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Discussion Starter #1
Just wondering if anyone has ran one of these "rattlers" before? I'm building a pretty mild lake cruiser and have an SFI approved cheaper balancer I planned to use but got this rattler in a box of parts I picked up. Heres a link to the summit add. Sounds like a good idea but I'v been lied to before!

http://www.summitracing.com/parts/TCI-870006/

 

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Just wondering if anyone has ran one of these "rattlers" before? I'm building a pretty mild lake cruiser and have an SFI approved cheaper balancer I planned to use but got this rattler in a box of parts I picked up. Heres a link to the summit add. Sounds like a good idea but I'v been lied to before!

http://www.summitracing.com/parts/TCI-870006/
Not sure what you mean by a "cheaper" SFI balancer, but there units out there that have no business being on a cheapo Pep Boys rebuild, let alone an even slightly warm marine engine.
The Rattler is not my first choice in dampers, but it is miles ahead of the vast majority of stuff out there. Depending in the "cheap" unit, I would go with the Rattler


ColtS please do not take offese to this statement, but IT IS the truth. Ask any number of members on this forum. In fact a member said as much once before about some of the ProComp stuff.

It never ceases to amaze me, the number of people that have no concept of what a part does in choosing a cheaper part. The impact a junk damper has on you crank can be HUGE! But if you are not aware of this fact, it natural to go with the cheaper "pulley mount"!
In the words of the "other" member here. "If it moves, by the best part you can afford and cheapen up on the none moving parts." Seriously, why will some of you buy 200.00 valve covers and a cast pistons. A 500.00 manifold and a cast crank with a 75.00 damper? 700.00 headers and a 150.00 oil pan because you can't SEE IT.

I don't understand the concept.



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Not sure what you mean by a "cheaper" SFI balancer, but there units out there that have no business being on a cheapo Pep Boys rebuild, let alone an even slightly warm marine engine.
The Rattler is not my first choice in dampers, but it is miles ahead of the vast majority of stuff out there. Depending in the "cheap" unit, I would go with the Rattler


ColtS please do not take offese to this statement, but IT IS the truth. Ask any number of members on this forum. In fact a member said as much once before about some of the ProComp stuff.

It never ceases to amaze me, the number of people that have no concept of what a part does in choosing a cheaper part. The impact a junk damper has on you crank can be HUGE! But if you are not aware of this fact, it natural to go with the cheaper "pulley mount"!
In the words of the "other" member here. "If it moves, by the best part you can afford and cheapen up on the none moving parts." Seriously, why will some of you buy 200.00 valve covers and a cast pistons. A 500.00 manifold and a cast crank with a 75.00 damper? 700.00 headers and a 150.00 oil pan because you can't SEE IT.

I don't understand the concept.
Colt, As Bob said.... you asked the question and Bob is offering you a good answer. I can't add anything to what Bob has not said other than agreeing with him fully and reinforcing the need for a good product. Some of the dampners that were good over the years were the Fisher and Fluiddampner, etc. My choice in our engines is the ATI. As Bob says, the "Rattler" is not my first choice, but is way ahead of a lot of the "imported" dampners.

Gear
 

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Discussion Starter #5
No offense taken at all! Thats why I ask here on the forum before I do something that may cost me in the long run. The cheaper balancer I was refering to was from a stock 454 build I did awhile ago and never planned to spin any real RPMs. I can see spending some real money on a balancer since it is bolted to the crank and Im ok with not going cheap here. Just wanted some opinions on the rattler. Never know when Ill actually score on a box find and from reading the summit description it sounded like a decent balancer. Theres also a reason Iv never seen one on a boat before or even heard of one! Thanks guys!
 

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So in using an ATI brand for an internally balanced motor. Does the whole rotating assembly have to be rebalanced using the new balancer or how does that work? Also what determines which diameter to use between the 7", 7.5" and 8"?
 

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Internally balance would need a neutral balanced dampner. Any neutral balance dampner would be interchangeable on an internal balanced motor with no additional balancing. Might be a good idea to have it checked to assure it has a zero or neutral balance. As far as the diameter, I've read stories about guys making more hp with the larger diameter, but I am no expert on that. I run a romac with no complaints on my Sbc spinning 5500+.
 

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Okay now I am curious as what the guru's here recommend? Please indulge me on an external or internal choice would be. I am serious here and would appreciate GN-7' s response. Mark
 

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No expert but, imho, internal balance is easier on parts. Externally, your hanging weights on the ends of the crank vs where it needs to be to correct the imbalance.
 

