International Full Size Jeep Association
Home Forums Reader's Rigs Tech Library Trail Stories FSJ-List
International Full Size Jeep Association  

Go Back   International Full Size Jeep Association > Tire Kickin' > General FSJ Tech

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 04-21-2013, 08:43 AM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
Which Flywheel for a 401

Hello IFSJA Forums

Need a little guidance here.

I recently picked up a 401(automatic), that I need to convert to a manual.
Having a little trouble ID'ing the proper flywheel.

I've heard that the flywheels differ for each of the V8's because they are balanced specifically for that motor.

JEGS has this one 555-601450
http://www.jegs.com/webapp/wcs/store... hTerm=601450

but it lists the 360 as an application as well

Any thoughts or recommendations on sourcing?

Thanks all
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #2  
Old 04-21-2013, 09:00 AM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
BJ's too

They also list both motors in their offering

http://www.bjsoffroad.com/prod-556.htm
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #3  
Old 04-21-2013, 10:54 AM
Carnuck's Avatar
Carnuck Carnuck is offline
 
Join Date: Feb 12, 2011
Location: Gold Bar, WA
Posts: 6,318
Hold up! Which crank flange do you have? (one has a centering ring and one doesn't)
__________________
Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental.
Reply With Quote
  #4  
Old 04-21-2013, 04:58 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
How do I tell the diff? Is it year based? If so, this supposed to be a 77

Guess I can take pic.
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #5  
Old 04-21-2013, 05:39 PM
SC/397's Avatar
SC/397 SC/397 is offline
Administrator
 
Join Date: Feb 01, 2010
Location: Michigan
Posts: 752
The 401 counter balance lug is about 1 1/4" wide and goes nearly flush to the outside of the flywheel.

The lug on a 360 flywheel is below flush by about 3/8". I have no clue what the aftermarket is selling. I asked for photos of the lug and they can't seem to supply it..

Here is the difference in crank flanges. '67 through '71 are flat like the 343. The 1972 and latter all have the flange like the 360 in the picture. The flange is based on year.
Reply With Quote
  #6  
Old 04-21-2013, 06:21 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
360/401 Flywheels

Quote:
Originally Posted by SC/397
The 401 counter balance lug is about 1 1/4" wide and goes nearly flush to the outside of the flywheel.

The lug on a 360 flywheel is below flush by about 3/8". I have no clue what the aftermarket is selling. I asked for photos of the lug and they can't seem to supply it..


Do you know what years the 360 and 401 are respectively in these photos?

I will go snap a pic of my flange, to at least answer the year question
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #7  
Old 04-21-2013, 06:47 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
Casting Numbers

Any chance you have the casting/part numbers from each?
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #8  
Old 04-21-2013, 07:12 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
My 401 Crankshaft Flange

__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #9  
Old 04-21-2013, 07:26 PM
SC/397's Avatar
SC/397 SC/397 is offline
Administrator
 
Join Date: Feb 01, 2010
Location: Michigan
Posts: 752
ALL cranks are flat from 1967 through 1971.
ALL cranks have the boss from 1972 until the bitter end.
If you have a 1977 then, the crank will have a boss on it.

Regardless, each engine WAS balanced individually. So if you swapping from a flex plate to a flywheel, you should have the engine balanced. The same can be said for vibration dampers. Most of the time, you can get away with swapping flywheels from engine to engine of the same displacement and it MIGHT be close enough. Not always.

The part number for the '72 and latter Flywheel is 321-2655

Last edited by SC/397 : 04-21-2013 at 07:45 PM.
Reply With Quote
  #10  
Old 04-21-2013, 10:21 PM
Carnuck's Avatar
Carnuck Carnuck is offline
 
Join Date: Feb 12, 2011
Location: Gold Bar, WA
Posts: 6,318
That flexplate on the 401 looks like it's for a 360 unless there is an extra weight on it? Maybe someone did the 360 crank in a 401 block?
__________________
Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental.
Reply With Quote
  #11  
Old 04-22-2013, 05:47 AM
SC/397's Avatar
SC/397 SC/397 is offline
Administrator
 
Join Date: Feb 01, 2010
Location: Michigan
Posts: 752
You can't tell if the flex plate is a 360 or 401 with out seeing the weight that is welded on it. Bur you are right, I don't see a weight in his picture above.

