Specifications of a 6BD1 Marine Engine

by Tim McQuadeUpdated July 17, 2023

The 6BD1 was a heavy-duty, diesel engine manufactured by Isuzu. The company first produced the engine in 1976 and continued to produce it into the 21st century. A turbocharged model, 6BD1T, was also manufactured, and that version was first produced in 1983. Isuzu also manufactured a four-cylinder version, referred to as the 4BD1, or the 4BD1T for the turbocharged version; these engines were first produced in 1979 and 1980.

Engine Specifications

The 6BD1 marine engine featured an inline, six-cylinder design. The pistons had a total displacement of 5,785 cc. The maximum power output measured 142 horsepower at 2,800 rpm, and the total torque output measured 289 foot-pounds at 1,600 rpm. The bore by stroke measured 4.02 by 4.63 inches, and the compression ratio measured 17.5:1. The engine utilized a 12 V starter and the cooling system used a liquid-cooled design. The fuel system featured direct injection technology, and the valve-train used an overhead valve layout.


The 6BD1 engine measured 44.6 inches in length, 24.6 inches in width and 33.2 inches in height. It had a dry weight -- without any fluids -- of 1,003 lb.

The turbocharged version had slightly different dimensions. It had a length of 44.6 inches, a width of 26.4 inches and a height of 37.4 inches. The turbocharged version also weighed slightly more, at 1,089 lb.


The engine featured a mechanical governor, as well as a tapered nose crankshaft. The crankshaft nose measured 1.65 inches. The engine also featured a vacuum pump, and the thermostat housing had six bolts. Isuzu also released a compressor-type 6BD1. The engine featured a tapered nose crankshaft that measured 1.65 to 2.04 inches.

The OEM engine number for the non-compressor 6BD1 was 89037991; for the compressor version, it was No. 89037993. The turbocharged version has OEM engine No. 89037995.

Turbocharged Version

Even though the turbocharged version -- also referred to as the 6BD1T -- had the same engine design and layout; due to the turbocharger, it had a higher power output and peak torque rating. The 6BD1T could achieve a power output as high as 163 horsepower at 2,500 rpm and torque levels increased to 375 foot-pounds at 1,800 rpm -- almost a 100 foot-pounds increase over the non-turbocharged version.

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