6.7 pistons in a 5.9
 

Can this be done?

In short no... Cant bore out the 5.9 enough to be safe. Not enough material in the cyl. walls. Thats only the first problem. :pca1:

you would have to bore the piss out of it, even if you sleeved it i doubt you can do it that much

I dont see why you would want them. id rather use a 12v piston

what would be the advantage of a 12 valve piston? i hear that 12valve rods are stronger, but i didnt think the 12valve pistons had the correct bowle for the cr's injector spray pattern, i know that they dont work right in 24valve engines. please elaborate on this!:pca1:

Bummer so the next question is can you use a 6.7 engine and 5.9 ECM?? Are the injectors different, head different?? Just a curiousity thing!! And I'll 2nd his question on the 12v pistons!

Stronger i have pulled a head off of a 95 12v that a pipe tap went through all it did was hit the piston and get stuck in it we drove the truck after the pipe tap broke for almost 100k pulled with it everything we could ran great. Ive seen 06 cummins blow up if you look at them wrong. 6.7 liters in my opinion cannot be that strong but only time will tell

you can use a 6.7 with 5.9 electronics its been done a few times up here.

and the 6.7 has been used for the last 10 years in IH combines

the 6.7 liters are actually stronger, well suppose to be, they had to upgrade the bottom end a bit for the new exhaust brake feature, so i have heard, no hard evidence on this

In many ways the 12V piston is inferior to a CR piston, specifically in the ability to cool the piston crown and bowl. Add to that the bowl is completely different and offset where a CR is centered, it no worky.

Comparing a 160 HP engine to 325 HP emissions motor doesn't give a true view of the capabilities. A CR takes more abuse in everyday driving than a 12V does when you hammer it. If a CR is having issues something is causing cuz the bottom ends are pretty damn good.

Aside from the siamesed block, the 6.7 is a good base to work from. The elctronics on the emissions pieces are the single biggest problem but the base engine shares about 40% of the parts with the 5.9 so its solid.

Still not enough data on the siamesed cylinders and the potential for problems under different conditions. Thats a big unknown at this point.

A 6.7 can run under the 5.9 electronics and work quite well. Even some swapping of heads and injectors can be done with some caveats.