ALLIS-CHALMERS DD MOTOR GRADERS

Technical Description

The 1980 Allis-Chalmers DD Motor Grader is a robust, diesel-powered machine engineered for heavy-duty grading and earthmoving tasks. It features a 6-cylinder, 4-cycle diesel engine with a displacement of 7.01 L (427.8 in³), delivering 176–196 hp (net) and operating at 2,000–2,200 rpm. The hydraulic system utilizes a closed-center, parallel circuit with a variable piston pump, providing up to 40.9 gal/min (155 L/min) flow and 3,503 psi output pressure at 2,200 rpm. Transmission hydraulic supply is managed by a gear pump, delivering 20.6 gal/min at 232–261 psi for clutch operation. Steering is precise, with a front steering max angle of 47.5°, frame steering angles of 20° left/right, and a front axle oscillation of 32° total. The grader offers a ground clearance of 10 in (255 mm) and a hydraulic actuated drum parking brake capable of holding on a 30% grade. The blade system allows for a maximum lift of 18.9 in (480 mm) and a maximum cut depth of 28.9 in (735 mm), with a 360° circle drive for full blade rotation. The rear scarifier features nine shanks spaced 9.8 in (250 mm) apart, with a maximum working width of 84.1 in (2137 mm) and a scarifying depth of 11.1 in (281 mm). The electrical system is 12V with a heavy-duty 24V, 150-amp alternator, supporting direct electric starting. The grader is equipped with hydraulic pilot valves and can be upgraded with integrated 3D control systems for automated blade positioning. Maximum forward speed is approximately 17.8 mph (28.7 km/h), with reverse speed around 11.4 mph. The machine is designed for operation in ambient temperatures up to 122°F (50°C) and typically features a moldboard blade up to 14 ft in length.