Allis Chalmers HD21

The Allis Chalmers HD21 is a tractor produced by Allis Chalmers. It is equipped with a 844 ci 13.8 L engine. The listed engine power is Diesel (listed): 225 hp / 167.8 kW. Transmission: 2 forward and 1 reverse. Drive type: crawler. Operating weight: 45500 lbs 20638 kg.

Engine Power

Diesel (listed): 225 hp / 167.8 kW

Drive & Traction

crawler

Fuel & Capacities

135 gal 511.0 L

Transmission

2 forward and 1 reverse

Operating Weight

45500 lbs 20638 kg

Overview

	1954 - 1965 Model year 1954-19581958-1965 Agricultural Crawler tractor

Production
Manufacturer	Allis Chalmers
Agricultural Crawler tractor
Built in Springfield, Illinois, USA

Allis Chalmers HD21 Engine
Allis-Chalmers 13.8L 6-cyl diesel
Fuel tank	135 gal 511.0 L
Engine details ...

Allis Chalmers HD21 Transmission
2-speed torque converter
Transmission details ...

Allis Chalmers HD21 Power
Engine	225 hp 167.8 kW
Drawbar (tested)	135.12 hp 100.8 kW
Performance test details ...

Mechanical
Drive	crawler
Contracting band brakes
Open operator station.

Dimensions & Tracks
Weight	45500 lbs 20638 kg
Tracks
Full dimensions and tracks ...

References

Engineering-in-Action published in 1956, by Allis Chalmers

Engine

Engine Detail — 844 ci / 13.8 L Diesel

Manufacturer	Allis-Chalmers
Configuration	6-cylinder, liquid-cooled vertical I-head
supercharged diesel
Displacement	844 ci 13.8 L
Bore/Stroke	5.25x6.50 inches 133 x 165 mm
Power	225 hp 167.8 kW
Air cleaner	oil bath
Compression	13.3:1
Rated RPM	1800
Starter volts	24
Coolant capacity	80 qts 75.7 L

Transmission

Transmission — 2 forward and 1 reverse torque converter

Type	torque converter
Gears	2 forward and 1 reverse

Dimensions

Allis Chalmers HD21 Tracks

Dimensions
Length	198 inches 502 cm
Height	99 inches 251 cm
Weight	45500 lbs 20638 kg

Tests

Nebraska Tractor Test 550
Diesel 2-speed crawler July 6 - 18, 1955 Link: Nebraska Tractor Test 550 file
Drawbar performance
Max power	135.12 hp 100.8 kW
Max pull	40563 lbs 18399 kg

Photos

Allis Chalmers HD21

Allis-Chalmers HD-21 bulldozer

Recommended Implements & Sizing Guide

Engineering recommendations for Allis Chalmers HD21 based on its 225 HP power envelope and ASAE agricultural standards.

Implement & Operation	Recommended Size	Workload Rating	Engineering Notes
Moldboard PlowPrimary Tillage	8+ Bottom On-Land Hitch8+ 铧重型机外牵引犁	Commercial / Field Scale	High horsepower articulated/4WD field plowing.
Rotary Cutter / MowerMowing & Clearing	15 to 20 ft Batwing4.6 - 6.1 m 宽幅折叠翼	Commercial / Field Scale	Large commercial field and roadside mowing operations.
Rotary TillerSeedbed Prep	90 to 120 in Heavy Duty230 - 300 cm 重型旋耕机	Commercial / Field Scale	Deep intensive seedbed preparation for commercial row crops.
Disc HarrowSecondary Tillage	24 to 36 ft Heavy Duty Field Disc7.3 - 11.0 m 超宽重型整地耙	Commercial / Field Scale	Broad-acre grain tillage for high-drawbar tractors.
Hay BalerHay & Forage	Large Square Baler (3x4 or 4x4)大方捆商用打捆机 (1.2x1.2 m)	Commercial / Field Scale	High-capacity commercial forage harvesting (1000 RPM PTO).

Sizing & Soil Condition NoteActual implement sizing varies depending on local soil conditions (heavy clay vs sandy loam), field slope, and operating speed. Heavy tillage implements may require front ballast weights and wheel weights.

Fluids, Capacities & Working Autonomy

Standard fluid requirements, service intervals, and continuous runtime estimates for Allis Chalmers HD21.

Estimated Continuous Field Runtime: 11.5 hrs

Approximately 11.5 hours of continuous field operation at ~75% rated power on a full tank (135 gal / 511 L).

Estimated 75% Load Fuel Burn~11.7 gal/hr (44.3 L/hr)

Engine Crankcase Oil

SAE 15W-40 (Heavy Duty Diesel)

Standard Spec: API CK-4 / CJ-4 Heavy Duty

Service Interval: 150 – 250 Hours

Transmission & Hydraulic System

UTTO (Universal Tractor Transmission Oil)

Standard Spec: ISO VG 46 / 68 (Wet Brake & Trans Compatible)

Service Interval: 600 – 1000 Hours

Engine Cooling System

50/50 Ethylene Glycol Pre-mix

Standard Spec: ASTM D6210 / Heavy-Duty OAT Antifreeze

Service Interval: 2 Years / 1500 Hours