Club Cobra Gas - N Exhaust  

Go Back   Club Cobra > Cobra Talk Areas > Scratch Builders Forum

MMG Superformance
Nevada Classics
Keith Craft Racing
Main Menu
Module Jump:
Nevada Classics
Nevada Classics
MMG Superformance
MMG Superformance
Advertise at CC
Banner Ad Rates
Keith Craft Racing
MMG Superformance
Keith Craft Racing
December 2024
S M T W T F S
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31        

Kirkham Motorsports

Like Tree32Likes

Reply
 
LinkBack Thread Tools Rate Thread Display Modes
  #1 (permalink)  
Old 06-09-2018, 02:59 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default Which differential for a scratchbuild?

In order to put the rear cross-member where it goes in the frame, I evidently need to decide on a differential.

As far as I know, there are the following choices:

1. Reproduction Salisbury (But where do you find these?)
2. Jag XJ6 https://www.ebay.com/itm/JAGUAR-XJS-...8AAOSwOd1azoV4
3. 90s Ford T-Bird, Lincoln, Cobra https://www.ebay.com/itm/Lincoln-Mar...-/302752932206
4. BMW E36 https://www.ebay.com/itm/BMW-E36-3-7...-/232794518308

Anyone have experience with any of these and have suggestions/sources?

Right now I am leaning toward the XJ6 diff.

Thanks!
Reply With Quote
  #2 (permalink)  
Old 06-09-2018, 03:35 PM
joyridin''s Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2009
Posts: 1,695
Not Ranked     
Default

I would go with either the T-bird or a Mustang Cobra rear. You might also want to look at a C4 Corvette rear. They are reasonably bulletproof and all aluminum. You would probably have to have the axles narrowed, but there are places that will do it for a reasonable cost.
Reply With Quote
  #3 (permalink)  
Old 06-09-2018, 04:31 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

Quote:
Originally Posted by joyridin' View Post
I would go with either the T-bird or a Mustang Cobra rear. You might also want to look at a C4 Corvette rear. They are reasonably bulletproof and all aluminum. You would probably have to have the axles narrowed, but there are places that will do it for a reasonable cost.
Either of those options are available, but would complicate the mounting, of course.

I found this picture of how the original were mounted in this thread Salisbury and Jaguar differentials

Reply With Quote
  #4 (permalink)  
Old 06-09-2018, 04:41 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

BTW, the XJ6 and C4 Corvette internals are structurally identical. They are both Dana 44s. Only the C4 rear requires redesign and re-engineering to fit into the space of a 289 leaf spring rear suspension. It "appears" as if the C4's mounting points are exactly where the leaf needs to go.
Reply With Quote
  #5 (permalink)  
Old 06-09-2018, 04:46 PM
LMH's Avatar
LMH LMH is offline
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2005
Location: Tucson, AZ
Cobra Make, Engine:
Posts: 5,391
Not Ranked     
Default

Of those, the Jaguar is the closet to the original 4HU differential. There are companies selling brackets that allow the Jag unit to be used with original mounts like would be in an original chassis.
The ultimate would be an aluminum 4HU, available from a couple different manufacturers.
Kirkham makes and sells one, that's what I have. I think they're around $5000 or were a few years ago. It has the correct mounting bosses in the nose of the case. Gerry Hawkridge in England also has them. You can contact him at Hawkcars.co.uk.

Larry
__________________
Alba gu brąth
Reply With Quote
  #6 (permalink)  
Old 06-09-2018, 05:05 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

Quote:
Originally Posted by LMH View Post
Of those, the Jaguar is the closet to the original 4HU differential. There are companies selling brackets that allow the Jag unit to be used with original mounts like would be in an original chassis.
The ultimate would be an aluminum 4HU, available from a couple different manufacturers.
Kirkham makes and sells one, that's what I have. I think they're around $5000 or were a few years ago. It has the correct mounting bosses in the nose of the case. Gerry Hawkridge in England also has them. You can contact him at Hawkcars.co.uk.

Larry
Like this one?

https://www.ebay.com/i/112333973510?chn=ps

And since I am fabricating the frame myself, I could make it fit.

Drew
Reply With Quote
  #7 (permalink)  
Old 06-09-2018, 05:25 PM
LMH's Avatar
LMH LMH is offline
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2005
Location: Tucson, AZ
Cobra Make, Engine:
Posts: 5,391
Not Ranked     
Default

I think so, yes. There are a few different 4HU diffs used in the Jaguar though. The issue with them all though is no front bolt bosses in the nose for mounting like the Cobra 4HU has. You can see them in the photo you posted above. Will the mounts you weld in be strong enough is the question.
I always felt like a mount could be fabricated that wrapped around the nose of the Jaguar differential and be bolted to the frame but I don't know of anyone who's done that. It's basically round and I would think it could be done. Side mounts could be fabricated that bolt to the existing side plates, so that's not that big of a deal.
Larry
__________________
Alba gu brąth
Reply With Quote
  #8 (permalink)  
Old 06-09-2018, 05:32 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

So I am wondering. If you need the nose bolts, why cannot you use the mid-90s XJ rear diffs? They have four nose bolts and the two casing bolts. While I don't know if they are located exactly in the right place, since I am fabricating the mounts anyway, what makes them not a candidate?

