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Ashley has not given me any specifics by any means about the bowl he uses but I've asked him about some "grey" areas and got some answers. It's not so the fuel burns good, it's the best design he has found for the most power. Also, what benefit are you gaining by running a 5.9 head on a 6.7 block? Just do a complete 6.7 long block with 5.9 electronics.


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I ran the 5.9 head because i already had it and it has a full p&p done to it. I thought i read somewhere that the injector bore depths were different on the 6.7 but i could be wrong. maybe it had to do with the injector itself.
 

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Been thinking of doing this swap when my motor finally lets go (hoping no time soon!). Noticed all of these were manual trucks though, would the swap be the same for a 48RE if you used all the 5.9 parts and electronics and just the 6.7 block?

And since you would still be running a 5.9 ECM I'm assuming any programmer you would have had on it before would still work after the swap?
 

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Been thinking of doing this swap when my motor finally lets go (hoping no time soon!). Noticed all of these were manual trucks though, would the swap be the same for a 48RE if you used all the 5.9 parts and electronics and just the 6.7 block?

And since you would still be running a 5.9 ECM I'm assuming any programmer you would have had on it before would still work after the swap?
I believe that is correct. Eventually I'm going to get a built top to bottom 6.7 long block putting all of my electronics on it and putting in bms injectors least 100% over.
 

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Yeah it's the same with an auto.

Just swap all your stuff (adaptor plate, flexplate, bolts, etc) from the back of your 5.9 onto the back of the 6.7 and it'll be a pain free swap.
 

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I've been thinking about this swap as well..
I have a 2006..
Would my 90 hp injectors with twin cp3 pumps work on the 6.7 block?
Also my head off my 5.9 is fire ringed... will this be an issue?
How will doing this swap effect my efi live? Do I just get it retuned for a 6.7??
 

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If you have '06 tips, then no they won't work in the 6.7. The 124* angle the '06 has is incompatible with the ~143* bowl.

No, the 5.9 has a smaller bore than the 6.7. I'm going to assume the rings were not cut far enough out.

Any tuner can tweak the tuning if needed.
 

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So can I keep my injectors, just change out tips then? If so then to what year model.
So my head will not work if it's fired ring?
 

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Wiring is a direct swap.

'03/'04 nozzles or BMS (Bosch Motorsport) nozzles. And then there is the discussion to be had on just nozzles; if the injectors are pretty new, probably ok to swap nozzles. If they have lots of miles on them, I personally would go for brand new injectors.

And the 5.9 head depends on where it's 'ringed, I just don't think they will be outside the bore in a 6.7 headgasket. And fire rings aren't needed on a CR.
 

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I have a 97 silverado with a 6.7 cummins/12valve pump. Did take the lower part from a 6.7 Cummins and the gear cover from a 12 valve. The head is from a 2000 model 5.9 24 valve cummins, it’s a great combination, 45 psi of boost gives me around 550-600 hp. I’m looking for piston with the older shape, so the combustion will work better with my injectors, does anyone know where I could get 6.7 pistons with the shape of the 5.9 12valve?
 

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If your using a 24v head you don't want 12v pistons. 12v pistons have off set bowls because to injectors are off set in the head.
Don't know if there's a difference between 24v and CR pistons.

If your wanting to change to a 12v head Cummins built a 12v 6.7 for ag and industrial apps

New Holland T6050 Delta tractor used a 6.7 12v Cummins
New Holland T6050 Plus used a 6.7 24v
New Holland T6050 Elite used a 6.7 CR

My 12v dual vented valve covers were for a NH T6050 Delta.
 

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Ok, I’m always getting so many questions about this subject. Obviously many of you are interested in doing such a conversion so I decided to write this thread about my own personal experience so that everyone can have one thread to reference back to in the future.

My 2005 Cummins had an injector failure which resulted in #6 piston being damaged so after removing the block and examining what damage had been done I decided to try something different. I started doing my research in my 6.7 manual and comparing everything to the specs on my 5.9. As far as I could tell there was no reason I couldn’t find a 6.7 bottom end and use my 5.9 head and electronics. At this point in time I couldn’t find anyone who had done this conversion. Google searches turned up nothing and everyone was telling me that it wouldn’t work. I build engines for a living, mostly class 8 truck engines but we do a lot with the 5.9 and 6.7 Cummins as well so I had a lot of spare parts at my disposal to make everything come together. It’s been a couple of years since I did this but I will try to remember everything to the best of my knowledge.

I started with a 2008 6.7 Cummins and a 2005 Cummins. We stripped both engines completely and performed all necessary machine work to the 6.7 block and to the 5.9 cylinder head. I wanted to continue to use my 5.9 head because of all the work I have done to it (bolt on intake, ported and polished, etc.). The blocks do have some differences but nothing that is a real issue for doing the conversion. Just make sure to use a 6.7 head gasket !!!

At this point I think I should make it clear that I used only the 6.7 block, crank, oil pump, pistons and rings. Everything else is from my original 5.9. That means I used my 5.9 front and rear housings. This is important when it comes to the clutch/flywheel you are going to be using. The oil pump is different from the 5.9 to the 6.7 and since I used the 6.7 block I had to use a 6.7 oil pump. Obviously I installed a new oil cooler but I don’t believe there is a difference between them.

You guys can see from my signature the components I chose to build my engine with. They work very well and I have no regrets about the path I chose. I did not have any issues with motor mounts, bell housings, cylinder head or anything else bolting to the 6.7 block. Everything was in the same location. I did not have any issues with connecting rods hitting the camshaft and I did not do anything with the coolant passages in the 6.7 block. They are simply blocked off by the cylinder head. I used injectors for an 03-04 Cummins because the most closely resembled the spray pattern/ bowl design. All electronics bolted right on and everything worked perfectly!

So, I hope I have answered most of your questions. I really encourage anyone that has been thinking about trying this to give it a go. You will NOT be disappointed! I’m sure I probably forgot a thing or two and might have to come back and edit this post later but if anyone has any questions or concerns please do not hesitate to ask. Thanks !!!
I did the 6.7 block and 5.9 head using the 6.7 head gasket. Head failed after a year. Do you think this is just a fluke failure or do you think this will be an ongoing problem?
Thank you
Pete
 

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OP last posted 2013.
Should start new thread, fill out sig, better describe what "head failed" means .;)
 

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Discussion Starter #78
I’m still here. I agree, need more info. Head failed how? Who tuned it and with what platform? What are egt’s and boost etc? What do you do with the truck.......daily driver, tow some massive camper, etc? Can you upload some pics of the failure?

Thanks
Chris


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