update on the CNG truck

I'm at 32,000 miles now. The first pm was done at 18,000 miles. The oil was almost as clear at it went in. The oil can be seen through at 18k miles. Always being around diesel engines this was a surprise. We had an issue with a small backfire but a software update video that. The other surprise was fuel range. They said engine break in is 50k miles. New the truck had a range of 250-300 miles on 80 gallons. I'm up to 400-450 pretty easy now on 80 gallons. (112 gallon capacity/local truck) Next up is valve adjustments and spark plugs. See below for previous post and truck specs:

The first 1500 miles:

just got our compressed natural gas trucks. After the first week with them I am impressed. I read a lot of rumors about cng trucks being under powered. Not true. it is not a 600hp engine but does just fine. My first load out of the box was a load of logs with a GVW of 85k lbs and it did well. They do run a little higher in the power band than a diesel. My Cummins N14 would pull well at any rpm above 1000 with the exact same gearing. These start in about 1200 and run really well up to 1800. Ideal seems be 1200-1600. This is comparing a 12l engine to a 14l engine. The truck runs 1350rpm at 65mph and 1580 at 75mph. I set the cruise at 65. Not real sure about the mpg yet. Some of the pumps are set for gas equivalent per gallon and some are set at diesel equivalent per gallon. The cost per mile is running .40-.44 cents per mile vs .58 in my diesel. We are a local company so neither diesel or ng are going to get great mpg. Ours have tanks for 112 gallons. They have tanks much larger but they stick up above the cab. We are in the woods a lot so that would not work for us. Saddle mounted tanks are made by a company called agility. They are crap. Trillogy makes the best fuel system hands down. I went to a class for a week to study different systems and we covered every nut and bolt on the fuel systems.

Truck Specs:
Kenworth T800
isx12 G 400/1450
eaton/fuller 10 speed .75 tenth ger
disc brakes
220 inch (I think)
3.42 drive axles
11r22.51 drive axles
11r22.5

 

Here is a little video
Cummins isx12 g CNG acceleration 15-55mph loaded: https://youtu.be/v4llNKNePJ4

 

The truck is at 150,000 miles / 3800 hours miles and still going strong. No problems with the drivetrain. (knock on wood) Fuel stations are growing rapidly. I'm a local driver in Houston with a day cab. I do spend 2-3 days a month going out to Tampa and Sarasota Fl. Not having to go to truck stops for fuel is nice. Most fuel stations are stand alone.

A little money info:

Spark plug kits come at 60-70k miles before is starts to misfire occasionally.Then it is time to change them. The kit for 6 plugs and boots from the dealer is 250.00. It takes about 1.5 hours to change out at our shop.

The overhead was done at 120k miles for 450.00 at cummins southern plains. If scheduled they can have it done in a day or less. I really like Cummins Southern Plains.

The fuel filers are air water separators. They are good for 80k miles. We wash them out at the oil changes.

Oil analysis shows on these engines is insanely clean. CNG doesn't build soot but does build acid levels. If changed at 18-20 miles the acid level only gains 1-2% from new oil. So far no one makes a synthic oil for the truck.

The cng system has had a few small leaks. Nothing major to shut a truck down. It is usually a $2.00 washer.

I'm not overly impressed with the paccar product. I've had numerous panels off inside the truck to deal with squeaks and rattles. The cab lights leaked from day one, had to reseal them with clear caulk. The other trucks have had odometer replacements, another with 24 days in the shop for a/c problem Performance Trucks of Houston can't figure out.