The Caterpillar C18 Marine Engine is a I-6, Four-Stroke–Cycle Diesel Engine
Straight or inline engines are internal combustion engines where all cylinders are aligned in a single row. They are common in four, six as well as eight cylinder configurations. A major advantage of this type of engines is their simplicity compared to horizontally opposed or even V designs. Their crankshaft and cylinder banks can be milled from the same metal casting The configuration requires fewer camshafts and cylinder heads Straight engines are usually small and can therefore be mounted in any direction The engine is much easier to maintain because most of its components and accessories are reachable from the sides rather than from the top or bottom of the cylinder banks.
The straight-six or I-6 layout is the simplest engine configuration that has both primary and secondary mechanical engine balance; and it does so without a balance shaft. It is characterized by much less vibration compared to engines with fewer cylinders.
This reduced vibration is achieved by mirroring the front and rear trio of cylinders. The pistons are designed to move in pairs, but 360out of phase; they also move on different strokes of a complete 4-stroke cycle. This eliminates the possibility of polar rocking motions. Its six crank throws are arranged in three planes with the planes offset at 120°. This way the sum of the secondary forces caused by differences in sinusoidal motion is zero. The C18 also possesses a carefully designed vibration damper that helps with absorbing torsional vibration.
Marine operators look for engines that are rugged and powerful and the I-6 is exactly that engine.
The Inline-six is known for:
- Low-end torque
- Smooth operation
- Very long lifespan
- Great dependability
Features to look out for Exhaustive instrumentation
The C18’s instrumentation has:
- An emergency stop button
- A diagnostic light
- Maintenance clear switch
- Maintenance due light
- A warning magnetic switch
- A start motor magnetic switch
- A start/stop switch
- A 24 volt instrumentation panel
- An electric service meter
- 15 and 3A breakers
- Available in Keel-cooled or heat-exchanger cooled designs
Narrow-boats will benefit from keel-cooled engines especially those operating on ports and estuaries with mud and fine silt that often block the normal heat exchange cooled engines. Keel-cooling would also suit most work boats.
Heat-exchange cooling is the more common type of cooling and can be used on just about any type of marine system. An electric governed control system that allows for electronic fault and diagnostics logging as well as fuel and air ratio control. It also has an electronic throttle position sensor and programmable low idle which helps save fuel. The cooling system is self priming and has a thermostat; a 1500Watt, 120V AC current block heater; a titanium plate heat exchanger or a keel-cooling circuitry; and 2 gear-driven water pumps, one a simple jacket pump and the other a seawater pump with a bronze propeller.
Specifications and dimensions
The Caterpillar C18 Marine engine has a displacement of 18.1L, a Rated Speed of 1800, turbocharged-aftercooled aspiration, and maximum exhaust backpressure of 6.7kPa which is equivalent to 26.9 In. in water. It has a cooling system refill capacity of 45.8L and lube oil refill capacity of 64L.
A dry, keel-cooled C18 engine weighs 1539kg while the heat-exchanger C18 weighs 1673kg. However, keel-cooled and heat-exchanger cooled have similar dimensions i.e.
Width 1077.2mm (42.1 in.)
Length 1504.88mm (59.24 in.)
Height 1143.9mm (45.04 in.)