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AMC Harmonic Vibration Damper Listing

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: http://theamcforum.com/forum/forum_posts.asp?TID=38898
Printed Date: Jul/21/2019 at 10:52am


Topic: AMC Harmonic Vibration Damper Listing
Posted By: SC397
Subject: AMC Harmonic Vibration Damper Listing
Date Posted: Apr/20/2012 at 11:13am

For reference, each damper was individually balanced to each crank. The drilled holes were part of the balancing process.

Vibration Damper Listing

'67-'69 290: #3180477
'70-'71 304: #3196924
'72+ 304: #3216083
'67-'69 343: #3181612
'70-'71 360: #3196925
'72+ 360: #3230131
'68-'69 390: #31916189
'70 390: #3196925 (same part number as a '70 360 but balanced differently at engine assembly)
'71 401: #3211454 3-bolt(this is according to old info. I have one with no numbers at all on it)
'7? 401: #3211454 4-bolt
'73/4 401: #3216085 4-bolt

 

290 Vibration Dampers.  The one on the left is 1966 only.  The one on the right is 1967-69

290 Damper on the left, '67-'69 343 on the right (Note no cut out in the weight pad)

'68-'69 390 Vibration damper on the left, 1970 390 Vibration Damper on the right.  The off-set weight goes 180 degrees on the 1968-1969 390. The off-set weight goes 240 degrees on a 1970 390  ( all are 3-bolt)

1973 and latter 4 bolt Dampers.  304, 360, 401.  The off-set weight goes 90 degrees around on a 304 (both 3&4 bolt)   The off-set weight goes 240 degrees around on a 360 (both 3 & 4 bolt)   The off-set weight goes 180 degrees on a 1971-1972 401. (3-bolt)    The Off-set weight goes 240 degrees on a 1973 and latter 401 (4-bolt)






Replies:
Posted By: SEdmonds
Date Posted: Apr/20/2012 at 11:19am
Great info - thanks for posting.

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http://s1110.photobucket.com/user/suzanneedmonds/media/sig.jpg.html" rel="nofollow">


Posted By: bigbadgreen
Date Posted: Apr/20/2012 at 11:39am
So 70 390 balancer won't work for 70 360? I thought they were same.


Posted By: SC397
Date Posted: Apr/20/2012 at 11:40am
(same part number as a '70 360 but balanced differently)


Posted By: Have2SC's
Date Posted: Apr/20/2012 at 2:10pm
  rick, useful info as always!! i believe you were the one that posted all that info on the forum months ago which is were i got my list of vibe damper part numbers from! 

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1971 SC360 Hornet 4 speed 1969 BBG AMX 390 Auto 1970 Javelin 390 4 speed "Base Model" 1967 Rambler 220 X code 343 4 speed


Posted By: carnuck
Date Posted: Apr/22/2012 at 12:01am
I need to make a 4 bolt balancer that will work with my 290 for the accessories from my '82 Honcho.

-------------
Got an Eagle?
http://forums.amceaglesden.com" rel="nofollow - http://forums.amceaglesden.com


Posted By: amx39068
Date Posted: Apr/22/2012 at 12:08am
Originally posted by SC397 SC397 wrote:



'70 390: #3196925 (same part number as a '70 360 but balanced differently)



This makes no sense to me. If I went to the dealer in 1978 and asked for part# 3196925 how would they know if I wanted the 360 version or the 390 version? So real question is are we talking about a casting number or part #

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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: amx39068
Date Posted: Apr/22/2012 at 12:09am
Originally posted by carnuck carnuck wrote:

I need to make a 4 bolt balancer that will work with my 290 for the accessories from my '82 Honcho.



There is no such thing. All you can do is take any 4 bolt balancer and match balance it to an original 290 balancer.

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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: carnuck
Date Posted: Apr/22/2012 at 12:21am
That's what I said

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Got an Eagle?
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Posted By: amx39068
Date Posted: Apr/22/2012 at 12:24am
what did you say? You said you want a 4 bolt balancer to go with a 290. It does not exist so you can take ANY 4 bolt blancer and have it match balanced but there no such thing as one to bolt on without first modifying it to match the 290.

The closest will probably be the 304.

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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: carnuck
Date Posted: Apr/22/2012 at 9:20am


 I need to MAKE a 4 bolt balancer that will work with my 290 for the accessories from my '82 Honcho. LOL  

Hi Dan!



