In 2016, Cummins Westport introduced a new dedicated natural gas engine for school bus, shuttle, transit, medium-duty truck, and vocational vehicle markets. Based on the Cummins ISB6.7 diesel platform, the Cummins Westport ISB6.7 G offers up to 240 hp (179kW) and 560 lb-ft (759 Nm) of torque, and is available with automatic transmissions. Not only does the ISB6.7 G meet U.S. Environmental Protection Agency (EPA) and California Air Resources Board (ARB) 2016 emissions regulations, it also meets ARB's optional low oxides of nitrogen (NOx) standard of 0.1 g/bhp-hr, and it meets 2017 EPA greenhouse gas (GHG) requirements a year ahead of schedule.
The ISB6.7 G features the same advanced combustion controls with Three-Way Catalyst (TWC) as Cummins Westport’s ISL G & ISX12 G engines. It operates on 100 percent natural gas, which can be carried on the vehicle in either compressed or liquefied form (CNG / LNG respectively). It can also run on 100 percent biomethane
or renewable natural gas, which meets published Cummins fuel specifications.
Note: The ISB6.7 G is no longer available. It has been replaced by the B6.7N—learn more here.
|Advertised Horsepower||240 hp||179 kW|
|Peak Torque||560 lb-ft||759 N•m|
|Governed Speed||2,630 rpm|
|Type||4-cycle, spark-ignited, inline 6-cylinder, turbocharged, CAC|
|Displacement||409 cu. in.||6.7 L|
|Fuel Types||CNG / LNG / RNG|
|Engine Model||Advertised Horsepower
(kW) @ rpm
lb-ft (N•m) @ rpm
|ISB6.7 G 200||200 (149) @ 2400||520 (705) @ 1600||2600 rpm|
|ISB6.7 G 220||220 (164) @ 2400||520 (705) @ 1600||2600 rpm|
|ISB6.7 G 240||240 (179) @ 2400||560 (759) @ 1600||2600 rpm|
Overall, maintenance for the ISB6.7 G is similar to that of diesel engines, but there are a few key differences:
|Check CAC cooler, piping, and Air cleaner||7,500 mi (12,000 km)||250||3|
|Oil and Filter*||15,000 mi (24,000 km)||500||6|
|Spin-On Fuel Filter||30,000 mi (48,000 km)||1,000||9|
|Spark Plugs||15,000 mi (24,000 km)||500||12|
|Overhead Adjustment||45,000 mi (72,000 km)||1,500||12|
|Standard Coolant||60,000 mi (96,000 km)||2,000||24|
|Crankcase Ventilation Filter||60,000 mi (96,000 km)||2,000||24|
|Ignition Coil Extension||150,000 mi (240,000 km)||5,000||5 yrs|
|Air Cleaner / Element||Follow manufacturer's published recommendations|
* Requires Natural Gas Engine Oil.