaft Outer Diameter, in (mm) ............... 0.748-0.749 (18.99-19.02)
Rocker Arm Bushing Internal Bore, in (mm) ............... 0.750-0.751 (19.05-19.07)
Rocker Arm to Shaft Oil Clearance, in (mm) ............... 0.001-0.003 (0.025-0.076)
Tappet Valve Lifter Body Diameter, in (mm) ............... 0.998-0.999 (25.34-25.37)
Tappet Lifter Bore in Block Diameter, in (mm) ............... 1.000-1.001 (25.40-25.42)
Tappet Lifter Body Clearance, in (mm) ............... 0.001-0.003 (0.025-0.076)

Tightening Torques

Cylinder Head Fasteners (Step 1), Nm (lb-ft) ............... 40 (30)
Cylinder Head Fasteners (Step 2), Nm (lb-ft) ............... 80 (59)
Cylinder Head Fasteners (Step 3), Nm (lb-ft) ............... 122-129 (90-95)
Main Bearing Cap Fasteners, Nm (lb-ft) ............... 115-122 (85-90)
Connecting Rod Cap Special Bolt, Nm (lb-ft) ............... 61-68 (45-50)
Flywheel Retaining Bolts to Crankshaft, Nm (lb-ft) ............... 75-81 (55-60)
Crankshaft Vibration Damper Pulley Bolt, Nm (lb-ft) ............... 176-190 (130-140)
Camshaft Thrust Plate Retaining Bolts, Nm (lb-ft) ............... 24-30 (18-22)
Camshaft Timing Gear Center Hub Bolt, Nm (lb-ft) ............... 81-88 (60-65)
Rocker Arm Shaft Support Bracket Bolts, Nm (lb-ft) ............... 34-41 (25-30)
Valve Rocker Arm Cover Gasket Screws, Nm (lb-ft) ............... 8-11 (6-8)
Timing Gear Case Cover Outer Fasteners, Nm (lb-ft) ............... 20-24 (15-18)
Timing Gear Case Backplate to Block Bolts, Nm (lb-ft) ............... 34-41 (25-30)
Oil Pan Sump Perimeter Rail Fasteners, Nm (lb-ft) ............... 16-20 (12-15)
Oil Pan Sump Bottom Drain Plug Bolt, Nm (lb-ft) ............... 47-54 (35-40)
Oil Pump Assembly Internal Housing Screws, Nm (lb-ft) ............... 20-24 (15-18)
Oil Pump Pickup Tube Support Flange Bracket, Nm (lb-ft) ............... 24-30 (18-22)
Intake Manifold Flange Fasteners to Head, Nm (lb-ft) ............... 27-34 (20-25)
Exhaust Manifold Flange Fasteners to Head, Nm (lb-ft) ............... 34-41 (25-30)
Water Pump Assembly Housing to Block Bolts, Nm (lb-ft) ............... 24-30 (18-22)
Water Pump Pulley Retaining Fasteners, Nm (lb-ft) ............... 16-22 (12-16)
Thermostat Housing Water Outlet Flange Bolts, Nm (lb-ft) ............... 20-26 (15-19)
Distributor Clamp Hold Down Locking Bolt, Nm (lb-ft) ............... 16-22 (12-16)
Spark Plugs Thread Engagement Seating Torque, Nm (lb-ft) ............... 27-34 (20-25)
Alternator Mounting Pivot Frame Bracket Bolt, Nm (lb-ft) ............... 41-47 (30-35)
Alternator Adjusting Link Tensioner Arm Bolt, Nm (lb-ft) ............... 20-26 (15-19)
Electric Starter Motor Mounting Flange Bolts, Nm (lb-ft) ............... 47-54 (35-40)
Governor Housing Assembly Attachment Bolts, Nm (lb-ft) ............... 24-30 (18-22)
Fuel Transfer Pump Flange Mounting Screws, Nm (lb-ft) ............... 16-22 (12-16)
Carburetor Mounting Flange Stud Nuts, Nm (lb-ft) ............... 20-24 (15-18)
Flywheel Housing to Engine Block Studs, Nm (lb-ft) ............... 54-61 (40-45)
Oil Pressure Sensor Sender Hex Body Unit, Nm (lb-ft) ............... 14-18 (10-13)
Coolant Temperature Sensor Hex Body Unit, Nm (lb-ft) ............... 16-20 (12-15)
Front Crankshaft Seal Carrier Retaining Bolts, Nm (lb-ft) ............... 11-15 (8-11)
Rear Crankshaft Seal Housing Retaining Bolts, Nm (lb-ft) ............... 11-15 (8-11)
Cylinder Block Oil Gallery Core Plugs Threaded, Nm (lb-ft) ............... 27-34 (20-25)
Cylinder Block Drain Cock Water Valve Body, Nm (lb-ft) ............... 14-20 (10-15)
Air Cleaner Housing Assembly Bracket Fasteners, Nm (lb-ft) ............... 16-22 (12-16)
Fan Blade Assembly Attachment Hub Bolts, Nm (lb-ft) ............... 16-22 (12-16)
Exhaust Pipe Flange to Manifold Stud Nuts, Nm (lb-ft) ............... 41-47 (30-35)
LPG Regulator Lock-off Assembly Bracket Bolts, Nm (lb-ft) ............... 20-26 (15-19)
Choke Cable Clip Retaining Small Screw, Nm (lb-in) ............... 3-4 (25-35)
Throttle Linkage Ball Joint Lock Nuts, Nm (lb-in) ............... 5-7 (45-60)
Crankcase Breather Baffle Plate Screws, Nm (lb-ft) ............... 8-11 (6-8)
Oil Screen Support Stiffener Bracket Bolt, Nm (lb-ft) ............... 24-30 (18-22)
Main Oil Gallery End Cap Plug Fasteners, Nm (lb-ft) ............... 41-47 (30-35)
Rocker Arm Adjusting Screw Lock Nuts Jam Nuts, Nm (lb-ft) ............... 16-20 (12-15)
Governor Control Shaft Lever Clamp Bolt, Nm (lb-ft) ............... 11-14 (8-10)

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• Continental Engines Specs
  
• Continental F209 Specs
  
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• Continental G193 Specs
  
• Continental M330 Specs
  
• Continental N62 Specs
  
• Continental TM27 Specs
  

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