HYDM282M Hydraulic Motor | 1.72 cid Marzocchi

HYDM282M Hydraulic Motor | 1.72 cid Marzocchi | Mid-Class Torque Driver

HYDM282M is where the motor line turns from speed to torque: a 1.72 in³ (28.2cc) Marzocchi gear motor whose displacement delivers roughly 17 horsepower of pump drive at 1450 RPM from its 2,755 PSI continuous rating — the appetite of the mid-frame XWL- and XW-class pumps that anchor 8-to-13 GPM washdown systems. Its 1800 RPM ceiling tells the design story plainly: this is a low-speed, high-torque unit, built to turn substantial pumps at their rated speed rather than to spin fast. Everything about its proportions serves that intent, from the 10.50 GPM oil rating at 1500 RPM down to gear geometry sized for sustained load rather than velocity.

The duty band it owns is the catalog’s productive middle. Below it, the small motors run out of torque before the 8 GPM packages reach full pressure; above it, the big-displacement units demand more oil than most machines carry. The HYDM282M threads that gap for the stronger auxiliary circuits and truck hydraulic systems that mid-class duty presumes — around 10 GPM of honest, sustained delivery — and turns the pumps that convert it into serious water: the 8 GPM step-up drives, the 13 GPM XWL platforms, the systems where washdown became production.

HYDM282M Specifications

• SKU: HYDM282M
• Manufacturer: Marzocchi (Bologna, Italy)
• Type: External gear hydraulic motor — low-speed, high-torque class
• Displacement: 1.72 in³ (28.2cc) per revolution
• Rated Oil Flow: 10.50 GPM at 1500 RPM; 13.40 GPM at maximum RPM
• Maximum Speed: 1800 RPM
• Pressure Ratings: 3,118 PSI peak / 2,755 PSI continuous / 2,900 PSI intermittent
• Case Drain: 1/4″ SAE-6 O-ring port
• Shaft: 5/8″
• Ports: 1-1/16-12UNF (SAE-12 O-ring)
• Drive Duty: Approximately 17 HP of pump drive at 1450 RPM within the continuous rating

Sizing the HYDM282M

The selection line — RPM ≈ 231 × hydraulic GPM ÷ 1.72 — lands the pump at 1450 RPM on about 10.2 GPM of oil, right at the motor’s design point with the 1800 RPM ceiling deliberately close above. Torque follows pressure — T ≈ 1.72 × ΔPSI ÷ 6.283 — so at 2,755 PSI continuous the shaft carries the ~17 HP tier: strong 8 GPM packages at full pressure and 13 GPM moderate-pressure platforms both land inside it. The qualifying question is your circuit’s sustained delivery: 10 GPM at working pressure all shift is this motor’s element; brochure numbers that sag under load are not. Measure honestly, mind the relief margin above 2,755 PSI, and call WSHPWR with flow, pressure, and target pump — we will confirm the pairing before the order ships.

The Low-Speed Design Choice

A motor that tops out at 1800 RPM has made a promise about how it intends to live: near its rated speed, under sustained torque, for hours. Gear geometry, bushing loading, and internal flow paths in this class are proportioned for exactly that — which is why the HYDM282M runs the mid-frame duty comfortably where a fast-spinning small motor pressed into the same job would live at its limits and age accordingly. Marzocchi’s execution compounds the advantage: ground gear profiles and concentric housing bores hold volumetric efficiency at torques that punish looser builds, so the pump still sees rated speed at year five. In the mid class, where the motor works hardest relative to its frame, build quality is not a preference — it is the service-life budget.

Completing the Build

The HYDM282M suits the flex-coupled and adjustable base architectures — the HYDBK2-class coupler builds and the long-travel HYDBK3 both serve mid-frame assemblies — bringing motor, pump, and mounting together as one coordinated order. It is equally the repower part for fielded 8-to-13 GPM systems: confirm shaft and mount against the installation, swap the component, and production resumes the same day. Operations running the mid-class platforms keep one on the shelf for precisely that arithmetic.

Installation & Operation Notes

Confirm rotation direction against your pump before plumbing — gear motors are direction-specific by port assignment, and reversed pressure and return lines spin the pump backward, with lubrication consequences no triplex forgives. Set the circuit relief at or below the 2,755 PSI continuous rating, specify 10–25 micron return filtration with an adequate beta rating, route the return short and unrestricted to tank, and plumb the 1/4″ SAE-6 case drain above reservoir oil level to prevent aeration. Oil cooling is not optional at this power level — 17 horsepower of continuous drive makes heat the cooler must remove — and at commissioning, verify pump speed by the flow-÷-displacement math or a phototach. The pump’s rated RPM governs; the 1800 ceiling is margin, not a target.

Quality Assurance & Maintenance

Every HYDM282M carries Marzocchi’s factory testing and is verified for fitment before shipment. The ongoing program stays gear-motor minimal — clean, filtered oil, a correct relief, periodic hose-end and drain-line inspection, no scheduled internal service — with cooling-system condition added to the checklist at this power level. Protected that way, the motor routinely outlasts the wet ends it drives.

HYDM282M Key Features & Applications

• 1.72 cid Marzocchi — low-speed, high-torque design purpose-built for the mid-frame pump classes.
• ~17 HP of pump drive at 1450 RPM from a 2,755 PSI continuous rating.
• Pump-speed drive on ~10.2 GPM of oil; deliberate 1800 RPM ceiling proportioned for sustained load.
• SAE-12 O-ring ports, 5/8″ shaft, dedicated 1/4″ SAE-6 case drain.
• Suits the HYDBK2/HYDBK3 base architectures; the repower part for fielded mid-class systems.
• Ideal for XWL/XW-class pump drives, 8 GPM package repowers, 13 GPM production systems, and truck circuits with mid-class flow to spend.