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Juggernaut
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Discussion Starter #21
smokinpete379, 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?
Like strokethis 07 said........
6.7 crank in a 5.9 block yields 371 cubic inches; the added cost of custom pistons (I believe) doesn't make it feasible.
ok so did you use the 6.7 rods or aftermarket? and is there any diferance in the topends ? is a 6.7 head better than a 5.9 ? (i know yours was ported ) i see you also installed a hamilton cam (i'm sure that helped ) along with the other goodies .

i would love to add some bore and stroke for the added lowend !!

can you buy new shortblocks ? how bad would the price be ?
I used custom 12 valve rods for my build. They worked perfectly !! There are some differences in the top end but I didn't care about any of that because I wanted to reuse my 5.9 head. I'm sure you can buy a new block right from Cummins and go that route. I did purchase a brand new crank for one 6.7 from Cummins and I'm thinking it was around $800 my cost. I hope that answers everyones questions. :thumbsup:
 

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Haha, ill x2 on the thread title.

It is by no means a stroked 5.9, its a 6.7 swap with a 5.9 head.

Nothing wrong with this, its just got nothing to do with a stroked 5.9 :D
 

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Did the South bend Clutch flywheel bolt right up to the 6.7 crank?

I'm also curious what the dimension differences are between 5.9 vs 6.7 injectors.

Sean
 

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I just did this same swap, ported 5.9 head, 188/220 cam, carrillo rods, big 03 injectors. Still working on tuning issues but it ran good till this morning.

To the op, why did you not drill for the steam holes on the head.

Also you must use a 6.7 head gasket, 6.7 dipstick and tube.
 

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Great write up either way.
Doesn't this change the bore from 4.02" to 4.21"?
I wonder what the difference is being less undersquare.

It should allow higher RPM and smoother due to less friction compared to the same displacement if it was a "stroked" or more engine.

It should raise peak torque RPM and allow higher peak HP.

If your a truck that want's lower lugging capability then stroked makes sense but if you want a performance engine bore makes sense. :confused013:

This is all assuming the bore change that I think it is.

Did you ever calculate the compression ratio with the combo knowing bowl volumes, gasket thickness, head bore etc?
 

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Juggernaut
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Discussion Starter #28
Did the South bend Clutch flywheel bolt right up to the 6.7 crank?

I'm also curious what the dimension differences are between 5.9 vs 6.7 injectors.

Sean
Sean,
Yes the South Bend flywheel bolted right to the 6.7 crank. No issues there at all. If you're buying a new 6.7 crank you just have to watch what you buy because the 2013 and 2014 cranks are different and require a recess to be machined in the back of the flywheel.

I just did this same swap, ported 5.9 head, 188/220 cam, carrillo rods, big 03 injectors. Still working on tuning issues but it ran good till this morning.

To the op, why did you not drill for the steam holes on the head.

Also you must use a 6.7 head gasket, 6.7 dipstick and tube.
Zap,
What would the advantage be to drilling the steam holes into my head? I don't see any advantage to it, and that's why I didn't do it. Also, I used my original dipstick and tube from my 5.9.

Great write up either way.
Doesn't this change the bore from 4.02" to 4.21"?
I wonder what the difference is being less undersquare.

It should allow higher RPM and smoother due to less friction compared to the same displacement if it was a "stroked" or more engine.

It should raise peak torque RPM and allow higher peak HP.

If your a truck that want's lower lugging capability then stroked makes sense but if you want a performance engine bore makes sense. :confused013:

This is all assuming the bore change that I think it is.

Did you ever calculate the compression ratio with the combo knowing bowl volumes, gasket thickness, head bore etc?
Wayward,
No, I did not calculate my compression ratio simply because it would not be any different than a stock 6.7 would be with flycut pistons etc. I did mill .010" off the top of the pistons before I flycut them but nothing drastic.
 

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Great write up either way.
Doesn't this change the bore from 4.02" to 4.21"?
I wonder what the difference is being less undersquare.

It should allow higher RPM and smoother due to less friction compared to the same displacement if it was a "stroked" or more engine.

It should raise peak torque RPM and allow higher peak HP.

If your a truck that want's lower lugging capability then stroked makes sense but if you want a performance engine bore makes sense. :confused013:

This is all assuming the bore change that I think it is.

Did you ever calculate the compression ratio with the combo knowing bowl volumes, gasket thickness, head bore etc?

It's not going to raise peak torque rpm. If anything it should be lower with more displacement. Quicker spool more torque earlier in the rpm range. It's a 6.7 short block, nothing stroked about it
 

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if you dont drill the steam holes out then where is the steam gonna go that can build up between the cylinders. if they werent needed then why did they cast the block with them there, MY thoughts atleast on the matter.
 

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It's not going to raise peak torque rpm. If anything it should be lower with more displacement. Quicker spool more torque earlier in the rpm range. It's a 6.7 short block, nothing stroked about it
That doesn't really meet the rules of less resistance. Can you please explain why that happens? Remember oversquare vs undersquare/ I'm only trying to learn and regurgitate the findings.
\
I'm still assuming the bore is larger by about an 1/8th.

EDIT:
A "stroked" engine creates more torque and HP at a slower RPM than a bored one.
Why can an F1 engine turn 16,000 plus RPM?
I prefer square or over square for RPM engines.
Dyno's and simply engines in production prove a higher rpm peak torque and HP on over square engines both diesel and gas.
 

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vvv SOME PEOPLE'S KIDS vvv
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That doesn't really meet the rules of less resistance. Can you please explain why that happens? Remember oversquare vs undersquare/ I'm only trying to learn and regurgitate the findings.
\
I'm still assuming the bore is larger by about an 1/8th.
It's .190" bigger not .125"
 

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vvv SOME PEOPLE'S KIDS vvv
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Your looking at .065" difference per cylinder and it adds up hahaha
 

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Your looking at .065" difference per cylinder and it adds up hahaha
UHHH Not really :doh:
I don't know where your getting .065" but it's not right. Try 5.8 inches per cylinder.

359 cu/inches stock

371 cu/inches if you stroke this 4.72 to 4.88 utilizing the 5.9 bore.
That's about 2inches per cylinder.

394cu/inches using the 6.7 bore 4.02 to 4.21 and don't stroke it.

So yeah almost triple the cu/inches by not stroking and boring instead.
 

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vvv SOME PEOPLE'S KIDS vvv
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UHHH Not really :doh:
I don't know where your getting .065" but it's not right. Try 5.8 inches per cylinder.

359 cu/inches stock

371 cu/inches if you stroke this 4.72 to 4.88 utilizing the 5.9 bore.
That's about 2inches per cylinder.

394cu/inches using the 6.7 bore 4.02 to 4.21 and don't stroke it.

So yeah almost triple the cu/inches by not stroking and boring instead.
Are you serious? I thought you were smarter then that.. Jesus man. It's simple math.

4.21~ 6.7 bore
4.02~ 5.9 bore
.190" difference between the 2.

.190" subtracted from .125" is .065". Meaning there a difference of .065" when you were thinking the bore was only 1/8" bigger.
 

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So yeah 394 cu/inches by using a 6.7 block
or 371 cu/in by stroking it.
HMMMMM
I thought the thread was about the swap of a 6.7 block. It gains volume better than I was originally thinking. Way better than stroking it.
 

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vvv SOME PEOPLE'S KIDS vvv
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I'm just talking bore size differences.
 

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vvv SOME PEOPLE'S KIDS vvv
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Edit.. found the answer.
 
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