Last edited by SC/397 : 04-22-2013 at 05:50 AM.
Reply With Quote
  #12  
Old 04-22-2013, 02:19 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
Is that info year dependant?

I'm being told by JEGS, that after 72 the flywheel/flexplates were externally balanced(meaning not included in engine rotating mass balance process).

So are either of those flexplates pre 72?
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #13  
Old 04-22-2013, 02:20 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
Quote:
Originally Posted by Carnuck
That flexplate on the 401 looks like it's for a 360 unless there is an extra weight on it? Maybe someone did the 360 crank in a 401 block?

Can I verify crank without dis-assembly?
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #14  
Old 04-22-2013, 07:23 PM
SC/397's Avatar
SC/397 SC/397 is offline
Administrator
 
Join Date: Feb 01, 2010
Location: Michigan
Posts: 752
NEVER ask Jegs or Summit for advise. You can look something up in a catalog as well as they can.

From the SAE report on the initial release of the American Motors Typhoon V-8 Engines: " Final balancing is accomplished on an engine assembly containing all rotating and reciprocating weights. This is accomplished on automated equipment, and final total engine unbalance is maintained at less than .5 oz,-in front and rear"

They did this by drilling to take weight out in both the flyhweel/flex plate and vibration damper as a rotating assembly. Granted, swapping common engine size flywheels and dampers will be close. However, most of the time is it is not close enough and the engine will vibrate.

Last edited by SC/397 : 04-22-2013 at 07:32 PM.
Reply With Quote
  #15  
Old 04-22-2013, 08:09 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
Quote:
Originally Posted by SC/397
NEVER ask Jegs or Summit for advise. You can look something up in a catalog as well as they can.

From the SAE report on the initial release of the American Motors Typhoon V-8 Engines: " Final balancing is accomplished on an engine assembly containing all rotating and reciprocating weights. This is accomplished on automated equipment, and final total engine unbalance is maintained at less than .5 oz,-in front and rear"

They did this by drilling to take weight out in both the flyhweel/flex plate and vibration damper as a rotating assembly. Granted, swapping common engine size flywheels and dampers will be close. However, most of the time is it is not close enough and the engine will vibrate.

And that was maintained throughout AMC V8 360/401 production?

I agree about the mass parts guys, hence the questions. My level of trust isn't that hi

Thanks for all the assistance and education.

Even though this motor has supposedly had a rebuild(20K) I think we will tear it appart to see what we have, crankshaft, rods, pistons, etc..
So adding the balancing isn't really a matter of time just more dinero

M
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #16  
Old 04-23-2013, 12:16 PM
austinaubinoe's Avatar
austinaubinoe austinaubinoe is offline
FSJ Maniac
 
Join Date: Aug 08, 2010
Location: Maryland/ Williamsport, PA
Posts: 2,995
Hays has 2 separate part numbers for a 360 and 401. But if they were balanced individually I dont see how that matters. This has always been an interesting topic for me and I like learning about it.

http://www.jegs.com/i/Hays/490/16-134/10002/-1

Why is this one 4 times the cost of the jegs?
__________________
Austin

1991 Hunter Green Grand Wagoneer
5.9 2bbl-727-NP229-TFI-30x9.5 Firestone M/T's-Brush Guard-tire mount
SOON: 4350 and cast iron intake

Others:
-1994 Baby Grand
-2000 XJ cherokee on Tons
-1953 REO M35A2 6x6
-1955 Willys Pickup



Quote:
Originally Posted by rustywagoneers_com
i am not an addict, i can stop anytime.
i dont have a problem, you people have the problem.
Reply With Quote
  #17  
Old 04-23-2013, 01:13 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
Quote:
Originally Posted by austinaubinoe
Hays has 2 separate part numbers for a 360 and 401. But if they were balanced individually I dont see how that matters. This has always been an interesting topic for me and I like learning about it.

http://www.jegs.com/i/Hays/490/16-134/10002/-1

Why is this one 4 times the cost of the jegs?

