12/1/2002
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Let It Snow: Winter White Stuff Can Bring Green To Engine Builders
By Doug Kaufman
According to popular legend, the Eskimo language has anywhere from 10 to 50 different words for "snow." To someone from Phoenix or Albuquerque, perhaps this seems like a big deal. To someone in Minneapolis, Cleveland or Buffalo, the list of English words to describe winter weather is even greater – and not all of them printable in this magazine.
To engine builders, a good word for snow may be "green," as in "money." Two- and four-stroke snowmobile repair can be a profitable niche business to help fill the cold winter months.
According to the International Snowmobile Manufacturers Association, there have been 134,082 snowmobiles sold in the United States and another 50,719 sold in Canada during 2002. There are approximately 1.65 million snowmobiles registered in the U.S. and 760,000 registered in Canada. Service on these sleds tends to be a seasonal job – typically owners will realize that work needs to be done only after the first snow has fallen.
If you’re currently offering snowmobile service, you’re probably faced with work already this season. But if this is a new market for you, what should you consider for the rest of this winter and the next?
Like personal watercraft, go karts, lawn equipment and mopeds, most snowmobiles are sold with two-stroke engines. But four-stroke technology has found its way into the snowfields and all major snowmobile manufacturers – Yamaha, Polaris Industries, Bombardier Inc. and Arctic Cat – have it in development or in place for their newest models. Redline Snowmobiles Inc. also has a line of four-stroke engines available in its performance sleds.
The two vs. four-cycle debate is a furious battle being waged between snowmobile enthusiasts and environmentalists. Enthusiasts don’t want to sacrifice performance while the concern over noise and air pollution has prompted the federal government to consider banning snowmobiles in Grand Teton and Yellowstone National Parks.
Snowmobiling is estimated to be a $10 billion annual industry in the U.S. and Canada, so it is not just an inconsequential debate. Where does the engine builder fit in the mix? Recognizing that these vehicles are out there in quantity, that they may need repair or other service to make them competitive with newer models as well as examining possible future retrofit opportunities can help you make green from the white stuff.
Service Opportunities
"When an owner doesn’t take the time to properly prepare his sled for off-season storage, there are bound to be problems when he goes to fire it up in November for the first time," says Kent Reisenauer, assistant professor in Recreational Engine Technology (R.E.T.) at North Dakota State College of Science (NDSCS) in Wahpeton, ND. The R.E.T. program at NDSCS consists of several theory and laboratory classes covering many different types of recreational engines, including snowmobiles. Reisenauer uses snowmobiles from members of the greater Wahpeton area in his lab work, and students get a lot of hands-on training in basic snowmobile engine repair.
"The theory courses cover two-stroke operating principles as well as complete service and trouble-shooting of the engine and its accessory systems, says Reisenauer. "Our discussions cover diagnosis and overhaul. When we move into the lab, students actually have hands-on experiences using manufacturers’ recommended procedures and specs."
Reisenauer points out that many of his classes are run in conjunction with the college’s automotive program. "Automotive engine builders can certainly do these repairs. The machining techniques are really the same – it’s just that the parts are smaller."
For Reisenauer’s students, typical snowmobile engine service goes like this:
"We’ll do an inspection and primary and secondary compression test to determine the cause of burndowns. With the two-cycle engines we can pressurize the engine with 8-10 lbs. of air to check for leaks. Then, we’ll look at the carburetors as well as the fuel injection systems. The newer snowmobiles have computer-controlled engines that actually provide trouble codes to engine analyzers. They’ll actually help identify component failures and intermittent problems," Reisenauer says.
During the teardown process, pay attention to the condition of all parts and components. Look for wear, stripped threads and damaged parts. Use your crack detection equipment to check for hidden damage, repair stripped threads and replace broken bolts to prevent leaks upon reassembly.
Reisenauer suggests the biggest opportunity for engine builders to make a profit from snowmobile service is in machining. "Boring cylinders, chamfering parts, balancing or truing crankshafts – maybe even rebuilding the cranks..." says Reisenauer. "There are many things experienced auto technicians can do to make money here."
