Cat C1.1 Specifications
| Engine Model: Caterpillar C1.1 |
| Engine Type: 4-cycle inline 3-cylinder direct injection liquid-cooled diesel |
| Total Displacement: 69 cu.in (1.13 L) |
| Rated Engine Power: 16-28 Hp (12-21 kW) at 2500 rpm |
| Aspiration Type: Naturally aspirated |
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The Caterpillar C1.1 is a compact,
fuel-efficient, three-cylinder industrial diesel engine engineered for
small construction equipment, agricultural machines, compact power
units, and stationary industrial applications. As part of Caterpillar’s
small-bore engine lineup, the C1.1 focuses on minimal fuel consumption,
low emissions, high reliability, and long service life in lightly to
moderately loaded duty cycles. Despite its small displacement, the
engine provides strong low-speed torque, excellent cold-start
capability, and stable operation in demanding ambient conditions. It has
become popular in compact excavators, skid steers, compressors, pumps,
and generator sets.
The C1.1’s simple mechanical design, parent-bore cylinder construction,
direct injection, and durable cast-iron components ensure
straightforward serviceability and long-term dependability. Its compact
dimensions make it suitable for equipment with tight engine
compartments, while optional EPA Tier-3–Tier-4 compliant configurations
allow use in regulated markets. As a result, the C1.1 remains a widely
adopted powerplant for small industrial equipment.
The Caterpillar C1.1 is a four-stroke, water-cooled, inline
three-cylinder diesel engine. Total displacement is 1.13 liters (69
cubic inches). Bore is 77 mm (3.03 in), and stroke is 81 mm (3.19 in),
giving the engine a nearly square geometry that balances torque output
and smoothness. Compression ratio typically ranges from 22.0:1 to
23.5:1, depending on emissions package.
Power output varies by configuration:
– Industrial versions: 18–28 horsepower (13–21 kW) at 2,200–2,800 rpm
– Agricultural/light-industrial uses: 16–24 horsepower (12–18 kW)
Peak torque commonly ranges between: 55 and 72 Nm (41–53 lb-ft) at
1,600–1,800 rpm. Idle speed is generally 850–950 rpm. Maximum governed
speed varies by application, commonly 2,600–3,000 rpm. Firing order is
1-3-2.
The crankshaft is forged steel, supported by four main bearings for
stable rotation under continuous duty. Pistons are lightweight aluminum
alloy with reinforced crowns and a three-ring pack (two compression
rings and one oil-control ring). The connecting rods are forged steel
with replaceable inserts. The camshaft is located in the block and
driven by gears for long-term timing stability.
The C1.1 block is cast iron with parent-bore cylinders, allowing for
honing and oversizing during overhaul. Thick walls and deep ribbing
enhance stiffness and vibration control. Coolant passages fully surround
the cylinders to maintain stable thermal characteristics. The block
integrates mounting bosses for alternators, pumps, compressors, and
engine-driven accessories used by OEMs.
The cylinder head is cast iron with direct-injection combustion
chambers. Each cylinder uses two valves—one intake and one
exhaust—actuated by rocker arms and pushrods from the gear-driven
camshaft. Valve seats are hardened, and ports are designed for efficient
airflow at low-to-mid RPM.
Cold valve-lash settings:
– Intake: 0.25–0.30 mm (0.010–0.012 in)
– Exhaust: 0.30–0.35 mm (0.012–0.014 in).
The C1.1 uses a mechanical direct-injection fuel system. A mechanical
lift pump supplies diesel from the tank through a water separator and a
fine-element fuel filter. Fuel is delivered to a mechanically governed
inline mini-injection pump or rotary pump depending on application.
Injection pressures typically range 150–250 bar. Injectors are
pintle-type or multi-hole depending on emissions level.
Fuel system maintenance:
– Replace fuel filter every 250 hours
– Drain water separator as needed
– Injector servicing every 1,000–1,500 hours
– Verify timing during major service intervals.
The lubrication system is a full-pressure wet-sump design with a
gear-driven oil pump. Oil flows through a full-flow filter before
entering the main gallery and reaching the crankshaft bearings, rods,
camshaft, and valvetrain.
Oil capacity: 3.5–4.0 liters (3.7–4.2 qt)
Typical oil pressure: 250–350 kPa (36–51 psi)
Idle pressure: 80–120 kPa (12–17 psi).
Recommended oil: SAE 10W-30 or 15W-40 diesel-rated oil (API CF or
higher). Oil change intervals typically every 250 hours.
Cooling is provided by a belt-driven centrifugal water pump circulating
coolant through the block, head, radiator, and optional oil cooler. A
thermostat begins opening at 82°C (180°F) and fully opens at 95°C
(203°F).
Cooling capacity varies by application: Generally 4–5 liters (4.2–5.3
qt). System pressure is maintained by a radiator cap rated at 70–90 kPa
(10–13 psi).
| Intake and Exhaust Systems |
Air intake systems vary by machine type:
– Construction: dual-stage dry filters
– Agriculture: cyclone pre-cleaners
– Stationary engines: heavy-duty canister filters
Turbocharging is optional in some versions, enhancing torque and
mid-speed efficiency. Exhaust manifolds are cast iron, designed to
withstand continuous high-temperature duty.
| Electrical and Starting Systems |
Available in 12-volt or 24-volt variants. Alternators typically produce
20–40 amps. Starter motors provide 1.5–2.5 kW. Available sensors include
coolant temperature, oil pressure, intake-air temperature, and optional
speed pickup.
Depending on OEM configuration, the C1.1
may support:
– PTO drives
– Hydraulic pump drives
– Air compressors
– Generator heads
– Remote cooling systems
– Belt-driven auxiliaries.
Approximate engine dimensions:
– Length: 480–520 mm (18.9–20.5 in)
– Width: 390–440 mm (15.4–17.3 in)
– Height: 570–620 mm (22.4–24.4 in)
Dry weight is typically: 95–120 kg (209–265 lb).
– Oil/filter: every 250 hours
– Fuel filter: 250 hours
– Air filter: inspect every 50 hours
– Coolant: replace every 2 years
– Valve adjustment: every 1,000 hours
– Injector servicing: 1,000–1,500 hours
– Compression testing: every 2,000 hours.
– Cylinder head bolts: 70–80 Nm (52–59 lb-ft)
– Main bearing caps: 85–100 Nm (63–74 lb-ft)
– Connecting-rod bolts: 40–50 Nm (30–37 lb-ft)
– Flywheel bolts: 90–110 Nm (66–81 lb-ft)
– Crankshaft pulley bolt: 140–160 Nm (103–118 lb-ft)
– Oil drain plug: 25–35 Nm (18–26 lb-ft)
– Injector hold-downs: 20–25 Nm (15–18 lb-ft).
The Caterpillar C1.1 engine is widely used
in:
– Compact excavators
– Mini loaders and skid-steer attachments
– Small telehandlers
– Agricultural sprayers and compact tractors
– Pumps and compressors
– Generator sets
– Hydraulic power units
– Light-industrial machinery.
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