1972 Brut LC44
Brutanza Engineering Inc. was formed in 1971 by former Polaris personnel that had worked in Research and Development and raced out of the factory race trailer.
Jerry Reese, Marley Duclo and Mike Baker had been responsible for numerous race victories and design innovations. An opportunity by a group of investors in Brooten, Minnesota was presented to Jerry Reese, with the goal of building a high performance snowmobile. In just 11 months, these individuals put together a team that would design, source an engine supplier, set up a manufacturing facility and begin building snowmobiles. That year a total of 1500 Brut LC44 snowmobiles were built – an amazing feat when you look at the time it took FAST to bring their Blade to market.
In the early 70’s, “High Performance” still meant being the first across the lake, but the consumer also demanded a machine that could run hard in ditches. Remember, snowmobile trails for the most part in the early 70’s were scarce, and in many areas simply did not yet exist.
The 1972 Brut LC 44 would bring a number of “firsts” to the snowmobile industry. Brutanza Engineering marketed the Brut as the “Third Generation Snowmobile”.
The management group at Brutanza Engineering set out with specific goals to address reliability and performance issues of current snowmobile designs. The objectives were:
– Design and build a Liquid Cooled (3 cylinder) engine.
– Reduce belt breakage
– Lower the center of gravity
– Maximize performance without com promising reliability.
Jerry Reese had experience with liquid cooled two stroke motors during his days with Polaris. Polaris had been testing liquid cooled (LC) engines in the late 60’s and early 70’s. He knew that liquid cooling would provide consistent engine temperature and eliminate the problems associated with free air engines such as fouled spark plugs, excessive noise, vapor lock and poor performance when air temperatures increased. As a side note, Polaris would not race an LC motor until the ’76 season, and the first production LC model would be sold in ’77.
The motor designed by Jerry Reese was manufactured by Fuji Light Industries of Japan, who was also building engines for Chaparral at the time. Everything except the crankcase was shipped to the Brut factory where the motor was assembled. The crankcase was built in the USA with tooling that allowed a triple and, in ’73, a twin (294 cc) to be built.
The Brooten engine was a 439 cc triple with a three into one exhaust. Why a triple 440 you ask? Lighter power spikes and better internal balance, which translates into fewer clutch problems. Or so was thought – more on that later. The port timing was conservative on this engine, which produced 50 hp @ 7200 rpm in its first year of production.
An innovative feature that was used to maintain consistent cylinder temperatures and reduce plug fouling was to restrict water flow to the PTO cylinder, which was found to run the coldest because of higher water flow. The orifice size on the inlet manifold was machined to provide balanced water flow to the cylinder head.
The motor also featured CD ignition which in 1972 was only found on factory race specials and select special build stock race sleds. It was another innovative feature that improved engine reliability.
Drive belt failure (blowing a belt) was commonplace on snowmobiles of the era. Anyone who snowmobiled in the early 70’s likely remembers having to carry a couple of belts on their person. Belts draped across your shoulders were so common, you were never finished dressing until you had a belt slung around your shoulders.
Marley Duclo and Mike Baker set out to solve one of the main contributors to drive belt failure: “clutch mis-alignment” between the primary and secondary. The “Power-Pac” drive train was a patented design whereby the engine and jack shaft were connected.
The industry standard at that time was to use a motor mount plate fastened directly to the crankcase with rubber bushings sandwiched between the mounting plate and chassis. The softer the bushings, the less transmitted vibration to the chassis, but the greater the degree of clutch mis-alignment under load. As HP increased, the motor mounts became more complicated which resulted in more weight and complexity. High durometer bushings were used, but they transmitted engine vibration to the chassis.
The “Power-Pac” design did not require a motor mount plate. The crankcase was supported using mounting lugs attached directly to the frame. A third mount is attached directly to the PTO cylinder head and the tunnel. The mount incorporated a bearing which supported the jackshaft and secondary clutch. The opposite end of the jackshaft was supported by the tunnel mounted chaincase.
This arrangement prevented misalignment between the primary and secondary clutch, as the engine acted as a rigid connection between the two. The design also did away with high durometer rubber bushings which minimized engine vibration transferred to the chassis.
The “Power-Pac” drive train required the engine to be laid down with the triple carbs pointed straight up to receive cool fresh air. Cool, dense air translates into more HP. The major draw back for this engine arrangement was the limited space for the exhaust. Marley Duclo would design triple pipes for a (100) limited build sleeved down 439cc to a 398 cc X-Country sleds for the 1972 I-500 Winnipeg to St. Paul race. The engine layout also lowered the center of gravity of the sled, to improve handling. Curiously, the Arctic Cat Firecat has taken this original Brut design element further by tipping the engine back and casting cylinders with the intake and exhaust ports on the same side. This provides all the benefits of the Brut with more room for a properly designed exhaust system.
In retrospect, the engineering that went into minimizing engine vibration transferred through the drive train and going with a three cylinder engine went up in pieces (literally) that first year. The Salsbury primary clutches used on the ’72 models were prone to failing. The problem was traced to a flaw in the casting.
Forced to come up with a primary clutch, Jerry Reese would design a primary clutch that used a cam (similar to a helix) which made the clutch not only rpm sensitive but also torque sensitive. A similar version is still available as an after market clutch.
The final major design feature, patented by Brut, was the design and application of tunnel mounted cooling extrusions. The original ’72 Brut used a radiator mounted in front of the driver under the hood. The sleds were prone to over-heating when idling at the start line for many cross country races. Midway through the ’72 race season, the factory team appeared with finned copper tubes running along the inside of the tunnel side walls. This design would evolve into an finned cooling extrusion mounted with the fins facing upwards. This allowed snow to build up in the cavities, which would maximize cooling efficiency. To circumvent the Brut patent, other sled manufactures would mount the heat exchangers above the track, under the running boards or in the front bulkhead.
Brutanza Engineering would build snowmobiles as an independent company for three years. The costs associated with upgrading the ’72 production with new clutches and the oil crisis hurt the company financially. In 1975 Brutanza Engineering was sold to Scorpion. The snowmobile was sold as the Scorpion Brut and offered in a 340 cc twin and 439 cc triple.
Scorpion built the sled for one more year in 1976, under the Massy-Ferguson brand name as the Cyclone. The major design upgrade was the addition of Mikuni VM-34 carbs .
Many of the design innovations brought to the consumer in the ’72 model year truly demonstrated “Out of the Box” thinking. A snowmobile with unconventional design offerings is not for everyone, however, the innovations found on the Brut and other independent designed sleds have brought major design breakthroughs to this sport to build the “Next Generation Snowmobile”.
