6.7 crank in a 12v

i'm so glad someone else finally mentioned it

I've been waiting for someone else to mention destroking one.

It makes so much more sense than trying to keep jambing more torque into the same RPM band.

Destroke it, don't change the bore or rod, take enough to bring it down to racing compression territory, and use the added rpm to build the HP!!!!!

We already know how to make whatever power we want out of the other components of the engine, why not sacrifice a little and get that HP punched out a little more?

It won't be as affective on the pulling track, but man it would be fierce in a drag truck
 
ride42 said:
How'd it run?
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pretty good ,,Darren Smith from daves diesel is the guy we became pretty good friends when he was the first to run the monster pump but things fell through so now this is what he runs

He placed 7th at scheids in 2.8 funny I placed 7th in 2.6
 
You know....
I read these thread like this alot on many of the forums and scratch my head as to why you would want to "stroke" an engine like ours for performance.While I will admit the old saying "There is no replacement for displacement" is true,for one who seeks bigger rpms I would not do it.My school of thought would be to bore the block as big as one could and shorten the stroke making the motor quicker to rev and allow it more ability to utilize its torque.......
 
IMHO, there is no good reason to make a motor smaller unless there are class rules for whatever form of motorsports you're running which require a certain engine size. I think if one could figure out how to give the cummins crowd real air flow via radical changes to the cylinder head ala a new casting that would by far be the best new path of development for these motors!
 
Nick...
By increasing the bore size you will be able to keep the same cubic inch even after you destroke the motor some.What it does is allow the motor rev quicker and get to its powerband faster.

I do disagree with RD on the loss of torque though.In all of the destroked motors I have used for different applications the torque on a Superflow dyno showed more efficent numbers and a better use of the power available.
 
NickTF said:
I think if one could figure out how to give the cummins crowd real air flow via radical changes to the cylinder head ala a new casting that would by far be the best new path of development for these motors!
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X2. Well said. Hate to see the price tag though :(
 
Hammer said:
My school of thought would be to bore the block as big as one could and shorten the stroke making the motor quicker to rev and allow it more ability to utilize its torque.......
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REVGAIN!!!!!
:rockwoot:
 
IMHO, there is no good reason to make a motor smaller unless there are class rules for whatever form of motorsports you're running which require a certain engine size.
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Inertial rotating mass (yeah I made it up, but it says what I mean) you can only move so far away from the rotating axis before **** is going to hit the fan at higher RPM. Hammer has me figured out exactly... Also, I can't think of the golden number, but John Lingenfelter used it extensively. It's a ratio that describes stroke compared to rod length. I'll have to dig for it since I don't have the book anymore.
 
In extensive conversations with Erik Koenig, instructor at School of Automotive Machinists (which turns out your top fuel mechanics, nascar mechanics, etc.) and the builder of the 434 darton wetsleeved long block I had in my now sold 2001 ss camaro, he indicated time and time again build it as big as you can. The rod to stroke ratios you speak of are wives tales and ar typically 2 to 1 down to as short rod/long stroke as 1.5 to 1 (350 chevy with 6" rods has a r/s ratio of 1.72). The only time you limit your motor size is due to motor size required in a class you may be running. Or if you don't have enough cylinder head/breathing components to maintain some particular rpm you happen to desire. IHRA pro stock motor run r/s ratios in the 1.3 zone if I remember correctly, which is terrible by the r/s ratio wives tales, and don't do tue bad making around 1900hp naturally aspirated.

Point, keep it big unless you are limited by a class or desire a certain rpm and don't have enough cylinder head/breathing capability.

Further, i doubt Lingenfelter used any specific r/s ratio. He's an advocat of the 427 small block which uses a 6.125" rod and 4" stroke equaling a 1.53 r/s ratio which most in the r/s ratio is everything world would tell you that's the Devil.
 
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