TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > Transmission & Drivetrain
  New Posts New Posts RSS Feed - 290 vs 343 flywheel??
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

290 vs 343 flywheel??

 Post Reply Post Reply Page  12>
Author
Message
knightflight View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Jan/30/2014
Location: Nor. Calif.
Status: Offline
Points: 286
Post Options Post Options   Thanks (0) Thanks(0)   Quote knightflight Quote  Post ReplyReply Direct Link To This Post Topic: 290 vs 343 flywheel??
    Posted: Jan/13/2019 at 12:21am
I am trying to figure out the difference between a 343 and a 290 flywheel. I don't have the two to compare but I notice they are being sold as one or the other. Since they are the same crankshaft (right??), why a different flywheel? Balancing has to be the same as well as clutch type. They seem interchangeable to me.. What am I overlooking?
I ask because I need one for each engine, but it seems to me that I'm needing two of the same thing..
Walt
'67 Rebel SST conv.
'68 Rebel SST coupe. (X2)
'69 SC/Rambler (#7 on registry)
'69 Javelin SST Go-Pak 390-4 speed
'70 Rebel Machine 4spd
'72 Javelin AMX 360 ram-air
'74 Hornet-X hatchback
Back to Top
401MATCOUPE View Drop Down
AMC Addicted
AMC Addicted


Joined: May/20/2010
Location: Salisbury, MD
Status: Offline
Points: 4727
Post Options Post Options   Thanks (0) Thanks(0)   Quote 401MATCOUPE Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2019 at 5:04am
the balance is different, remember the balance is done with all rotative components...yes the crank is the same and so are rods/rod bearings.....BUT different pistons, rings and front dampener.  The raw casting would be the same, but if you are trying to swap, it needs to come from know engine size.  If you are rebuilding and re-balancing anyway......you can use either in the initial balance and it will be adjusted (adding and subtracting weight)
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
Back to Top
SC397 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Apr/30/2009
Location: Michigan
Status: Offline
Points: 2839
Post Options Post Options   Thanks (0) Thanks(0)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2019 at 8:04am
Upper left is a 290 flywheel.  Upper right is a 343 flywheel.  The only visual difference is the balancing holes that were drilled in to the 343 flywheel (bottom area of the flywheel)
290242390 by Rick Jones, on Flickr
Back to Top
pacerman View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum


Joined: Jul/03/2007
Location: United States
Status: Offline
Points: 8076
Post Options Post Options   Thanks (0) Thanks(0)   Quote pacerman Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2019 at 8:41am
Anecdotal I'm sure:   I am finally assembling my 343 factory short block for my AMX.   I could not find a 343 flywheel but I did find a NORS Scheiffer 40-pound flywheel with the correct part number for a 343.  I had the whole assembly precision balanced as recommended by the Scheiffer literature.  The balance shop in Gilroy said it was 52 grams out of balance so I'm glad I did it.  Joe
Happiness is making something out of nothing.
Back to Top
knightflight View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Jan/30/2014
Location: Nor. Calif.
Status: Offline
Points: 286
Post Options Post Options   Thanks (0) Thanks(0)   Quote knightflight Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2019 at 5:20pm
Hey guys, thanks for the informative input. So, from all that, it looks like I CAN use either one, as long as I am having it balanced with an engine rebuild...correct?
Walt
'67 Rebel SST conv.
'68 Rebel SST coupe. (X2)
'69 SC/Rambler (#7 on registry)
'69 Javelin SST Go-Pak 390-4 speed
'70 Rebel Machine 4spd
'72 Javelin AMX 360 ram-air
'74 Hornet-X hatchback
Back to Top
purple72Gremlin View Drop Down
AMC Addicted
AMC Addicted
Avatar
Charter Member

Joined: Jul/01/2007
Location: Illinois
Status: Offline
Points: 14782
Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2019 at 5:51pm
make sure the machine shop understands that the AMC v8 is externally balanced.  I paid a machine shop to balance my one 360 with a 304 flywheel and balancer....it still vibrated..total waste of my money.
Back to Top
401MATCOUPE View Drop Down
AMC Addicted
AMC Addicted


Joined: May/20/2010
Location: Salisbury, MD
Status: Offline
Points: 4727
Post Options Post Options   Thanks (0) Thanks(0)   Quote 401MATCOUPE Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2019 at 6:44pm
Walt, you are absolutely correct, I have never had a AMC vib after rebuild/rebalance, I do everyone, same shop...over 100 of them now.
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
Back to Top
SC397 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Apr/30/2009
Location: Michigan
Status: Offline
Points: 2839
Post Options Post Options   Thanks (0) Thanks(0)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2019 at 8:07pm
Originally posted by 401MATCOUPE 401MATCOUPE wrote:

Walt, you are absolutely correct, I have never had a AMC vib after rebuild/rebalance, I do everyone, same shop...over 100 of them now.


Same here.
Back to Top
knightflight View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Jan/30/2014
Location: Nor. Calif.
Status: Offline
Points: 286
Post Options Post Options   Thanks (0) Thanks(0)   Quote knightflight Quote  Post ReplyReply Direct Link To This Post Posted: Jan/13/2019 at 8:13pm
SC397...
It appears the flywheels you have pictured are all indexed in the same mount position, right? I see the red marks at the 7 o'clock hole on each one. I assume that is why those are there. The pics helps a lot, thank you.
Walt
'67 Rebel SST conv.
'68 Rebel SST coupe. (X2)
'69 SC/Rambler (#7 on registry)
'69 Javelin SST Go-Pak 390-4 speed
'70 Rebel Machine 4spd
'72 Javelin AMX 360 ram-air
'74 Hornet-X hatchback
Back to Top
SC397 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Apr/30/2009
Location: Michigan
Status: Offline
Points: 2839
Post Options Post Options   Thanks (0) Thanks(0)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/14/2019 at 7:13am
Yes, they are all indexed in the same position.  Here is a picture of the other side.
867 by Rick Jones, on Flickr
http://rebsamcandjeep.proboards.com/thread/585/amc-290-401-flywheels-flexplates


Edited by SC397 - Jan/14/2019 at 7:16am
Back to Top
 Post Reply Post Reply Page  12>
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.077 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or