86 International 6.9 idi. Motor Transmission Advise Needed.

[runsalot]

I have a 1986 5 window International school bus that had a 6.9 idi and Allison 545 transmission. Transmission is good but engine needs rebuilt or replaced.

I would love to install a dt466 and Allison 3000 series transmission as most of the posts I have read indicate are best. But looking at the engine it just seems so huge for our small bus, And also I am just a little overwhelmed with all the details needed for that major of a conversion.

So what are the thoughts on a 7.3 idi attached to an Allison 2000 series transmission? I know that several posts say it is to light for a full size bus but just thinking it might work for our smaller bus. Also considering a T444e as it would most likely fit in with less modifications, but would rather stay as simple as possible.

We are very new to this and have been reading and researching a lot so any advice or help would be much appreciated.

 

[kromboy]

Is the bus already built out?

Sounds like sunk cost fallacy at hand here, if you haven't put any money into actually converting the bus, might be cheaper to just get a different bus and start fresh. Unless there's something specific about this bus that you just really love.

 

[runsalot]

Is the bus already built out?

Sounds like sunk cost fallacy at hand here, if you haven't put any money into actually converting the bus, might be cheaper to just get a different bus and start fresh. Unless there's something specific about this bus that you just really love.

Might be true, but we do like the bus so looking for everyone's thoughts.

 

[Ronnie-SKO]

The 7.3 is basically a 6.9 bored out, same external dimensions as far as I know. The 444 is also the same thing. All the same family of engine, so swapping one for the other is no problem as far as space is concerned.


Cadilackid has far more expertise on these engines then I , so his input would be very worthwhile.


But for now here is what I know,
the 6.9 and the 7.3 came in non turbo charged versions slow but reliable
7.3 later ones had a turbo and are well liked and can put out good power
444 and 444e are specifically medium duty truck engines based on the 7.3 This ( the E version) is what I would use if mating it to an Allison 2000, so that the two can talk to each other. In fact you should be able to find a mated pair in the junkyard. Get everything, especially the wiring harness and computers, and the vin number off the donor vehicle.

 

[cadillackid]

The 7.3 is basically a 6.9 bored out, same external dimensions as far as I know. The 444 is also the same thing. All the same family of engine, so swapping one for the other is no problem as far as space is concerned.


Cadilackid has far more expertise on these engines then I , so his input would be very worthwhile.


But for now here is what I know,
the 6.9 and the 7.3 came in non turbo charged versions slow but reliable
7.3 later ones had a turbo and are well liked and can put out good power
444 and 444e are specifically medium duty truck engines based on the 7.3 This ( the E version) is what I would use if mating it to an Allison 2000, so that the two can talk to each other. In fact you should be able to find a mated pair in the junkyard. Get everything, especially the wiring harness and computers, and the vin number off the donor vehicle.

this is pretty much it..


the turbo 7.3 IDI were rare.. i think there were kits to add a turbo to a 7.3 IDI.. the non turbo versions are dogs...



I dont know much about modding the IDI's for horsepower..



you can swap a DT in place of the 6.9 or 7.3, the chassis will handle it.. watch txstreetman vides on youtube.. he swapped a 7.3 IDI that blew up for a mechanical DT360.. ( a mechanical 466 would be the same prociedures).. that does involve modding the firewall and floor and installing a doghouse.. and of course all the other stuff when going from a V8 to an I6.. intake piping, exhaust, coolant lines, etc...



when chasnging engines one of the things often overlooked is the radiator hoses and where they come out on the engine vs where they come out on the radiator... fan offset is another... the radiator sits further forward in the V8 as opposed to the I6.. (they want to have zero doghouse on the V8 so the engine needed about an inch to clearance the turbo at the firewall..


an allison 2000 can run behind a mechanical engine you need to fashion uo a throttle sensor (TPS)for it.. companies like transmissiontuner dot com and CAC, xcaliber, and others sell the throttle pieces to make that work..



going electronic.. it could be done.. youd have to have a nice donor bus that wasnt torn up to be able to grab a virgin wiring harness from it.. and spend alot of time properly harvesting it by unbolting and disconnection as opposed to cutting wires...

 

[bluebird90]

The 7.3 idi will be a direct bolt in replacement. otherwise use a dt466 mechanical.

 

[runsalot]

Thanks for the advice very very much

Engine

Thinking I will stay with the 7.3 idi or 444e. That way I don’t have to do any body mods. Does the 444e have the computer attached to the engine like the DT466e or is it in the cabin? Also, I saw a 444e near me in Ohio on market place. Owner removed the engine from a bus to harvest the turbo for a ford powerstroke truck he owns. Any issue with getting another turbo? Are they hard to find? Expensive? Multiple models of turbos to be concerned with. Anyway, engine is $750 with 110,000 miles. Seemed like a fare deal. Also comes with a transmission assuming it a 545 however.

Transmission

First choice would be to find an engine with an Allison 2000 or 3000 series attached. However, if that is not an option may try to find a separate transmission. I assume the transmission has a computer. Is it typically attached to the trany? Or in the bus cabin typically. As for the throttle sensor will all the allision 2000 models work with that?

Transmission information.

