Volvo Penta DPX 600 and DPX 500 Engines: Power Move

The Volvo Penta DPX 600 can be used in single- or twin-engine setups in high-performance powerboats.

Introduced in 2000, the DPX 600 and DPX 500 engines are the high-performance flagships of Volvo Penta's gasoline-powered stern-drive line. Both are based on cast-iron blocks from General Motors. The 540-cubic-inch DPX 600 develops 560 horsepower at the propshaft, while the 502-cubic-inch DPX 500 develops 475 horsepower at the propshaft.

The DPX 600 model has a displacement of 8.8 liters (540 cubic inches), which is the result of a wider bore and longer stroke over the DPX 500, which has a displacement of 8.2 liters (502 cubic inches). Each engine is hand-built and test-run for an hour under load prior to release from the factory.

Self-adjusting hydraulic valve lifters, which are driven off a single camshaft in the engines, eliminate the need for regular adjustments. Rollers on the rocker arms reduce wear and frictional loss.

Fuel is delivered by a multi-port electronic fuel-injection system that integrates with the engine management system, which controls and monitors the primary engine functions. The system is responsive to atmospheric conditions, including barometric variations, and features self-diagnostic capability.

The high-speed DPX stern drive with counter-rotating propellers was introduced on Volvo Penta's DPX 385 and DPX 415 models in 1997. The DPX unit is designed specifically for high-performance boats.

The DPX drive comes equipped with its own hydraulic power-steering system called Xact by Volvo. It's comprised of two cylinders mounted outside the boat directly on the drive, a power steering pump and a helm control valve. Steering is direct, yet responsive with 2.7 turns of the steering wheel, lock to lock. An oil cooler is provided to prevent overheating of the power-steering hydraulic fluid.

There are three different gear ratios available for the DPX gearcase. The DPX 500 offers all three ratio options, while the DPX 600 offers two. For both models there is a choice of three matched pairs of stainless-steel propellers.