-------------
Got an Eagle?
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Posted By: amx39068
Date Posted: Apr/22/2012 at 9:29am
Well there you go Jim. Just match balance any 4 bolt balancer up with a 290 balancer and all will work fine. I have not done it but as stated, suspect the 304 would be the best place to start. I have aq couple of spare 304 balancers and can get one match balanced if you don't have anyone local to do it up your way.

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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: carnuck
Date Posted: Apr/22/2012 at 9:38am
I guess I should've been more clear. I meant to ask if the newer balancers would work on the older cranks. Especially ID and belt alignment. We have Perpetual balance here for the matching (they balance turbine aircraft engines as their day job)

-------------
Got an Eagle?
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Posted By: budryzer
Date Posted: Apr/22/2012 at 10:17am
Thanks for posting. This is a great resource for determining the correct H/B's.

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1968AMX Stroked 369
"UNCLE SAM" tribute
04 H2
04 BMW 325
A/W 95 Ultralight Hobbycopter
85 CR500 x 2 and 13 other open Class Bikes
77 Hercules
Chinook Flt Lead
Prev
1970AMX390/4spSonicw/mask&3Gremm's


Posted By: amx39068
Date Posted: Apr/22/2012 at 10:50am
Now I get your question.

All AMC genII and genIII V-8 crankshaft snouts are the same OD so all the balancers from the 290 to the 401 will bolt right on. The pulleys and water pump however are different due to the greater balancer depth on the later engines. You will need to get a full pulley setup, including PS and alternator pulleys plus a 72 and up water pump and all will be good.

BTW, I've seen where some folks shim the old style pulleys with washers but that is kind of hokey and not a great idea due to variances in washer thickness that can easily cause pulley wabble or misalignment from one pulley to the next.

Lots of guys on here, myself included, have bins full of pulleys and I am sure you someone can come up with a set if you can't find them locally. The biggest issue however is water pump shaft length so be sure to get the water pump for 72 and above which is mostly all that is available anyway.

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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: carnuck
Date Posted: Apr/23/2012 at 1:29am
That's the plan. I'm keeping the Delco alt (I have a 90 amp 10SI on it) and I considered serpentine belts, but the pulleys seem to only come in sets.

-------------
Got an Eagle?
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Posted By: Peter Marano
Date Posted: Apr/23/2012 at 9:02am
Originally posted by amx39068 amx39068 wrote:

Originally posted by SC397 SC397 wrote:



'70 390: #3196925 (same part number as a '70 360 but balanced differently)



This makes no sense to me. If I went to the dealer in 1978 and asked for part# 3196925 how would they know if I wanted the 360 version or the 390 version? So real question is are we talking about a casting number or part #


Dan is correct.  When I worked at the Kenosha plant I researched this.







Clearly if you ordered a damper assembly for a 1970 390 or a 1970 360 you would receive 3196925.  It would have the imbalance shown in note 4.  This would not have been as accurate as the factory balance on the engine but I suspect this was done many times without imbalance problems.

When the crankshafts were redesigned for the 1970 model year they were designed with the same imbalance.  Inspection of used dampers may show a trend that 360 dampers were balance drilled at the factory alike and that 390 dampers were balance drilled alike also but that would point to trends in the crankshaft balance not a design difference.







Posted By: Peter Marano
Date Posted: Apr/23/2012 at 9:13am
Later dampers had a longer interference diameter and a shorter clearance diameter.

If using a later damper use the key with the extensions.




Posted By: SC397
Date Posted: Apr/23/2012 at 6:28pm
Looks like Rick is right too.  I will fix the wording so that it is more clear.


Posted By: Peter Marano
Date Posted: Apr/23/2012 at 9:33pm
Originally posted by SC397 SC397 wrote:

Looks like Rick is right too. 


Absolutely.


Posted By: j2sax
Date Posted: Apr/23/2012 at 10:24pm
I have had a slew of bad balancers lately on later 360's and 258's... 

Without having to go full boogey SFI rated, are there any good new replacement balancers to be had out there?  

Thanks, 

Jesse


-------------
j2sax@yahoo.com
Plenty of FSJ's Eagles and other AMC's near Springfield, MO


Posted By: bigbadgreen
Date Posted: Apr/23/2012 at 10:50pm
how about the 66 290 version.does it just look different? or is it actually ballanced different? that would make a 66 290 pretty rare if it was....also im getting ready to put a 66 balancer on my 68 290Confused


Posted By: bigbadgreen
Date Posted: Apr/24/2012 at 9:12am
Rick?


