Newbie Here Drive train questions

[Busfamilytime]

Hey folks! It's been a blast perusing this forum for ideas and tips as my wife and I are preparing to pull the trigger on a full size conversion.

I am a GC/carpenter/fine woodworker so I'm feeling good about the conversion itself, but the actual bus acquisition has me scratching my head. There seem to be so many options and I feel I'm getting caught up in a cycle of opinions.

Does anyone have a good baseline to help me parse it out? I feel like cummins 5.9 has a good history here, but then the dt466 keeps popping up. Also a fair amount of the buses I think I'm interested in will say "Allison transmission". Does that mean something to anyone here based on the year of the bus and engine type?

I'm located in the northwest, and it looks like Franklin Pierce (a local school district) is shedding some inventory via auction and they have records of a consistent 2,000mi 6month maintenance plan for all their buses.

This looks good to me? But also they are MVP-ERs or MVP-EFs. Which seem to be a "lighter duty" bus? Is this a bad idea for a conversion bus? Again the internet is full of opinions so I was hoping to gain some clarity through you fine folks about some of this. We plan to lift the roof 10-12 inches as I'm 6'5" if that matters?

Anyway,
Thank you in advance!

[musigenesis]

Allison essentially makes all school bus transmissions and they're all automatics (very rarely a Spicer manual comes up), so "Allison transmission" means nothing. Many buses from before 2000 or so have the AT545 which is undesirable especially for mountain travel and towing, but at least it's relatively cheap to replace if you destroy it (unless you destroy it in the middle of nowhere and have to pay for a long tow are at the mercy of whatever shop you get towed to). All other transmissions you'll find in buses are good, with the MD3060 being the cream of the crop.

Buses from 2003 or earlier will have engines without emissions control hardware which may or may not require expensive repairs (some say engines before 2007 are generally OK too, but most agree that engines get worse and worse the newer they are, with 2010+ being especially problematic). T444E and Cummins 5.9 are good but relatively weak, DT466e and Cat 3126 are good (DT466e can be rebuilt in-frame which is cheaper) and Cummins 8.3 is the king of the hill.

Roof raise doesn't really matter - you can do it on any school bus and they're all equally easy/difficult. At 6'5" a raise is a must unless you enjoy slouching and hitting your head a lot.

How fast you can go on the highway depends on what transmission you have but even more importantly on the bus' rear gear ratio (something that is almost never listed in sales ads). If you want to go fast without blasting your engine near its RPM limit for long stretches, you want a rear gear ratio in the 3s or 4s (my bus has a pretty bad 6.17 and can do 65 mph at about 2600 RPMs; its ideal cruising speed at 1800 RPMs is about 48 mph).

[Sehnsucht]

Agree with what Musigenesis already shared. I will add that if you have your choice of buses, generally the sports team or event bus is worth a little more upfront price. Daily route school buses are all stop and go, underpowered and rarely need to go fast. Event buses do more highway driving, have bigger engines, taller gears, usually storage bays underneath and perhaps even air conditioning. They may have fewer miles but more engine hours on them which isn't necessarily bad. And often a better funded school may have bought that bus exclusively for that purpose so it may not even have lights/signs to remove but may be painted in school colors or have a body wrap graphic.

As far as roof raises, my understanding (not personal experience) is an IC / AmTran is better for roof raises than a Thomas because the Thomas body style has a bend in the wall at the window line. You can lift it from the seat line but not the window line because of the angles. ICs are apparently totally vertical to the roof line so straight up is no issue at any point along the side wall.

Electronics are nice but expensive when they fail. If you're not mechanically inclined or know someone who is a diesel mechanic, either way you need to budget for maintenance and repairs if - no WHEN - something breaks down. People here who know their own engines save a lot because they can work on it themselves as long as its mechanical but the newer it is the more it relies on computers and sensors and even a simple sensor malfunction can shut you down. Just be forewarned.

[LargeMargeInBaja]

Recommendations / suggestions depend on your RequirementsStatement.
.
For example, our RequirementsStatement specified travel instead of mired in research/planning/building, filing-to-fit and painting-to-match.
.
Accordingly, we acquired and outfitted our rig in less than a week -- while selling everything -- and hit the road.
As we traveled, our conversion happened organically based on our experiences.
.
For us, trundling up rough logger tracks to remote mountain lakes or across deserts to isolated Baja beaches -- with complete confidence in our equipment -- is our priority.
.
For somebody else, a priority might be a RecreationVehicle park with shuffleboard marathons and canasta tournaments.
And an 'Entertainment Director'.
[Yikes!]
.
Our rig has a Cummins 505ci mechanical, a stouter version of the 359ci (metrifiacal equivalent for foreigners -- '5.9 quarts/liters') you mention.
.
For a SpecialSenseOfSuperiority, I read forums for RecreationVehicle owners.
Apparently, later engines use Exhaust Fluid, and the failure rate of the injections is nearly total.
Some Exhaust Fluid injectors FAIL ON THE WAY HOME FROM THE DEALER.
And apparently, parts are not available, so the rig sits at the dealer, unusable except as a planter/paper-weight.
.
Our RequirementsStatement specifically prohibits using our rig as a drooling door-stop.
.
.
You are probably familiar with that 'rain combined with gravity' business, and its tendency to percolate into buckets on the floor.
As you develop your RequirementsStatement, see if you can work in a section about avoiding holes in the roof.

[Busfamilytime]

Originally Posted by musigenesis

Buses from 2003 or earlier will have engines without emissions control hardware which may or may not require expensive repairs (some say engines before 2007 are generally OK too, but most agree that engines get worse and worse the newer they are, with 2010+ being especially problematic). T444E and Cummins 5.9 are good but relatively weak, DT466e and Cat 3126 are good (DT466e can be rebuilt in-frame which is cheaper) and Cummins 8.3 is the king of the hill.

Thank you for taking the time. I’ve been scouring for the 8.3 and the 466e but I’m dry to date. I’m looking at a bus currently though and what it says for engine type is “international 7.6” but when I try to dig into that I come back with either the dt466 or max force 466. If you’ve got any light to shed you’d be very appreciated.

Cheers,
-Luke

[musigenesis]

Originally Posted by Busfamilytime

Thank you for taking the time. I’ve been scouring for the 8.3 and the 466e but I’m dry to date. I’m looking at a bus currently though and what it says for engine type is “international 7.6” but when I try to dig into that I come back with either the dt466 or max force 466. If you’ve got any light to shed you’d be very appreciated.

I was going to add that two engines you absolutely do not want are the Ford/Navistar 6.0L and anything labeled "MaxxForce". The DT466e was rebranded as the MaxxForce DT starting in 2007, so the vintage of the bus you're looking at will tell you which one it has. Many sellers of later-model IC buses with MaxxForce DT engines state that they have a DT466e (or a 7.6) because they know what a bad reputation the MaxxForce has.

FYI if you click on User CP in the upper left corner and fill out your profile details, people here will always know where on earth you are (and eventually what kind of bus you have) and we can tailor our advice to help you.