Absolute Pace

Go Back   Club Cobra > Club Forums > Australian Cobra Club

Welcome to Club Cobra!  The World's largest non biased Shelby Cobra related site!

  •  » Representation from nearly all Cobra/Daytona/GT40 manufacturers
  •  » Help from all over the world for your questions
  •  » Build logs for you and all members
  •  » Blogs
  •  » Image Gallery
  •  » Many thousands of members and nearly 1 million posts! 

YES! I want to register an account for free right now!  p.s.: For registered members this ad will NOT show

MMG Superformance
Nevada Classics
Keith Craft Racing
Main Menu
Nevada Classics
Nevada Classics
Keith Craft Racing
Advertise at CC
Banner Ad Rates
MMG Superformance
MMG Superformance
Keith Craft Racing
March 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            
  #1 (permalink)  
Old 10-29-2011, 11:31 PM
byroncobra's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2008
Cobra Make, Engine: HARRISON, FORD 302, SOLD
Posts: 771
Not Ranked     
Default Harrison Bump Steer Fix

Fellas

My car's currently with a reputable engine builder north of Brissy having a bit done

He observed that my cars pretty lively up front and that early Harrisons', as mine is, had bump steering issues.

Apparently there's a fix that will help settle things down.

Can anyone advise thanks?
Reply With Quote
  #2 (permalink)  
Old 10-30-2011, 01:33 AM
AC-460's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2008
Cobra Make, Engine: BBF 545 Stroker Alloy Heads Roller Cam Aluminium Flywheel Twin plate Clutch TKO600 9inch Independent Rear 335x17 Rear 315x17 Front 1140kg
Posts: 292
Not Ranked     
Default

You may have to lift or lower the rack to fix the problem....
Reply With Quote
  #3 (permalink)  
Old 10-30-2011, 02:16 AM
Merv and Sharon's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jun 2007
Location: Sunshine Coast Qld, QLD
Cobra Make, Engine: Harrison # 80; Ford 5.0L HO Trickflow heads, cam and rockers and MassFlow EFI
Posts: 3,482
Send a message via Skype™ to Merv and Sharon
Not Ranked     
Default

I don't seem to have problem with that Greg. Is your steering rack higher?
__________________
Merv

Ford Cobra
Harrison #80.
Peregian Beach
Sunshine Coast Qld.
Reply With Quote
  #4 (permalink)  
Old 10-30-2011, 03:26 AM
CC Member
Visit my Photo Gallery

 
Join Date: Mar 2001
Location: E BRUNSWICK N.J. USA,
Posts: 3,841
Not Ranked     
Default There are kits sold to do this yourself

Byroncobra The dirt track guys have a setup tool for doing this to your car. About 2 years ago the Kit Car mag did a complete bumpsteer fix on a GT-40. This will also apply to a cobra or any Mustang with a rack and pinion setup. You change the outter tierod ends to longer stud and add spacers. It will take some work but when done the handling will improve alot when turning. Dean Lampe is in the article for this. Long acre sells the board kits for the measurements. Sears sells a digital angle reader for the control arms. Yopu will need a bottle jack and remove the shock and spring. You are going to measure the car flat and then up 2" and down 2" from center. You will add shims and retest. Looking to get close to "0" as possible. Goggle Bumpsteer and there should be some articles on how to do. Good luck Rick L.
Reply With Quote
  #5 (permalink)  
Old 10-30-2011, 02:53 PM
byroncobra's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2008
Cobra Make, Engine: HARRISON, FORD 302, SOLD
Posts: 771
Not Ranked     
Default

Thanks Fellas

Merv, my car has double A arms unlike the later cars with a Commodore front end. Apparently the geometry was known cause twitchy steering and one of the Qld Club members whom I thought may frequent this forum has a fix.

I think the rack needs adjusting and perhaps tierods as Rick and AC mentions.

I've always thought my car was lively in the front end, but as with most of us I guess, I've only driven my car and assumed that they're all like that. Now that I'm registered I must get up to Warwicks and get him to give it a shakedown and comment on how it feels.
Reply With Quote
  #6 (permalink)  
Old 10-30-2011, 03:47 PM
Merv and Sharon's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jun 2007
Location: Sunshine Coast Qld, QLD
Cobra Make, Engine: Harrison # 80; Ford 5.0L HO Trickflow heads, cam and rockers and MassFlow EFI
Posts: 3,482
Send a message via Skype™ to Merv and Sharon
Not Ranked     
Default

