The Cat 3126B engine is designed and built to take full advantage of a “gear fast, run slow” strategy. Unlike mechanically governed engines of the past, the fully electronic 3126B need not be gear-bound to limit maximum vehicle speed — this should be done using Vehicle Speed Limiting (VSL) and Protection.
For the best balance of performance and fuel economy, spec axle ratios and tire sizes to obtain: 2000 rpm @ 60 mph (97 km/h) subject to the following: Maximum cruise speed of 65 mph (105 km/h) or below. Maximum recommended engine speed at cruise — 2400 rpm. Minimum recommended engine speed at a cruise speed of 55 mph (89 km/hr) — 1800 rpm.
CAT 3126B Engine Specs
- 420-860 lb-ft @ 1440 rpm Peak Torque, 6-Cylinder, 4-Stroke-Cycle Diesel
- Bore — in (mm) - 4.33 (110)
- Stroke — in (mm) - 5.0 (127)
- Displacement — cu in (L) - 439 (7.2)
- Aspiration - ATAAC1
CAT 3126B Engine Compression Ratio
- 175-300 hp - 16:1
- Rotation (from flywheel end) - Counterclockwise
- Cooling System2 — gal (L) - 3.5 (13.2)
- Lube Oil System (refill) — gal (L) - 4.75 (18.0)3
- Weight, Net Dry (approx) — lb (kg)
- Including Flywheel - 1295 (588)
- 1 Air-to-Air AfterCooling
- 2 Engine Only. Capacity will vary with radiator size and use of cab heater.
- 3 Optional 28L (7.5 gal) oil pan also available in some chassis.
CAT 3126B Engine Accessory Equipment
- Air compressor: gear driven, 0.37 m3/min (13.2 cfm) or 0.46 m3/min(16.5 cfm)
- Air conditioner compressor mounting
- Air inlet elbow
- Auxiliary brake compatible (exhaust)
- Ether starting aid/adaptation
- Fan drive mounting bracket
- Fan drive
- Front engine support
- Front PTO adapter
- Jacket water heater
- Rear power take-off
- Starting motor: 12 V or 24 V
- Turbocharger compressor outlet elbow
- Hydraulic pump drive, SAE A
CAT 3126B Engine Standart Equipment
- Air inlet manifold heater
- Cooling: belt-driven jacket water pump, oil cooler
- Crankcase breather
- Electronic Control Module (ECM)
- Electronic Data Link, SAE J1922, J1939, ATA J1587
- HEUI Fuel System (Hydraulically actuated, Electronically controlled Unit Injector)
- Flywheel and SAE No. 1 or SAE No. 2 housing
- Fuel: spin-on secondary filter, transfer pump, hand priming pump
- Governor: full-range, electronically controlled
- Lifting eyes
- Lubrication: gear-driven pump, front or rear sump, full flow spin-on filter, left-hand side oil level gauge (dipstick)
- Turbocharger
- Vibration damper
CAT 3126B Engine Dimensions
Caterpillar 3126B Engine (DM3276) Performance Data
- Max hp (kW) - 175 (131)
- Advertised hp (kW) - 175 (131)
- Operating Range (rpm) - 1440-2500 (1060)
- Maximum Engine rpm - 2640
- Governed Speed rpm - 2500
- Peak Torque — lb-ft (N•m) - 420 (569)
- Peak Torque rpm - 1440
- Torque Rise (%) (Gov. rpm) - 25
- Altitude Capability — ft (m) - 10 000 (3050)
Caterpillar 3126B Engine (DM4201) Performance Data
- Max hp (kW) - 207 (154)
- Advertised hp (kW) - 190 (142)
- Operating Range (rpm) - 1440-2500 (1060)
- Maximum Engine rpm - 2640
- Governed Speed rpm - 2500
- Peak Torque — lb-ft (N•m) - 520 (705)
- Peak Torque rpm - 1440
- Torque Rise (%) (Gov. rpm) - 27
- Altitude Capability — ft (m) - 10 000 (3050)
Caterpillar 3126B Engine (DM3287) Performance Data
- Max hp (kW) - 330 (246)
- Advertised hp (kW) - 330 (246)
- Operating Range (rpm) - 1440-2400 (960)
- Maximum Engine rpm - 2640
- Governed Speed rpm - 2400
- Peak Torque — lb-ft (N•m) - 860 (1166)
- Peak Torque rpm - 1440
- Torque Rise (%) (Gov. rpm) - 19
- Altitude Capability — ft (m) - 10 000 (3050)
CAT 3126B Engine Electronic Features
- Electronic self-diagnostics
- Compatible with Caterpillar electronic technician (ET), electronic control analyzer programmer (ECAP), and MPSI Pro-Link service tools
- Cold weather startup strategy and electronic idle control functions
- ECM storage of operational, maintenance, and diagnostic data
- J1939 compatible — ABS, Allison WT
- Customer selectable, re-programmable operational parameters:
• Engine Monitoring System — off, warning, derate, or shutdown
• Cruise control with exclusive SoftCruise
• Vehicle speed [mph (km/h)] limiting and protection
• Idle shutdown timer & override
• 2-speed fast idle
• Maintenance monitor [miles (km) or hours]
• Cooling fan control
• Customer password protection
• Exhaust brake operational modes
• Theft deterrent
• Adjustable low idle rpm
• OEM parameter lockout - Programmable Power Take-Off (PTO) functions:
• Adjustable speed control [mph (km/h)] of vehicle while in PTO mode
• Adjustable maximum engine rpm speed
• Adjustable minimum engine rpm speed
• Limit engine torque to driven equipment
• Adjustable ramp rate up or down between PTO set speed(s)
• Adjustable rpm “bump” intervals
• Selectable PTO configuration for “in cab” or station of remote operation
CAT 3126B Gearing Considerations
Depending on the application, the absolute minimum startability in first gear should be 6 percent, preferably in excess of 10 %.
On/off highway severe
service applications will require considerably greater startability.
Minimum gradeability should be 1.5 percent (1.8 percent recommended) at
peak torque in top gear, and 0.5 percent at cruise rpm.
To
further optimize the matching of your truck to the performance
characteristics of the engine, a computerized spec’ing tool called
Caterpillar Truck Engine Pro (TEP) is offered by your Caterpillar
dealer. It calculates the effects of various driveline variables on
engine operation such as transmissions, axles, and tires. This lets you
see the results before you finalize your truck specs.
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