Posted By: SC397
Date Posted: Apr/24/2012 at 8:22pm
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..



Posted By: 401MATCOUPE
Date Posted: Aug/31/2013 at 8:55pm
So not to flog a dead subject here but I do remember seeing info about the dampener getting "fine" balance at assembly.  I just found the document about the balance.  It is in the last sentence under the Harmonic Balancer Section.  Also check out the comments on the flywheel, it says it was drilled on final balance??  Any comments



-------------
Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar)
68X,GoPac,390,4sp,52A
69X,GoPac,390,4sp,64A
70X,GoPac,390,4sp,87A,8
70X,GoPac,390,4sp,BBO,8
70 Jav SST,390,AT,BSO
74MatX,401,AT,Prototype
74MatX,401,AT


Posted By: KLW
Date Posted: Aug/31/2013 at 9:53pm
Here's a dumb question, but why do you need a 4 bolt damper? From what I understand, the accessories (like the alt, ps pump, etc) from a 4 bolt will line up just fine if you use a 3 bolt damper and pulley.

PLEASE correct me if I'm wrong!


-------------
1981 Spirit
(420 cu in stroker - 570 hp)
1966 Ford Fairlane Convertible
(331 Cu In - 450 HP)


Posted By: amx39068
Date Posted: Aug/31/2013 at 9:58pm
not a dumb question at all. The 4 bolt damper pulley is a different depth than the three bolt so things like alternator and water pump pulleys and or shafts are different depths as well.  Likewise the 4 bolt setup pulleys are actually a different diameter as well so that the water pump pulley will usually contact the damper pulleys when you mix and match them.

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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: KLW
Date Posted: Aug/31/2013 at 10:48pm
Good to know. Here's what I'm doing and I hope it works out. I bought a Performance Products # 90101, a water pump off a 304 and the brackets off a 401 or 360. It seems like that would work OK, but we'll see!

Let me know if you have a better set up for my 390 based stroker (neutral balanced).


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1981 Spirit
(420 cu in stroker - 570 hp)
1966 Ford Fairlane Convertible
(331 Cu In - 450 HP)


Posted By: amx39068
Date Posted: Aug/31/2013 at 11:03pm
should work fine.  All the same model year stuff is a good thing.

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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development


Posted By: 6PakBee
Date Posted: Sep/01/2013 at 8:14am
The amount of down and dirty technical knowledge on this forum never ceases to amaze me.  I just finished archiving all of this on my PC for future reference.  This should be a sticky.  
:beer:




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Roger Gazur
1969 'B' Scheme SC/Rambler
1970 RWB 4-spd Machine
1970 Sonic Silver auto AMX

All project cars.



Posted By: Glenn
Date Posted: Oct/20/2013 at 10:21pm
Good thorough discussion on dampers, most of which I was unaware. I thought if they were of the same type and bolt pattern they would work. I was oblivious to the degree cut outs etc.


Posted By: Glenn
Date Posted: Oct/20/2013 at 10:24pm
Can I add another question here or should it be a new topic? I want to know if this information holds true in later Chrysler made 360s? I have a Jeep 360 used in later models.


Posted By: carnuck
Date Posted: Oct/21/2013 at 3:09pm
If it's pre '92 Grand Wagoneer, then yes. '93 Grand Wagoneer and Grand Cherokee used the Mopar 360 which is otherwise not related to Jeeps or AMC.

-------------
Got an Eagle?
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Posted By: typhooner
Date Posted: Jan/15/2014 at 12:43pm
Here's another one for your list. The outside damper weight says it's for a '70 390. The inside/backside hub spokes say '69 390.

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1969 Hurst SC/Rambler A Scheme
1967 Rogue Convertible
1969 Rebel Raider Electric Green (BBG
1969 Rebel Raider Blue You've Never Seen (BBB)


Posted By: amc67rogue
Date Posted: Jan/20/2014 at 4:24pm
That is a 70 , same as the 70-71 360 .

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Keith Coggins 67Rogue X code


Posted By: 70BBO360
Date Posted: Aug/25/2014 at 8:12pm
Thanks for the info, this help me identify a few of the parts I have laying around.


