HYDM352M Hydraulic Motor | 2.15 cid Marzocchi

HYDM352M Hydraulic Motor | 2.15 cid Marzocchi | The Heavy-Class Precise Match

HYDM352M gives the heavy end of the motor line its own in-between rung: a 2.15 in³ (35.2cc) Marzocchi gear motor seated deliberately between the 2.01 cid class entry and the 2.38 cid workhorse above it. The same matching logic that justifies the mid-line’s precise-fit displacement applies with more money on the table here: at 20-plus horsepower of pump drive, a motor rounded too small lives against its pressure ceiling and converts the shortfall into heat and early wear, while one rounded too large starves on the circuit’s real flow and leaves the pump under speed — and at this class, either mistake is buried inside a truck build that cost five figures. The HYDM352M exists so heavy-class circuits landing between the standard sizes get matched, not rounded.

The band it serves is specific: roughly 24 horsepower of pump duty at 1450 RPM on about 13.5 GPM of oil — the strong 13 GPM platforms working near their ratings, the extreme-pressure production strip units, and the XW/SXW-class systems whose duty sits a notch above what the class entry carries comfortably and a notch below the workhorse’s appetite.

HYDM352M Specifications

• SKU: HYDM352M
• Manufacturer: Marzocchi (Bologna, Italy)
• Type: External gear hydraulic motor — heavy-frame class
• Displacement: 2.15 in³ (35.2cc) per revolution
• Oil Flow for Pump-Speed Drive: Approximately 13.5 GPM at 1450 RPM
• Pressure and Speed Ratings: Marzocchi heavy gear class — confirm the build sheet with WSHPWR for your duty point
• Drive Duty: Pump duties in the ~24 HP band at 1450 RPM
• Shaft: 7/8″ class
• Ports: SAE-16 O-ring class

Sizing the HYDM352M

The arithmetic — RPM ≈ 231 × hydraulic GPM ÷ 2.15 — lands the pump at 1450 RPM on roughly 13.5 GPM of oil, and torque follows pressure at T ≈ 2.15 × ΔPSI ÷ 6.283, producing shaft power in the ~24 HP band at heavy gear-class working pressures. The qualifying question is your circuit’s honest, sustained delivery: a system carrying 13-to-14 GPM at working pressure all shift puts this displacement exactly in its element; measurably less or more belongs with a neighbor. Measure the real number under load rather than reading the brochure, then send WSHPWR flow, pressure, and the target pump — the pairing and the Marzocchi build sheet get confirmed before anything ships.

The Cost of Rounding at This Class

Wrong-size pairings in the compact classes waste some efficiency; wrong-size pairings in the heavy class waste equipment. A motor pressed against its continuous pressure rating for every working hour runs hot, spends its relief margin, and delivers its failure years early as a mystery no one connects to a sizing decision made at the parts counter. A motor starving on flow turns the pump at 1,250 RPM instead of 1,450, the system delivers 90% of everything, and the “underpowered truck” gets blamed on the pump, the nozzles, and the operator before anyone divides flow by displacement. The HYDM352M’s whole role is deleting that failure pair for the band between the standard sizes — and Marzocchi’s execution, with ground gear profiles and clearances that hold volumetric efficiency under sustained load, keeps the correct match correct across the years the truck is financed for.

Completing the Build

The HYDM352M lives in the heavy mounting world — the HYDBK4-class cast-iron-mount architecture and the adjustable HYDBK3 base both serve it, with coupling and interface confirmed against your pump at order. It is also the natural diagnostic repower: a fielded heavy system that never quite made rated performance on its original rounded motor, brought to life by the displacement that actually matches the circuit. WSHPWR fields that call at this class more often than the catalogs would suggest, and confirms fitment on every heavy-class order before shipment.

Installation & Operation Notes

Confirm rotation direction against your pump before plumbing — gear motors are direction-specific by port assignment, and at this torque a backward start is expensive. Set the circuit relief within the motor’s rating, specify 10–25 micron return filtration with an adequate beta rating, route the return generously to tank, and plumb any case drain above reservoir oil level to prevent aeration. Treat oil cooling as a first-class design item at this power, torque mounting hardware to spec on structure worthy of the assembly, and verify pump speed at commissioning by the flow-÷-displacement math or a phototach — the pump’s rated RPM governs the ceiling, always.

Quality Assurance & Maintenance

Every HYDM352M carries Marzocchi’s factory testing and ships only after WSHPWR confirms the fitment against your stated pump and circuit. The ongoing program is the gear architecture’s standing gift — clean, filtered oil, a correct relief, periodic hose-end and drain-line inspection, no scheduled internal service — and the correctly matched pairing this displacement enables keeps the pump’s own wear curve on schedule alongside it.

HYDM352M Key Features & Applications

• 2.15 cid Marzocchi — the precise-match rung between the heavy class’s standard sizes.
• Pump-speed drive on ~13.5 GPM of oil; serves the ~24 HP pump band at 1450 RPM.
• Deletes the round-up/round-down failure pair where the mistakes cost the most.
• 7/8″-shaft, SAE-16-port heavy-frame class; suits the HYDBK3/HYDBK4 mounting architectures.
• The diagnostic repower for heavy systems that never made rated performance.
• Ideal for strong 13 GPM platform drives, production strip units, XW/SXW-class systems, and heavy circuits whose honest delivery lands between the standard displacements.