Product Overview
The GHP2A-D-22/25/30/34/37/40/50-FG are core models of the Italian MARZOCCHI GHP series high-pressure external gear pumps. Founded in 1961 and headquartered in Bologna, Italy, MARZOCCHI has become one of the world’s largest manufacturers of gear pumps and gear motors through decades of continuous investment and product development.
The GHP series and ALP series are MARZOCCHI’s two core product lines—GHP is commonly used in high-pressure hydraulic systems, while ALP is used in medium-to-low pressure systems. The GHP1A, GHP2A, and GHP3A correspond to Group 1, 2, and 3 frame sizes, with displacements ranging from 1.4 to 87 cc/rev.
The GHP2A series belongs to Group 2, with displacements from 4.5 to 35.2 cc/rev. The pump body is manufactured from special high-resistant extruded aluminum alloy, while the flange and cover are made of spheroidal cast iron, ensuring minimized deformation under high pressure. Gears are made of special steel which are ground and fine-finished for an excellent surface profile.
Engineered as a direct OEM-replacement solution for MARZOCCHI original products, the GHP2A series fully complies with MARZOCCHI original design standards and SAE mounting interface specifications, offering 100% direct interchangeability. Every unit undergoes 100% workload simulation testing prior to shipment, rigorously validating pressure retention, volumetric efficiency, and internal leakage performance to meet or exceed OEM standards.
Model Code Breakdown :
GHP — Series: MARZOCCHI High-Pressure Gear Pump
2 — Group: Group 2 (medium frame, displacement 4.5–35.2 cc/rev)
A — Design version (A Series)
D — Interface: SAE flange interface
22 / 25 / 30 / 34 / 37 / 40 / 50 — Displacement code
FG — Shaft and mounting configuration code (flange mount, keyed shaft)
Technical Specifications
GHP2A Series General Specifications
Series: MARZOCCHI GHP2A High-Pressure External Gear Pump
Group: Group 2 (medium frame)
Displacement Range: 4.5 – 35.2 cc/rev
Rated Pressure: Up to 280 bar (depending on displacement)
Speed Range: 500 – 3600 r/min
Housing Material: Special high-resistant extruded aluminum alloy
Flange & Cover Material: Spheroidal cast iron
Gear Material: Special hardened steel
Mounting Flange: SAE A 2-bolt flange
Recommended Media: Hydraulic oil
Operating Temperature Range: -20℃ to +80℃
GHP2A-D-22-FG Specifications
Model: GHP2A-D-22-FG
Displacement: 16.0 cc/rev
Rated Pressure: 280 bar
Peak Pressure: 290 bar
Rated Flow (@1450 rpm): 22 L/min
Maximum Speed: 2800 r/min
Port Size: G1/2″
Connection: Diamond flange
Weight: Approx. 4.0 kg
GHP2A-D-25-FG Specifications
Model: GHP2A-D-25-FG
Displacement: 17.9 cc/rev
Rated Pressure: 260 bar
Maximum Speed: 2500 r/min
Inlet Port: #12 SAE (3/4″)
Outlet Port: #10 SAE (5/8″)
Mounting Flange: SAE A 2-bolt flange
Shaft Type: 5/8″ keyed shaft
Weight: 4.2 kg
GHP2A-D-30-FG Specifications
Model: GHP2A-D-30-FG
Displacement: 21.1 cc/rev
Rated Pressure: 280 bar
Maximum Speed: 2800 r/min
Inlet Port: #12 SAE (3/4″)
Outlet Port: #10 SAE (5/8″)
Mounting Flange: SAE A 2-bolt flange
GHP2A-D-34-FG Specifications
Model: GHP2A-D-34-FG
Displacement: 23.9 cc/rev
Rated Pressure: 280 bar
Maximum Speed: 2800 r/min
Inlet Port: #12 SAE (3/4″)
Outlet Port: #10 SAE (5/8″)
Mounting Flange: SAE A 2-bolt flange
GHP2A-D-37-FG Specifications
Model: GHP2A-D-37-FG
Displacement: 26.0 cc/rev
Rated Pressure: 280 bar
Maximum Speed: 2500 r/min
Inlet Port: #12 SAE (3/4″)
Outlet Port: #10 SAE (5/8″)
Mounting Flange: SAE A 2-bolt flange
GHP2A-D-40-FG Specifications
Model: GHP2A-D-40-FG
Displacement: 28.2 cc/rev
Rated Pressure: 250 bar
Peak Pressure (short-term <10 min): 315 bar
Maximum Speed: 2500 r/min
Inlet Port: #12 SAE (3/4″)
Outlet Port: #10 SAE (5/8″)
Mounting Flange: SAE A 2-bolt flange
GHP2A-D-50-FG Specifications
Model: GHP2A-D-50-FG
Displacement: 35.2 cc/rev
Rated Pressure: 160 bar
Maximum Speed: 2000 r/min
Inlet Port: #12 SAE (3/4″)
Outlet Port: #10 SAE (5/8″)
Mounting Flange: SAE A 2-bolt flange
Shaft Type: 9T 16/32DP splined shaft
Key Technical Advantages
1. Spheroidal Cast Iron Flange & Cover – Minimal Deformation Under High Pressure
The GHP2A series flange and cover are manufactured from spheroidal cast iron, ensuring minimal deformation under continuous high pressure, intermittent high pressure, or peak pressure compared to standard aluminum pump bodies. This design maintains high volumetric efficiency across the full operating pressure range.
