By Brad Murphy
Although many lawns and turf surfaces may be fragile, the edger, seeder or trimmer being used to keep them manicured must be rugged and powerful in order to get the job done. And a valuable piece of equipment can depend on many factors. But to make sure the equipment you choose will perform at its best, it’s important to consider the powerhouse, the driving force behind the equipment — the engine.
With so many makes and models of engines on the market these days, it’s difficult to know which one is best. The huge array of power equipment at rental centers and dealerships can be overwhelming, and the amount of engine choices for a particular piece of equipment is increasing more and more. But choosing an engine doesn’t have to be difficult — it basically comes down to knowing what features to look for. To ensure optimal performance, make sure to consider a few important engine criteria when selecting a piece of equipment.
Most landscaping equipment is available with one of two different engine designs — pushrod overhead valve (OHV) or overhead camshaft (OHC). There are advantages and benefits to both styles, and each will lead a piece of equipment — such as an edger, pressure washer or lawn vac — to perform in a slightly different way.
By offering an efficiently configured combustion chamber, pushrod OHV engines boast the ability to provide exceptional power and performance in a small package.
For the last 25 years, the pushrod OHV has been a functional and recognized design in general-purpose air-cooled engines. But engineering, design and innovation didn’t stop at OHV configurations. Recently, a different style has been gaining popularity.
On various pieces of outdoor power equipment, including lawn and landscape products, some manufacturers have begun to offer engines featuring OHC technology. This type of configuration places the camshaft within the cylinder head, above the combustion chamber, allowing the valves to be driven in a more direct manner compared to OHV designs. The placement also eliminates the need for pushrods, the driving force in OHV engines. Overall, the OHC engine is carefully designed to run at an optimal level at all times — therefore, the equipment it’s powering will too.
OHC engines start easier, are much quieter, and offer greater power output compared to other similar-class engines. They also lessen fuel consumption and reduce emissions, which is crucial for meeting strict EPA regulations. Some OHC engines also incorporate a hemispherical combustion chamber. It’s specifically designed to achieve maximum combustion and allow the engine to utilize a higher compression ratio, which results in greater power and torque.
A quality engine, whether OHV or OHC, is the key to enhancing equipment performance and productivity on the job site. But regardless of configuration style, it’s important to choose a piece of equipment that will meet the demands of any landscaping project. One way to ensure this is to look for an engine that can handle varying weather conditions.
Because outdoor power equipment typically runs throughout the majority of the year in most parts of the country, the engine must be one that can handle a variety of weather conditions and changing temperatures. Some engines have actually been designed for multi-season operation, and provide peace of mind during both the coldest and warmest months of the year.
During the summertime, the temperature in most parts of the country easily exceeds 100 degrees Fahrenheit. Overheating is one of the primary causes of engine failure; so, without proper cooling technology, an engine won’t last long in elevated temperatures. Between juggling multiple projects during the peak of summer season, contractors have enough to worry about, and don’t have time for their equipment to be stalled due to engine failure. To avoid overheating issues, look for an engine that offers advanced cooling features. Some engines incorporate 360-degree airflow, which provides much-needed cooling to the exhaust and intake valve stem areas. When combined with other features such as heat dissipation fins, the engine can provide optimal operation all day long.
Except for a few of the coldest, snowiest areas of the country, much of the winter season can stay fairly busy for landscape professionals — just because the temperature dwindles doesn’t necessarily mean the work does. This is why it’s important to have an engine that can handle cold weather and wet conditions. Since many states experience damp, cold and even freezing conditions with the occasional snow flurry, an engine that can hold out in these less-than-favorable environments is imperative.
Some engines incorporate special features that will direct heat from the cylinder head back to the carburetor to keep it warm. This ensures ideal engine temperature and aids in easy machine start-up. By allowing heat into the air cleaner system, potential ice build-up and airflow restriction is eliminated. Additionally, many engines offer strategically placed guards designed to stop snow and ice from entering the engine and freezing up, and causing damage to the governor system, vital controls and linkages. Any or all of these features will go a long way in enhancing engine performance and providing easy start-up on cold days.
An engine that’s designed well and is able to perform in most weather conditions is crucial in obtaining optimal equipment performance. But while these advantages are important, they’re not the only factors to consider. Another aspect to look at is the amount of noise the engine emits.
