Your donations help keep this valuable resource free and growing. Thank you.
|
1970 360 flywheel in a 1970 390?? |
Post Reply | Page 123> |
Author | |
SANCAPJJ
AMC Addicted Joined: Jan/14/2009 Location: US Status: Offline Points: 934 |
Post Options
Thanks(0)
Posted: Mar/21/2014 at 8:10am |
Hi all - I asked this once before - but want to be sure. I have a 1970 390 that I will be putting in my Javelin project. The project did not come w/ a flywheel. A parts car I purchased (also 1970) has a 360 w; flywheel. Can I use the flywheel from the 360 in the 390? The part numbers are the same - but I read somewhere that there may a difference in where the weights are placed. My ultimate question is - can I use the 360 flywheel "as is" in the 390. Thanks in advance for any help - John J
|
|
FuzzFace2
AMC Addicted Joined: Jul/05/2007 Location: Angier, N.C. Status: Offline Points: 10343 |
Post Options
Thanks(0)
|
No you can not use it "as is" with out issues if not right a way but will down the road.
Each flex plate (auto) or fly wheel is balanced for the size motor it is to be used on.
So even that the 360 fly wheel will bolt up you need to have it match balance to a 390 fly wheel or flex plate.
If you do not have either you will need to borrow one or take the motor apart to have the crank/pistons & rings/rods/front bal./flywheel assy. balance.
Dave ----
|
|
TSM = Technical Service Manual
75 Gremlin X v8 for sale 70 Javelin 360/auto drag car 70 Javelin 360/T5 Street car |
|
SANCAPJJ
AMC Addicted Joined: Jan/14/2009 Location: US Status: Offline Points: 934 |
Post Options
Thanks(0)
|
That's what I thought was the case. I do not have a 390 flywheel to do a comparable balance from. Is my best bet to go with a new one? I am doing a complete restoration on this car. - JJ
|
|
bigbadgreen
AMC Addicted Joined: Jan/07/2009 Location: WI Status: Offline Points: 1770 |
Post Options
Thanks(0)
|
Part #s same...balance different. How about balancers?
|
|
White70JavelinSST
Supporter of TheAMCForum Joined: Aug/08/2012 Location: Minnesota Status: Offline Points: 4867 |
Post Options
Thanks(0)
|
The 1970 390 is a one year engine. Only a 1970 390 flywheel will be close enough to balance with the engine reciprocating assembly with a minimal of machining required. There is a chance that a 71 401 flywheel will be close enough to balance with the 390 parts.
Every so often a 1970 390 flywheel becomes available. Here's a new one from ebay
If that doesn't work, keep looking, you may get lucky and find a used one. As an option take the 360 flywheel to the machine shop and ask them how far out of whack everything is and if it's possible drill holes in the correct spot to rebalance or add Mallory metal in the correct spot to correct the balance.
Armand
|
|
70 Javelin SST, second owner, purchased 1972
|
|
401MATCOUPE
AMC Addicted Joined: May/20/2010 Location: Salisbury, MD Status: Offline Points: 5368 |
Post Options
Thanks(0)
|
A m71 401 Flywheel is not the same also.......................don't take chancs, get your rotating assembly balanced, once and for don't it will never haunt you. I by alot of flywheels to use!!
Ross
|
|
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 |
|
1970390amx
AMC Addicted Joined: Jul/11/2008 Location: colorado Status: Offline Points: 3312 |
Post Options
Thanks(0)
|
I have been told that AMC had a machine in there engine room to spin the rotating assembly of a short block then remove metal from flywheel and balancer to balance. If this was true no replacement flywheel is 100% correct without balancing the entire engine.
|
|
1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box |
|
Class Guy
AMC Addicted Joined: Jul/02/2007 Location: Arkansas Status: Offline Points: 969 |
Post Options
Thanks(0)
|
Balance specifications for 1970 390 and 360 are the same. The flywheels will interchange.
|
|
typhooner
AMC Addicted Joined: Jun/28/2011 Location: Minnesota Status: Offline Points: 1184 |
Post Options
Thanks(0)
|
Iiiinteresting! I can't wait to see where this goes. I think there was something in the Harmonic balancer sticky about the '70 360 and 390 balancers having the same part number but weighted in a different clocking position. I don't recall if the different clocking position make them interchangeable or not. I imagine the same rules would apply to the flywheel factory balancing. Meaning the clocked position of balancing between 360 and 390 flywheels. It would be a Godsend to see a pic of both 360 and 390 '70 flywheels side by side.
|
|
1969 Hurst SC/Rambler A Scheme
1969 Rebel Raider Electric Green 1962 IH/AMC SC/out |
|
WARBED
Supporter of TheAMCForum Joined: Feb/12/2011 Location: Edinburg TX Status: Offline Points: 1677 |
Post Options
Thanks(0)
|
I have a 70 390 balancer and a 72 360 balancer. Tomorrow I must match them up. both are 3 bolt design, I am currious. yea and I know this is a old post. I should have the flexplate from the 70 390 engine laying around here also but it's the Borg Warner design.
|
|
59 American 2dr S/W. 70 390 AMX. 70 232 javelin. Kelvinator fridge ice cold beer storage.
|
|
Post Reply | Page 123> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |