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Old 11-24-2015, 01:22 PM   #1
johnmi
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Default balance flywheel and pressure plate

A lot of guys balance the flywheel first and then balance the flywheel and pressure plate together. What good does it do to balance flywheel alone when you have to rebalance it when you attach pressure plate and redrill flywheel.Thanks John
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Old 11-24-2015, 01:27 PM   #2
katy
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Default Re: balance flywheel and pressure plate

Practice.
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Old 11-24-2015, 02:02 PM   #3
Dave in MN
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Default Re: balance flywheel and pressure plate

After balancing the flywheel they do not/should not alter it. The pressure plate is altered to make the combined assembly "balanced". So flywheel first then add the pressure plate.
If guys are altering the flywheel after adding the pressure plate...I would agree it is just for practice...but not a good practice.
Good Day!

Last edited by Dave in MN; 11-25-2015 at 10:28 AM.
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Old 11-24-2015, 02:02 PM   #4
2manycars
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Default Re: balance flywheel and pressure plate

The purpose of that is to be sure the flywheel is balanced. Balancing the pressure plate is just a bonus, and if you change the clutch in the future, the flywheel is still in balance.
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Old 11-24-2015, 02:34 PM   #5
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Default Re: balance flywheel and pressure plate

I agree wit 2many to the extent the flywheel will still be in balance, but to do any good the balanced pressure plate must go back on exactly as it came off, if changing just the clutch. If changing the clutch and pressure plate, the new plate must be balanced also. Some advise that one balance the clutch disc also. Sounds reasonable, probably more so for a high revving engine.
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Old 11-24-2015, 02:42 PM   #6
Kevin in NJ
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Default Re: balance flywheel and pressure plate

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It is all for nothing if the crank is not machined right.

Many are not. Ford had them less then .001" off center.
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Old 11-24-2015, 04:41 PM   #7
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Default Re: balance flywheel and pressure plate

Where Do you alter the pressure plate to make the combined assembly balanced there is not much there. John
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Old 11-24-2015, 04:54 PM   #8
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Default Re: balance flywheel and pressure plate

Quote:
Originally Posted by johnmi View Post
Where Do you alter the pressure plate to make the combined assembly balanced there is not much there. John
Anybody who knows what they are doing balances the combined assembly by drilling in the appropriate place around the flange of the pressure plate where it sits against the flywheel. Pressure plates are pretty close to balanced anyway so there is no need to remove much metal. I've seen them done with one indent from a 1/2" drill that didn't even go all the way through.
PS I make sure the pressure pate goes back in the same place as it was when balanced by putting in a couple of dowels almost 180 degrees apart.
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Old 11-24-2015, 04:55 PM   #9
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Default Re: balance flywheel and pressure plate

I changed a lot of clutches in the past 50 years, in many cars and trucks, and never balanced the pressure plate, and never had a problem. Are today's pressure plates that bad?
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Old 11-24-2015, 04:56 PM   #10
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Default Re: balance flywheel and pressure plate

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Originally Posted by johnmi View Post
Where Do you alter the pressure plate to make the combined assembly balanced there is not much there. John
Generally additional weight is welded on to the pressure plate, not ground off.
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Old 11-24-2015, 04:58 PM   #11
Dave in MN
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Default Re: balance flywheel and pressure plate

The web address below explains the process of balancing an engine. The last page of 4 describes a method for the pressure plate. This link should take you to page 4. If you click on the photos in this article, you can expand them for a much larder view.
Good Day!

http://www.fordmuscle.com/archives/2...bly/index4.php

Last edited by Dave in MN; 11-24-2015 at 05:06 PM.
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Old 11-24-2015, 06:47 PM   #12
Dan Partain
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Default Re: balance flywheel and pressure plate

I had my flywheel and pressure plate balanced. First the flywheel, then the flywheel with the pressure plate attached. You can see in the photo how weight was added by installing some allen screws into the holes in the pressure plate.
-DAN
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Old 11-24-2015, 08:42 PM   #13
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Default Re: balance flywheel and pressure plate

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Originally Posted by 2manycars View Post
Generally additional weight is welded on to the pressure plate, not ground off.
A lot of people do it that way because it is quick.
It is wrong and definitely not safe.
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Old 11-24-2015, 08:46 PM   #14
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Default Re: balance flywheel and pressure plate

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Originally Posted by Dan Partain View Post
I had my flywheel and pressure plate balanced. First the flywheel, then the flywheel with the pressure plate attached. You can see in the photo how weight was added by installing some allen screws into the holes in the pressure plate.
-DAN
The factory adjusts weight that way but only because it is quick. It is not right. Today's society only sees the bottom line. Those slugs come out quite often.
The right way is to drill the spring stands.
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Old 11-24-2015, 08:57 PM   #15
J Franklin
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Default Re: balance flywheel and pressure plate

I had my flywheel and pressure plate balanced by Edelbrock, I never gave this any thought.
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Old 11-25-2015, 09:30 AM   #16
J and M Machine
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Default Re: balance flywheel and pressure plate

Hello: There's no reason that any machine shop should balance them separately and then balance them together.?
Clearly you should find a better machine shop as you only need to pay to have them balanced as a unit; Once.

If you'll notice the photo's here is the typical Model A flywheel and pressure plate mounted as a unit and spun.
After I input the information to the balancing machine of diameter and area of correction and spin.
The machine will measure unbalance and tell me where to remove or add material.
You may notice in the flywheel photo where I have drilled to remove weight.
doesn't take much to make it right. That's why I question the posts of doing separately then together.?

This particular flywheel assembly was off 71 grams and after weight correction it is .3 grams. A major improvement.

www.jandm-machine.com
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Old 11-25-2015, 10:03 AM   #17
Terry, NJ
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Default Re: balance flywheel and pressure plate

Possibly the idea of balancing the flywheel and then the the flywheel and Pressure plate together, comes from the fact that the FW becomes a jig to hold the PP. while balancing the two as a unit. One would want the "Jig" to have as little error as possible. I don't know, I never balanced and thing, except a lawnmower blade My first FW that I turned myself but later had balanced was only the weight of a 5/16" X 5/16" hole. Imagine what that weighs and you've got the amount of inbalance. Of course, we didn't know that until the FL was put on the machine. I would imagine that the 5/16" X 5/16" slug was less than an oz., probably around 22-25 Grams. Not much when you consider the FW weighs now about 54 lbs. But it is right now!
Terry

Last edited by Terry, NJ; 11-25-2015 at 10:09 AM.
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