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Discussion Starter #1
I was wondering if anyone would happen to know off the top of their head what the 5.9L's crankshaft is made with and if its a cast or forged piece before I go into researching if its worth the time to machine what I plan on machining into one for my race engine.

Thank you!
 

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Discussion Starter #2
Found something on Engine Builder's website

"Crankshafts
The first design crankshaft is forged steel with induction-hardened journals and eight flywheel bolts. The thrust flange is on the number 6 main journal. This crankshaft was used in the “12 valve” engine beginning in 1983 and was used from 1989 through 1997.5 and 1995.5-2002 in the Dodge Ram applications. The difference is obvious and apparent when looking at Figure 4.

The second-generation crankshaft is forged steel and induction hardened as well. It also has 8 flywheel bolts and includes two dowel pin holes for flywheel location. This crankshaft was used from 1997.5-1999.5 for Dodge and 1997.5 through 2002 for non-Dodge application. In Figure 4 you’ll notice the slightly different relief as well as other differences. This crankshaft uses a bolt-on crankshaft position trigger ring, which is manufactured in two pieces. It could actually be replaced in-chassis if it needed to be done that way."
Here is the link
http://www.enginebuildermag.com/2008/06/ram-tough-rebuild/
 

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Discussion Starter #3
Found this on AERA website

"CRANKSHAFTS
According to engine-build manager Jonathan Music at Enterprise Engine Performance, the stock Cummins cranks are great units, but for racing applications, they don’t feature enough counterweight mass to maintain rotating balance at about 5000 rpm or higher. As a result, Enterprise adds welded-on additional counterweights to their cranks. In stock form, the Cummins 5.9 and 6.7L engines produce peak horsepower at about 2000 rpm (and torque at about 1600 rpm), with the crank weights designed to handle that peak speed. Enterprise Engine performance services any make/model diesel engine, but they specialize in power-building the Cummins 5.9L. They offer a variety of specialty components that they’ve developed in-house.
Jonathan noted that some of their twin-turbo engines pull peak power in the 5000 to 6500 rpm range, so adding the necessary counterweight is mandatory.
Over-stroking is generally a no-no, simply because there’s not much room inside the blocks to accommodate additional stroke length. In other words, things are pretty tight inside from the get-go.
However, according to Music, the Cummins 6.7L can be stroked as much as 5.500”, although you’ll face quite a bit of grinding to obtain rotating clearance. The longest stroke that’s more practical is 5.350”, but you’ll still need to clearance grind."
Here is this link
http://www.aera.org/engine-professional/diesel-performance/
 
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Discussion Starter #4
Coming into another thought, undersized bearings for ground journals. I see Jegs with .25mm undersized for sale on con-rods and mains, however, whats the standard for re-ground crankshafts, does anyone know?

.25mm = 0.0098425"
 

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Jim, those are all good questions and some answers. I was wanting to build a 5.25 stroker in a 6.7 block and p-pump it droping it into a 94 short standard cab but I have just too many projects to get done, maybe in a couple of more years, Say just before I turn 70. Yes I am old.
 

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Discussion Starter #6
Reground undersized bearings out there for anyone interested.

besides the already stated we have

.50mm
and
.75mm
 

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Offset grinding and .75mm is not going to give you much of a stroke increase. I was thinking about annealing the crank then building it up and adding say .375 stroke. Then get a deck plate and sleave the block. I think it should have a chance of working.

I would assume the deck plate will need to be bolted down and torqued, while the sleaves are being installed.

And the crank will need to have the journals chromed and tempered, maybe cryo.

I have never done this but it seams like it should work. What do you think?
 

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Discussion Starter #8
Well, if we were to do undersized bearings I posted them because they are obviously not out in the open. and I am sure many would like to know the standard regrind sizes unless they decide to go further with larger cube changes through stroking or destroking along with journal diameter changes. I have never done nitriding or other processes to crankshafts etc myself but there is also micro-polishing too.

I am right at a little stall on planning my crankshaft because I have not found a rod to run just yet, I have my pistons in mind but no rod chosen, I may have to get a set of kustom rods made.

So we have a stock rod journal of 2.7160" and a stock main journal of 3.2672" according to AGkits.com. My Motors manual lists each measurement .0010 smaller in diameter for a small end measurement as well.

If you have a .375 in stroke increase we move from the 4.72 up to 5.095" stroke.

4.02 x 4.02 x 5.095 x .7854 x # of cylinders = 388.006 cubic inches of displacement.

Are you keeping your current pistons since you mention a deck plate?
 

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I have a complete 6.7 sitting on the bench. I was thinking about stock rods, cleaned up and stock pistons with the bowls opened up to drop the compression down to 15 to 1.

