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Flywheel and clutch balancing #2995784
12/16/21 12:10 PM
12/16/21 12:10 PM
Joined: Jun 2016
Posts: 907
Washington
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hemienvy Offline OP
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hemienvy  Offline OP
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Joined: Jun 2016
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Washington
Been reading about this on all different car sites.

It seems some manufacturer's flywheel / clutch assemblies, intended for internal balance crank assembly, do NOT have good neutral balance.

McCleod, Spec, others.

If seems to be agreed that balancing your flywheel and clutch separately from the crank is a good idea. Even separately from each other, flywheel, then clutch.

Not every machine shop is equipped, or is willing, to do this.

Anyone know of particular shops that will do flywheel / clutch dynamic balancing ?

Re: Flywheel and clutch balancing [Re: hemienvy] #2995845
12/16/21 03:44 PM
12/16/21 03:44 PM
Joined: Sep 2014
Posts: 4,457
Washington
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madscientist Offline
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Washington
Originally Posted by hemienvy
Been reading about this on all different car sites.

It seems some manufacturer's flywheel / clutch assemblies, intended for internal balance crank assembly, do NOT have good neutral balance.

McCleod, Spec, others.

If seems to be agreed that balancing your flywheel and clutch separately from the crank is a good idea. Even separately from each other, flywheel, then clutch.

Not every machine shop is equipped, or is willing, to do this.

Anyone know of particular shops that will do flywheel / clutch dynamic balancing ?


It’s a balanced assembly. That means you get the flywheel, disc and pressure plate to zero and then it goes onto crank to finish.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Flywheel and clutch balancing [Re: hemienvy] #2995854
12/16/21 04:37 PM
12/16/21 04:37 PM
Joined: Dec 2004
Posts: 10,554
Rittman Ohio
fourgearsavoy Offline
I Live Here
fourgearsavoy  Offline
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Joined: Dec 2004
Posts: 10,554
Rittman Ohio
I just bolt the plate to the flywheel and chuck it up on our digital wheel balancer and go from there. It gets it down to 0-3 grams which is pretty good to me shruggy I've seen guys just bolt them on and trust the clutch and flywheel vendors word eek

Gus beer


64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
Re: Flywheel and clutch balancing [Re: fourgearsavoy] #2995860
12/16/21 04:59 PM
12/16/21 04:59 PM
Joined: Oct 2005
Posts: 8,873
Ontario, Canada
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Stanton Offline
Don't question me!
Stanton  Offline
Don't question me!
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Joined: Oct 2005
Posts: 8,873
Ontario, Canada
Quote
It’s a balanced assembly. That means you get the flywheel, disc and pressure plate to zero and then it goes onto crank to finish.


If you've bought a balanced bottom end then you're pretty much stuck with having to balance the flywheel and clutch separately.

To me, balancing these separately makes absolute sense as you wouldn't want to disassemble a motor for balancing if you ever had to or wanted to change the flywheel and or pressure plate or even switch to an automatic.

As to part two of the OP's question, I know a guy BUT he's in Ontario, Canada !!!

Re: Flywheel and clutch balancing [Re: fourgearsavoy] #2995863
12/16/21 05:11 PM
12/16/21 05:11 PM
Joined: Oct 2014
Posts: 103
Washington
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weedburner Online content
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weedburner  Online Content
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Posts: 103
Washington
Couldn't be happier with the before/after 8600rpm results from my DIY flywheel/clutch static balancing fixture...
DIY Static Balancing Fixture Webpage

Grant

Re: Flywheel and clutch balancing [Re: hemienvy] #2995944
12/16/21 09:37 PM
12/16/21 09:37 PM
Joined: Oct 2007
Posts: 4,206
New York
polyspheric Offline
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polyspheric  Offline
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Joined: Oct 2007
Posts: 4,206
New York
The flywheel is bolted to the crank flange, the pressure plate bolted to the flywheel, so it makes sense to balance them as an assembly (assuming the PP is indexed, asymmetrical bolt pattern etc.).
However, the disc lands on the other 2 surfaces differently every time the clutch is re-engaged.
How can this work?
The disc's friction part of the radial mass is so evenly distributed that a tiny balance error is harmless. If its perimeter were 3" thick or 30" OD it would have to be neutral balanced separately.

How do simple rotational and dynamic balance differ?
If the pieces were all completely symmetrical in 3 dimensions this would work, but the largest piece (PP) is probably eccentric as to weight distribution in its thickness (front to back distance) even if radially correct.
This means the center of mass is not exactly parallel to the rotational center, but mis-aligned. The PP tries to rotate on its mass axis, and introduces a new vector. Dynamic balance senses this and IDs the correction.


Boffin Emeritus
Re: Flywheel and clutch balancing [Re: weedburner] #2995955
12/16/21 10:20 PM
12/16/21 10:20 PM
Joined: Mar 2003
Posts: 9,100
Rogue River, OR
Jeremiah Offline
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Jeremiah  Offline
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Joined: Mar 2003
Posts: 9,100
Rogue River, OR
Originally Posted by weedburner
Couldn't be happier with the before/after 8600rpm results from my DIY flywheel/clutch static balancing fixture...
DIY Static Balancing Fixture Webpage

Grant


There is so much good stuff on that page. I am going to tighten up the face plated 3-4 slider on my a833 this winter. Thanks Grant!



Re: Flywheel and clutch balancing [Re: weedburner] #2995972
12/16/21 11:25 PM
12/16/21 11:25 PM
Joined: Mar 2011
Posts: 3,077
Michigan
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A727Tflite Offline
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Joined: Mar 2011
Posts: 3,077
Michigan
Originally Posted by weedburner
Couldn't be happier with the before/after 8600rpm results from my DIY flywheel/clutch static balancing fixture...
DIY Static Balancing Fixture Webpage

Grant


Great info and impressive approach.

Your door closer provided me with a solution on an issue I was currently working on.







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