Seeking advice on John Deer CNG 8.1

[BugsBunny]

Hi all,

Looking at a 1997 Blue Bird taken out of service June 2018. I don't know anything about the John Deer CNG 8.1 and would appreciate all comments.

[Kubla]

Unless you live in a state that sells CNG at normal gas stations, don't buy it, not easy to convert to normal gas, only exception is if it's dual fuel already

[cadillackid]

CNG is definitely only available in select areas.. California being one of them as it receives tons of government grants for alternative fuels.. you can usually find stations in major metro areas... sometimes in areas where farming is big as some farm operations use it.. but its definitely not as available as diesel or gasoline..



you also have to note if the station you are attending is a fast-fill or a standard time fill station... fast fill is newer tech and isnt everywhere.. some stations were on a gallon or 2 per hour... fast fill is similar in time to normal gasoline or diesel fill up...

[Mark_In_MA]

I'd also avoid CNG because it's so rare around here. A couple of the local transit authorities run it, and that's it. There aren't many places to fill it, and there are even fewer people around here who can fix it.

I don't see anything in particular that indicates that its popularity is going to grow in the future either.

[turf]

pass on cng - you want to start with the right powerplant.

[EastCoastCB]

Plus CNG tanks expire and have to be recertified.
Plus John Deere aren't very good anymore. We used to put JD engines in cement haulers we fabbed and they were problematic. Switched to Cat then Perkins and now IDK what they're using. Medium Duty engines are a joke these days.

[cadillackid]

its very regional... its expanded and expanding here in ohio only because the natural gas industry here is Huge... its big on the coasts because of remaining government grant money till trump kills that off...


the city of columbus is moving its whole fleet of city busses rather quickly over to it.. however the fueling station for them is a private center not available to the public...

-Christopher

[Mark_In_MA]

I know a retired bus mechanic from Boston.

The CNG buses aren't all that great. They have problems in summer sometimes that the gas valves by the tank freeze, because they get too cold from the expanding gas. Because there's a giant gas tank on the roof, the buses can't share any of the stations that also have overhead wire (for the all-electric buses or streetcars.) I don't think the buses can be serviced full either - so the gas tank has to be emptied outside. You open the valve. . . and wait. There are special rigs that re-capture some of the gas, but its still wasting a lot.

The newest model of articulated buses that they bought are diesel-electric - the diesel engine drives a generator, which drives the wheels through electric motors - no standard transmission. They're quieter, smoother, and came in at about the same price to operate as the CNG. Some of the non-articulated diesel-electric buses have smart start - get to a stoplight, and the diesel shuts down. Off the line, I think it's battery power that gets is moving while the diesel fires back up. There's no delay in moving, just a delay in the rumbling starting up from behind the rear seats.

[cadillackid]

Originally Posted by Mark_In_MA

I know a retired bus mechanic from Boston.

The CNG buses aren't all that great. They have problems in summer sometimes that the gas valves by the tank freeze, because they get too cold from the expanding gas. Because there's a giant gas tank on the roof, the buses can't share any of the stations that also have overhead wire (for the all-electric buses or streetcars.) I don't think the buses can be serviced full either - so the gas tank has to be emptied outside. You open the valve. . . and wait. There are special rigs that re-capture some of the gas, but its still wasting a lot.

The newest model of articulated buses that they bought are diesel-electric - the diesel engine drives a generator, which drives the wheels through electric motors - no standard transmission. They're quieter, smoother, and came in at about the same price to operate as the CNG. Some of the non-articulated diesel-electric buses have smart start - get to a stoplight, and the diesel shuts down. Off the line, I think it's battery power that gets is moving while the diesel fires back up. There's no delay in moving, just a delay in the rumbling starting up from behind the rear seats.

I rode one of those new Arty's when I was out there this late may / early june.. only had 29k on the hib odometer.. nice riding busses.. seems MBTA still has a lot of diesel rigs out there and hasnt gone the way like my city of going all CNG.. I didnt realize they cant be serviced full.. but makes sense they dont want a full tank of CNG getting loose inside the garage area..

-Christopher