Reply With Quote
  #9 (permalink)  
Old 06-09-2018, 05:39 PM
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2002
Location: Grand Rapids, MI
Cobra Make, Engine: FFR Challenge Car, RDI aluminum 427w
Posts: 355
Not Ranked     
Default

What about the 2015 Mustang IRS? Mounting system is straight forward.

Factory Five is using these. Good selection of gears, plenty strong (stronger than the old Super Coupe version), reasonably compact. It uses CVs for output and CV input but Factory Five adapts to a flange yoke & u-joint.

Cheap plug, I have an extra that is available.

Jim
Reply With Quote
  #10 (permalink)  
Old 06-09-2018, 05:55 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

I guess I am concerned about how the leaf spring suspension will fit with one of those.

Drew
Reply With Quote
  #11 (permalink)  
Old 06-09-2018, 05:59 PM
LMH's Avatar
LMH LMH is offline
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2005
Location: Tucson, AZ
Cobra Make, Engine:
Posts: 5,391
Not Ranked     
Default

I suppose that mid 90's Jag could be used but I don't know anything about them. I'm always looking to copy what was original, so beyond that, I can't advise very well.

I did use a 2003 aluminum Mustang Cobra 8.8" in my Hurricane. Nice differential and strong. Just change the rear cover to one that's a lot stronger if you go that route. The production cover is the weak point on that one.
Larry
120mm likes this.
__________________
Alba gu brąth
Reply With Quote
  #12 (permalink)  
Old 06-09-2018, 07:24 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

Quote:
Originally Posted by LMH View Post
I suppose that mid 90's Jag could be used but I don't know anything about them. I'm always looking to copy what was original, so beyond that, I can't advise very well.

I did use a 2003 aluminum Mustang Cobra 8.8" in my Hurricane. Nice differential and strong. Just change the rear cover to one that's a lot stronger if you go that route. The production cover is the weak point on that one.
Larry
I'm thinking based on affordability and my half-butt accuracy requirements, the XJ6 diff is the way to go. Now to find the bracket you speak of.

I talked to David Kirkham tonight, and their differentials are now $6k new, and $5k rebuilt, and come with diff only.

Drew
Reply With Quote
  #13 (permalink)  
Old 06-09-2018, 07:34 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

I founded a picture of a side by side adapted Jag unit next to a Kirkham unit.



It was in this thread.

Differential unit
Reply With Quote
  #14 (permalink)  
Old 06-09-2018, 09:08 PM
LMH's Avatar
LMH LMH is offline
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2005
Location: Tucson, AZ
Cobra Make, Engine:
Posts: 5,391
Not Ranked     
Default

Yeah, I remember that thread. Those are the brackets I was referring to. It allows the Jag 4HU to be bolted into an original or original style frame. Seems to be a nice set up.
Larry
120mm likes this.
__________________
Alba gu brąth
Reply With Quote
  #15 (permalink)  
Old 06-09-2018, 09:52 PM
CC Member
Visit my Photo Gallery

 
Join Date: Jan 2005
Location: Hillsboro, OR
Cobra Make, Engine: Scratch built CSX style frame, Carbon fiber body, 393 Stroker, T-bird IRS, T5
Posts: 1,623
Not Ranked     
Default

I installed an 8.8 Tbird IRS in and original style frame. It was a bit of work, but it fit and was affordable and I was able to adapt the Ford uprights with my scratch built control arms to make it all work. Let me know if you need any pictures and I'll see what I can do. Much cheaper than the Jag IRS pumpkin and a much, much less than the Kirkham offerings and original style uprights.
If you are building a 289 leaf spring chassis and original uprights, this can also be adapted to that unit easily.

Bob
120mm likes this.
Reply With Quote
  #16 (permalink)  
Old 06-09-2018, 10:19 PM
CC Member / Sponsor
Visit my Photo Gallery

 
Join Date: Jan 2002
Location: Provo, UT
Cobra Make, Engine: Daytona Coupe
Posts: 1,359
Not Ranked     
Default

The pictured Jag diff top adapter mount in post #13 will not work in an original specification 289 leaf spring chassis, it is too tall and will hit the frame. However, that adapter mount will work in an original specification 427 coil spring chassis.
120mm likes this.
__________________
Evolve Lubricants
https://evolvelube.com/
Cubic Performance
Reply With Quote
  #17 (permalink)  
Old 06-09-2018, 10:41 PM
eschaider's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2006
Location: Gilroy, CA
Cobra Make, Engine: SPF 2291, Whipple Blown & Injected 4V ModMotor
Posts: 2,725
Not Ranked     
Default

The Dana 44's are very nice units and have served well for several decades, increasing power levels not withstanding. There is a relatively good supply of aftermarket parts available for them and by and large I have not heard of people who had any significant design, fabrication or installation issues with them. If I were going to use one I would definitely use one of the Kirkham units, that are easily the very best and nicest Dana 44's available anywhere today.

