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Cummins ISC-315 Specifications
| Engine Model: Cummins ISC-315 |
| Engine Type: 4-cycle 6-cylinder CAPS or common-rail fuel injection liquid-cooled diesel |
| Total Displacement: 505 cu.in (8.3 L) |
| Rated Engine Power: 315 Hp (235 kW) at 2200 rpm |
| Aspiration Type: Turbocharged and aftercooled |
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| General Technical Data |
The Cummins ISC-315 is a high-output, electronically controlled, turbocharged and aftercooled inline six-cylinder diesel engine designed for medium- and heavy-duty trucks, buses, vocational equipment, construction machinery, industrial platforms, agricultural machinery, and generator systems. As part of the Cummins ISC/ISL engine family, the ISC-315 provides exceptional torque delivery, fuel efficiency, and emissions compliance for its production era. With a rated output of approximately 315 horsepower, the engine is engineered for high performance under continuous-duty and mixed-duty cycles, offering robust acceleration, strong load acceptance, and long overhaul life.
The ISC-315 combines a high-pressure fuel
system, precise electronic control, advanced air handling, cooled EGR
capability, and a durable cast-iron structure to meet demanding service
environments. Renowned for its balance of power, reliability, and
serviceability, the ISC-315 remains widely used in global industrial and
transportation sectors.
The Cummins ISC-315 is a four-stroke, inline six-cylinder diesel engine
with a displacement of approximately 8.3 liters (505 cubic inches). Bore
typically measures 114 mm (4.49 inches), while stroke measures 135 mm
(5.31 inches), yielding a long-stroke design optimized for high torque
output and fuel efficiency. Compression ratio commonly ranges between
16.5:1 and 17.5:1 depending on calibration. Rated power output is
approximately 235 kW (315 horsepower) at around 2200 rpm.
Peak torque generally ranges from 1050 to 1250
Nm (774–922 lb-ft), typically available between 1300 and 1500 rpm. Idle
speed is normally set around 750 ± 50 rpm. The firing order is
1–5–3–6–2–4. Turbocharging and air-to-air charge-air cooling enhance
intake density, improving performance, reducing emissions, and
strengthening load response. Electronic engine management synchronizes
fuel delivery, boost control, timing, and protection functions for
optimal performance.
The ISC-315 cylinder block is cast from high-strength iron to withstand
the elevated cylinder pressures associated with turbocharged and
EGR-equipped engines. Reinforcement ribs enhance rigidity and minimize
block flex under heavy load. The forged-steel crankshaft is supported by
seven large main bearings engineered for reduced torsional vibration and
long service life. Internally machined oil galleries distribute
lubrication to critical rotating components.
Coolant jackets cast into the block maintain
consistent temperature distribution across cylinders, reducing localized
overheating. Piston cooling jets are integrated to manage crown
temperatures and prevent thermal fatigue. Threaded accessory mounting
bosses provide flexibility for alternators, PTOs, hydraulic pumps, and
other industrial attachments. The robust block structure supports
continuous operation in vocational vehicles, buses, and stationary
installations.
The cast-iron cylinder head incorporates direct-injection combustion
chambers developed for efficient fuel-air mixing and stable combustion.
Each cylinder includes four valves–two intake and two exhaust–to support
airflow, emissions control, and torque output. Valve actuation occurs
through rocker arms and pushrods driven by the engine’s camshaft, which
is block-mounted. Depending on configuration, hydraulic lash adjusters
may be provided, reducing maintenance requirements.
Hardened valve seats and high-temperature-resistant valve guides withstand severe thermal cycling associated with turbocharged and EGR systems. Advanced combustion chamber design enhances swirl, atomization, and flame propagation, reducing particulate formation. Integrated coolant passages stabilize cylinder head temperature to prevent cracking and gasket failure during extended heavy-duty operation.
| Fuel System |
The ISC-315 uses a high-pressure electronic fuel system, often the CAPS (Cummins Accumulator Pump System) or high-pressure common rail depending on production year. Fuel is drawn from the tank by a lift pump and passes through primary and secondary filtration stages before entering the high-pressure system. Injection pressures commonly exceed 1400–1600 bar (20,300–23,200 psi). Electronically actuated injectors deliver multiple injection events–including pilot, main, and post injections–to minimize noise, improve cold starts, reduce smoke, and enhance fuel efficiency.
