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1932 Vibration Dampener Puzzle


scott12180

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I?m loosing my mind.

I took apart the vibration damper (harmonic balancer) on my 1932 Standard Eight Packard because there was a knocking at road speeds characteristic of a frozen dampener. I cleaned out all the rust and freed up all parts.

This dampener has twelve rubber buttons that sit into machined holes in the outer disk, along with twelve small springs.

Now when I try to reassemble it, I notice that there is a gap of 0.040? between the two outer halves. This is because the rim of the inner friction disk that nests into the machined ridge on the two outer halves is about 0.040? THICKER than where it sits in the gap formed by the outer halves. (If you can picture that.) The allowed space is too small (by a long shot!! )for the disk that?s supposed to sit there.

This means that when assembled the outer halves are clamping hard on the inner disk, prohibiting any independent movement. That can?t be, right? The inner disk must move freely inside the outer disk. Right?

So, was there supposed to be a spacer or shim between the outer halves? There was not one when I took it apart, but I also do not remember there being a 0.040? gap between the outer halves.

What am I doing wrong? Or was this thing improperly assembled to begin with?

Thanks for any comments.

--Scott

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Guest imported_Speedster

I think everyone is having a difficult time visualizing the problem, I know I sure am. It seems that when you bolt the assembly together, the outer halves would be pulled together. There should not be any free movement in the assembly, anywhere. It's the spring loading of inner ring to outer halves that give it the dampening effect.

Sorry, it's very hard to know without seeing it. <img src="http://forums.aaca.org/images/graemlins/crazy.gif" alt="" />

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Good point --- I should have posted a couple of photographs...

So I just took two photos but I have no idea how to attach them to this note. It wants the "complete URL for the photo" Huh????

Anyway,

The inner disk is bolted to the crankshaft. The outer disks (two pieces) are bolted around the inner disk such that the outer disk is free to move --- not rotate, but just wiggle to and fro in the direction of rotation. The inner disk holds the outer disks in place with rubber mounts and springs. It would be easy to see if I could post a photo.

My problem is that when I bolt the outer disks around the inner disk, the outer disks clamp down fully on the inner disk preventing any motion that is supposed to absorb the damping. My question is: is there a spacer that keeps these outer disk halves apart enough to prevent them from clamping down on the inner disk? I don't have that and don't think I ever did.

Part of the problem is that these dampeners changed design frequently during this period, so if you haven't had one apart from a 1932 Packard, what I am saying probably doesn't make sense.

--Scott

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Guest imported_Speedster

I don't think there should be any wiggle or looseness between inner and outer parts of the assembly. Definitely not any looseness that you can feel with your hands. The outer halves Should be clamped down on inner disk.

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I don't think you could feel wriggle looseness with your hands, but if the outer halves are clamped down tight against the rim of the inner disk, then why bother having twelve springs and rubber knobs? Seems that if it's clamped tight it would negate any function of the inner disk and turn the whole thing into a mini flywheel.

A very helpful fellow offered to post my photographs --- Thanks Wayne !

Hopefully seeing them will help.

--Scott

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Guest imported_Speedster

As an example:

I recently did a '29 dampener, and all those have between inner and outer parts is a thin washer, made from a fiber material (like clutch disks are made from), about 5" outside diameter. The inner and outer parts are clamped tightly against that disk/washer. It's only when the high twisting torque forces of the engine are applied, that the outer part will slightly move in relation to inner part. Which absorbs the shock vibration. We are talking about Unmeasureable movement when engine is running properly.

If it was allowed to spin it would not act as a vibration dampener and it would probably heat up from friction and not last long.

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Guest imported_Speedster

From what I can tell from pics, all the parts appear to be in Very Good condition. <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" /> Even the bearing surfaces of outer halves don't appear to be worn much. As long as all the rubber pins are in good condition and are seated properly, I think it should work fine.

I'm sure there is a torque spec on the bolts that hold it together, so you need to find out what that is, and make sure it is evenly torqued. I remember someone asking what that torque spec is, about a year ago, on this forum, but don't remember if we ever found an answer or not? Anyone else remember that?

They appear to be 1/4" bolts, so the torque required would not be much.

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Guest imported_Speedster

Back you your Original problem:

Did you check for a loose timing chain? If it's not something like that, then the problem is probably a worn rod or crank bearing. <img src="http://forums.aaca.org/images/graemlins/crazy.gif" alt="" />

A dampener would have to be coming apart to cause a knocking sound, and yours appears to be in good condition, so it's not the dampener causing the knocking.

BTW, I once ran a '29 Standard-8 engine with No Dampener installed and couldn't even tell it was gone. But I didn't ever get it above 1,500 RPM or so, don't know if I would have noticed any difference at higher RPM or not.

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Guest imported_Speedster

I've always felt the when the Clutch is engaged, The flywheel and clutch become the Primary 'Vibration dampener', and the dampener on front of engine only becomes primary dampener when the clutch is disengaged.

So if you ran an engine with No or a loose dampener and disengaged the clutch, you may get a noticable vibration? But probably not since the vibrations are at harmonic frequencies, which are very high frequencies, so we probably wouldn't hear them.

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Mystery solved.

I met a bunch of vintage Packard people at a party last night and had it explained to me.

The outer halves are supposed to clamp down hard on the inner disk. This isn't where relative motion is supposed to occur.

An ohm meter tells the story. There is no conducting path between the hub and the outer ring of the disk. The hub is connected to the studs which hold the rubber buttons. The hub and those studs form a six-pointed star around which rubber is moulded. And that rubber holds the outer metal portion of the disk. That outer portion is clamped down hard onto the outer halves of the damper.

Relative motion occurs within the rubber itself, effectivly between that six-pointed star and the outside of the inner disk. Very, very little motion is allowed, but it's enough to absorb vibrations.

In response to Speedster's question about the source of my knocking, yes it is possible that the vibration damper was not the cause. I am replacing the connecting rob bearings as the old babbitt was literally crumbing apart. That could have been the knock. I'll find out when I get it on the road again. Hopefully whatever I am doing --- damper or rods or new air freshener --- will eliminate the knock.

Thanks to all for their suggestions.

--Scott

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Guest imported_Speedster

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Mystery solved.

Thanks to all for their suggestions.

--Scott </div></div>

Since, I was the only one that Replied, I suppose you are talking to Me?

If so, 'You are Very Welcome'. <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" />

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>>Since, I was the only one that Replied, I suppose you are talking to Me?

If so, 'You are Very Welcome'.

Gee, now that I look back, you were the only one who replied with an answer. Thanks !

Thanks, also, to Wayne for posting my photos.

And yes, it was a good party --- 4 guys owning 1926 Eight Phaeton, 1926 Eight RHD Phaeton, 1927 Eight Roadster, 1932 902 Sedan, 1932 902 Victoria Coupe, 1936 120 Sedan, 1937 Twelve Sedan, 1938 Super 8 Sedan. Would have made a nice car show !

--Scott

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Guest imported_Speedster

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Gee, now that I look back, you were the only one who replied with an answer. Thanks !</div></div>

No Problem, I was just trying to 'Get in a Dig'. <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" /> <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

But it is Nice to be Appreciated, Some Time. <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" /> <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

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Guest imported_Speedster

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> And yes, it was a good party --- 4 guys owning 1926 Eight Phaeton, 1926 Eight RHD Phaeton, 1927 Eight Roadster, 1932 902 Sedan, 1932 902 Victoria Coupe, 1936 120 Sedan, 1937 Twelve Sedan, 1938 Super 8 Sedan. Would have made a nice car show !</div></div>

That's Not only a Party, that's a Rolling Museum! <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

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