New high—and low—for Briggs & Stratton: company expands commercial lineup with new engines at both ends of the spectrum; 31 hp largest air-cooled engine in B&S history - Gasoline Engines - Company Profile

Diesel Progress North American Edition, Jan, 2003 by Mike Brezonick

Over the last several years, Briggs & Stratton has been one of the busier small engine manufacturers around. Significant milestones have included the expansion of the top rating of its liquid-cooled 3LC engine line and the development and introduction of a two-cylinder liquid-cooled engine.

But while the liquid-cooled engines have been grabbing the headlines of late, it's important to remember that Briggs & Stratton's heritage is air-cooled technology. And recently, the Milwaukee, Wis.-based company took yet another big step -- or more correctly, steps -- in that arena with the introduction of two new engines to its Vanguard commercial gasoline engine range. The biggest news is literally the biggest engine, as the company unveiled a new Vanguard air-cooled V-twin rated 31 hp. It is the largest air-cooled engine in the company's history.

At the other end of the Vanguard line, Briggs & Stratton also introduced a 2.4 hp single-cylinder engine targeted at smaller equipment such as edgers and trimmers. In all, the two new engines allow the Vanguard single- and twin cylinder engines to span a range of 2.4 hp to 31 hp. Factoring in the 3LC family, Briggs & Stratton can offer gasoline engines to 34 hp.

The new engines also fit well into what could be called the company's value strategy. Over the last several years, Briggs & Stratton has focused on a goal of developing a range of products that could provide horsepower at whatever value level a customer needed. Premium OEM products can use the high-end liquid-cooled twins and three-cylinder engines. Lower cost machines can use standard, less expensive air-cooled units. And in the ranges where there is overlap, a customer has a choice of which direction to go.

"Our customers challenged us to produce an air-cooled engine that could meet the increased performance and durability requirements of their commercial equipment," said John Stauder, product manager for Vanguard engines. "The new Vanguard 31 hp provides horsepower and torque numbers that surpass the best two-cylinder liquid-cooled engines and because the engine is air-cooled, it is lighter, less expensive to purchase and is easier to maintain."

The Vanguard 31 hp offers a peak torque output of 48 lb.ft. at 2200 rpm and is targeted at a range of mobile and stationary applications, including commercial turf and concrete equipment, welders, generators, pumps and pressure washers. It incorporates an all-new block design which allows a larger 750 cc displacement, up from the 700 cc displacement of the previous high end of the range. Bore x stroke is 85.5 x 78 mm.

The block also incorporates cast iron cylinder sleeves for durability and replaceable steel/aluminum main bearings. Despite the larger displacement block, the engine still comes in at the relatively modest weight of 122 lb.

The engine is equipped with a float feed, two-barrel carburetor fuel system with a fixed main jet and adjustable idle and afterfire solenoid. The fuel system can be adjusted for high altitude operation, the company said. Ignition is electronic, utilizing Briggs & Stratton's Magnetron system.

Other engine features include full pressure lubrication system; solenoid shift electric starter; 20 amp alternator (with 20/50 amp alternator optional); industrial Donaldson-type 5 in. centrifugal air cleaner with a three-position outlet; and large volume muffler with baffled chambers.

Recognizing that excessive heat can shorten an engine's lifespan, the Vanguard 31 engine also includes an advanced debris management system. A rotating steel screen at the flywheel breaks down debris and chaff so it can easily pass through the cooling system. A labyrinth interface between the rotating screen and the engine's blower housing makes it virtually impossible for debris to bypass the screen and enter the engine, the company said.

The Vanguard 31 hp engine, which the company said complies with CARB and EPA emissions standards, is scheduled to go into production in the second quarter of 2003. It is built at Daihatsu Briggs & Stratton, the joint venture between Briggs and Stratton and Japan's Daihatsu Corp.

At the other end of the spectrum, 2.4 hp Vanguard OHV, a single-cylinder, horizontal shaft engine designed to provide lighter and smoother performance on smaller horsepower commercial applications. The 2.4 hp Vanguard engine has a 52 mm bore x 38 mm stroke for an overall displacement of 80 cc. Like several of the other small Vanguard singles, it incorporates a pent roof combustion chamber design that increases airflow in the cylinder and improves combustion, and is certified to CARB and EPA emissions requirement.

In the pent roof design, the top of the combustion chamber is angled and the valves are positioned at a 45[degrees] slant relative to the center of the cylinder. This configuration intensifies intake airflow, improves air-fuel mixing and reduces dead volume and airflow losses.

Other engine features include an all-aluminum block and head for low weight (21 lb.); cast iron cylinder liner for improved durability; float feed carburetor and Magnetron electronic ignition system; dual ball bearings; and two-stage air filter. The engine also incorporates Briggs & Stratton's Oil Guard low-oil shutdown system.