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AMC Harmonic Vibration Damper Listing

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hacksaw1971 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote hacksaw1971 Quote  Post ReplyReply Direct Link To This Post Topic: AMC Harmonic Vibration Damper Listing
    Posted: Jan/03/2022 at 7:47am
Originally posted by SC397 SC397 wrote:

(same part number as a '70 360 but balanced differently)
 im using the 390 wheel (from a member) and a damper (from A P D) on my S/C.  the shop will fine tune then when thay balence the spinny stuff. .  the last time i swapped a damper on a flat crank 360 it was on the car.  it worked fine. (again from A P D)  in my case if it shook i never felt it. but yes ya should have it done if ya can. everything i said here was just what i did and it worked out well..  it mite act differnt for you if someone has been inside the mill your working with. i have been very happy with these folks, she will even pick up the phone and knows what she it talking about.... 
its the little things that make the biggest difference
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Dec/03/2020 at 7:23am
Originally posted by klvn8r klvn8r wrote:

Hey Rick,

Could you describe how the 71 401 damper is different from the 68-69 390 damper?   
The weight pad is the same.  The only difference is in the final balancing.
I'm working on a 72 401 (very early??) that has a 3 bolt damper....but am considering using a four bolt version from another 401.  Thoughts??
It will not be a problem if you have the rotating assembly balanced.

klvn8r


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Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: Dec/03/2020 at 1:29am
For reference, DAMPENERS from AMC 67-72, AMC 73-78, & 1974-76 Jeep Parts Manuals:


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Post Options Post Options   Thanks (0) Thanks(0)   Quote klvn8r Quote  Post ReplyReply Direct Link To This Post Posted: Dec/02/2020 at 4:51pm
Hey Rick,

Could you describe how the 71 401 damper is different from the 68-69 390 damper?    I'm working on a 72 401 (very early??) that has a 3 bolt damper....but am considering using a four bolt version from another 401.  Thoughts??

klvn8r

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Post Options Post Options   Thanks (0) Thanks(0)   Quote MoGas Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2020 at 8:49am
Originally posted by SC397 SC397 wrote:

The 66 290 one looks different on the front AND the back.  I believe the mass is the same.  Why they changed it... no clue. Probably for manufacturing reasons.
Here is something to watch for on one of the aftermarket dampers..
Professional Products design their Powerforce harmonic damper (# 80101) specifically for the latter engines.  I don't know when AMC did it but they changed the seal area in the timing covers some time in the '80's and took out the front lip at the seal.  The good thing was you could now change the seal with out taking the timing cover off.  The bad thing is now there is interference with the damper counterweights with the old design front cover.  Just one more part that has to be worked on to make right...
 

The other thing that I always have to do is open up the inside diameter.  They made the counter bore too shallow so the damper doesn't even engage on to the key before the press fit starts to engage.  So, I sand out the step with a die grinder.  If I don't do this I will actually achieve max torque before it fully seats against the oil slinger.  I will have to call them again to see if they will fix any of this stuff..



Do you know if this has been addressed? I am getting ready to assemble a 360 with an early cover and 80101 balancer.  Do I need to go get a new cover? Do I still need to perform the other modification mentioned?

Thank you,
Dave
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Post Options Post Options   Thanks (1) Thanks(1)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/02/2020 at 6:33pm
I thought that I would post these pictures up based off of 3 bolt dampers and 4 bolt dampers to make it all a little more clear.  Again, each damper was balanced individually to each engine.  So if you are swapping a damper,  the rotating assembly should be re-balanced.
3- Bolt Vibration Dampers.
The '68-'69 390 damper is different than a '70 390 damper
The '70 390 and the 3-bolt 360 damper is the same part but balanced differently.
The 3-bolt 401 damper and the '68-'69 390 damper are the same but balanced differently.
IMG_3490 by Rick Jones, on Flickr

4-Bolt Vibration Dampers.
Easy to tell the difference because they are all different.
If for some reason you wanted to replace a 3-bolt damper with a 4-bolt damper, just make sure the weight is the same and of course, have it balanced.  In other words,
A 4-bolt 401 damper could be used on a '68-'69 390 if re-balanced.
A 4-bolt 360 damper could be used on a '70 390 if re-balanced.
Not sure if a 4-bolt 304 damper could be used on a 290/343 or not - I will find out some day.
IMG_3491 by Rick Jones, on Flickr
 


Edited by SC397 - Jul/02/2020 at 6:41pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote HannuV Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2019 at 4:45pm
Here is a picture of the damper.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote HannuV Quote  Post ReplyReply Direct Link To This Post Posted: Jul/04/2019 at 3:19pm
I bought a vibration damper and crank pulley from a friend. He has a 74 Javelin with 360 engine on it. The damper came from that engine, but I don´t  think the 360 really is the original engine.

The damper is three bolt type and also has 180 degree weight on it. There is casting number 3211454 on damper, this should be from 71´ 401 engine, or am I missing something here ? 

Could someone help me figure out, what I just bought ? Thank you Smile 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KLW Quote  Post ReplyReply Direct Link To This Post Posted: May/30/2019 at 11:04am
I thought the 70 390 had the 360 balance on it???
1981 Spirit
(420 cu in stroker - 570 hp)
1966 Ford Fairlane Convertible
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1969rebelsst Quote  Post ReplyReply Direct Link To This Post Posted: May/29/2019 at 3:04pm
So helpful, thanks guys! 
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