SN 6400 VT365_ISL400 Repower

SlimTim · 07-15-2022, 02:20 PM

I decided to repower my 2010 6400 SN with a Cummins ISL 400 and an Allison 3000 transmission. I am not quite finished with the project but I feel I am close enough to start posting some photos.

To start I looked at the International DT466/570, Cummins 6.7 ISB and Cummins ISL 400 as possible replacement engines. However Ultimately I decided on the Cummins ISL for the following reasons:

The DT466/570 would have been the simplest but unless you want to purchase a remanufactured engine it is hard to find one with less than 250k miles. Also the max stock HP for these engines is around 300 HP, but high HP/torque DT466's are nearly impossible to find. Because of this I dropped the DT466/570 from my list of possible engines.

The Cummins 6.7 ISB was a very strong contender and if I was to do this again I would likely go with this engine. The 6.7 engine was used in many RV's and low mileage engines can be easily found. Another advantage of the 6.7 is that you can retain the stock SN Allison 2500 transmission and this would make the repower much easer (and cheaper). Ultimately the reason I dropped this from my list of possible engines was because I wanted more HP.

With the DT and ISB engines eliminated the Cummins ISL 400 (8.9L Engine) seemed to be the best choice. However because the ISL has 400 HP and 1200 FT LB torque I needed to also upgrade the Allison 2500 to a 3000 series transmission adding a significant amount of work and additional cost.

Assuming I can remember how to upload photos to the forum I will start posting some pictures.

SlimTim · 07-15-2022, 03:01 PM

Here are a phew photos of setting the ISL in the frame. I had to change the motor-mount location, change the oil pan on the engine from a rear sump to a front sump, modify the front frame cross member, and change the turbo location to get everything to fit.

Sorry about the sideways images. I am not sure how to rotate them once they are uploaded.

SlimTim · 07-15-2022, 03:13 PM

Making a new fan shroud out a fiberglass. I should have spent more time filling and sanding down the finished shroud before painting it. But I was tired of fiberglass dust on everything and wanted to get on with other tasks.

SlimTim · 07-15-2022, 03:22 PM

Several months into this project I followed this rig into the gas station and I thought to myself "Maybe this person is onto something".

pwerwagn · 07-24-2022, 01:21 PM

I was wondering when you were gonna start a thread on this!!!

Looks great!!

Also, I have a 6x6 military deuce. My favorite part about driving it is after I get out of it and into the supernova, it makes the supernova feel like a hot rod !

bhplumber · 07-25-2022, 01:31 PM

ST, Great to see someone take the leap. I am considering on swapping mine to a 6.7 Cummins mainly thinking it will be the most affordable and easiest way to get better reliability. I am pretty good at the fab aspect so I'm thinking getting it in wont be to bad but as far as getting it to run, work with the trans, and have working gauges I'm kind of lost. I don't even know what it will require or where to find what I need. I will be following your build for sure..

SlimTim · 07-30-2022, 03:54 PM

Quote:

Originally Posted by bhplumber

ST, Great to see someone take the leap. I am considering on swapping mine to a 6.7 Cummins mainly thinking it will be the most affordable and easiest way to get better reliability. I am pretty good at the fab aspect so I'm thinking getting it in wont be to bad but as far as getting it to run, work with the trans, and have working gauges I'm kind of lost. I don't even know what it will require or where to find what I need. I will be following your build for sure..

A 6.7 repower would be very easy to do. The stock Allison 2500 could be used and I don’t t think you would need to move the transmission back. The only big purchase item would be the Cummins 6.7. You would want to get a complete engine out of a wrecked RV or a delivery truck. DO NOT GET a 6.7 from a Dodge truck. If you get a RV/truck 6.7 ISB it will be basically plug and play. All gauges will work you just need to connect the Cummins J1939 communication bus into the International trucks J1939 communication bus. You may want to open up 6th gear on the Allison transmission as the 6.7 turns a few less RPM than the VT365.

bhplumber · 07-31-2022, 06:25 PM

Cummins offers a 6.7 repower for the 4200 bus chassis but they told me it will only work on a bus not a truck chassis. It’s just hard for me to believe the 2 chassis are different. Would I want an 08 cummins engine so it’s pre def? I’m just thinking it might be hard to find a low mile engine that old. Thanks for your input

SlimTim · 07-31-2022, 11:27 PM

Quote:

Originally Posted by bhplumber

Cummins offers a 6.7 repower for the 4200 bus chassis but they told me it will only work on a bus not a truck chassis. It’s just hard for me to believe the 2 chassis are different. Would I want an 08 cummins engine so it’s pre def? I’m just thinking it might be hard to find a low mile engine that old. Thanks for your input

Yes I would get an 07 to 09 pre DEF engine. In regards to finding a low mileage engine I would look at the RV salvage yards such as https://colawrvsalvage.com. Also keep a look out for engines on your local Craigslist. You will want to purchase a complete engine with electronics pumps motor mounts plugs and etc. you will also want an engine with the turbo mounted Toto the front of the engine.

Vinnie · 07-26-2022, 10:45 AM

Very, very cool. It would have been nice if Navistar had been made to come up with a repower kit as part of the lawsuit.

CTMICH5 · 08-17-2022, 08:51 AM

Thanks for the info gentleman! good stuff, i may plan an isl swap in the future, i want it to run for 1,000,000 and keep going... Not anything i plan to do immediately as the rig has 7,800 miles, but before i retire (or right when i retire) it will be on the books.... slimtim, when you are wrapping up, let me know what the biggest hurdles were so i can start putting them down and working on them over time... thanks a million!!!

SlimTim · 08-19-2022, 08:46 PM

The Cummins Supernova drove out of the shop today under its own power. I took a few laps around my driveway and mother fell off or blew-up. Thanks not two issues I have are:

My stupid Wabco brakes are throwing a code

For some reason my power steering is not working.

