FNM 42HPE-350 High-Output Inboard Marine Diesel Engine

Description

Tactical boat captains face severe engine thermal strain when pursuing offshore targets at wide-open throttle. The FNM 42HPE-350 High-Output Marine Diesel Engine solves thermal limits by outputting 350 BHP at 3,800 RPM from a 4.2L inline-6 package. This high-boost unit demands clean 2-micron diesel fuel and regular checks of the bronze raw water pump impeller.

Engine structure features an ASTM parent-bore cast iron block paired with a 24-Valve cast iron monobloc cylinder head and single overhead camshaft. Electrical systems function on a 12V negative ground system powered by a 12V 2.8 kW starter and a 12V 120A alternator. Dry engine mass measures 992 lbs across an engine stance measuring 45.3in long by 28.3in wide and 30.9in high. Sump oil volume totals 2.77 US gal.

Key Features of FNM 42HPE-350

Customs chase boat commanders buy FNM 42HPE-350 high-output engines to achieve maximum tactical intercept speed. This commercial workboat diesel engine repower core mates flush with ZF 85A and Twin Disc MG-5065A hydraulic marine transmissions.

• High-boost variable geometry turbocharger alters exhaust flow to create immediate hole-shot acceleration under throttle.
• Oversized seawater charge air intercooler drops intake air heat to support 350 BHP sprint power.
• Common rail direct electronic fuel injection operates at 1,800 bar to eliminate soot on stern hulls.
• Heavy-duty 24-Valve cast iron cylinder head endures severe combustion pressures during emergency sprint operations.
• Standard SAE 3 flywheel housing couples flush with an SAE 11.5 flywheel drive plate.
• Closed tubular heat exchanger with bronze raw water pump prevents salt scale inside the block jackets.
• High-capacity 12V 120A marine alternator supplies abundant electrical power for high-draw tactical radar rigs.

Dynamometer Tactical Load Test Limits

Dyno bench evaluation records 250 BHP continuous output at 3,200 RPM and 350 BHP intermittent sprint power at 3,800 RPM. Shaft torque reaches 495 ft-lbs at 2,400 RPM under 2.0 bar of turbocharger boost air. Rail fuel pressure holds at 1,800 bar during sustained maximum throttle testing. Pre-turbine exhaust gas temperatures peak at 1,180°F under high boost. The closed-circuit heat exchanger holds internal coolant at 185°F. Main journal runout measures 0.0004in TIR, and lube oil gallery pressure sustains 52 PSI across a 25° tilt.

Tactical Interceptor Operation Service Guidance

Electronic helm throttle levers respond with 1 lb of smooth control resistance without cable friction. Do not drop this high-boost sprint engine into continuous displacement pushboats, river towboats, or slow cargo barges running 24-Hour bollard thrust. The sprint profile is engineered for commercial workboat diesel engine repower installations on fast interceptors and emergency response craft.

• Drain engine lube oil and replace spin-on oil filters every 250 operating hours with 15W-40 oil.
• Replace primary 2-micron fuel water separator filter elements every 250 operating hours to preserve injectors.
• Inspect bronze high-flow raw water pump impellers and replace sacrificial zincs every 150 operating hours.

Commercial Marine Warranty Crate Contents

FNM CMD backs this propulsion engine with a 2-Year limited commercial marine manufacturer warranty. The factory wooden crate includes the bobtail engine core, 12V starter, 12V 120A alternator, rubber vibration isolation mounts, digital instrument panel, wiring harness, exhaust connection elbow, and complete factory operator service manuals.