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Vibration Damper/Harmonic Balancer


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Posted

My jeeps broke and I'm driving the beater full time for a few weeks now. Started it up today and it had a strange noise on acceleration. After some inspection I find the the vibration damper, or Harmonic balance, is just spinning freely on the end of the crankshaft. WHat's the deal? Is it supposed to be keyed in, spline? What holds it in place. There is about 1/4 inch on either side of it and it just spins around.

I started this on another thread, but I figure it's better to post it as a new thread. Here's a pic of Don C's vibration damper and mine appears the same. My question is: What the heck happened? I just can't figure how the pulley works fine, and is secure and the but the vibration damper just spins around? It does have 6 bolts going through it. WHat the heckdampermods2.jpg

Posted

On my car it is the same way. The pulley is actually pushed on and pulled off, held on by a large nut in the center. The six bolts actually hold the damper onto the pulley. So the pulley would spin with the crankshaft if the bolts were missing.

DSC01117.jpg

Posted

That couldn't be right Mike. I thought these were keyed, but if not, yours must need a good tightening at the very least. I'll call you tomorrow. My heart may be in New Mexico but my tools are here in Glendora.

Posted

The big bolt secures the hub to the crankshaft. The six bolts hold the pulley

and the damper to the hub. The rubber in the damper can and will

delaminate allowing the damper to freewheel.

The 6 bolts will only line up one way. One of them is drilled

slightly off center.

Here is the hub.

hub3.jpg

Here is the pulley and damper.

damper_1.jpg

Complete assembly

felt2.jpg

Pulley and hub

damper_4.jpg

Posted

Couple questions for you guys...on two engines of mine, both 53 vintage, there is no damper, only the pulley and hub. Any idea when they discontinued the damper and why?

Also, sounds like the pulley's gotta come off for repair on Mike's car. Can that be done with the motor in the car or...?

Posted
Couple questions for you guys...on two engines of mine, both 53 vintage, there is no damper, only the pulley and hub. Any idea when they discontinued the damper and why?

Also, sounds like the pulley's gotta come off for repair on Mike's car. Can that be done with the motor in the car or...?

Good questions on the damper on damper off issues. My 53 Desoto engine had a damper. I have seen D-24 engines thad did not have a damper but had the provisions on the front hub for a hand crank even though there was not a crank hole in the radiator. I conclude that the factory used what ever parts they had available at the time of assembly.

To repair/replace the damper on Mikes car simply remove the 6 bolts and it should come off directly. No need to remove the big nut and the hub. No puller required. The radiator may have to be removed and possibly the front of the engine may have to be jacked up a bit. Remember the 6 bolt holes will only line up one way.

  • Like 1
Posted

I would think thats ok since lots of the flatheads only have a pulley on the crank.

Posted
One more question...I can't see from the

photos where the rubber part would be located. If the thing is bolted directly to the pulley, where is the rubber part that delaminates?

In this picture you can see the rubber just behind the front plate.

Some of the rubber has chipped off and is no longer smooth. Blue

paint hides many flaws:D

damper_2.jpg

Posted

Cool, thanks for the pics and responses. I pulled the radiator yesterday but did not want to disassemble until I got your valuable input. I am goint to try to take it off this evening and hopefully send some pics. Anyone have a spare in their junk pile that they want to sell me as I kind of need to keep this beast rolling for a while. I figure I can pull off the damper and run with the pulley until I can locate a spare. Unfortunately, it's my driver right now so down time is not really an option. I have my girls car until wed. so I have to do something kinda quick.

Thanks

Posted

Let me see if I have one of the p15 engine laying under my workbench. Getting it off while under there might be another story....... I should have one off the p15 I just parted out too but I'm not sure where that one went.

Posted
Good questions on the damper on damper off issues. My 53 Desoto engine had a damper. I have seen D-24 engines thad did not have a damper but had the provisions on the front hub for a hand crank even though there was not a crank hole in the radiator. I conclude that the factory used what ever parts they had available at the time of assembly.

To repair/replace the damper on Mikes car simply remove the 6 bolts and it should come off directly. No need to remove the big nut and the hub. No puller required. The radiator may have to be removed and possibly the front of the engine may have to be jacked up a bit. Remember the 6 bolt holes will only line up one way.

This brings me to another question. The engine I just took out of my car had the single pulley with the center bolt that had the cutouts for the hand crank to be inserted. No damper, just pulley. I went ahead and used that one on my engine as when I went to reinstall the damper and pulley I have the part of the damper where the bolts go thru was damaged in removal. So the damper would not fit over the hub flush. I figured I would need to take it to a machine shop to have them fit the two back together.

I didn't want to mess with that at the time and put the single pulley on the rebuilt motor without the damper. Now lately I've been having issues with the rear bolt on the lower generator bracket continuing to get loose after driving for several miles. Could there be too much vibration from the damper not being on the motor? I wouldn't think it would matter as I had the same setup on the engine I just took out. Any opinions?

Posted

I have several cars with 34 to 54 or later engines in them

Some have dampeners some do not. On my 50 fastback I removed the dampener and wide pulley and installed a narrow pulley from junk car- I cannot tell any difference.

G. Asche says He really has no idea why they quit using dampener or for that matter why they ever used it. He claims make no difference.

Lou

Posted

My truck engine with 3k miles on it to date. I say go ahead and run it without. This is actually a P23 car engine but I dont believe any of the trucks had the dampeners

withengine2.jpg

Posted

Thanks for the advice. I'll put it back together minus the damper tomorrow night. I need to be driving it on Thursday. I think I'll be sticking around here a little more often than I have been lately. It's a great thing being able to tap the knowledge on this site at a moments notice. Normspeed, give me a call. We got to get together for some beers before you go to NM...I'll let you guys know how she runs without the damper, only bummer is that the damper had the timing marks on it. What do you suggest I do about that?

mike

Posted

I suggest you don't try to time your engine until you get a new dampener!

Posted
Now lately I've been having issues with the rear bolt on the lower generator bracket continuing to get loose after driving for several miles. Any opinions?

Use service removable loctite on the offending bolt.

I just pulled the damper off. What do ya suggest? Can I run it without the damper while I either obtain one or fix mine?

Yes

only bummer is that the damper had the timing marks on it. What do you suggest I do about that?

mike

Nothing. Unless your engine timing is "off". If it is off then use a vacuum gauge to time your engine. Set the timing at the higest vacuum reading on the gauge.

On another issue PBR is not my first choice.:eek:

Posted
Turned the page in my parts book and found some more listings for damper use up thru 54. (book only goes to 1954)

I do not doubt this but I have2 53's and no dampener a 54 with dapper and wide belt- it seems all across the board

Lou

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