Are there any resources that you know or websites that give a detailed description of the Allison transmission electronics so I can read up?…

Truck Junk Yards

Also Ronnie mentioned finding an engine and transmission combined from am junk yard. I noticed a post with some listings for used bus parts. All I saw in Ohio seemed to only have a few buses. Any thoughts for larger yards that would have truck engines as Ronnie suggests?

 

[cadillackid]

Thanks for the advice very very much

Engine

Thinking I will stay with the 7.3 idi or 444e. That way I don’t have to do any body mods. Does the 444e have the computer attached to the engine like the DT466e or is it in the cabin? Also, I saw a 444e near me in Ohio on market place. Owner removed the engine from a bus to harvest the turbo for a ford powerstroke truck he owns. Any issue with getting another turbo? Are they hard to find? Expensive? Multiple models of turbos to be concerned with. Anyway, engine is $750 with 110,000 miles. Seemed like a fare deal. Also comes with a transmission assuming it a 545 however.

Transmission

First choice would be to find an engine with an Allison 2000 or 3000 series attached. However, if that is not an option may try to find a separate transmission. I assume the transmission has a computer. Is it typically attached to the trany? Or in the bus cabin typically. As for the throttle sensor will all the allision 2000 models work with that?

Transmission information.

Are there any resources that you know or websites that give a detailed description of the Allison transmission electronics so I can read up?…

Truck Junk Yards

Also Ronnie mentioned finding an engine and transmission combined from am junk yard. I noticed a post with some listings for used bus parts. All I saw in Ohio seemed to only have a few buses. Any thoughts for larger yards that would have truck engines as Ronnie suggests?

ohio you have Mike and B sales, Pauls equipment, Myers, starks, not sure if warner still has busses.. , I know a guy near richmind kentucky that scraps busses though he tends to stay with the mechanical as he sells mechanical-only engines to exporters.. we can ask if he gets any electronic..


if you want a T444E setup, go for 97and newer with the single-box computer attached to the side of the motor.. the 94-96 used as 3-box systen which has many parts of it becoming obsolete..



if you want a factory attached allison 2000 series look for generally 02-04. agan the biggest expensee is in the wiring harnesses themselves.. scrapyards that pull engines often just slice the wiring to bits .. you may want to look for a rusty old bus you can get as a donor and do the take-out yourself.. that way you can harvest the wiring for both allison 2000 and the engine.



installing a DT466 mechanical eliminates the wiring pieces you just need to cut the cowling for the doghouse. there are various parts on DT60 / DT466 enthusiast groups and websites for adapting nice pumps like the P7100 and different turbos.. a P-pump snd a holset HX50 turbo with some upgraded injectors can make you a nice stout DT466 mechanical that will scoot you down the road,

 

[#1FordFan]

I have a 89 Ford with a 7.3 IDI it is resting in my back yard, and has nearly 500K on it. It has always been working hard in my tow truck Most of the time it was loaded to about 20K lbs. I live in the more hilly area of Ohio. These IDIs are quite reliable, and simple with no electronics (except for the glow plug module)
My 7.3 will get fresh internal bits when I have the funds.
I know it does not have the fat power of the more modern models but I know it will get the work done.

 

[Omnibot2000]

Here is a thought.

You could put in a 466, check your front axle rating before that. You would still have the 545. If you want to put in a 2000 or 3000 trans you would be messing with electrical.

If your not scared of the electrical as your at that point already. Maybe try doing a repower.

Look for any Ford or chevy product. I'm a Ford guy but lean toward the chevy for the transmission and the engine. Duramax is a little more reliable then a 6.0L or 6.4 powerstrokes but the 6.0L can be built to be reliable day in and day out on stock tunes. The duramax is not immune to blown headgaskets as some may think. I've helped pulling cabs and head gasket jobs on enough to know at my buddies shop. Also seen them with cracked pistons as well but generally they are running a hot tune. Purchase a complete truck that was in an accident or something and take the whole system out and transplant.

Your bus is a 5 window, its not exactly big enough to be concerning for the weight. the 5r110 is pretty strong itself. The Alison.....we all know is good.

I excluded dodge because their transmissions are not the best but again, can be built like anything else.

Get something pre emission. EGR I don't mind and inexpensive to delete on those platforms in the grand scheme of repowering, when I say pre emission, its in regards to DPF and SCR.

 

[nikitis]

As Cadillackid stated. Stay away from 3-box T444E's. They work great and are easy to understand once you dig into them, and even offer the ability to still run somewhat if the VPM of the 3-box's die on you, you won't be stranded, just running in default mode vs a 1-box when it dies you are dead in the water, however as he stated the 3-box computers are very hard to find now and even if you find a working one on ebay or somewhere, the software revisions between the 3 computers (ECM, VPM, IDM) have to be within a certain range or they won't be compatible, and you cannot flash them if the VPM is dead because the flashing process goes through the DCL and ACL lines. If the VPM is working and you replaced the ECM or IDM, International can flash and update a replaced EDM/IDM if the VPM is working. They had to rip 4 buses apart to find a working VPM in my case, and there aren't a ton of 3-box's left with working VPM's (One of the 3 box computers).

1-Box T444E's start in late 1997 and onwards.

I'm not the last person here to buy a 3-Box, I think there were 2 others who attempted it, and luckily had working computers, but I think I'm the last one to try to fix a 3-box computer here, and try to warn others about them or at least inform them of the risks more accurately.