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Author Topic:   balancers
charlie_two
Dirt Full Roller

Total posts: 53
posted October 24, 2001 06:51 PM
hey what do u guys think about the speedway fluid damper. is it any good. it says sfi certified, just wondering if anyone has ran them on a 350 and had any luck with them. thanks, also if not which do u guys prefer

charlie

jammin
Dirt Administrator

Total posts: 5556
posted October 24, 2001 07:04 PM UIN: 16262997
I have heard some bad bad things about fluid dampers. Most of what I have heard was that they have a habit of breaking the crankshaft to which they are attached. I have heard of many snots being broken off. I think i will continue to run regular sfi approved balancers.

jammin

dreamcatcher
Dirt Maniac

Total posts: 128
posted October 24, 2001 07:45 PM UIN: 14464409
a guy i know done this. take an old balencer and take the outer ring off and then have your rotating asembly rebalenced. this realy does work, the guy was real fast and won many features with it. as far as timing when you asemble your motor, make a tab that will reach what is left of you ballencer and make sure your #1piston is on compresion stroke and at tdc and mark it. it has a real quik rev and is all ballenced. hope this helps


jammin
Dirt Administrator

Total posts: 5556
posted October 24, 2001 08:37 PM UIN: 16262997
There is a problem with what you stated though. That ring on the outside of the balancer is what dampens the harmonics of the crankshaft. It is a gamble. If the harmonics of that crank match any rods or any other part within the line, it will go boom! I have seen some guys do this also, but make sure you take a look at the bearings during rebuilds...you will see noticeable wear in them. This is because the harmonics are not being dampened effectively. Personally, I would not take the chance that the harmonic frequencies of my rods, pins or any other part matched the crank...if it does..your waisting your money.


jammin

Red Dog
Dirt Roller

Total posts: 9
posted October 24, 2001 11:47 PM
quote:
Originally posted by jammin:
There is a problem with what you stated though. That ring on the outside of the balancer is what dampens the harmonics of the crankshaft. It is a gamble. If the harmonics of that crank match any rods or any other part within the line, it will go boom! I have seen some guys do this also, but make sure you take a look at the bearings during rebuilds...you will see noticeable wear in them. This is because the harmonics are not being dampened effectively. Personally, I would not take the chance that the harmonic frequencies of my rods, pins or any other part matched the crank...if it does..your waisting your money.


jammin


harmonic frequencies ????????

I've read that on this board before. What gives?

jammin
Dirt Administrator

Total posts: 5556
posted October 25, 2001 07:50 AM UIN: 16262997
When you turn an engine at high RPM, each part will give off a frequency. If that frequency matches any other frequency in the motor, there are going to be problems. That is exactly what a harmonic dampner is for. It is built to dampen the frequencies of the crank so that it does not match any other moving parts. We have a system that we can check this in crankshafts, rods etc. It will also show you if there is a problem with the casting internally where you can't see it if you mag it. The higher the RPM you turn this engine, the more likely you are to reach the harmonic match of another part. This is simply because the range of the frequency is a broad and you have a better chance of seeing something like this happen. If you take the dampening ring off of the harmonic, you have just taken the dampening effect out of the dampner.

jammin

dreamcatcher
Dirt Maniac

Total posts: 128
posted October 25, 2001 08:31 AM UIN: 14464409
i have heard of the freqencys too, but didnt know how it worked thank you jammin for the info. i was going to try it but, i cant afford to blow a motor. that is why i like this board. thank you again jammin for the tip,
charlie norris

c21
Dirt Freak

Total posts: 346
posted October 25, 2001 11:51 AM
On the topic of the small fluid dampner that speedway offers: We used one a few years ago, it looked poorly crafted and did not inspire confidance. We replaced it with an ATI at the recommondation of our motor builder. I have heard that the tide of positve opinion on fluid dampners (both high and low quality)has turned and that many engine builders are no longer using them. For the money you can't beat a stock type unit.

And .... any engine builder that would have you put together a motor with a fully dis-abled balancer (as mentioned by dreamcatcher)... probably doesn't even have enough sence to properly turn down a rotor!

dreamcatcher
Dirt Maniac

Total posts: 128
posted October 25, 2001 03:01 PM UIN: 14464409
i never said that an engine builder told him to do it. i said he did it, and he did win many features with the motor and it did last 2 seasons and yes he can turn a rotor. i dont understand people like you that think you have to be a smart a$$ about something like this. that is why i come to this forum is to get an honest opinion without a smart a$$ coment. he is a good freind of mine who helps me alot. to the person who started this post im sorry i give you the wrong info but thanks to jammin i to have learned something. charlie norris


c21
Dirt Freak

Total posts: 346
posted October 25, 2001 03:58 PM
Dreamcatcher please except my apology, it was not my intention to insult you or your friend or to be a smart a$$. I was referring to the individual who balanced the rotating assembly with a broken balancer, I assumed he was the builder as well .... he should know better. Congratulations on your friends good racing and good fortune.

dreamcatcher
Dirt Maniac

Total posts: 128
posted October 25, 2001 04:10 PM UIN: 14464409
thank you very much and it is accepted. i to am sorry that i got so upset. that is why i like this forum so much level headed people like you are here. have a nice day and talk to ya later. charlie
p.s. all of our input is very valuable some might be wrong and some right but that is what it is all about.
thank you c21


Gene
Dirt Freak

Total posts: 230
posted October 25, 2001 07:09 PM
Have ya ever seen a sprint car run a dampner?

awkwardjeff
Dirt Freak

Total posts: 458
posted October 25, 2001 11:06 PM

When you drive the water pump off the frontof the crank you are dampening the harmonics,,,,,,,,,,,,,,,,,,

jammin
Dirt Administrator

Total posts: 5556
posted October 26, 2001 07:58 AM UIN: 16262997
Your right Jeff, you are. Even the hub itself will dampen a little bit, but are you gonna bank your 10,000 dollar motor on a belt?

