Cummins QSB6.7 Workboat Inboard Marine Diesel Engine

Description

Handling passenger water taxis and harbor construction tenders demands reliable push and maneuverability. The Cummins QSB6.7 Workboat Inboard Marine Engine produces 305 BHP continuous and 380 BHP intermittent power from a 6-Cylinder 6.7L platform. Electronic engine management governs every injection cycle, though harbor mechanics must maintain clean fuel lines via 2-micron primary filters to protect injection pumps.

Foundry crews cast this parent-bore cylinder block from gray iron to endure relentless dock collisions and heavy thrust loads. A single-piece 24-Valve cylinder head controls gas exchange via 4 valves on every cylinder. The 24V isolated ground electrical system pairs with a 4.5 kW starter and 70A alternator to protect aluminum hulls. Dry weight measures 1,450 lbs, within an installation envelope of 49.7in length, 35.4in width, and 33.7in height, with a 4.0 US gal sump.

Key Features of Cummins QSB6.7 Workboat Inboard

Marine contractors buy Cummins QSB6.7 Workboat Inboard engines to power commercial dive boats and pilot vessels across busy ports. This commercial platform lowers fuel expenses and meets federal emissions standards without expensive urea exhaust scrubbers.

• Continuous P1 commercial rating supplies 305 BHP at 2,600 RPM for heavy work shifts.
• Intermittent P3 rating yields 380 BHP at 3,000 RPM for rapid harbor dispatch runs.
• Bosch high-pressure common rail injection minimizes visible smoke during throttle changes.
• Heavy marine heat exchanger stabilizes core operating temperatures under full load.
• SAE 3 flywheel housing integrates with Twin Disc MG-5065A and ZF 280-1A transmissions.
• Deep commercial oil pan carries 4.0 US gal to lubricate steep vessel inclinations.
• EPA Marine Tier 3 compliance satisfies strict municipal harbor environmental codes.
• Isolated ground 24V marine wiring stops stray electrical current from corroding hull plates.

Workboat Dynamometer Thermal Test Benchmarks

Dynamometer tests confirm 305 BHP continuous output at 2,600 RPM with 735 ft-lbs peak shaft torque. Boost pressure stabilizes at 2.15 bar while Bosch injection rail pressure sustains 1,600 bar under continuous load. The heavy tubular heat exchanger maintains internal coolant temperatures at 185°F during full bollard pulls. Exhaust gas pyrometer readings level off at 940°F ahead of the water mixer. Lube oil pressure tracks at 48 PSI at idle and reaches 68 PSI under sustained load with journal runout below 0.0005in TIR.

Harbor Tender Installation Duty Guidelines

Electronic controls pair with CAN bus stations while manual mechanical override arms require 8 lbs of push-pull cable force. Do not install this commercial workboat diesel engine repower package into lightweight recreational skiffs or high-speed racing skiffs that require 3,300 RPM sprint speeds and lightweight unballasted hulls.

• Change engine oil and spin-on primary lube filters every 250 operating hours.
• Replace the 2-micron primary fuel water separator element every 500 operating hours.
• Clean and inspect heat exchanger seawater tube bundles every 1,000 run hours.

Factory Commercial Warranty Crate Manifest

Cummins covers this commercial workboat engine with a 2-Year or 2,000-Hour factory warranty. Each wooden shipping crate contains the assembled bobtail engine, 24V 4.5 kW starter motor, 70A marine alternator, flexible engine mounts, vessel display wiring harness, oil pressure senders, and comprehensive factory operator manuals.