Posted By: kenjon11
Date Posted: Sep/14/2014 at 11:39am
I am in needed of a engine damper aswell. I need one for a 304 engine. Is there anyone out there willing to donate one for my car project. Or have one for cheap. i need one as soon as possible. Contact (414) 736-3571 Ken. Leave message aswell.


Posted By: kenjon11
Date Posted: Sep/14/2014 at 12:02pm
I need to find a 3 bolt harmonic damper for a 304 engine. Can anyone help me out in finding one.



Posted By: rebel-misfit
Date Posted: Sep/21/2014 at 7:39am
I do believe I have one on a '70 304. I can take a look and see if it's still there if your interested.


Posted By: captscot
Date Posted: May/20/2015 at 8:13pm
I'm building (piecing together)a 401 for a 1972 Javelin where all the parts (part numbers) are from 1972. However, the crankshaft I bought has a later part number (73' or 74'). Would a 401 harmonic damper for a '72 with the three holes for the three hole pulley, adequately balance the 401 crankshaft as intended? I assume all the 401 cranks are the same over the couple of years though the part number on each changed? Thanks, Scott

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1972 Javelin AMX - orig owner
1985 Grand Wagoneer
1967 Jeepster
1968 Jeep Gladiator
1959 Jeep CJ5
1929 Marmon model 68


Posted By: captscot
Date Posted: May/20/2015 at 9:10pm
Someone on Ebay has "AMC 401 3 bolt harmonic balancer" with casting number 3216085. I notice your list does not include a damper for a 1972 401, could this 3 bolt version be the damper used in 1972? Your list has a 401 damper #3216085 as a 4 bolt type.

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1972 Javelin AMX - orig owner
1985 Grand Wagoneer
1967 Jeepster
1968 Jeep Gladiator
1959 Jeep CJ5
1929 Marmon model 68


Posted By: 304-dude
Date Posted: May/21/2015 at 5:43am
In 72 they went with a 4 bolt damper and a change in offset on the pulleys. Plus the power steering unit had changed to GM Sagnaw.

-------------
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker


Posted By: captscot
Date Posted: May/21/2015 at 6:22am
I'm the original owner, my 304, car built late in May '72, has the 3 bolt damper, but yes has the GM pump. AMC for that year produced the 401 with different pulleys and a 4 bolt damper?

-------------
1972 Javelin AMX - orig owner
1985 Grand Wagoneer
1967 Jeepster
1968 Jeep Gladiator
1959 Jeep CJ5
1929 Marmon model 68


Posted By: Hurst390
Date Posted: May/21/2015 at 7:10am
I have a 73 401 with a 3 bolt damper and 090 heads..I believe early 73 production

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SC/Hurst Rambler

11.62 120

100% Street Legal


Posted By: captscot
Date Posted: May/23/2015 at 8:58pm
Here's a 3 bolt for a 290 on ebay.

http://www.ebay.com/itm/AMX-AMC-Javelin-290-Harmonic-Balancer-Ambassador-Rebel-/141297447044?hash=item20e5fbf084&vxp=mtr

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1972 Javelin AMX - orig owner
1985 Grand Wagoneer
1967 Jeepster
1968 Jeep Gladiator
1959 Jeep CJ5
1929 Marmon model 68


Posted By: 70amcpwr
Date Posted: Jun/30/2015 at 7:03am
So.....if your stock motor is rebuilt (say my Oct build 360), new pistons used and bored .030 over, flywheel changed (correct replacement), should you change your damper. Obviously this won't match the "factory" balance as pistons and bores were match sized. I've had a vibration ever since the rebuild in 2005. The crime was it didn't need to be bored and the pistons were perfect (and got scrapped before I got there to p/u the motor).

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70amcpwr You just can't fix stupid.
SOLD 1970 BBO Javelin, wifes 73 AMX 360 4spd. Next project 1969 AMX


Posted By: j2sax
Date Posted: Jun/30/2015 at 7:36am
Probably would have been a good idea to have the engine "balanced" at that time... that vibration is killer on bearings and will greatly reduce the life of the engine, though it will likely not cause a catastrophic failure.  So a 100,000 mile engine becomes an 80,000 mile engine (for example, not saying that is true of your case!)  

During balancing they spin balance the crank, balancer and flywheel and then weight match the pistons and rods to the lightest unit.  

