Most of today’s natural gas engines are based on proven diesel designs. For example, there is more than 80 percent parts commonality between the Cummins ISL diesel engine and the Cummins-Westport natural gas engine, says Jeff Campbell of Cummins-Westport.
When it comes to maintenance, here are three of the biggest differences between diesel and natural gas engines:
SPARK PLUGS. For technicians, the reintroduction of spark plugs to an industry that moved largely to diesel decades ago is the most noteworthy change. Plugs will need to be replaced every 45,000 miles or so.
DEPOSITS AND OIL. Because natural gas engines run significantly hotter than diesel engines, they vaporize oil and create ash. This can form deposits in the combustion chamber and disrupt firing patterns. “A specialized motor oil with lower ash levels that can perform in these higher operating temperatures is a must,” says Jim Gambill, Chevron’s Delo brand manager, Americas.
DRAIN INTERVALS. Oil change intervals are shorter for natural gas engines – another consequence of higher temperatures. In harsh applications, drain intervals as low as every 7,500 miles might be needed. Intervals could extend to 15,000 miles in light-duty applications.