5.9 and 6.7 questions

R

RXT

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I have a question. A buddy of mine is interested in purchasing a hurt 3rd gen. Apparently the engine has rod knock and he tells me that he would like to install a 6.7 crank in it, if he can get it for cheap. After some discussion on the feasibility of this, and not getting into the 6.7 "Ag" crank, I know that the 6.7 as used in Dodge trucks doesn't have much additional throw than the 5.9 crank which means you won't gain much additional displacement by swapping cranks, and he would have to mill down the 5.9 pistons to clear the head…but this got me to thinking. I know the 6.7 uses larger diameter pistons, so the logical conclusion would be why not just bore out the block to accept the 6.7 pistons? Or is it not that simple? So questions. Is there enough "meat" in the cylinder walls to bore out the .20 something needed for the 6.7 pistons? And, does the 5.9 and 6.7 blocks have the same deck height?? I know it's probably easier to just use a 6.7 block, but it's more of a curiosity thing

Thanks Ed
 
the blocks have to have a different deck height, because all commonrail rods are interchangeable.

I would recommend using a factory crank, the work involved in using a 6.7 crank far outweigh the benefits.

please discontinue your cousin fuker talk
 
JSYK, 6.7 and 5.9 CR blocks both use the same CCL to deck height, it is the piston pin height that differs, along with the stroke.
The ring height is adjusted in there, as well as bowl volume and shape.

Mark.
 
Cylinder walls will be extremely thin trying to bore the 5.9 block. 6.7s also have Siamese cylinder walls. Hence the steam holes on a 6.7
 
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