The other very good choice as several have already said is the 8.8 inch Ford IRS center section as used in several of their passenger cars. I would recommend you look for an 8.8 IRS housing out of an Explorer rather than a passenger car. The Explorer 8.8 IRS housings are by far the most robust of all the aluminum 8.8 IRS housings Ford has ever produced. Be sure you get a 2007 through 2010 housing. Those are the ones with the massive front ears for locating the nose of the housing.

When ACE23 was struggling with the same decision alternatives you currently are I posted up some pics and suggestions for him on the site here. This is a link to the post => Ford 8.8 IRS Suggestions.

You might find something in there that could be helpful as you go about noodling out the best alternatives for your build.

BTW congrats on the decision to do a scratch build. It is the best way to get your Cobra exactly they way you always wanted and thought they should be — lots of work but also lots of satisfaction and immense pride in the finished product that is YOUR Cobra.


Ed
120mm likes this.
__________________


Help them do what they would have done if they had known what they could do.

Last edited by eschaider; 06-09-2018 at 10:46 PM.. Reason: Spelling & Grammar
Reply With Quote
  #18 (permalink)  
Old 06-09-2018, 10:44 PM
LMH's Avatar
LMH LMH is offline
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2005
Location: Tucson, AZ
Cobra Make, Engine:
Posts: 5,391
Not Ranked     
Default

Yeah, that's true! The brackets I was thinking about bolt onto the side, more like the original does. It doesn't use that top bracket.

Larry
__________________
Alba gu brąth
Reply With Quote
  #19 (permalink)  
Old 06-10-2018, 12:06 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

Quote:
Originally Posted by Three Peaks View Post
I installed an 8.8 Tbird IRS in and original style frame. It was a bit of work, but it fit and was affordable and I was able to adapt the Ford uprights with my scratch built control arms to make it all work. Let me know if you need any pictures and I'll see what I can do. Much cheaper than the Jag IRS pumpkin and a much, much less than the Kirkham offerings and original style uprights.
If you are building a 289 leaf spring chassis and original uprights, this can also be adapted to that unit easily.

Bob
That is good to know. My wife and I are adding up the costs of this build and would like a more affordable option.

I would very much like pictures of your setup. It will help with the decision, for sure.

Quote:
Originally Posted by Tom Kirkham View Post
The pictured Jag diff top adapter mount in post #13 will not work in an original specification 289 leaf spring chassis, it is too tall and will hit the frame. However, that adapter mount will work in an original specification 427 coil spring chassis.
Also very good to know.

Quote:
Originally Posted by eschaider View Post
The Dana 44's are very nice units and have served well for several decades, increasing power levels not withstanding. There is a relatively good supply of aftermarket parts available for them and by and large I have not heard of people who had any significant design, fabrication or installation issues with them. If I were going to use one I would definitely use one of the Kirkham units, that are easily the very best and nicest Dana 44's available anywhere today.

The other very good choice as several have already said is the 8.8 inch Ford IRS center section as used in several of their passenger cars. I would recommend you look for an 8.8 IRS housing out of an Explorer rather than a passenger car. The Explorer 8.8 IRS housings are by far the most robust of all the aluminum 8.8 IRS housings Ford has ever produced. Be sure you get a 2007 through 2010 housing. Those are the ones with the massive front ears for locating the nose of the housing.

When ACE23 was struggling with the same decision alternatives you currently are I posted up some pics and suggestions for him on the site here. This is a link to the post => Ford 8.8 IRS Suggestions.

You might find something in there that could be helpful as you go about noodling out the best alternatives for your build.

BTW congrats on the decision to do a scratch build. It is the best way to get your Cobra exactly they way you always wanted and thought they should be — lots of work but also lots of satisfaction and immense pride in the finished product that is YOUR Cobra.


Ed
I can literally buy a half dozen of those today, and even better, it appears as if they come in 3.73, which was similar to the original competition cars 3.77 final drive ratio.

Thanks for the congratulations. It's been a very long time coming, and I've finally refined my goals in the build.

1. I want to learn about the processes and gather the tools necessary to scratch build a car
2. I want to end up with a 289 Cobra that not only replicates the look, but also replicates the "feel" of an original competition car
3. I want a "piddle around" business in my retirement where I build a car that interests me, play hard with it and then sell it to finance my next project. And I'm not in the position to become Jay Leno and actually buy and keep all those exotic cars I've always wanted.

All of this has been very helpful. Thank you very much!

Drew

Last edited by 120mm; 06-10-2018 at 12:08 PM..
Reply With Quote
  #20 (permalink)  
Old 06-10-2018, 12:15 PM
120mm's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2015
Location: Clarksville, TN
Cobra Make, Engine: Scratchbuild, 289 FIA Replica
Posts: 198
Not Ranked     
Default

Aaaand..... Look what fell in my lap today!

https://www.ebay.com/itm/113051509277

Reply With Quote
Reply


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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 06:23 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: CC Policy
Links monetized by VigLink