When saying "big buses" is that going to be everything larger than a shortie?
Last question and I think I will have most questions answered. Are hours OR miles on an engine more important? I truly don't know how this works. It looks like from google research most engines need to be rebuilt around ~9000 hours?
Is there an average on the amount of hours until a rebuild is necessary? I requested maintenance records as well to see if any overhaul was done.
Hours/miles are kinda subjective. Were the miles freeway cruising on flat land? Heavy stop and go in the mountains? Long trips? Lots of start ups and shut downs? Get the idea?
Dunno...
I have a 10k LB rig that is 22.5' long with a 5.9 that may give you a pretty good challenge.
I have not owned a T-444E. I have had a couple of Powerstrokes and, again, my preference is for the I6's. There are lots of great T444 and GM 6.6 Duramax that do a fantastic job. My preference is for I6. If you want big displacement then the 8.3 is another great engine.
I will make an exception for the DD two strokes. No logic there. A modern I6 four stroke is superior in so many ways. I just love a two stroke DD.
One thing about the DD 2-stroke engines is that they produced power on each stroke of the piston, as opposed to every other stroke on other engines.
The V-8 style T444 (and it's "E" variant) and other V8 style diesel engines (excluding the DD 2 stroke) is that they simply don't generate as much torque as most straight 6's do. Consider this ... a racecar might generate 600 horsepower. It will accelerate quickly, have a high top speed, and the engine will spin many RPM's ... but don't last long, and don't generate much torque. A big truck might have a 600 HP engine (Cummins ISX for example) and won't accelerate as quickly and certainly not have as much top speed, but it will haul absurd amounts of weight up steep hills. It'll have a top RPM much lower than the racecar, and may last over a million miles. A locomotive may also have a 600 HP engine (old switcher type), have a redline of 900 RPM, but generates *GOBS* of torque ... enough to move a number of heavily loaded railcars.
In our world, horsepower comes second to torque. The two are related mathematically but ultimately it translates to an old racer's saying. "Horsepower determines how fast you can go, torque determines how heavy of a trailer you can pull." Compare a T444 and DT466. Engine displacement is fairly close, but the DT466 only has 6 cylinders instead of 8. Each will have a larger diameter, and more importantly for generating torque, a longer stroke. The 8.3 Cummins simply has a larger displacement than the DT466, and the potential for more torque (depends on how they are spec'ed and programmed). An L10 Cummins, M11 Cummins, N14 Cummins will each have more displacement (respectively) and each could generate more power. (And yes, the N14 was listed as factory engines on some school buses!)
PNW_Steve - could you expand on that please? - no gas or propane?? - I have my eye on a 'possible' skoolie purchase, right size, already registered locally as a motor home, that has been converted to propane and the owner claims gets 'good mileage - I also have my eye on a moderately low mileage fairly high end motorhome that has water damage with a 454 and Ram Air - repairing water damage is the least of my worries
The problem with all of the gas/propane powered buses up until the last few years is they were under powered and gas hogs. 4-5 MPG with an automatic was great fuel mileage compared with 8-11 MPG with a diesel in the same size bus.
has anyone figured the cost of repairs into it? - lots of cheap parts and experienced mechanics when it comes to a chevy 454 - not so much when it comes to diesels - I always figured you had to count on adding a "0" to the cost of fixing a gas engine when it came to fixing a diesel - I would welcome alternative thoughts
Here in the states, Propane is fairly uncommon for highway use. There aren't many refueling stations and it's partly because the EPA has stringent regulations on propane conversion kits. They simply never became popular. It is my understanding propane is much more common in Canada, and may be a more feasible alternative. Propane engines need far fewer oil changes (I've heard of some going 50K between oil changes).
The thing is, diesel engines, by their very design, use inherently less fuel than their ignition based competitors. The latter require a specific fuel-air mixture at all times, where a diesel intakes plain air, compressed to a high temperature on the compression stroke, and just enough fuel injected to meet the load. There may be unused air if the engine is idling. Also, diesel has more heat energy per gallon than gas does (About 20% IIRC), thus less is needed for the same amount of power.