Boring snowmobile cylinders offers benefits to both performance enthusiasts and trail riders alike. You can repair damage to the cylinder wall caused by debris or piston seizure, bring the compression back to its original factory condition or increase engine displacement by going to an oversize cylinder bore. Check with your suppliers for the parts and equipment necessary to meet these various needs.
"A lot of the snowmobiles today have Nikasil or other performance coatings, so we can’t just bore them out," explains Reisenauer. "We’ll either replate the cylinders or bore them oversize and resleeve them – whatever works best for the customer." Most modern Japanese two-strokers have coated cylinders, so boring and sleeving is necessary on many damaged cylinder walls and for future repairs.
An engine is, after all, basically an air pump. Air comes into the engine through the intake or reed valve and out through the exhaust port. Port chamfering will allow smoother airflow within the engine, resulting in more torque at a lower rpm and better acceleration. Computer software is available to help determine what porting will do for specific rpms and compression.
Snowmobile crankshaft service is another potential profit center, points out Reisenauer. Whether single- or multi-cylinder crankshafts, a straight crankshaft is critical to performance.
Frequent Engine Builder contributor Paul Savadin has preached the gospel of small engine crank service for years. Grinding, welding and straightening of small crankshafts can be a very profitable use of your time compared to standard automotive crankshafts.
"With small cranks, you can make the same profits, or better, without all the hassle of those heavier automotive cranks," Savadin says. "The grinding charge on a small engine crankshaft is usually only a few dollars less than that of a V-8 or six cylinder automotive crankshaft."
Two-Stroke Future: Yes or No?
Because of the nature of a two-stroke engine, there has been talk of banning their use in snowmobiles. Bryan Willson, professor of mechanical engineering and research director of the Engines and Energy Conversion Laboratory at Colorado State University explains that because a two-stroke uses an air-fuel mixture to push the exhaust products through the engine as much as 35 percent of a sled’s fuel is wasted in scavenging losses. This results in extremely high noise and air pollution complaints.
The move to four-stroke snowmobiles will obviously help meet the concerns of the green crowd, tree huggers, but die-hard performance enthusiasts will fight giving up their exciting, lightweight and powerful two-stroke snowmobiles. Who’ll blink first?
According to Willson, neither will have to. Thanks to the Clean Snowmobile Challenge, sponsored annually by the Society of Automotive Engineers (SAE) research is being conducted on existing two-stroke engines to make them as quiet and clean as a modern four-stroke engine. The tests to date have been, according to Willson, impressive.
"Our students participate in this program to develop the cleanest, quietest snowmobile," says Willson. "Using existing technology – direct in-cylinder fuel injection used mainly for outboard boat motors – we have been able to reduce hydrocarbon emissions from an average two-stroke motor by about 90 percent. Installing an oxidation catalyst yielded a 99.4 percent reduction in CO emissions and an 88.6 percent reduction in hydrocarbons."
Of course, simply adding fuel injectors was just part of the story. In addition, Willson’s students had to redesign the cylinder heads, which contain the combustion chambers and spark plugs.
The Colorado State University team did not win last year’s competition. Although their engine was by far the most emissions friendly of all in the contest – including some four-strokers with three-stage catalysts and O2 sensors and computer controls – their sled was a half-decibel too loud. "Guess what we’re working on for this year’s competition," he says.
Proving the technology works has not been a huge challenge, says Willson, but overcoming perceptions can be more difficult. "It allows you to get the same performance with very low emissions. Plus, you’ll probably see a 35-40 percent reduction in fuel consumption. I think it’s a viable option. To me, it makes a lot of sense."
Will the U.S. market beg for direct injection upgrades to the two-stroke engine market? Perhaps it will be a viable add-on to the performance snowmobiler, but Willson says a more likely scenario would be to see technology – tested here – be used overseas, where more than 100 million polluting two-stoke engines are used for daily transportation. "That’s where it could be a truly beneficial retrofit."