GM Vortec 8100 V8 Vortec Gas Marine Engine

GM Vortec 8100 gas V8

Vortec is the trademarked name for a line of General Motors engines. The Vortec trademark first appeared back in 1988 on a 4.3-Liter, V-6 gas engine that created a vortex of swirling air and fuel in its combustion chambers promoting a better mix of air/fuel.

General Motors big-block V-8 Vortec 8100 (8.1 liters/496 cubic inches) is rated 375 horsepower with the high-performance version rated 415 hp. According to GM, Vortec 8100 is particularly durable. During development, engineers ran the big, pounding V-8 at wide-open throttle for 300 hours in a 60-minute duty cycle. Translation: The engine was run at WOT for 55 minutes, idled for five, then revved back up to WOT. According to GM the Vortec's marine durability testing is more severe than the one for truck engines!

Key features include port fuel-injection, aluminum cylinder heads, a coated, cast-aluminum intake manifold, and a tough-as-nails, silicon-carbide, sealed water pump with a bronze impeller. An eight-quart cast aluminum oil pan with a V-profile is suited to marine installations. Special spark-plug wires route around the marine exhaust manifold. Most impressive of all, EFI programming allows boat builders to fly-by-wire with an electronic throttle kit. There's no need for a tortuous path of mechanical throttle cables. In addition to marine applications, the new Vortec also will find service in tow vehicles, providing them with up to a 12,000-pound towing capacity. For the record, GM's first marine engine was the small-block Chevrolet V-8, rated 185 hp. Owens/Flagship, Chris-Craft and Crusader were the first builders to marinize the venerable 283-cid motor.

The 8100 Vortec first saw duty in 2001 in Chevrolet and GMC heavy-duty pickups. Crate engines were sold to Volvo Penta, MerCruiser, Indmar, and PleasureCraft Marine, Crusader Marine and Flagship Marine, all of which marinized long blocks by adding intake and exhaust manifolds, either a carburetor or fuel injection and a marine grade starter and alternator.

This engine is no longer manufactured, having been replaced by an 8.2-Liter V-8. See that engine's profile at: MerCruiser 8.2L