Crank lightening

The vibration on a 6 cylinder is far greater because of the fewer power pulses per revolution and the length vs a v8 crank and removing metal (weight) from the crank will make it weaker. as in the JD case above .....but the balance will be fine. the crank may not withstand the harmonic vibration even with a wheel of death size balancer.


But balance is not vibration although if it were out of balance it would vibrate.

ttammeslehto,
crank is starting to look pretty good keep up the work despite the naysayers
 
GOT-Torque said:
Wade,

Will the crank balance and will the crank be reliable are two completely different questions.

Will it balance? YES (no more discussion is necessary, just read above)

Will it be reliable? Timo will find out.

Pics look good...
Click to expand...

What he said !!!!!!x2
 
Dumb question.

I'm in the camp of, the crank will balance.

BUT...

When you have counterweighs right at the rod bottom, the mass is directly absorbing the combustion pulse and helping to dampen the acceleration of the crank right there.

If you remove the counterweights, you are depending on the opposing cylinder completely to help balance out the hammering. Since that balancing or opposing force is not located right there, but further down the crank, the rotational vibration could be much worse. The torsional load and harmonics increase and breaking cranks becomes more likely.

Or do I have my head completely out of whack?

Same reasoning people prefer internally balanced V8 cranks versus having that 20 lb balancing mass out on the nose.
 
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nwpadmax said:
Dumb question.

I'm in the camp of, the crank will balance.

BUT...

When you have counterweighs right at the rod bottom, the mass is directly absorbing the combustion pulse and helping to dampen the acceleration of the crank right there.

If you remove the counterweights, you are depending on the opposing cylinder completely to help balance out the hammering. Since that balancing or opposing force is not located right there, but further down the crank, the rotational vibration could be much worse. The torsional load and harmonics increase and breaking cranks becomes more likely.

Or do I have my head completely out of whack?

Same reasoning people prefer internally balanced V8 cranks versus having that 20 lb balancing mass out on the nose.
Click to expand...

Agreed, I don't think it would survive a lot of timing.
 
That's the thing to deal with, at least around idle rpm's. Most likely I need adjustable timing, which is mapped against rpm,tps,maybe boost etc.
Lets focus those later on, after the test run is done. This thread just went up to the moon, more bull than a real thing.

Timo
 
nwpadmax said:
Dumb question.

I'm in the camp of, the crank will balance.

BUT...

When you have counterweighs right at the rod bottom, the mass is directly absorbing the combustion pulse and helping to dampen the acceleration of the crank right there.

If you remove the counterweights, you are depending on the opposing cylinder completely to help balance out the hammering. Since that balancing or opposing force is not located right there, but further down the crank, the rotational vibration could be much worse. The torsional load and harmonics increase and breaking cranks becomes more likely.

Or do I have my head completely out of whack?

Same reasoning people prefer internally balanced V8 cranks versus having that 20 lb balancing mass out on the nose.
Click to expand...
Yep. Keep thinking of the 2nd and possibly 3rd order harmonics and how the are different at different places on the crank.
 
Give'er hell Timo!

I'm excited to see what happens, but I'm going to bet on some crank breakage. Just like others have said I think relying on the opposing cylinder weight to keep it balanced is too much stress to stay together, but I hope im wrong and it does great none the less.
 
I was curious so this weekend I showed the pictures to Tommy Costales of Houston Engine and Balancing- a professional engine shop which, as the name implies, specializes in balancing and rotating assemblies- especailly in performance applications. He has done this for his entire life and took the business over from his father who did it his entire life. Tommy does a TON of quality engine work for racers in and around the Houston area.

The short version is this- Tommy said it would work. Not sure on longevity, but they would routinely cut down the counterweights on inline 6 crankshafts intended for performance applications.
 
Back in Dad's dirt track days, some classes ran 300ci. I6 Fords up to around 9000rpm. I have a pile of those cranks laying around the shop and the ones that aren't lightened like this are knife-edged. It will balance and run fine, just how long we don't know yet. Where are all the people that were sceaming this was crazy and wouldn't work? It's not something for a daily driver truck or anything, but I don't recall Timo ever saying it was! Steven.
 
Bullrack said:
Back in Dad's dirt track days, some classes ran 300ci. I6 Fords up to around 9000rpm. I have a pile of those cranks laying around the shop and the ones that aren't lightened like this are knife-edged. It will balance and run fine, just how long we don't know yet. Where are all the people that were sceaming this was crazy and wouldn't work? It's not something for a daily driver truck or anything, but I don't recall Timo ever saying it was! Steven.
Click to expand...

They realized there knowledge wasn't what they thought it was.
 
Bullrack said:
Back in Dad's dirt track days, some classes ran 300ci. I6 Fords up to around 9000rpm. I have a pile of those cranks laying around the shop and the ones that aren't lightened like this are knife-edged. It will balance and run fine, just how long we don't know yet. Where are all the people that were sceaming this was crazy and wouldn't work? It's not something for a daily driver truck or anything, but I don't recall Timo ever saying it was! Steven.
Click to expand...
So your dads lightened cranks look identical to this one? Post up some pics if you dont mind.
renopker said:
They realized there knowledge wasn't what they thought it was.
Click to expand...

Until it is balanced and data is gathered it isnt worth continueing in my mind. Funny thing is ive asked quit a few other engine builders and its 50/50 so i will wait and see if it balances and will live
 
wow... these guys go from "it won't work, your an idiot and I KNOW IT" to "well, maybe your not so stupid, and it might work"

thank god for the internet.....


f*ckin keyboard racers.......
 
Keyboard racer? Who are you to call anybody that and what have you done?

I havent gone from anything. im still on the side of it wont work. I said why i didnt think it was going to work and will stand by that until i see data to prove my thinking wrong besides I just have more important things to do then argue on here. So i guess only time will tell.
 
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DISTURBED said:
Keyboard racer? Who are you to call anybody that and what have you done?

I havent gone from anything. im still on the side of it wont work. I said why i didnt think it was going to work and will stand by that until i see data to prove my thinking wrong besides I just have more important things to do then argue on here. So i guess only time will tell.
Click to expand...

X2 :Cheer:
 
fwiw we built a 240 ford inline 6 vintage circle track motor last year and pulled about 17 pounds off the crank by cuttin counter weights. it ran all season just fine at 7500 rpm. granted yes it is a different motor but same concept. like everyone else who was right stated, it will balance just fine!! in an application like that, will it last.....again time will tell.
 
Is it REALLY relevant anymore to discuss whether it will balance or not? Or break or not break?

I think that the opinions of everybody who has participated to this thread are very clear. Or do you think it's woth it to say the same thing for the 10th time?

Timo has the ball now. Let's give him a chance to throw it without judging prematurely and let's look at where it lands and how it will fly.

Let's concentrate on HELPING him instead of throwing stones.
 
Timo probably spent more time building his own "made from scratch" muffler for his cummins suburban than most people spend on their entire truck build project. He really knows his stuff. Besides; It's a diesel. They're tough. It'll work.
 
Timo is a good friend of mine. He is quite capable of thinking and doing tech stuff. We have discussed a lot about his crank as well as other things. Give the guy a break.
 
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