6BT cummins (24 valve) swap

[4x4nutz]

Has anyone done the 6BT cummins (24 valve) swap and used the same 4L80E tranny? I have an 1151 with a turbo and I am not happy with the power. I also have a free cummins motor. Any help would be appreciated.

 

[Mogman]

Moved to appropriate forum.

 

[4x4nutz]

Moved to appropriate forum.

Lol...right after I put the post in, I tried to put it in the right place and couldn't figure it out. Thanx brother!

 

[Mogman]

I have cruised a few Cummins sites and it looks like an expensive adapter. the common wisdom is without allot of upgrades the 24V will tear up the 4L80 because of the massive torque.

Adapter Plate: 1989-2002 Cummins 12V/24V to 4L60E, 4L80E & Allison. Requires DCS Flex Plate (SKU 1327). Uses Ford 6.4L starter

This adapter plate will mate the following GM automatic transmissions to a Cummins 12 Valve and 24 Valve engines: 4L60E, 4L80E, Allison 5-speed, & Allison 6-speed. *Some 4L60E Transmissions use a 300mm torque converter. If your 4L60E transmission has

dieselconversion.com

https://www.crossmembers.com/products/1989-2002-cummins-chevy-adapter-kit

 

[Mogman]

Interestingly enough there were some van or bus applications that used the 6BT and a 4L80, that adapter angled the engine for clearance, I wonder if that would be useful in a HMMWV conversion????
I have no idea what mods were done to the engine as far as oil pan/pump pickup that may have been necessary
It looks like the 47RH is the preferred trans for many swaps, no computer and it can handle the 6BT power.
What is behind the 24V now??

 

[4x4nutz]

Funny...I just read what your taking about. I also read that you can't go over 400hp on the 4L80...we will still be under 300 I believe...even with the added turbo. Will keep you posted. Thanx for all your help brother!

 

[Barrman]

It isn’t the horse power that kills the automatics. It is the relentless torque and compression stroke power surges. Even the NV4500 manual had to go through several upgrades to handle the 6BT over the years. It never did get “bullet proof.” I suggest that whatever transmission you end up going with. Get 2. Don’t build the second unit until you figure out what fails on the first unit. Maybe by your 4th or 5th generation of improvements you will have THE 6BT automatic set up.

Kind of like Jericho Transmissions:

https://www.jericoperformance.com/about.html#:~:text=One%20of%20the%20best%20is,time%20for%20a%20factory%20team

.

 

[4x4nutz]

Thank you! This is new deal for me, so all the info we can get helps. Just finding motor mounts has been an issue. Pretty expensive.

 

[Mrgior31513]

According to specs, the ISB 5.9 24v cummins puts out varied torque numbers, I would highly recommend looking up the specifics of the engine that you have. The 4L80E is rated at 440ft-lb of input torque. The stock 6bt is about that, but the ISB 5.9 puts out considerably more torque on some of those engines. The torque varies on the ISB from 420-610 ft-lbs. Here is a link that has torque ratings for different years ISB 5.9 from Dodge donor:

ISB 5.9L 24 Valve Engine - In-Depth Look at Design and Reliability

What is the ISB 5.9L 24 Valve Engine? Is it good or bad? Read about Cummins ISB 5.9L 24 Valve Engine design and features, its the most common problems and relaibility.

www.motorreviewer.com

If you want to use the 4L80E, here is something I found on some aftermarket modifications that may have some value if you want to use that transmission:

https://www.motortrend.com/how-to/building-4l80e-handle-torque-power/

 

[98G]

It isn’t the horse power that kills the automatics. It is the relentless torque and compression stroke power surges. Even the NV4500 manual had to go through several upgrades to handle the 6BT over the years. It never did get “bullet proof.” I suggest that whatever transmission you end up going with. Get 2. Don’t build the second unit until you figure out what fails on the first unit. Maybe by your 4th or 5th generation of improvements you will have THE 6BT automatic set up.

Kind of like Jericho Transmissions:

https://www.jericoperformance.com/about.html#:~:text=One%20of%20the%20best%20is,time%20for%20a%20factory%20team

.

G56...

 

[Mogman]

Dang I did not realize the 6BT weighed 320lb more than the Dmax... it is however all cast iron which does have its advantages.
The Dmax only weighs about 80lb more than the 6.5T, adding 400lb will be noticed.

 

[TOBASH]

Use a 4BT if you want less weight

 

[98G]

Use a 4BT if you want less weight

The 4BT is what these things should have had OEM. Similar power, 10 times the life expectancy, and it'd fit better.

 

[Jh_hay]

Has anyone done the 6BT cummins (24 valve) swap and used the same 4L80E tranny? I have an 1151 with a turbo and I am not happy with the power. I also have a free cummins motor. Any help would be appreciated.

Any update on how this project is going?

 

[WillWagner]

Interestingly enough there were some van or bus applications that used the 6BT and a 4L80, that adapter angled the engine for clearance, I wonder if that would be useful in a HMMWV conversion????
I have no idea what mods were done to the engine as far as oil pan/pump pickup that may have been necessary
It looks like the 47RH is the preferred trans for many swaps, no computer and it can handle the 6BT power.
What is behind the 24V now??

It was a 4B, Frito Lay had a fleet of them, like 200 nationwide.

When swapping, remember, the RPM of the inline engine and V are different. 2500 max on the inline, unless it is a Dodge take out, then it was 2800 and I believe 4k on the V. Each 100 RPM is apx 2-3 MPH, so if one were cruising at 2500 RPM with the V, that would be redline on the inline, there is nothing more. With the V you still have more RPM to overtake, downshift on a hill, etc.

You will need gearing.