Still have fun and getting closer to my first road text.

SlimTim · 09-24-2022, 07:10 PM

I took the ISL / 6400 out on the road for the first time today. Unfortunately I did not make it very far. Actually on the first attempt I did not even make it out of the driveway. I had two big charge air leaks and every time I stepped on the throttle it made a heck of a load whistling noise. Back to the shop and a couple new hose clamps installed and I was ready to try it again. The second time I made it onto the road and about 2 or 3 miles from my house and the engine started to overheat and the transmission threw a code. I pulled over and let the engine cool down and was able to drive it back home.

Once I got it back to the shop and inspected everything, it appears the engine had an air pocket around the thermostat. I think the air has left the system now because it’s a gallon low on coolant and prior to taking it on the road it was filled to the full mark (it did not blow it out the vent tube).

The transmission code was a pressure out of range. I know the transmission was a little low on oil so I am going to top off the oil clear the code and try it again.

Fun times.

CTMICH5 · 08-19-2022, 09:53 PM

That’s awesome! Congrats Tim! I pick up my rig in 5 days in California and have to drive it back to Michigan �� we do have a local 6.0 diesel guy we call 6-0 Joe… he charges about $5k for full bulletproof with ARP head studs, then ordering the Orion programmer, called and talked to them and hypermax and did confirm that the hypermax is just FICM tunes so I will be going with the Orion once the engine is ready… probably won’t have it bulletproffed until next year! Plan on using it that way for a few years as I accumulate parts and pieces for swap like Tim did! Can’t wait to hear all the kinks are worked out!!

CTMICH5 · 08-21-2022, 09:06 AM

Picked up my 8.9 ISL today, found one paired with a B400r trans still not planning to do it right away but I will be slowly getting it ready 👍

SlimTim · 09-24-2022, 07:27 PM

Quote:

Originally Posted by CTMICH5

Picked up my 8.9 ISL today, found one paired with a B400r trans still not planning to do it right away but I will be slowly getting it ready 👍

What year is the engine? Is it a common rail or is it a CAPS engine? If it is a CAPS engine you may want to consider holding off for a common rail engine.

That looks like a GEN 3 transmission but I could be wrong. If it is a Gen 3 the good news is that it will work. The bad news is that it will be more difficult to make it work. Also Gen 3 TCM’s are getting hard to find and they can be expensive when you do find them.

Gen 3 Allison transmissions require three transmission control modules (TCM’s). The Gen 4 and 5 Allison transmissions use a single TCM. The Allison 2500’s in our RV’s are Gen 4 so you can use the stock connectors and much of the stock wiring. My ISL came with a Gen 3 and I ended up purchasing a Gen 4 because it was going to be way easier to do the install.

CTMICH5 · 09-25-2022, 07:46 AM

The engine is a caps, in my research people were saying to stay away from the first few years of common rails as they were problematic over the caps style, is that not true? Will I have problems meshing the computer into the system? The engine is a 2008, I figured same year as the coach would be most similar to mesh in as communications should be similar (same year as if it was originally put in). How do i tell which trans I have? The transmission was rebuilt by ww Williams and they removed the original data plate and put on their own, I don’t see a lookup on their website like Allison has… might take some digging…. 👎

SlimTim · 09-25-2022, 10:36 AM

Quote:

Originally Posted by CTMICH5

The engine is a caps, in my research people were saying to stay away from the first few years of common rails as they were problematic over the caps style, is that not true? Will I have problems meshing the computer into the system? The engine is a 2008, I figured same year as the coach would be most similar to mesh in as communications should be similar (same year as if it was originally put in). How do i tell which trans I have? The transmission was rebuilt by ww Williams and they removed the original data plate and put on their own, I don’t see a lookup on their website like Allison has… might take some digging…. 👎

If it’s a 2008 I would assume it’s an 8.3L ISC, not an ISL. I think 2003 was the last year for a CAPS ISL. 2004 and up ISL’s are all common rail.

There is a group of ISL engine serial numbers in the 2004/2005 time range that had issues with the connecting rods (I think it was the connecting rods). It is well documented and you can Google it to find out what serial numbers were affected. It was a manufacturer defect, not a design issue. Other than this issue the common rail ISL’s have been very dependable.

Meshing the engine ECM to International electronics should work just fine. You will need to find out what ECM the engine is running. It will be something like CM850 or CM2150. You will need to know this to figure out the wire connections.

If the transmission serial number tag has been removed it will be hard to get any information from Allison. The reason I think it’s a Gen 3 transmission is because of the round wire connector you can see in the photo. Gen 4/5 transmissions used a square or rectangular connector. Also the GEN 4/5 connectors are directly mounted to the transmission; not on a pigtail like the one in the photo.

In summary if it is an ISC that’s ok because the ISC was a good engine and could be configured up to approx. 365 HP and approx. 1100 torque. However I would look at swapping the Gen 3 transmission for a Gen 4 as this will make things much easier for you.

SlimTim · 09-25-2022, 10:46 AM

As an FYI - the ISC and ISL engines look nearly identical and share some common parts. One big difference is the ISL switched to the common rail system in 2004.

Looking at Cummins documents it looks like both the ISC and the ISL changed to common rail in 2004. If this is correct I don’t know how your engine could be a 2008 CAPS engine. can you post a photo of the other side of the engine?

CTMICH5 · 09-25-2022, 12:19 PM

Here is the data plate from Cummins, I assure you it is a caps engine. I will grab some pictures when I have a second. Also you are 100% correct, my trans has a pigtail with a round connector.

Now that you mentioned the years, I am wondering if the engine was older and rebuilt by Cummins, I think there is a remanufactured sticker from Cummins.

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