Crank lightening

i bet the weight reduction is closer to 35-40lbs....That crank is a about as far from useable as one of swoles melted pistons....

Like i said with out welded counterweights put on, it wil never ballance out.


The drilling into the throws was not a bad idea, assuming you missed the jurnal oiling holes, but the rest was IMO a waste of a good crank...
 
Crank has been losing around 15kg. 33lbs will loose a bit more before done. On the pic what LReiff paste you could see blue drawing lines in yellow, that's the oil riffle. What comes to balancing, it shouldn't be an issue, of course I could be wrong but we will find out. Counter weights aren't there to balance the crank, since crank throws are arranged in three planes offset at 120°. They are there to dampen torsional vibrations, which is something to worry about, in a worst case the lifespan of the crank is really short. Although the mass and structure is now totally something else than in a stock crank, meaning the vibrations, modes and nodes aren't like they used to be. I just gotto finish it, put in an engine, fire it up and see what happens.

Timo
 
i see where your coming from, butin crank ballanceing, what you do to one side you have to do to the other or it wont ballance.

Now on to the other part, the throws.... Remember that you have heavy pistons pins and rods bolting onto the crank at that point, there needs to be a weight counter action for each opposing end. So with out the counter weights i find it hard to see how it will ballance much less absorb harminic vibrations..
 
My thinking on the balance I do know that when we ran 466 with out a HB on the front the crank broke I would think with the mass machined off the spikes will appear in a big way.
 
ttammeslehto said:
Crank has been losing around 15kg. 33lbs will loose a bit more before done. On the pic what LReiff paste you could see blue drawing lines in yellow, that's the oil riffle. What comes to balancing, it shouldn't be an issue, of course I could be wrong but we will find out. Counter weights aren't there to balance the crank, since crank throws are arranged in three planes offset at 120°. They are there to dampen torsional vibrations, which is something to worry about, in a worst case the lifespan of the crank is really short. Although the mass and structure is now totally something else than in a stock crank, meaning the vibrations, modes and nodes aren't like they used to be. I just gotto finish it, put in an engine, fire it up and see what happens.

Timo
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When we get a crank lightened for our bmw's inline 6 cylinder race engines they still have the counter weights and they spin them close 10,000 rpms but they have material removed from both the counter weight and journal ends.
If this was a good idea the German's would be doing it in the bmw's seeing how they over engineer everything for those engine.

I would like to see this crank on a balancer to see exactly how far off it is. Are you going to balance it yourself?
 
I'm taking it back to work and let them do the balance job, will be watching for sure. Think this more as a prototype, if it all blows up. I just gotto start again up with a fresh crank and cut only, lets say half of the counterweights off. There's still plenty of cranks out there. You are right about spikes, they are now much harder when the mass goes down. Which leads to a possible problem at idle or just above. That can be altered with idle speed adjustment or better yet, less timing when at idle or combination of both.

Timo
 
DISTURBED said:
If this was a good idea the German's would be doing it in the bmw's seeing how they over engineer everything for those engine.
Click to expand...

Yes and no. Some of the German engines out there have the oil pumps driven with little chains...I know *why* they did that, but it's not the most robust design in terms of longevity. That said, the Germans make some of the most impressive and innovative engines out there.

The OEMs design their engines to hopefully last beyond the warranty period while still providing a good balance between NVH, efficiency and meeting established power goals. The engineers would love to create a light crankshaft that still meets all of the aforementioned requirements, but for the sake of saving money they too have to compromise. Especially with high volume, cost sensitive engines - they're trying to maximize the margins and spend the money elsewhere - like places where the general public would actually notice.

With experiments like this, there's a fine line to walk between eliminating weight on the recriprocating assembly and sacrificing strength - Timo's goal is to figure that all out. There are other OEM crankshafts out there in the world without counterweights and they seem to run just fine...so we're not at the point where we can say this will not work.

Lastly, the sooner you figure out that telling a Finn "No, you can't do that." is like adding gasoline to a camp fire, the better off you will be. :D

Cheers,

Matt
 
First off i could careless were this guy is from, he could be from the moon for all i care, a reckless/ misguided build is what im concerned about. Without proof this will work it probably shouldnt have been posted.

We dry sump alot of the higher hp engines we build for the reason of the oil pump but in stock OEM form the chain is fine and some of the lower builds we do it is also fine. So you say there are OEM's out there that build cranks without counter weight? Post up some cranks that are OEM that dont have some kind of counter balance that turn more then 1500 rpm's
 
Holeshot said:
Yes and no. Some of the German engines out there have the oil pumps driven with little chains...I know *why* they did that, but it's not the most robust design in terms of longevity. That said, the Germans make some of the most impressive and innovative engines out there.

The OEMs design their engines to hopefully last beyond the warranty period while still providing a good balance between NVH, efficiency and meeting established power goals. The engineers would love to create a light crankshaft that still meets all of the aforementioned requirements, but for the sake of saving money they too have to compromise. Especially with high volume, cost sensitive engines - they're trying to maximize the margins and spend the money elsewhere - like places where the general public would actually notice.

With experiments like this, there's a fine line to walk between eliminating weight on the recriprocating assembly and sacrificing strength - Timo's goal is to figure that all out. There are other OEM crankshafts out there in the world without counterweights and they seem to run just fine...so we're not at the point where we can say this will not work.

