Subaru’s EX Series engines are the first to utilize high performance chain-driven overhead cam (OHC) technology in the industrial air-cooled market. Featuring four models with power ranges from 4.3 to 14 horsepower, the EX Series offers more power, easier starting and quieter operation than same-class competitive engines. In addition, the EX Series is covered by Subaru’s new 5-year limited warranty.
A standard for high-performance automotive engines, chain-driven OHC technology allows the intake and exhaust valves to be positioned for optimum engine performance. This offers lower resistance for the air/fuel mixture flow. Designed with a highly efficient pent-roof-type combustion chamber, the EX engines are able to utilize a high compression ratio, producing higher power and torque while limiting exhaust emissions and fuel consumption.
Easier starts are another advantage of the EX engines. An automatic decompression system reduces the required recoil pulling force by 30- to 40-percent when compared with overhead valve (OHV) engine designs. In conjunction with the newly designed combustion chamber, starts are fast and easy with no perceptible kickback.
With fewer moving parts, OHC engines produce less mechanical noise than competitive technologies. The EX engines take it a step further by utilizing optimized-capacity rigid mufflers. Together these features make the EX engines a full 2dBA (decibel level) quieter and softer in exhaust tone than other same-class engines.
Excessive heat is the primary cause of engine failure. To combat this problem, Subaru engineered a patent-pending technology to provide outstanding cooling performance for its line of EX engines. To utilize every possible cooling area, special heat dissipation fins have been built into the mounting base, cylinder and both the inner and outer crankcase surfaces. Additionally, the OHC technology allows for 360-degree airflow around both the exhaust and intake valve stem areas.
Engine durability is further enhanced by a patent-pending oil delivery system. A unique oil scraper attached to the connecting rod supplies oil to the cam chain. The cam chain then carries the oil to the overhead cam and valve train. A special rocker cover design and breather system keep the camshaft and rocker arm bathed in oil, yet prevent spouting — whether the engine is level or inclined.
Maintenance is simplified through high parts commonality. With more than 50 percent of component parts shared between the four EX models, maintenance and parts availability is improved. Additionally, serviceability is further enhanced by eliminating the need for special tools for routine maintenance, assembly and disassembly.
EX Series engines include the EX13, EX17, EX21, EX27, EX30, EX35 and EX40 models, which produce 4.3-, 6-, 7- 9-, 9.5-, 12- and 14-horsepower respectively. Ideal for use in general construction equipment, compaction equipment, portable generators, pumps, compressors and other industrial engine applications, all models comply with both EPA and CARB emission regulations.