At this point there is not much you can do short of that, though you may want to verify your flywheel part number if you did not previously... I have seen more than one build screwed up because the flywheel/flexplate was for the wrong engine.  




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j2sax@yahoo.com
Plenty of FSJ's Eagles and other AMC's near Springfield, MO


Posted By: 70amcpwr
Date Posted: Jun/30/2015 at 8:03pm
I actually got the flywheel myself so I know it's right. Wondering about a fluid damper? Isn't the torque converter balanced also?

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70amcpwr You just can't fix stupid.
SOLD 1970 BBO Javelin, wifes 73 AMX 360 4spd. Next project 1969 AMX


Posted By: carnuck
Date Posted: Jul/04/2015 at 5:38pm
AMC converters are zero balanced, unlike Chrysler ones, even though they use a modded Chrysler trans. It's essentially a slant 6 converter without the ring gear attached.

-------------
Got an Eagle?
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Posted By: 70amcpwr
Date Posted: Jul/07/2015 at 7:05am
Any luck with fluid dampers?

-------------
70amcpwr You just can't fix stupid.
SOLD 1970 BBO Javelin, wifes 73 AMX 360 4spd. Next project 1969 AMX


Posted By: 7172AMX
Date Posted: Jul/27/2015 at 6:42pm
Originally posted by Hurst390 Hurst390 wrote:

I have a 73 401 with a 3 bolt damper and 090 heads..I believe early 73 production
Seems 73 was transition year for this. The taller water pump was introduced then coinciding w/the 4 bolt damper but early prod possible exception. 
I've gotten a belated balancer education on this thread. I'm looking to smooth out my 72 360 727 after replacing the cracked damper [w/4 bolt style] due to the major leak the previous moron's over-torquing created. Some highway vibration resulted and i went back to a 3 bolt which was slightly worse. Having no idea these were p/n for specific cid, I realize now I've got a pair of 401 dampers. With the counter weight so far off from the 360 I'm surprised the vibe is only minor. 
I do not want to tear it down just for a balance issue. If I locate the correct 360 damper will that make it better [not perfect]? Will either 3 or 4 bolt work? [pulleys not an issue] Sadly I tossed the orig damper when I moved, so match balancing is outOuch  
Thanks for any help on this ultimate resource or corrections on my info. 
Henry


Posted By: purple72Gremlin
Date Posted: Jul/27/2015 at 6:58pm
Originally posted by 304-dude 304-dude wrote:

In 72 they went with a 4 bolt damper and a change in offset on the pulleys. Plus the power steering unit had changed to GM Sagnaw.
I have a 1972 304 HB that is a 3 bolt. and I have a 1972 401 that is also a 3 bolt HB.


Posted By: purple72Gremlin
Date Posted: Jul/27/2015 at 7:01pm
Originally posted by purple72Gremlin purple72Gremlin wrote:

Originally posted by 304-dude 304-dude wrote:

In 72 they went with a 4 bolt damper and a change in offset on the pulleys. Plus the power steering unit had changed to GM Sagnaw.
I have a 1972 304 HB that is a 3 bolt. and I have a 1972 401 that is also a 3 bolt HB.I also have a 1973 360 that has a 4 bolt HB...... but I would not be surprised to see 4 bolt HB on 1972s and 3 bolt HB on 1973s.


Posted By: dltowers
Date Posted: Aug/08/2015 at 12:03pm
Good info

-------------
Original Owner, 1974 Javelin:
360ci,2v,727TC. Motorola Multiplex with 8-Track.
G4 Plum exterior with 421Q Black Uganda Interior. Purchased on July 16, 1974 from Hooker AMC, Sherman, TX for $4500.20


Posted By: mrblatzman
Date Posted: Aug/25/2015 at 9:37am
Im still in the dark on iding these...I have a NOS 3 bolt one I got from the LAPD stuff, but cant find a number on it anywhere..on one edge there is a circular ground out area maybe 3 inches long that was done when it was made..So how do I determine what it is supposed to be used for....Thankyou    Bob in Alabama

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Thankyou....Bob


Posted By: captscot
Date Posted: Oct/19/2015 at 6:30pm
Looking for a 3-bolt hole damper for a 1971 401.

Since the photo of a '73 damper with 4-bolt holes has a 180 degree counter weight, would a '68-'69 damper with 3-bolt holes which has a 180 degree counter weight work on the '71 401? Essentially the same engine except for the stroke?