Lastly, the sooner you figure out that telling a Finn "No, you can't do that." is like adding gasoline to a camp fire, the better off you will be. :D

Cheers,

Matt
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Sorry but there is no recipricating mass on the crank.....and there is no strength on the counter weights...
 
Since this thread was started under 'Extreme Engine Tech' - one would expect to see projects or ideas thrown around that aren't yet fully proven...this is precisely the place for such a discussion. You can't have a meaningful discussion by doing nothing but bash an idea/project...

You have to give the guy credit for even trying something like this...and being willing to share it for the whole world to see.

He has done a lot of really interesting work over the years all on his own - and any successes or failures were all learning experiences. Let him be, in your words, misguided or wreckless...at the very least we might discover what NOT to do. Afterall, if we were always careful and avoiding the unknown, we'd still be living in caves.

Yes, a lot of the cranks without counterweights aren't high RPM engines, but when you turn the wick up on them (as the tractor pullers have been known to do from time to time...), the crankshaft doesn't seem to be an issue.

Sorry for hijacking the thread - just adding my $0.02 worth.

Cheers,

Matt
 
DIESEL_POWER said:
Sorry but there is no recipricating mass on the crank.....and there is no strength on the counter weights...
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That was a bad choice of words on my part. I was referring to the crank, rods, pistons as an assembly - saving weight there has its advantages but it often comes at the expense of sacrificing strength.

I agree - there is no strength to be added by having the counterweights - so getting rid of them shouldn't detract from anything on that front. What we're waiting to see is if it affects other areas.

Cheers,

Matt
 
What i find funny is there is always somebody trying to reinvent the wheel. If this was a good working idea and there are a ton of smarter people then us that would already be doing it. The diesel game is fairly new, they have been thrashing gas stuff since the 1940's this has been tried and since you dont see it in today world im betting it didnt work. Now a Billet crank that is engineered to run like this may be ok but not a crank thats designed to run a certain way.
 
Holeshot said:
That was a bad choice of words on my part. I was referring to the crank, rods, pistons as an assembly - saving weight there has its advantages but it often comes at the expense of sacrificing strength.

I agree - there is no strength to be added by having the counterweights - so getting rid of them shouldn't detract from anything on that front. What we're waiting to see is if it affects other areas.

Cheers,

Matt
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The counter balance absolutly add strength to the crank. It may not add to the strength in a sence that the crank is stronger if you try to break it by snapping or twisting it off but in a centrifical strength they do. As the rod comes around centrifical force is throwing the counter weight away from the rod, if you remove that weight now the deflction in the crank is mutiplied (by what im not sure)
 
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Remember that a 6 cyl crank is not balanced with bob weights. It is a self balancing engine, due to the design vs a V-8. I am curious how this crank with light pistons and pins would change the HP, and ability to rev up. My uninformed testing showed HP gain from reciprocating weight loss and rev improvement from rotating weight loss.

I think Timo's crank may be easy to balance if the weight on each pair of cylinders (1-6, 2-5, 3-4) has like removal...

Or not. Going to be interesting to watch, Timo, GO FOR IT!
 
innovation comes from research and design, trying new ideas. not reinventing the wheel, but improving on ideas. i say go for it, it is interesting to watch and see new ideas tried. i guess backyard wrench spinners that cant think outside of the box they live in cant fathom a new idea. keep the pics and information coming, success or fail.
 
Its not about innovating, or reinventing the wheel. It's his money and he can do with it how he wants, thats fine.

But every crank needs counter ballance to work period---just stating the facts. Could this work......Not likley, because there is *NO* counter weight left, and because there is 40-45lbs of recipricating mass in the 6 cylinder cummins 5.9, you need at least that on the other end to counter ballance the crank.


Some of you think that diesels are out of this world animals that cant be tamed....well i got news for you, they are not as hard to figure out as you think, mainly because most of the gasser world has done things 20 years ago that were just figuring out.....


So - with that said, what you do to one side of a crank, you must also do to the other side. This is why they call it BALLANCE! :Cheer:
 
dieseldragster said:
Remember that a 6 cyl crank is not balanced with bob weights. It is a self balancing engine, due to the design vs a V-8. I am curious how this crank with light pistons and pins would change the HP, and ability to rev up. My uninformed testing showed HP gain from reciprocating weight loss and rev improvement from rotating weight loss.

I think Timo's crank may be easy to balance if the weight on each pair of cylinders (1-6, 2-5, 3-4) has like removal...

Or not. Going to be interesting to watch, Timo, GO FOR IT!
Click to expand...

Scott, the crank you had for sale back then as I remembered looked the same as this, seems the ad said it was a new never ran crankshaft. Was it bought new like that or did you have it machined down like this, you even told me what it weighed vers the stock crank just can't remember the numbers. I see it a very poss. major issue to get ballanced, but very curious non the less; hope it works out for you though. Better to be a Do'er and fail than a damn talker like most.
 
Cranks

Anybody remember the old 3cyl. motorcycles? How about boat motors? I think he will be fine if the rod/piston weight is correct. I don't think it will last 300k but in a race app he should be fine. Wade, didn't you already invent this? Jeff
 
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