Allis Chalmers B Overview
The Allis Chalmers B was built from 1938 through 1957 as a small row-crop tractor for mid-century farms.
Most B tractors came from West Allis, Wisconsin, and the model changed enough over time that serial range and engine matter. Engine entries include an early Waukesha engine, a 116.1 ci Allis-Chalmers BE engine, and the later 125.2 ci Allis-Chalmers CE engine.
Nebraska Test 439 covers the later 125 ci gasoline, 3-speed, 2WD Model B tested in May 1950. Use those tested-power figures for the matching configuration, then use the operator manuals and parts catalogs for controls, lubrication, serial range, and parts checks.
Allis Chalmers B Quick Answers
- Production yearsThe Allis Chalmers B was produced from 1938 through 1957.
- PowerNebraska Test 439 lists 22.25 observed maximum belt horsepower and 19.51 observed maximum drawbar horsepower for a 125 ci gasoline, 3-speed, 2WD Model B.
- Engine optionsEngine entries include the early 113 ci Waukesha, 116.1 ci Allis-Chalmers BE, and later 125.2 ci Allis-Chalmers CE gasoline engines.
- PTO and hitchThe listed rear PTO is transmission-driven at 560 rpm, and the hitch entry is the Allis Snap Coupler.
- Service capacitiesEngine oil capacity is 4 qts (3.8 L); coolant capacity is 8 qts (7.6 L).
- WeightWeight is 2060 lbs (934 kg).
Engine and Power
The B's engine data is split by serial range: an early 113 ci Waukesha engine, the 116.1 ci Allis-Chalmers BE engine through serial 64500, and the 125.2 ci Allis-Chalmers CE engine from serial 64501. Match the engine before comparing tune-up data, capacities, or Nebraska Test 439 power figures.
Gasoline engine
Allis-Chalmers CE / gasoline / 4-cylinder / liquid-cooled / Final engine, used from 1943 on, SN 64501
| Displacement | 125.2 ci 2.1 L |
|---|---|
| Bore Stroke | 3.375x3.50 inches 86 x 89 mm |
| Air Cleaner | oil bath |
| Compression | 5.75:1 |
| Rated Rpm | 1500 |
| Firing Order | 1-2-4-3 |
| Starter Volts | 6 |
| Engine Oil Capacity | 4 qts 3.8 L |
| Sparkplug | Autolite AN 7 |
| Sparkplug Gap | 0.035 inches 0.889 mm |
| Point Gap | 0.020 inches 0.508 mm |
| Intake Valve Clearance | 0.010 inches (hot) 0.254 mm |
| Exhaust Valve Clearance | 0.010 inches (hot) 0.254 mm |
Gasoline engine
Allis-Chalmers BE / gasoline / 4-cylinder / liquid-cooled vertical I-head / Second engine, used until 1943, SN 64500
| Displacement | 116.1 ci 1.9 L |
|---|---|
| Bore Stroke | 3.25x3.50 inches 83 x 89 mm |
| Compression | 4.92:1 |
| Rated Rpm | 1400 |
| Firing Order | 1-2-4-3 |
| Coolant Capacity | 8 qts 7.6 L |
| Sparkplug Gap | 0.040 inches 1.016 mm |
| Point Gap | 0.020 inches 0.508 mm |
| Intake Valve Clearance | 0.010 inches (hot) 0.254 mm |
| Exhaust Valve Clearance | 0.010 inches (hot) 0.254 mm |
Gasoline engine
Waukesha / gasoline / 4-cylinder / liquid-cooled / Original engine, used in 1937 on the first 96 tractors built
| Displacement | 113 ci 1.9 L |
|---|---|
| Bore Stroke | 3.00x4.00 inches 76 x 102 mm |
| Rated Rpm | 1400 |
Manufacturer
Manufacture years
PTO and Hitch
The listed PTO is transmission-driven at 560 rpm, with an Allis Snap Coupler hitch entry in the spec rows. Match implements to the tractor's actual PTO equipment, hitch hardware, tire setup, and ballast before planning work.
