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.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 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.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 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?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 have a 06 that did the same thing but mine was a complete lose on the lower endsmokinpete379, What damage was done to your original 5.9 block? Im just curious to why you didn't buy the 6.7 crank and throw it in instead of buying a whole 6.7. Which way do you think would be cheaper in the end?