The ECM continuously monitors numerous parameters including rail pressure, crankshaft and camshaft position, manifold pressure, intake temperature, EGR flow, coolant temperature, and exhaust temperature. Fuel control algorithms manage injection timing, duration, and pressure to optimize power output and emissions compliance. Fuel return circuits stabilize injector temperature and maintain pressure balance.
| Lubrication System |
The full-pressure lubrication system utilizes a gear-driven oil pump. Oil is drawn through a sump strainer and pumped through a high-capacity full-flow filter before entering the main gallery. Pressurized lubrication is supplied to crankshaft bearings, connecting rod journals, camshaft bearings, rocker arms, turbocharger bearings, and auxiliary drives. Piston cooling jets spray oil onto the underside of the pistons to control crown temperatures during full-load operation.
Normal operating oil pressure typically ranges between 300 and 500 kPa (44–72 psi), while idle pressure normally falls between 100 and 150 kPa (15–22 psi). Oil capacity generally ranges from 20 to 25 liters (21.1–26.4 US quarts), depending on sump configuration. Engines equipped with aftertreatment systems require low-ash, high-performance lubricants to protect components such as DPFs.
| Cooling System |
The cooling system is a closed-loop arrangement operated by a belt-driven centrifugal water pump. Coolant flows through cast-in block and head passages to remove heat and maintain stable operating temperatures. The thermostat begins opening near 82°C (180°F) and is fully open around 95°C (203°F). Cooling system pressure typically ranges from 90 to 110 kPa (13–16 psi). Coolant capacity usually falls between 25 and 35 liters (26.4–37.0 US quarts).
Air-to-air aftercooling reduces intake temperature, improving combustion stability and reducing NOx emissions. Regular maintenance of radiators, charge-air coolers, hoses, clamps, and coolant chemistry is crucial to prevent overheating and coolant degradation. The ECM monitors coolant temperature and activates derate or shutdown strategies if overheating or coolant loss is detected.
| Other Systems |
Turbocharging increases intake air density and enhances torque output across the engine’s operating range. Depending on version, the ISC-315 may use wastegated or variable-geometry turbochargers. Charge-air cooling improves performance and reduces combustion stress. The intake system incorporates a heavy-duty air filter with optional dual-stage filtration for dusty environments. The exhaust manifold is cast from heat-resistant iron designed to withstand repeated thermal cycling.
The electrical system operates on 12- or 24-volt configurations, with alternators typically providing 60–120 amperes. The ECM provides advanced diagnostics, fault detection, derate protections, and programmable features tailored to specific applications. PTO drives, hydraulic pump mounts, front-end accessory drives, and auxiliary equipment brackets expand the engine’s versatility for vocational and industrial applications.
| Dimensions and Weight |
Length: 1150–1350 mm (45.3–53.1 inches)
Width: 750–900 mm (29.5–35.4 inches)
Height: 1050–1350 mm (41.3–53.1 inches)
Dry weight generally ranges between 650 and 800 kg (1433–1764 lbs),
depending on turbocharger configuration, aftercooling components,
emissions equipment, and accessory installation. The compact, modular
design simplifies installation in medium-duty trucks, buses, and
stationary generator frames.
| Maintenance Data |
Oil and filter changes are recommended every 500 hours or 15,000–25,000 km (9,300–15,500 miles), depending on usage and environmental conditions. Fuel filters should be replaced every 500 hours, with water separators drained regularly. Air filter service intervals vary from 250 to 500 hours depending on dust exposure. Coolant replacement occurs every two years or according to coolant manufacturer guidelines.
Valve lash inspection may be required on non-hydraulic lifter versions. Emissions-related components such as EGR valves, DOCs, or DPFs may require periodic inspection, cleaning, or regeneration. The ECM stores diagnostic codes and operational data used for troubleshooting and predictive maintenance.
| Tightening Torques |
Cylinder head bolts: 180–210 Nm (133–155 lb-ft)
Main bearing caps: 150–180 Nm (111–133 lb-ft)
Connecting rod bolts: 70–90 Nm (52–66 lb-ft)
Flywheel bolts: 220–260 Nm (162–192 lb-ft)
Crankshaft pulley bolt: 240–280 Nm (177–207 lb-ft)
Injector hold-down: 20–25 Nm (15–18 lb-ft)
Intake heaters / glow plugs (if equipped): 10–15 Nm (7–11 lb-ft)
Oil drain plug: 30–40 Nm (22–30 lb-ft).
| Vehicle Applications |
The Cummins ISC-315 is widely used in medium-duty trucks, municipal and vocational vehicles, regional buses, construction machinery, agricultural tractors, wheel loaders, excavators, cranes, generator sets, industrial compressors, and specialized off-highway platforms. Its balance of torque, power, emissions capability, and durability makes it one of the most adaptable midrange diesel engines in commercial and industrial segments.
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