-------------
1972 Javelin AMX - orig owner
1985 Grand Wagoneer
1967 Jeepster
1968 Jeep Gladiator
1959 Jeep CJ5
1929 Marmon model 68


Posted By: captscot
Date Posted: Oct/25/2015 at 9:31am
1972 seems to be the transition year. In the last photo you print:

"The off-set weight goes 180 degrees on a 1971-1972 401. (3-bolt)"

Therefore, can a 3-bolt damper for a '68-'69 390 with a 180 degrees off-set weight work on a '71-'72 401? They seem identical.

-------------
1972 Javelin AMX - orig owner
1985 Grand Wagoneer
1967 Jeepster
1968 Jeep Gladiator
1959 Jeep CJ5
1929 Marmon model 68


Posted By: amc67rogue
Date Posted: Oct/25/2015 at 6:00pm
All the 401 dampners have a thicker outer ring, they are 180 deg. like the 68-69 390s but thicker.

-------------
Keith Coggins 67Rogue X code


Posted By: AMC Okie
Date Posted: Nov/09/2015 at 12:23pm
Where would you get a new one, or get one rebuilt?


Posted By: 401MATCOUPE
Date Posted: Nov/09/2015 at 1:25pm
Damper Doctors has done all my AMC Dampers....

-------------
Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar)
68X,GoPac,390,4sp,52A
69X,GoPac,390,4sp,64A
70X,GoPac,390,4sp,87A,8
70X,GoPac,390,4sp,BBO,8
70 Jav SST,390,AT,BSO
74MatX,401,AT,Prototype
74MatX,401,AT


Posted By: sweatlock
Date Posted: Nov/09/2015 at 4:28pm
I contacted Damper Doctors to have my 360 damper rebuilt - no response. I ended up just re-using it since it really wasn't bad, just figured I'd have it re-done while I had it off. Still though, not bothering to answer a potential customer's inquiry..oh well. Hopefully you'll have better luck.


Posted By: AMC Okie
Date Posted: Nov/10/2015 at 10:29am
Is there any way to tell on a 390 c.i. if the engine is a 68-69 or a 70 in case the wrong Harmonic balancer was used?
Also any way to tell if the crank is 68 -69 or 70?
The car is a 69 AMX and it does have a vibration that goes from heavy to light continuously . ....Does that make since? 


Posted By: 401MATCOUPE
Date Posted: Nov/10/2015 at 10:31am
look at the casting numbers on the damper....70 damper ends in 6925. The number is cast into the face of the outer ring.

-------------
Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar)
68X,GoPac,390,4sp,52A
69X,GoPac,390,4sp,64A
70X,GoPac,390,4sp,87A,8
70X,GoPac,390,4sp,BBO,8
70 Jav SST,390,AT,BSO
74MatX,401,AT,Prototype
74MatX,401,AT


Posted By: AMC Okie
Date Posted: Nov/10/2015 at 11:51am
Thanks for the info on the balancer.
Do you know how to tell what year the block or crank is?


Posted By: 401MATCOUPE
Date Posted: Nov/10/2015 at 3:22pm
Block is easy...1/2" head bolts and casting number on back of block....

All 390 cranks are forged, most 70 cranks are re-part numbered 68/9 cranks.....all are flat flanged.  The crank also has a month/date stamped in the wide counter balance throw.  like 11 over 69....they all use the same size bearings (nominal).  The rod is the big difference in 68/9 and 70.  The 68/9 rod ends in 1739 and the 70 rod ends in 7047.  Hope this helps


-------------
Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar)
68X,GoPac,390,4sp,52A
69X,GoPac,390,4sp,64A
70X,GoPac,390,4sp,87A,8
70X,GoPac,390,4sp,BBO,8
70 Jav SST,390,AT,BSO
74MatX,401,AT,Prototype
74MatX,401,AT


Posted By: AMC Okie
Date Posted: Nov/10/2015 at 5:00pm
Yes, all this info is helpful. I worked on alot of amc's in my late teens & early twenties but I've forgot a lot of what I learned, and didn't learn as much as I thought I needed to know about amc's.
I just got off work and looked and it does have a 68/69 balance. I could not find the numbers but it looks like the 68/69 on the first page.
Thanks 


Posted By: jrpark22000
Date Posted: Nov/11/2015 at 3:24pm

I've read through this and the countless other damper threads. I haven’t been able to find a definitive answer. 