I also considered coating the piston tops and just the cylinder area on the head for heat rejection.
 

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I think our goals are somewhat different, I want a very street friendly 500 to 600 hp. And don't mind taking my time getting there.. My guess is you are wanting to race. I have no issues with that I just want a 12 second truck on the street well 13.2 will work for me now, as I get older I will need something slower, I know my reactions are getting slower and my vision is going down hill, I lost my General Avaition ticket due to going deaf in one ear, so I can see the down hill slide, but I still want to have a little fun.
 

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Discussion Starter #11
Yep, different but still comparable. Your plan seems to be inline with your goals, you know they say you'll go deaf listening to that rock n roll music too loud :rock :)

I have my mind set on my crankshaft now. I know how I will be reducing reciprocating weight and crankpin weight and control my rings better now. My bore will be slightly larger but I will keep the factory stroke length.

I am interested in your piston crown change you speak of, you should post a thread up and if you can before and after pics of your changes. Combustion has always intrigued me to make changes in that department whether it could be good or worthless result.
 

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Discussion Starter #12
If we calculate the old 4.02 bore 4.72 stroke
4.02 x 4.02 x 4.72 x .7854 x # of cylinders = 359.448 cubic inches
The new bore diameter which is 0.040 larger
4.06 x 4.06 x 4.72 x .7854 x # of cylinders = 366.636 cubic inches

I have been told by a parts manufacturer I had spoken to the other day many pullers have been making 6000 rpm with stock rods and pistons and most likely stock crankshaft too (unsure?) so what I am doing I should be fine with my weight reductions and strength increases by changing designs in this realm for my crankshaft rod journal up to my piston crown.

One thing since you don't mind taking your time is have your counterweights shaped to shed oil and reduce windage and take all other stress risers out as well.
 

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Discussion Starter #13
You know, I missed one thing here, the bearing design & bearing material that I plan to use! :damnit At least I have just been laying the groundwork out thus far.
 

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Lets see back in the stone age we use crank scrapers to help shed oil on motorcycle engines, we needed a crank with the correct shape and very close tolerances.

On the reciprocating mass issue, there is just so much you can do with stock rods, they will stand 1200 to 1500 hp but the only way to significantly reduce that will be a alloy Ti or Al rods and aftermarket pistons. They will not last long, Ross told me their pistons in a daily driver might last 40,000 miles, but they make enough performance pistons for sled draggers that they will get the bowls right and keep that weight down some.

You are correct for performance a 5.9 will keep the head gasket in place better than a 6.7. And a stroker motor will not perform much better. As you well know more air flow will always out perform displacement. Torque will get you out of the hole but Horsepower gets you down the track.
Or that is just my 2cents.

My pistons will just be opened up to go from the stock 16.3 to 1 to 15 to 1 and add a coating should be on the simple side. I have a machine shop I like but the owner and my brother do not like each other, so it is difficult for me to get things done, not impossible but close. I usually grow a beard and don't cut my hair for 6 month or more before going in the machine shop, but that a-hole can get things perfect, and that personality may be what it takes to be that good. Next week I want a hair cut so I may need to go by the machine shop first. Do you have any suggestions as to P-pump conversions or stand alone ECM?
Thanks
Lee
 

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Discussion Starter #15
Thats a bummer on the machine shop deal.

Think about the variables between a P-pump and ECM.
1) You have a fixed setting with variable possibilities through a flyweight governing mechanism (centrifugal).
2) Electronic, programmable injection points along with quantity carried by a brain that will signal when injectors will fire. (taylored by dyno runs for more precise settings)

Its more of a preference Lee, I think. Old School versus new school.
 

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True, but the ECM can offer multiple injections per combustion event reducing smoke and give a slight improvement on low end torque + spool the turbo sooner.

The P-pump can run less expensive injectors.

I will just need to check the bank account before making a decision.
 

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Discussion Starter #17
I have made the decision I plan to hope to use a common rail system on my 5.9 12v so I can tune it better and not have a fixed setting. Take full advantage of the torque curve :)

So If I remember right, seeing info from Agkits said the 5.9 crank is 128lbs, would you agree Lee?
 

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Discussion Starter #19
I wonder how much weight will be dropped when I go from 2.7160" to a 2.4764" diameter. Totaling 0.2396" reduction in diameter, the weight will not be much, but it is always nice to tally up for engine weight comparing it to stock specs in addition to the benefit of reduced bearing speeds. Lee, do you or anyone else for that matter happen to know factory bearing materials on the Cummins 5.9? I have not looked yet if it is Aluminum or Babbitt.
 
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