I've been spending most of my time on this search for the last couple months. I toyed with the box truck idea for a hot second, but they simply explode in any sort of collision. Appropriate reinforcement of the living structure would end up looking a lot like a school bus...
I feel decently informed enough to provide some thoughts, given what I have learned myself, and heard from others:
1. Engine- Ik DT466, DT530 or Cummins 8.3 are all good, but what about Cummings 5.9?
I almost bought a 5.9 RE bus. General consensus is that it can be underpowered in some larger buses, but there are members here on the forum that are perfectly happy with theirs. One benefit is that it's basically a large pickup-truck engine, so parts, service and even upgrades are easier to come-by.
2. What are the engines to stay away from?
You'll get a lot of different answers. I decided to stick with proven winners (as you listed basically) and we're about to pick up our bus with the 8.3 Cummins.
Don't forget to consider the transmission. Buses are sometimes built to never leave the city and only travel 50mph max, others have to climb over the Rocky Mountains every day. You can find a lot of info by simply tacking the word "skoolie" onto the end of your google search query. I usually get several threads back here on skoolie.net with info on what I need.
3. Is there a specific year school bus we don’t want cause it has repeated problems?
Given there are several school bus manufacturers, model year doesn't matter as much in terms of specific known issues with certain models. Once you narrow down your search (I ended up with just 3-4 exact models I was considering), then you can look into issues with those specific models and figure out which years to avoid. One easy answer to this question is: nothing newer than 2010...but it's more complicated.
The rule of thumb I have seen most often is that you want to try for 2004 or older. The goal is to avoid the more expensive-to-maintain emissions equipment that was added to every manufacturer's existing engine models as environmental regulations were enacted and revised over the years. If you want to avoid emissions equipment entirely, look for pre~1996 and read up on the pros/cons of all-mechanical drivetrains. Modern vehicles have a computer brain keeping everything in sync and monitoring for faults. A mechanical engine is 'analog' and theoretically would survive an EMP...but don't quote me on that.
4. Any guidance on a roof raise? We’re both 5’9- and how tall could we really get it?
First instinct is, at 5'9" I think you could easily get away with not raising the roof. I myself am 6'0" and while I may change my tune when I actually start spending time in my bus, I am not 100% on a roof raise.
You will learn to look for "activity buses" and other buses with a higher-than-standard roof. They also tend to be lower miles for sports team or band camp use, etc. Handicap/paratrans usually has high roof for mobility's sake. You'll see how the wall above the windows extends upwards a bit more than standard, which almost immediately starts to curl into the roof above the windows.
If you already know all this and just want to max out, I wouldn't go taller than about 18". Others may argue that more is fine, but I think 18" is where normal meets extreme.
5. What mileage is too high for gas?
Unless you're specifically looking for a certain kind of bus, it's unlikely that you end up with a gas motor. But, if you did, then like the "model years to avoid" question, it will simply be a matter of research. For simplicity's sake I would think of it like any other used car purchase and start to have doubts over about 100k. Some would set that line at 60k, others 120k so best to make an effort to educate yourself on the specific model you end up considering.
6. What milage is too high on diesel?
*Insert "I AM NOT A MECHANIC" disclaimer here*
Ditto above. I gather that pretty much all of these medium-duty engines that were spec'd for school bus use generally fall into the following pattern:
250k miles - time to do a rebuild
10k hours - time to do a rebuild
You can get more technical by doing things like oil analysis, but this is a general guideline for browsing listings. A 250k bus is gonna be a big dice roll even with immaculate service records.
A rebuild, if you are unfamiliar, is just the process of partially disassembling the engine and replacing worn-out internal parts with new ones. For some buses this can be done without removing the engine from the bus (in-frame rebuild). For others, you gotta pull the engine out and it's a whole thing. Just check which applies to whatever bus you may find. It's an expense, but just the same a hot-water-heater or a new AC unit for your brick-and-mortar home would be, I consider it a normal expense that can be anticipated.
I set a limit of 200k miles and/or 7500hrs, knowing that a rebuild is a fact of life in the mid-term future for most skoolies...because if you build your whole-ass home in this thing and the engine fails, you're going to have a different set of decisions on your hands than if you just couldn't afford to repair your personal car.
7. What are the questions I should be asking when searching for a bus?
Asking the seller?
These may or may not be good suggestions but here are some of the common questions I found myself asking:
On gov't auctions:
- <Please clarify XYZ technical information about the bus> i.e. what transmission does it have?
- Are you willing to be flexible with the timeline for pickup after the auction closes? Might need an extra day or two if travelling far.
- Other than that, keep in mind that the people managing these auction listings are regulated by law. If they are willing to answer your questions, they are doing so presumably understanding that they have a legal liability not to lie or misrepresent the facts of the property for sale.
On private listings i.e. Facebook/craigslist:
- XYZ technical info about the bus. You'll need to get familiar with what you need to know and get that info if it's not listed. I tend to assume things are omitted for a reason, until proven otherwise. Forum members here can help you with model-specific stuff. You can assume someone here has already built a skoolie out of the bus you end up considering, so seek out those resources.
- How did you find this bus? (Get them to admit they bought it at auction and are flipping it for profit, if nothing else)
- Why are you selling the bus? (I personally believe the usual answer, whether they admit it or not, is, "We bought this bus when we were under-informed about what we wanted/needed and now we have buyers remorse OR we started the project and realized some time later that we weren't up for it/couldn't afford it. Now we are hoping to get some of our money back by offloading it on someone else who is also under-informed.
Best of luck with your search. I think based on what you said, that you have arrived at the logical conclusion!
