Maintenance Sparks Attention for NGV Fleets

Vehicle maintenance is a common discussion point with all fleets, especially those using natural gas vehicles (NGVs). Although over 80% of NGV engine components are identical to those of diesel (and built on the same assembly lines), differences do exist and as a result, maintenance must be considered upfront to avoid drastic cost or mile variances.

 

Spark plugs matter 

So, what is different? NGVs are designed to run on a spark ignition technology, meaning the spark plugs are actually igniting the fuel in the engine. To no surprise, spark plugs are one of the most important components to maintain (on schedule) if you want to keep vehicles running smoothly.

 

TIPS from the experts

Since the spark plugs are so essential to the performance of NGVs, Jason Bauer, a tenured technical expert at Cummins Westport Inc., recently shared best practices for maintaining NGV spark plugs. See his comments below: 

• The maintenance interval for spark plugs is 1,000 hours for the ISX12G/N and 1,500 hours for the ISL G, L9N, and B6.7N. We recommend using two methods to calculate ignition maintenance on your CWI natural gas engines. Estimate the hours of operation by either installing an hour meter on your engine or calculating the hours based on the total average vehicle speed which is available on the Cummins Insite tool.
• Only replace the spark plug and the boot during the interval. Coils and coil extensions should be inspected and only replaced when not meeting the published reuse guidelines.
• Ignition coils are not a maintenance item; however, failures are typically attributed to exhausting spark plug life (1,000 hours on the ISX12G/N or 1,500 hours on ISL G, L9N, and B6.7N).
• It is not necessary to re-gap or check the gap on new pre-set spark plugs. Re-gapping the spark plug risks removing or damaging precious metals on the plug electrode that will lead to premature failure or reduced plug life. If you feel you must check the gap before installing, only use a wire/pin style gauge available through Cummins (part number: 5394864). The blade/leaf style or the flat disk gap gauges that we’ve all used on other engines have been known to damage the precious metal that is on the electrode of the new spark plug. If you have a new spark plug that appears to be out of spec, just return it for a replacement. Do NOT adjust the gap.

But that’s not all. Be sure to keep the porcelain part of your spark plug clean and remove any trace oil when changing them. A good practice is to use a new spark plug socket to install the spark plugs so that the foam portion of the socket will not contaminate the porcelain.

 

Oil is another factor 

Okay, enough about spark plugs. Let’s cover one other significant variance to consider as part of your NGV maintenance plan: oil. Operators are directed to use oil specifically designed for NGVs which can be purchased through a Cummins dealer. This may require fleets to stock two different types of oil: one for use in their diesel fleet and the other for NGVs. However, Valvoline, Inc. recently announced the availability of its Premium Blue One Solution™ 9200 which can be used in both NGVs and diesel engines. This is a real game-changer for fleets that have various engine technologies in operations. No more stocking two types of oil—shops can now consolidate with ease.

 

It’s not that bad, we promise

We’ve gone to great lengths discussing how to maintain spark plugs and oil properly for NGVs, but the part we haven’t addressed are some of the maintenance benefits of NGVs. Yes, there are considerations, but, technicians don’t have to worry about diesel particulate trap filters nor do they require the use of DEF. And, natural gas as a fuel is odorless; technicians really enjoy working on these vehicles because the smell doesn’t stick with them all day.

Bottom line—consider your maintenance plan upfront for any new technology. This is essential whether you insource or outsource your maintenance. Time spent upfront will help you maintain low maintenance costs, keep your trucks on the road, and facilitate a smooth experience with NGVs.