I think I know who is working on your car - should be a good job then! I don't seem to have had any bump steer probs so far. Still sorting out the rear however. Will be off to Fulcrum Suspensions in a week or so to get the corner weights done and associated adjustments.
__________________
Merv

Ford Cobra
Harrison #80.
Peregian Beach
Sunshine Coast Qld.
Reply With Quote
  #7 (permalink)  
Old 10-30-2011, 04:07 PM
sambo's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jan 2007
Location: Melbourne, VIC
Cobra Make, Engine: Harrison, 6.0L Chev
Posts: 2,513
Not Ranked     
Default

Merv your car isn't an early one and will have the Commodore lower arms, hence no bump steer. At least this is true for mine, which is an earlier build than yours.
Reply With Quote
  #8 (permalink)  
Old 10-30-2011, 06:12 PM
Merv and Sharon's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jun 2007
Location: Sunshine Coast Qld, QLD
Cobra Make, Engine: Harrison # 80; Ford 5.0L HO Trickflow heads, cam and rockers and MassFlow EFI
Posts: 3,482
Send a message via Skype™ to Merv and Sharon
Not Ranked     
Default

Yes Paul - number 80.
__________________
Merv

Ford Cobra
Harrison #80.
Peregian Beach
Sunshine Coast Qld.
Reply With Quote
  #9 (permalink)  
Old 10-31-2011, 07:24 AM
Krait's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Mar 2008
Location: Gold Coast, QLD
Cobra Make, Engine: Harrison #69, HSV LS2, T56, Custom rear suspension
Posts: 604
Not Ranked     
Default

Greg,

Pete Dore had bumpsteer issues as well. You might want to catch up with him at the next breakfast unless he chimes in.

Cheers
__________________
Geoff
Cobra Car Club of Qld - UAE Chapter
Reply With Quote
  #10 (permalink)  
Old 10-31-2011, 12:54 PM
Roush #1's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Mar 2007
Location: Waco, TX
Cobra Make, Engine: Lone Star Classics / Roush 427 SR
Posts: 280
Not Ranked     
Default

A quick explanation of bump steer problems is that the toe-in changes as the suspension moves up and down....simple enough to check!
J
__________________
Roush #1
Lone Star Classics
Roush Edition #01
Roush 427 SR #444
Reply With Quote
  #11 (permalink)  
Old 11-01-2011, 02:31 AM
AC-460's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2008
Cobra Make, Engine: BBF 545 Stroker Alloy Heads Roller Cam Aluminium Flywheel Twin plate Clutch TKO600 9inch Independent Rear 335x17 Rear 315x17 Front 1140kg
Posts: 292
Not Ranked     
Default

To check your Bump steer in your own shed just do the following;
1. Jack up the front and remove front wheel and coilover
2. Get and old Rim... on the outer bottom of the rim weld a piece of 25 x 25 rhs about 2metres long
3. put the rim on the car the rhs should be sticking a metre and a half out the front of the car
4. with the rim hanging approx. 75mm down on ride height mark the ground at the end of the rhs
5. lift the rim up all the way and watch if the rhs moves in or out at the end
for zero bump steer the Rim should travel up and down and the end of the rhs shouldnt move in or out
If the RhS moves out when the rim moves toward the top of its stroke the rack needs to be lifted

This is only a primitive method for those of us that dont have access to do it on a wheel alignment machine but it tells you exactly whats happening
Reply With Quote
  #12 (permalink)  
Old 11-01-2011, 02:15 PM
byroncobra's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2008
Cobra Make, Engine: HARRISON, FORD 302, SOLD
Posts: 771
Not Ranked     
Default

Thanks for you explanation AC et al.

The steel rod is a simpler form of a the following test using laser:

Cobra Bump Steer 2.wmv - YouTube

I've spoken to Scott at Venom who has had lots of experience with Harrisons having fabricated the original A arms. He's going to take a look at the setup for me.
Reply With Quote
  #13 (permalink)  
Old 11-01-2011, 10:51 PM
Merv and Sharon's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jun 2007
Location: Sunshine Coast Qld, QLD
Cobra Make, Engine: Harrison # 80; Ford 5.0L HO Trickflow heads, cam and rockers and MassFlow EFI
Posts: 3,482
Send a message via Skype™ to Merv and Sharon
Not Ranked     
Default

You are on the right track with Scott. I was going to suggest him. I seem to recall that Aussie Mike had a post a couple of years ago on a bump steer measuring device.
__________________
Merv

Ford Cobra
Harrison #80.
Peregian Beach
Sunshine Coast Qld.
Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 11:52 PM.


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