Most landscaping companies understand the significance of quiet equipment. Beyond some neighborhoods having decibel level restrictions, commercial properties and city parks also appreciate quieter equipment, and may demand it. This is why an engine designed to limit noise emissions is extremely valuable. While it may not be an issue for a piece of equipment such as a leaf blower, which is relatively loud on its own, for some pieces of equipment, such as a lawn mower, an engine that reduces noise will be important.
OHC technology lessens noise levels by reducing the number of moving parts. As a result, OHC engines produce less noise than similar OHV units. Some manufactures have even engineered models to have up to 33 percent fewer moving valve train parts than comparable OHV styles.
Furthermore, certain parts of the engine can also be designed to help reduce noise emissions. Specially designed mufflers provide greater sound cutback than standard engine mufflers. And, when paired with OHC features, noise levels are significantly lessened.
Between engine design and special heat- and noise-combating features, there is a lot to consider when choosing an engine. Thankfully, a rental center operator or equipment sales associate will likely be able to aid in the purchase and tell customers whether an engine is OHV or OHC, and if it has special multi-seasonal or noise-reducing features. But it doesn’t end there — remember the old saying, “It’s what’s inside that counts”? A quality engine is only as good as its components, making it crucial to further investigate the engine and what’s beneath the surface.
Good on the inside
In recent years, more and more plastic has been integrated into internal engine construction. While acceptable for lighter duty engines, it’s important for a commercial engine to have precision steel parts. Components such as piston rings, timing chains, crankshafts and rocker arms should all be constructed of steel. This allows for improved wear quality over engines manufactured with plastic elements.
It will be advantageous to look for a cast-iron cylinder liner. Most outdoor power equipment engine blocks are made from aluminum, which, compared to the steel or chrome rings on the pistons, is a very soft material. This variation in hardness causes the piston rings to quickly wear away the aluminum cylinder walls. As the cylinder walls wear down, compression is lost and the engine can no longer produce the necessary amount of power to run the equipment properly. To avoid this problem, look for an engine with a cast-iron cylinder liner. Because the material is much tougher than aluminum, cylinders with a cast-iron lining wear much better, offering increased engine life.
Also essential in a quality engine is ball-bearing support of the crankshaft. Ball bearings reduce friction, resulting in an increase of power delivery to the crankshaft. Additionally, ball-bearing support prevents problems caused by placing a crankshaft directly on an aluminum housing. Because aluminum is a soft material, the crankshaft will wear away at the housing and eventually cause oil leaks during operation.
All the pieces to the engine’s design add up to make a huge difference from one to the next. But it’s more than just the overall design and construction that lead to a quality engine. The final piece to the complete package is the added features – the extra items that seem small on their own, but add up to great value.
Just as excessive heat can reduce engine life, dirt infiltration is also detrimental. When dirt gets into an engine, it can infiltrate the oil and cause additional wear on the connecting rod and crankshaft. To prevent this, look for an engine with a high-quality air cleaner system to keep engine operation in optimal condition. An efficient air cleaner will prevent dirt, dust, and other harmful particles from entering the engine, resulting in reduced wear on the valves and rings. To ensure optimum protection against fine dirt particles, choose an air cleaner with a dual element and small micron size.
The air filter is a vital part of the air cleaner system, and some manufacturers now offer high-quality washable filters. A washable filter is typically more effective at trapping and holding dirt, which will ultimately result in a longer engine life. As an added benefit, these easy-to-clean filters are reusable, virtually eliminating waste and replacement costs.
A low oil sensor is also an important extra feature. If the operator allows the oil to fall below a safe range, the sensor will ground out the ignition and stop the engine before potential damage occurs. Especially as workloads ramp up, deadlines loom and the business in general just becomes hectic, it’s not uncommon for busy contractors to overlook basic maintenance items such as checking the engine’s oil. A low-oil sensor will prevent potential damage to the engine due to operator neglect.
Another beneficial bonus is a durable, high-strength recoil guard. Typically made from a sturdy yet lightweight poly material, a guard will protect the engine’s recoil from damage sustained on the job site and during transport. An undamaged recoil will start much easier and save the operator repair or full replacement costs.
On a final note, it’s a good idea to choose an engine from a reputable and trusted manufacturer. A company with a good warranty program and service network will ensure that any problem is handled promptly and professionally.
At first glace, choosing the best engine for a piece of landscape equipment may seem confusing. Although there are many features and components to consider, doing a little research beforehand can pay off in a big way, as a quality engine will provide optimal equipment performance and increased return on investment.
Brad Murphy is vice president, sales and marketing, Subaru.