Rear PTO
Rear PTO type
Fluids, Battery, and Service Facts
Maintenance notes cover capacities and basic service data: engine oil 4 qts (3.8 L); coolant 8 qts (7.6 L); battery 6V; spark plug gaps at 0.035 in (0.889 mm) and 0.040 in (1.016 mm); point gap 0.020 in (0.508 mm); valve clearances 0.010 in (hot) for intake and exhaust. Cross-reference fluids, filters, belts, and specific parts with catalogs or manuals before ordering.
Fuel tank
Battery volts
Tires and Dimensions
Tire and dimension values can vary by wheel, axle, and configuration.
Configuration-specific values are split out where the same model has documented differences by engine, transmission, or equipment.
Wheelbase
Weight
Length
Width
- 5.5 inches 13 cm
- 52.7 inches (minimum) 133 cm
Front tire
Rear tire
Ag front
Ag rear
- 9-24
- 10-24
Electrical
Electrical rows are included when documented.
Ground
Charging system
Charging amps
Battery volts
Serial Number Lookup
Serial rows help narrow the Allis Chalmers B by model year. Factory prefixes, regional builds, and serial breaks require supporting documentation before applying a year table beyond the stated range.
Configuration-specific values are split out where the same model has documented differences by engine, transmission, or equipment.
1938
1939
1940
1941
1942
1943
1944
1945
1946
- 72265
- 1001 (IB)
1947
- 73370
- 1003 (IB)
1948
- 80556
- 1010 (IB)
1949
- 92295
- 1282 (IB)
1950
- 102393
- 1556 (IB)
1951
- 114527
- 1879 (IB)
- 4001 (EB)
1952
- 118674
- 2219 (IB)
- 6861 (EB)
1953
- 122310
- 2570 (IB)
- 9200 (EB)
1954
- 124201
- 11120 (EB)
1955
1956
1957
final
Manuals and Documents
Operator manuals and parts catalogs fill in controls, lubrication, parts diagrams, and serial-range coverage. Nebraska Test 439 adds tested-performance context for the later 125 ci gasoline tractor.
Coverage is not identical across these references. Some manuals apply to a serial range, and some parts catalogs cover B, C, and IB tractors together, so check serial number, engine, and equipment before making service or parts decisions.
Tractor test report
- Test 439: Allis-Chalmers Btested performance
Nebraska Tractor Test report for the later 125 ci gasoline Model B tested May 17-24, 1950.
Open source
Parts catalog
- Allis Chalmers B Parts Manualparts matching
Allis-Chalmers Model B parts manual; 191 pages; exploded views; reprint of original factory manual.
Open source
Operator manual
- Operator's Manual for Allis Chalmers Model Boperation, lubrication
Digitally enhanced reproduction of original operator manual; SN# 5756-127461; 40 pages.
Open source - Allis Chalmers Model B Tractor Operator's Manual (SN 5756-127461)operation, maintenance
Operator's manual for Allis-Chalmers Model B; SN range 5756-127461; reproduced.
Open source
Manufacturer document
- Parts Manual for Allis Chalmers models B, C, IB Tractors (AC1033)parts matching
Parts manual for Allis-Chalmers B, C, IB tractors; includes B-125 Power Unit.
Open source
Parts Checks Before Ordering
Do not order Allis Chalmers B parts from the model name alone. Match the part to the tractor's model code, serial range, engine, transmission, and PTO setup.
Filters, fluids, belts, electrical parts, clutch and PTO parts, and hydraulic parts can vary by setup. Exact part numbers require catalogs, manuals, or trusted supplier sources before they become recommendations.
Accuracy Note
Tractor specifications can vary by year, region, factory configuration, installed equipment, and later repairs. Match serial range, engine, transmission, PTO setup, and model code before ordering parts or doing service work.