MIAMI – GM Marine’s new 4.3L V-6 Small Block engine for sterndrive applications is a lightweight, technologically advanced and efficient performer designed to deliver excellent performance while using less fuel than many V-6 marine engines.
It is based on the fifth generation of General Motors’ legendary Small Block architecture, which was introduced 60 years ago and powers through the 21st century with advanced performance- and efficiency-optimizing technologies, including variable valve timing and direct fuel injection.
“The Small Block was adapted for marine use soon after it was introduced and we have worked for decades with marinizers to refine the engine family for the unique requirements of powerboats,” said Gary Halligan, GM Marine engineering.
“The new Gen V Small Block architecture represents an unprecedented investment in engine design, which leveraged the depth and breadth of GM’s powertrain resources to bring to the market one of the most efficient, powerful and technologically advanced engines in the marine industry.”
The new Gen V 4.3L V-6 shares the same design attributes as the Small Block engine family found in the latest Chevrolet Silverado, Tahoe and Suburban trucks and SUVs, as well as the high-performance Corvette Stingray.
“Allowing the marine industry to take advantage of proven automotive technology is a win for the boating world,” said Patrick Koenigknecht, GM director of Marine Original Equipment sales. “Direct injection and continuously variable valve timing technologies are perfect for the marine industry because they result in more power and better fuel efficiency – and the customer benefits from factory-proven reliability and durability built on years of tough truck engine design, development and testing.”
Volvo Penta is a marinizer already working with the new Gen V engine.
“We’ve trusted GM engines for years and want to get the latest technology to the customer as soon as possible,” said Ron Huiber, president, Volvo Penta. “We believe this new engine will help transform the boat industry with its great balance of power and efficiency – and the durability customers have come to rely on for decades.”
Advanced combustion system drives performance, efficiency
The power and efficiency of the GM Marine Gen V marine engine are due to an unprecedented level of analysis, including computational fluid dynamics, to make the most of the combustion system and the direct injection fuel system and variable valve timing systems that support it. More than 10 million hours of computational analysis were conducted on the engine program, including 6 million hours (CPU time) dedicated to the advanced combustion system.
Direct injection is new to the engine architecture – and marine engines – and is a primary contributor to its greater combustion efficiency by ensuring a more complete burn of the fuel in the air-fuel mixture. This is achieved by precisely controlling the mixture motion and fuel injection spray pattern, including pistons that feature uniquely sculpted topography to precisely direct the fuel spray for a more complete combustion. Direct injection also keeps the combustion chamber cooler, which allows for a higher compression ratio – which supports greater power.
Continuously variable valve timing, which GM pioneered for overhead-valve engines, further enhances performance, efficiency and reduced emissions.
Additional engine features:
All-aluminum block and oil pan: Lighter than conventional cast iron, the aluminum cylinder block and heads of the Gen V engine help reduce the boat’s overall weight, enhancing performance and efficiency. The Gen V block was developed with math-based tools and provides a light, rigid foundation for an impressively smooth engine. Its deep-skirt design helps maximize strength and minimize vibration. Its bulkheads accommodate six-bolt, cross-bolted main-bearing caps that limit crank flex and stiffen the engine’s structure. The block also features nodular iron main bearing caps, which represent a significant upgrade over more conventional powdered metal bearing caps. They are stronger and can better absorb vibrations and other harmonics to help produce smoother, quieter performance.
Advanced oiling system: The oiling system is driven by a new, variable-displacement oil pump that enables more efficient oil delivery. Its dual-pressure control enables operation at a very efficient oil pressure at lower rpm and delivers higher pressure at higher engine speeds to provide a more robust lube system for the high-rpm engine operation that’s characteristic of powerboat operation. Standard oil-spray piston cooling sprays the underside of each piston and the surrounding cylinder wall with an extra layer of cooling, durability-enhancing oil. For optimal efficiency, they are used only when needed the most such as start-up, giving the cylinders extra lubrication, and at higher engine speeds.
Positive Crankcase Ventilation-integrated rocker covers: One of the most distinctive features of the Gen V engine is its domed rocker covers, which house an integrated positive crankcase ventilation system that enhances oil economy and oil life, while reducing oil consumption and contributing to low emissions. The rocker covers also hold the direct-mount ignition coils for the coil-near-plug ignition system. Between the individual coil packs, the domed sections of the covers contain baffles that separate oil and air from the crankcase gases.
GM supplies engines to many industrial and marine original equipment manufacturers. GM’s range of marine engines ranges from a 3.0L 140-hp four-cylinder engine to a 6.2L 550-hp supercharged V-8. GM has been supplying engines to the marine industry since 1958 and pioneered marine application of electronic fuel injection since 1991.
General Motors Co. (NYSE:GM, TSX: GMM) and its partners produce vehicles in 30 countries, and the company has leadership positions in the world’s largest and fastest-growing automotive markets. GM, its subsidiaries and joint venture entities sell vehicles under the Chevrolet, Cadillac, Baojun, Buick, GMC, Holden, Jiefang, Opel, Vauxhall and Wuling brands. More information on the company and its subsidiaries, including OnStar, a global leader in vehicle safety, security and information services, can be found at http://www.gm.com
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