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No expert but, imho, internal balance is easier on parts. Externally, your hanging weights on the ends of the crank vs where it needs to be to correct the imbalance.
I completely agree! Thank you but engines have been built for many years and the technology has changed so much that I want ALOT of opinions here and their are alot in this forum that I want opinions from. Internal harmonics can kill an engine in a heart beat and have known this fact for years. I am in the progress of a test on an engine as we speak just to prove a point to myself. If I come up wrong it will be an expensive lesson to be learned and will pay the price myself to check it out! M
 

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I completely agree! Thank you but engines have been built for many years and the technology has changed so much that I want ALOT of opinions here and their are alot in this forum that I want opinions from. Internal harmonics can kill an engine in a heart beat and have known this fact for years. I am in the progress of a test on an engine as we speak just to prove a point to myself. If I come up wrong it will be an expensive lesson to be learned and will pay the price myself to check it out! M
I hope it is on a dyno..Internal balance is the only way to go.
 

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I totally respect that. I'll be watching this thread to see where this goes. I'm sure there will be a lot of useful info and a spattering of bs to follow. Lol.
 

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.....ColtS please do not take offese to this statement, but IT IS the truth. .......
:)eh:) SAY WHAT!! Is this Bob being all moderate and stuff??!! Maybe I'm in the wrong forum?.... :D

....... A 500.00 manifold and a cast crank with a 75.00 damper? 700.00 headers and a 150.00 oil pan ......
I can explain, it makes total sense. It really was only a $100 manifold, but it cost $400 to polish it so there wasn't any budget left for a steel crank and a good damper?? :thumb:

..... "If it moves, by the best part you can afford and cheapen up on the none moving parts." .....
Seriously though, good advise right there....:thumb:

The other half of the damper issue is how it fits on the crank. It has to be tight, I mean really tight... The damper is trying to "dampen" oscillations that are going back and forth a hundred or more times a second. If the damper fit is loose, it isn't able to do it's job and tightening the bolt isn't enough by itself. Do not hone them to make them easier to install...
 

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:)eh:)

Seriously though, good advise right there....:thumb:

The other half of the damper issue is how it fits on the crank. It has to be tight, I mean really tight... The damper is trying to "dampen" oscillations that are going back and forth a hundred or more times a second. If the damper fit is loose, it isn't able to do it's job and tightening the bolt isn't enough by itself. Do not hone them to make them easier to install...
I'm not sure this is correct here, but, maybe it was meant in a different way or application ?

ATI when new, need to be honed to fit your crank. All cranks are different sizes !

We hone them otherwise you won't be able to install them.

These are two piece units, the outer sheel and then the crank hub. You hone the hub to get the correct "press" fit.
For us, we take the honed hub, warm it up in the oven or rod heater, coat the crank snout w/ red loctite, slide the warm hub on,
install the crank bolt and torque it up.

When you take it off, it takes just a slight amount of pressure to pop the loctite, the hub comes right off.

The loctite also keeps the crank and the hub from transfering metal when you rattle the engine.

On the fuel car, if you don't use loctite, you WON'T ever get the hub off, 4130 or titanium, without cutting it off !
 

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I'm not sure this is correct here, but, maybe it was meant in a different way or application ?

ATI when new, need to be honed to fit your crank. All cranks are different sizes !

We hone them otherwise you won't be able to install them.

These are two piece units, the outer sheel and then the crank hub. You hone the hub to get the correct "press" fit.
For us, we take the honed hub, warm it up in the oven or rod heater, coat the crank snout w/ red loctite, slide the warm hub on,
install the crank bolt and torque it up.

When you take it off, it takes just a slight amount of pressure to pop the loctite, the hub comes right off.

The loctite also keeps the crank and the hub from transfering metal when you rattle the engine.

On the fuel car, if you don't use loctite, you WON'T ever get the hub off, 4130 or titanium, without cutting it off !
Sounds like you're talking about serious blown alky applications, a bit different deal. There's a few schools of thought regarding how the blower belt effects the torsional dynamics and whether you need anything more than a hub or not. If you're transfering metal between the hub and the crank, you have movement between the two parts (kinda obvious ;) ) and the damper isn't dampening (absorbing torsional oscillations). To be honest, I've never looked at the dynamic stiffness of a press fit using loctite.... I'm gonna look into that, it might change the fit enough. So what do you consider a correct press fit? Should be tigher than metal to metal cold. Bottom line though, if it's working for you, that's good enough...
 

