User's Manual

Sturdy
mainframe
The L250’s
mainframe is
a rugged one-
piece iron casting
which provides excellent
vibration-dampening characteristics and
long-term stability to minimize line bore
distortion. Further strength and rigidity
are added by bolting main bearing caps
both vertically and horizontally. The lube
oil gallery and passages are cast or drilled
into the frame to provide lubrication to
all vital engine areas with no pipe or hose
connections within the frame, to help
eliminate leaks or loss of lubrication.
Turbocharger
The L250 uses a new, high-eciency,
radial ow and water-cooled turbocharger
to achieve EPA Tier 3 emissions without
sacricing engine performance. Depending
on duty cycle and application, response
time and fuel eciency have improved
over the L250 Tier 2 engines and fuel
consumption improved 5% to 6% at
85% of MCR.
Crankshaft and engine drive train
The crankshaft is press-forged, high-
quality alloy steel. Oil passages drilled
in the crankshaft allow oil delivery to
connecting rod bearings and pistons. A
ywheel with ring gear for the starting
motor is bolted directly to the crankshaft
ange.
One-piece liners
The sti, one-piece,
mid-stop liner has an
integral external water
jacket that removes
the possibility of water
leaks. An anti-polishing
ring provides a durable
running surface, improving lube oil
consumption and liner life. The top one-
third of the liner is cooled.
Power assemblies
The L250’s power assemblies
are designed to meet the
high-pressure demands of
the engine while adhering to
strict reliability requirements
and an easy-to-maintain
assembly concept. Unitized
cylinder assembly enables
quick change-outs and
increased engine uptime.
Each assembly is mounted
directly to the mainframe
and includes liner assembly,
cylinder head, intake and
exhaust valves, valve linkage
and a high-pressure fuel-injection
pump and nozzle. This design enables
excellent ow paths for combustion,
lower fuel consumption and reduced
emissions. Design improvements will
result in a signicant reduction in lube oil
consumption over L250 Tier 2 engines.
L250 components — Marine class. Inline design.