2. Special High-Resistant Extruded Aluminum Housing – Lightweight & High Strength
The pump body is manufactured from special high-resistant extruded aluminum alloy, delivering lightweight construction without compromising structural integrity. Optimized heat dissipation effectively reduces operating temperatures.
3. Optimized Gear Profile – Low Pulsation & Low Noise
Gears are made of special steel that is ground and fine-finished for an excellent surface profile. Proper tooth profile design and geometric proportions ensure low pulsation and low noise levels during pump operation.
4. Superior High-Pressure Capability
The GHP2A-D-40-FG delivers peak pressure up to 315 bar. The combination of high-strength spheroidal cast iron covers and precision-machined gears ensures long-term stability under high-pressure conditions.
5. Flexible Configuration & Modular Design
The GHP series offers multiple flange, shaft, and port options. Configurations include single, tandem, and multiple pump assemblies. Reversible pump versions are also available (ROTAZIONE “R”).
Application Areas
The GHP2A series gear pumps are widely used in the hydraulic systems of the following equipment:
Construction Machinery: Excavators, loaders, bulldozers, and other mobile machinery
Industrial Hydraulic Power Units: HPU systems for various industrial equipment
Machine Tools: Metal cutting and forming machinery hydraulic systems
Agricultural Machinery: Tractors, combine harvesters, and agricultural equipment
Material Handling Equipment: Forklifts, lift platforms
Mining Machinery: Mining equipment hydraulic systems
Marine Equipment: Marine hydraulic systems
Expert Maintenance Tips
1. Model Confirmation
The GHP2A series includes multiple displacement options (22/25/30/34/37/40/50 corresponding to 16.0/17.9/21.1/23.9/26.0/28.2/35.2 cc/rev). Before installation, confirm the correct displacement based on system flow requirements and verify the complete model code on the pump nameplate. Distinguish between GHP2A (Group 2) and GHP1A (Group 1) / GHP3A (Group 3) frame sizes.
2. Rotation Direction Confirmation
The standard version features clockwise rotation (viewed from shaft end). Counter-clockwise versions are available. Before installation, always verify that the PTO rotation direction of the host machine matches the pump’s rotation direction—incorrect rotation will result in pump failure to prime and may cause severe damage to gears and bearings within a short period.
3. Installation Precautions
Thoroughly clean the SAE A 2-bolt flange and shaft mating surfaces before installation to ensure no debris remains
Inlet port: #12 SAE (3/4″), Outlet port: #10 SAE (5/8″)
Use MARZOCCHI-specified torque values for mounting bolts—avoid over-tightening which may cause distortion of the aluminum housing
GHP2A-D-22-FG features a diamond flange connection, allowing direct motor mounting without a coupling
Direct drive with flexible coupling is recommended—avoid subjecting the pump to axial or radial loads
4. First Start-Up and Bleeding
Before first start-up, must fill the pump with hydraulic oil through the inlet port—never start dry
After start-up, run at low speed with no load for 2–3 minutes to ensure complete air evacuation from the system
Check for abnormal noise or leakage—aluminum housing pumps are particularly sensitive to cavitation
5. Fluid and Filtration
Use high-quality anti-wear hydraulic oil compliant with DIN 51524 standards
Maintain system oil cleanliness to ISO 4406 18/15 or better
Maintain operating temperature within recommended range
Regularly replace return line filters to prevent contaminants from entering the pump
6. Periodic Maintenance
Check mounting bolt torque every 1,000 operating hours
Regularly monitor system operating pressure—GHP2A-D-40-FG not to exceed 250 bar (315 bar peak); other models not to exceed 280 bar
Regularly inspect shaft seals to prevent leakage
If flow output decreases, noise levels increase abnormally, or system temperature rises excessively, inspect and replace worn components promptly