AMC 360 dampers– did they only come with 180deg weighted, only come with 240deg or a mix depending on the year?

From what I’ve gathered from all the reading I think they were only 240deg weighted.

Why I’m asking;

I ordered a 360 short block from CME and had them order an ATI damper and flywheel so it could be computer balanced. To my surprise when I received the shipment the ATI damper they sent was the 180deg version, part# ATI917942.  I don't have or know what damper came on the motor from AMC.

When I opened the damper box there’s no way they installed it on the crank, there are no marks inside the hub or key way. There’s also new balancing holes drilled into the crank front two counterweights and another in the rear most counterweight. I don’t want to find out the hard way on first startup I’ve the wrong parts.


Thanks Guys. 



Posted By: jrpark22000
Date Posted: Nov/17/2015 at 8:12pm
The answer for anyone following this in the future is 360s were 240 weighted only. 

http://theamcforum.com/forum/topic74921_post677719.html#677719




Posted By: amcenthusiast
Date Posted: Apr/26/2017 at 9:07am
If you need help internal balancing your AMV8 rotating assembly, PM or or contact me through link below.



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Link to XRV8 Race Parts website: www.amcramblermarlin.1colony.com


Posted By: DHACKING
Date Posted: May/05/2018 at 10:27pm
I HAVE A 1970 AMX THAT WAS AN ORIGINAL 360...NOW HAS 1970 390 IN IT.
THE CASTING # ON THE HARM BALANCER IS '70 390: #3196925.
THE PREV OWNER ALSO PUT IN A 727 TRANS.
SHOULD I BE CONCERNED ABOUT CHANGING THE BALANCER??
THANX...
CONFUSED


-------------
RAYMON H


Posted By: 304-dude
Date Posted: May/06/2018 at 5:11am
Originally posted by DHACKING DHACKING wrote:

I HAVE A 1970 AMX THAT WAS AN ORIGINAL 360...NOW HAS 1970 390 IN IT.
THE CASTING # ON THE HARM BALANCER IS '70 390: #3196925.
THE PREV OWNER ALSO PUT IN A 727 TRANS.
SHOULD I BE CONCERNED ABOUT CHANGING THE BALANCER??
THANX...
CONFUSED


Pre 72 cranks don't match to a TC tranny, only BW. So either one of three options can be done.

A custom kit for tranny swaps, or a swap of a 401 crank into the 70 390 block (which could be done cheaply, and very easily from the late 70s to early 90s), or by machining (70 crank to fit the TC converter, or converter snout to fit 70 crank).

I assume the flex plate should be a match from a 401 with TC automatic.

The question is can a 70 3 bolt balancer properly balance as well as a 72 on up balancer for the mix match??? To me it's negligible, as it is street driven mostly and not cracking over 4700+ RPM constantly.






-------------
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker


Posted By: 401MATCOUPE
Date Posted: May/06/2018 at 5:58am
Originally posted by DHACKING DHACKING wrote:

I HAVE A 1970 AMX THAT WAS AN ORIGINAL 360...NOW HAS 1970 390 IN IT.
THE CASTING # ON THE HARM BALANCER IS '70 390: #3196925.
THE PREV OWNER ALSO PUT IN A 727 TRANS.
SHOULD I BE CONCERNED ABOUT CHANGING THE BALANCER??
THANX...
CONFUSED

Raymon......the first thing to know is did the previous owner ever have the 70 360 and torqueflight combination running??   If so that could solve a host of problems issues up front....

You say you have the 70 390 in it already, so you must have already taken step to adapt the Torqueflight to the early flat flange crank.  Forget about the style of balancer, 70 360/390 used the same casting number....they did have a different balance.  BUT since 70 390 never had a Torqueflight and it sounds like some other unknowns, it should have been re-balanced with a Torqueflight flex plate (a 401 flexplate would be best choice)........honestly you have a bit of dice rolling going on.  A re-balance is the only way to ensure a vibration free installation with this combination.

If you have it all installed with the 70 390, try it.........