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There is a proper amount of press for any damper. ATI gives recommendations of .0005- .0007 for crank snouts up to 1.6000". The larger dia. the crank snout, the less press required (more surface area). I just did a very expensive balance job on a Bryant crank and the ATI for that one didn't need honing. It had .0005" press right out of the box, but you should always check.
 

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Also wanted to add to this thread...don't confuse a damper with a balancer. If the engine is internal balance, the damper is not acting as a balancer. One of teh drawbacks of an external balance...the damper is doing double-duty.
 

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Lets clear the air about what the thing is and is not.
Unless it has some sort of counterweight attached to it, it balances NOTHING. No more than a hub does. If it has a counterweight, it does have an effect on the assemblies balance, but again, no more than a counterweighted hub would. If you look at a Fluidamper, or ATI with a counterweight, you will see they are a two pieces, a hub, and an enertia ring assembly. If you install only the hub, it has zero effect on the balance of the engine compared to the whole assmebly. As long as the hub is there, the enigne is balanced. THE DEVICE IS NOT A BALANCER!!!! the best that can be said is that the HUB of a counterweighted assembly is a balancer.

The very best description was posted here years ago by Brian of B&D Marine. IT IS A TORSIONAL DAMPER. Now by design, most will also snub HARMONICS, somewhat like putting your finger on a bell snubs the ring. What the device is design to do is arrest this:

TORSIONAL REBOUND
In the process, harmonics are also snubbed. The idea is not unlike what a shock absorber does to a spring, or the FLAT DAMPER does in a valve spring. Arrest the rebound forces and stop them from osillating. It can't stop the initial twist forces. Those come from the forces of the combustion process and the force that turns the crankshaft. But those forces deflect the crankshaft throw, and twist it up lengthwise. When these forces subside as the cylinder pressure drops, added the forces of compression on the next cylinder, the crank will SNAP back passed its NORMAL position. The DAMPER job is to arrest this, or at least minimize it.

Internal VS External.
First, it is way more convienent if you are racing, and the interchangability of components is a huge benefit. Imagine every engine needing a different flywheel and damper assembly due to different balancing. Unless you have the same crankshaft, rods and pistons in every one, its doubtfull you could manage to make the same unbalnced flywheel and damper workable on them all. You might be able to get your machine shop to work around the same flywheel and damper, but its still a pain in the ass.
There some benefits to internal on a non race engine, but in my mind it depends.
First, lets recognize that VERY FEW engines that claim to be internal actually are. Tell me how a crankshaft with this on the OUTSIDE of the engine, literally a 1/2 offplane of the flywheel is worse than the weight being on the flywheel. IT SIMPLY ISN'T WORSE. PERIOD! Unless your crank flywheel flange is perfectly round and and blanced, it IS NOT internally balanced, its NUETRALLY balanced, which means you can use a zero balnced flywheel. But if its better the bearing and crank to have the weight on the flywheel flange than on the flywheel itself, its very marginal at best.
This is in NO WAY a INTERNALLY BALANCED crankshaft. I don't care who tells you it is. And that includes EAGLE! It is a NUETRAL balanced crankshaft, nothing more!


One the front of the engine, its a another story. The weight is out on the end of the crank snout. You can imagine the bending forces of unbalanced damper hub has on the snout. On a BB Ford its much worse than a chevy because it further out there. The snout is just that much longer and the weight is that much further from the front bearing.
If I had to have external weight OUTSIDE my engine, I perfer the flywheel end to the snout anyday. 99% of the time, the flywheel flange is counterweight anyways, so what if some is in the flywheel.
But on the front, added with the blower drive issues, plus driving the boat off the end, plus its diameter, I'll give the snout every break I can give it.

As for a blower HELPING in all this. Thats a whole other deal and I am not at all convinced. I know David didn't say IT DOES, he simply stated he has heard it helps. I've heard it too. We all have. I am not convinced. Driving a blower actually has its own set of torsional issues. Using this thought, snout driven boats should help also, but all props pulse. U joints pulse. All that pulsing is seen by the crank, and IT IS enough to deflect the crank, specially if the rear of the crank is free. All this adds up to flywheel or flexplate failures which is a whole other mixed bag. This whole topic could on and on, so I will stop here.



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