Bottomend
Dirt Roller

Total posts: 10
posted October 26, 2001 07:41 PM
The also say any pump, fuel, water, oil, power steering, basicly any Belt driven pump that is driven off of the crank. (sorry, forgot that part)will handle the harmonics. Remember, it is a harmonic damper not a balancer.

Scott

[This message has been edited by Bottomend (edited October 26, 2001).]

awkwardjeff
Dirt Freak

Total posts: 458
posted October 26, 2001 07:51 PM
quote:
Originally posted by jammin:
Your right Jeff, you are. Even the hub itself will dampen a little bit, but are you gonna bank your 10,000 dollar motor on a belt?

Jammin, I wasn't running a belt drive water pump........crank hub pump......that's all I'm saying in response to Gene's question.
I personally run a damper on all my motors now, the good ones are too expensive to break, and the cheap ones aren't strong enough to run without breaking the crank.......LOL

But, my reply was on a hub driven water pump.
This works like a built in fluid damper.....
.....does that make more sense?


Jeff

[This message has been edited by awkwardjeff (edited October 26, 2001).]

dirtracer14
Dirt Freak

Total posts: 499
posted October 27, 2001 02:41 PM UIN: 23443678
Excuse me but may i jump in here? Let me start by saying i am not a engine builder nor do i do much work on my own motors ( idont have patiance). From what i am reading is that if you run a belt drive water pump and say a kse belt mount that it would help to eliminate the harmonics? Then if you were to have a balanced crank then all you would need is a very small hub on the crank to mount the mandrall to? Remember i am no motor build just a guy with thoughts and try to find ways to lose rotating weight. Thanks again for this forum and the freedom to express my ideas with others and receive both good and bad input. Have a nice day

jammin
Dirt Administrator

Total posts: 5556
posted October 27, 2001 04:48 PM UIN: 16262997
Jeff,
It will dampen, but how much is the question. I larger dampner will ensure proper dampening. Go with a smaller one, will it bring the frequencies down enough? That is the question. There is a way to tell. I could test a crank with a dampner and a hub and see how much difference there is in frequency. That would be the only sure fire way to tell.

jammin

[This message has been edited by jammin (edited October 27, 2001).]

awkwardjeff
Dirt Freak

Total posts: 458
posted October 28, 2001 09:43 AM
Jammin, After re-reading your post I'm not sure you understand what I'm trying to say.
in order for you to test the frequencies of the cranks you stated you would need a crank with a damper and a crank with a hub......NO,
take a crank with a damper, then for mine you will need a crank with a hub that is directly hooked to the water pump....NO BELTS
then you would compare apples to apples.
My reply was to Gene about sprint cars not running dampers........I believe in running a damper, I was explaining why sprint cars don't run a damper and don't brake the motor all to heck.........with the crank directly driving the water pump is just like a fluid damper..........that's my only point.

Jeff

jammin
Dirt Administrator

Total posts: 5556
posted October 28, 2001 10:23 AM UIN: 16262997
ok....no sweat dude....

Gene
Dirt Freak

Total posts: 230
posted October 29, 2001 03:53 AM
Boy, I really started some stuff here. My intent was for c21's remark ie: " any engine builder that wont use a dampner is so stupid he cant turndown a brake rotor" or something very close to that. I'm pretty certain all those 40,ooo dollar sprint car engines out there, were'nt built by wanna-be Midas or Tuffy rejects

jammin
Dirt Administrator

Total posts: 5556
posted October 29, 2001 08:01 AM UIN: 16262997
It's all good guys.....heated discussion on issues is where we gain info....nothing wrong with that.


jammin

c21
Dirt Freak

Total posts: 346
posted October 29, 2001 11:28 AM
Gene, Thank you for the dose of humility. I should be more careful about making sweeping statements that go beyound the small pond I dwell in.
c21

Gene
Dirt Freak

Total posts: 230
posted October 29, 2001 04:19 PM
c21, okay, no harm done, its like I aint never stuck my foot in my mouth befor either! Sometimes we all gotta just sit back and laugh at our own foolishness. Gene

NWModracer
Dirt Full Roller

Total posts: 51
posted October 29, 2001 04:59 PM
Any vibration in an engine can lead to a disaster. Jammin covered harmonics some already, and touched on what is the real issue and that is generating a frequency that that results in RESONANCE. Take a look at a resonance mistake by engineers. http://www.kettering.edu/~drussell/Demos/TacomaNarrowsBridge.mpg

I know all or most of us make some compromises or risks for that extra bit, and regarding rotating mass, we have all looked for areas to reduce. If I thought I needed it, reducing rotating mass by removing material from the balancer is an option. Without a vibration analysis, I would say you're taking a risk.

awkwardjeff
Dirt Freak

Total posts: 458
posted November 01, 2001 09:19 AM
I didn't know this topic got heated, I thought everyone had good points. After going back and reading the whole post again, I feel this heated part is my fault. In my first reply I should have gone into more detail of my wroking knowledge of crank driven water pumps on sprint cars.

In the future I will try to explain my position more in-depth, as to keep confussion to a lesser degree.

Gene, I did like your comments about the muffler guys..........i'm still laughing.

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