They are all over the place, some folks have one for both engines others have seperates. And then there are the billet aluminum and billet steel(lightened) versions.

Need to talk with an engine builder, perhaps the difference is how the balancing was performed.

Balancing
factory build = Crank/Pistons/Rods/Dampner/Flywheel-Flexplate
Subs. rebuild = just the Crank/Pistons/rods/Dampner(Depending on Builder)

Hungering for info.....

M
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T

Last edited by MMinMN : 04-23-2013 at 01:31 PM.
Reply With Quote
  #18  
Old 04-23-2013, 01:29 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
Tuff Dawg

Apparently their 401 engines;

The balanced rotating assembly (typically includes crankshaft, pistons, rings, connecting rods, rod bearings, and balancer)

Which would mean you would use an externally balanced flywheel.

And since my 401 is missing the weight on the flexplate that would have been present from a factory build, suggests it was balanced similarly

Thoughts?
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #19  
Old 04-23-2013, 01:33 PM
MMinMN's Avatar
MMinMN MMinMN is offline
Member
 
Join Date: Nov 30, 2009
Location: Lake Wobegon, Minnesota
Posts: 167
Quote:
Originally Posted by MMinMN
Apparently their 401 engines;

http://www.tuffdawgengines.com/amc_401_408hp_turn.htm
__________________
1979 Cherokee Chief W/T - M/T: Project
1987 Grand Wagoneer W/Excellent Interior: Project Donor
And the past:
1979 Bronze Cherokee Golden Eagle W/T - 360 A/T
1978 Charcoal Gray Cherokee Chief W/T - 401 A/T
1966 Navy Wagoneer w/Vigilante 327 M/T
Reply With Quote
  #20  
Old 04-23-2013, 02:13 PM
Carnuck's Avatar
Carnuck Carnuck is offline
 
Join Date: Feb 12, 2011
Location: Gold Bar, WA
Posts: 6,318
Quote:
Originally Posted by austinaubinoe
Hays has 2 separate part numbers for a 360 and 401. But if they were balanced individually I dont see how that matters. This has always been an interesting topic for me and I like learning about it.

http://www.jegs.com/i/Hays/490/16-134/10002/-1

Why is this one 4 times the cost of the jegs?

SEFI certification is expen$ive

Quote:
Originally Posted by MMinMN
Apparently their 401 engines;

The balanced rotating assembly (typically includes crankshaft, pistons, rings, connecting rods, rod bearings, and balancer)

Which would mean you would use an externally balanced flywheel.

And since my 401 is missing the weight on the flexplate that would have been present from a factory build, suggests it was balanced similarly

Thoughts?


The flexplate photo below for 401 is not early factory design. It's a 360 plate with weight added to match the 401 or from '75 or newer 401.

Quote:
Originally Posted by SC/397
You can't tell if the flex plate is a 360 or 401 with out seeing the weight that is welded on it. Bur you are right, I don't see a weight in his picture above.


It looks like there is a spot where the weight is welded on the other side. This is a 401 plate. Note the cutout is almost completely filled.

__________________
Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
304 manual flywheel on a 401 Knuck General FSJ Tech 5 11-12-2009 09:51 PM
401 flywheel ? 86cj7 General FSJ Discussion 4 03-10-2009 02:06 PM
360 flywheel to a 401?? MrThorn General FSJ Tech 9 08-17-2007 06:54 PM


All times are GMT -6. The time now is 09:31 AM.


Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
corner corner