Just a Good Vibration

The first thing I noticed about the new Volvo Penta D-12 700-bhp diesel, the company's premier marine engine for pleasurecraft, was its lack of noise and vibration. The new engine, the largest in the D-12 series, is built with a heavy ladder frame bolted onto a cast-iron block, seven bearings on the crankshaft, and two vibration dampeners on the camshaft to keep rattling to a minimum. In addition, the electronic diesel control (EDC) module ensures automatic engine synchronization on a twin-engine boat, which keeps them both in tune.

The second thing I noticed about the D-12 700-I had the chance to experience a pair of them in action aboard a 53' Hatteras-was how quickly it brought the boat onto plane. Volvo engineers designed the D-12 to exert high levels of torque at the beginning of the rpm cycle, allowing for the most rapid acceleration to occur between 1000 and 1400 rpm. This helps the large vessels it'll be installed in jump onto plane more quickly.

The 12.1-liter in-line-6 D-12 700 weighs 3,461 pounds-heavy, to be sure, but that bulk is representative of its solid construction. That sturdiness also contributes to noise reduction. It has a 5.16" bore-by-5.91" stroke, 740.2 cid, and a 1.65:1 compression ratio. The six direct injectors are controlled by the EDC so that the most efficient fuel-air mixture is provided to each cylinder throughout the rpm range. The D-12 700 has turbochargers, aftercoolers, and a self-contained freshwater cooling system, which reduces the corrosion associated with raw-water cooling. As with pretty much every new diesel on the market, the D-12 700 is IMO compliant, meaning it meets all the latest emissions standards, making it a lot healthier to stand in the cockpit. Plus it's much more fuel efficient than the big blocks of the past, further increasing your cruising range. Contact Volvo Penta at 757/436-2800, www.volvo.com.