-------------
Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar)
68X,GoPac,390,4sp,52A
69X,GoPac,390,4sp,64A
70X,GoPac,390,4sp,87A,8
70X,GoPac,390,4sp,BBO,8
70 Jav SST,390,AT,BSO
74MatX,401,AT,Prototype
74MatX,401,AT


Posted By: DHACKING
Date Posted: May/06/2018 at 9:38am
yes I bought it this way 390 in it...I checked the casting # on the balancer to see if it was 360 or 390 balancer and found out they have the same casting.
I have no way of knowing where the torqeflight came from. thanx for the replies the rest is left unknown.
raymon

-------------
RAYMON H


Posted By: 304-dude
Date Posted: May/06/2018 at 9:51am
Originally posted by DHACKING DHACKING wrote:

yes I bought it this way 390 in it...I checked the casting # on the balancer to see if it was 360 or 390 balancer and found out they have the same casting.
I have no way of knowing where the torqeflight came from. thanx for the replies the rest is left unknown.
raymon


You can check the flex plate for identification, without removal.

There is a flex plate thread with pix. You can ID a 401 version by counter weight location and size.

You need to either post a good picture or look through the thread that i will add, for you to verify on your own.

With the inspection cover off, You will need to manually crank the engine to the drain plug hole on the flex plate. Take note to see the counter weight edge just under the converter, it may be further up and barely visible.

Here is a picture...



If your flex plate is from a 401 it will be 180° from the drain plug hole. So crank about 1/4 turn more to verify that the counter weight is barely shown through the access cover opening.

Rotate further to get a good measurement of how far the weight is from the drain plug hole. Then once you have that measurment, measure the width of the counter weight.

Here is the flex plate thread.

http://www.theamcforum.com/forum/flex-plate-id_topic4832.html" rel="nofollow - http://www.theamcforum.com/forum/flex-plate-id_topic4832.html

-------------
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker


Posted By: 401MATCOUPE
Date Posted: May/06/2018 at 10:27am
Raymon.....do you have it running???  That is the key, hopefully the last owner was smart enough the have it balanced.  If it was rebalanced, it does not matter what flex plate is in there, the Machine Shop would have add/subtracted weight as required and then should be fine.

-------------
Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar)
68X,GoPac,390,4sp,52A
69X,GoPac,390,4sp,64A
70X,GoPac,390,4sp,87A,8
70X,GoPac,390,4sp,BBO,8
70 Jav SST,390,AT,BSO
74MatX,401,AT,Prototype
74MatX,401,AT


Posted By: dltowers
Date Posted: May/06/2018 at 9:05pm
Not sure if this will help, but here are a couple of photos of the original factory Harmonic Counter Balancer that was on my wife's 1974 Javelin, build date is June 1974.
Drive train:  360, 2 barrel, 727 TC.
Looks like the part number is:    3216084....






-------------
Original Owner, 1974 Javelin:
360ci,2v,727TC. Motorola Multiplex with 8-Track.
G4 Plum exterior with 421Q Black Uganda Interior. Purchased on July 16, 1974 from Hooker AMC, Sherman, TX for $4500.20


Posted By: amx007
Date Posted: Feb/22/2019 at 2:18pm
can I get my 290 one rebuilt the rubber is bad machine shop need it for engine balancing
gary

-------------
dream red white and blue
1968 Chicago auto show amx 290 4 speed
1969 driver Amx 290 auto


Posted By: Bruce Clarkson
Date Posted: Feb/27/2019 at 8:49pm
Various folks such as Damper Doctor can fix the Damper. Then your rebuilder can balance with it.

Bruce Clarkson


-------------
Bruce Clarkson


Posted By: javideofree
Date Posted: May/06/2019 at 2:08am
So 70 390 balancer won't work for 70 360? I thought they were same


Posted By: oldamcer
Date Posted: May/20/2019 at 8:48pm
OK guys here is one for ya! #3230132 I can't find this one. Thanks

-------------
40 HudsonCoupe 304/904
64 AmericanGasser 390/998
69 AmboWagon"The Flower Car"
69 AMX 343/5 Spd
50 StudeGasser360/T-400
74 HornetHatch 304/6-spd
55 Hudson360/904/TorqueStorm
77 Jeep J-10 258/4spd

 


Posted By: 1969rebelsst
Date Posted: May/29/2019 at 3:04pm
So helpful, thanks guys! 


Posted By: KLW
Date 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
(331 Cu In - 450 HP)


Posted By: HannuV
Date 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 


Posted By: HannuV
Date Posted: Jul/04/2019 at 4:45pm
Here is a picture of the damper.





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