| Manufacturer | Nuffield |
| Price | - |
| Model | PM-4 |
| Equipment Type | Utility Tractors |
| Factory | Birmingham, England |
VARIANTS
| PM3V | gasoline tricycle |
| DM3V | diesel tricycle |
NEBRASKA TRACTOR TEST 559 2
| Description | Gasoline 5-speed 2WD August 29 - September 8, 1955 Link: Nebraska Tractor Test 559 file/Drawbar performance Gear 3 used for power test Gear 1 used for pull test |
| Belt power (max) | 38.4 hp / 28.6 kW |
| Belt fuel use (max) | 3.9 gal / hour 14.8 l / hour |
| Max power | 33.66 hp / 25.1 kW |
| Max pull | 5216 lbs / 2365 kg |
NUFFIELD PM-4 POWER
| Engine | 40.8 hp / 30.4 kW |
| Drawbar (claimed) | 34.2 hp / 25.5 kW |
| Belt (claimed) | 43.5 hp / 32.4 kW |
| Drawbar (tested) | 33.66 hp / 25.1 kW |
| Belt (tested) | 38.4 hp / 28.6 kW |
ENGINE DETAIL
The Nuffield PM-4 tractor, powered by a 4-cylinder Morris Motors gasoline engine with a displacement of 3.8 L, delivers 40.8 hp at a moderate RPM of 2000, making it suitable for general agricultural tasks. Its oil bath air cleaner enhances filtration, while a 6:1 compression ratio allows for efficient fuel usage but may limit power output at higher elevations. With a peak torque of 226 lb-ft at 950 RPM, it excels in low-speed operations, making it ideal for heavy implements but potentially less responsive at higher speeds.
| Description | Morris Motors gasoline 4-cylinder liquid-cooled vertical L-head |
| Displacement | 230 ci / 3.8 L |
| Bore/Stroke | 3.937x4.724 inches/100 x 120 mm |
| Power | 40.8 hp / 30.4 kW |
| Air cleaner | oil bath |
| Compression | 6:1 |
| Rated RPM | 2000 |
| Torque | 226 lb-ft / 306.5 Nm |
| Torque RPM | 950 |
| Starter volts | 12 |
| Coolant capacity | 18 qts / 17.0 L |
NUFFIELD PM-4 ENGINE
The Nuffield PM-4 tractor boasts a Morris Motors 3.8L 4-cylinder gasoline engine, providing efficient power delivery for various agricultural tasks. With a fuel tank capacity of 16.8 gallons, it supports extended operation, while the auxiliary tank of 1.8 gallons offers additional fuel for increased runtime, ideal for remote field work. Key considerations include the tractor's weight and maneuverability, which can impact performance in soft or uneven terrain.
| Description | Morris Motors 3.8L 4-cyl gasoline |
| Fuel tank | 16.8 gal / 63.6 L |
| Aux. fuel | 1.8 gal/6.8 L |
TRANSMISSION
The Nuffield PM-4 tractor features a 5-speed forward and 1-speed reverse gearbox, allowing for versatile speed control and efficient operation across various terrains. The 280mm dry disc clutch provides reliable engagement and disengagement of power, although it may require more frequent maintenance compared to hydraulic systems under heavy load scenarios. Overall, its mechanical simplicity can be advantageous for ease of repair, but operators should be aware of potential wear and overheating during prolonged use.
| Type | gear |
| Gears | 5 forward and 1 reverse |
| Clutch | 280mm dry disc |
MECHANICAL
The Nuffield PM-4 features a 4x2 2WD chassis, providing adequate traction for lighter agricultural tasks but may struggle in muddy or uneven terrain. The manual steering and independent mechanical expanding band brakes offer simplicity and reliability, but they may require more operator effort and may not provide the stopping power of hydraulic systems. The 5-speed transmission allows for versatility in speed management, making it suitable for various applications, although the lack of a closed cab may reduce operator comfort during extended use.
| Chassis | 4x2 2WD |
| Steering | manual |
| Brakes | independent mechanical expanding band |
| Cab | Open operator station. |
| Transmission | 5-speed gear |
HYDRAULICS
| Type | open center |
| Pressure | 1200 psi/82.7 bar/2000 psi/137.9 bar (1955 onward) |
POWER TAKE-OFF (PTO)
| Rear RPM | 540 (1.375) |
| Engine RPM | 528@1400 |
NUFFIELD PM-4 TIRES
The Nuffield PM-4 tractor features Ag front tires sized 7.50-18, which provide optimal traction and stability for lighter front-end applications, while the rear tire options (13.00-30, 14.00-30, and 9.00-36) offer versatility depending on load requirements and terrain conditions. The larger rear tire sizes enhance power transfer and soil compaction reduction, beneficial for heavy-duty tasks such as plowing and tilling. However, it's essential to match tire sizes and tread patterns with the intended use to avoid potential drivetrain stress and impact on maneuverability.
| Ag front | 7.50-18 |
| Ag rear | 13.00-30/14.00-30/9.00-36 |
DIMENSIONS
| Wheelbase | 78 inches / 198 cm |
| Length | 121.7 inches / 309 cm |
| Height (hood) | 59.5 inches / 151 cm |
| Height (exhaust) | 80.7 inches / 204 cm |
| Operating weight | 5,307 lbs / 2407 kg |
| Ballasted weight | 7,765 lbs / 3522 kg |
| Ground clearance | 21 inches / 53 cm (at frame) |
| Clearance (front axle) | 17 inches / 43 cm |
| Clearance (drawbar) | 21.4 inches / 54 cm |
| Front tread | 52.8 to 70.9 inches / 134 to 180 cm |
| Rear tread | 53.2 to 88.2 inches / 135 to 224 cm |
DIMENSIONS & TIRES
The Nuffield PM-4 tractor features a 78-inch wheelbase, providing good stability on uneven terrain but may limit maneuverability in tighter spaces. Weighing 5,307 lbs, it offers substantial traction for plowing and heavy-duty tasks, although the front tire size (6.00-16) may not adequately support increased load demands compared to the larger rear tires (11.00-36), potentially affecting weight distribution and front-end lift. Overall, this model is well-suited for medium-sized farms, particularly in applications requiring robust power but may face challenges during tight-turn operations.
| Wheelbase | 78 inches / 198 cm |
| Weight | 5,307 lbs / 2407 kg |
| Front tire | 6.00-16 |
| Rear tire | 11.00-36 |