GermanLook Forums  

Go Back   GermanLook Forums > Technical Section > Suspension

Reply
 
Thread Tools Display Modes
  #1  
Old May 17th 2005, 11:48
SilverBullet SilverBullet is offline
Registered User
 
Join Date: Jul 2002
Posts: 428
Torque bar snapped!

It finally happened! One of the bar snapped at the area where bar meets the screw on head, the bar connecting the trans fork to the top of the shock mount. Now I've got to drive slower as I've got monoball spring plates and no torsion bar. I'll get the welder to make a similar bar but maybe out of iron!
__________________
T4 2666 1303s
Reply With Quote
  #2  
Old May 17th 2005, 13:37
Kafer_Mike Kafer_Mike is offline
Registered User
 
Join Date: Dec 2002
Location: Indianapolis
Posts: 270
Which bar/brace are you using? CSP? First I've heard of one snapping...
__________________
Kafer_Mike
Build 'em fast...or let 'em sit.
Reply With Quote
  #3  
Old May 17th 2005, 23:13
SilverBullet SilverBullet is offline
Registered User
 
Join Date: Jul 2002
Posts: 428
Yes the CSP's torque bar! My mechanic told me when installing that it wouldn't be that strong plus not using torsion bar, the bars especially the ones from the horn to top shock mount will be under alot of stress and also taking the bulk of the cars weight. I'll try to take some pictures of it and post it.
__________________
T4 2666 1303s
Reply With Quote
  #4  
Old May 18th 2005, 07:24
Wally's Avatar
Wally Wally is offline
Registered User
 
Join Date: Nov 2002
Location: The Netherlands
Posts: 2,528
Sad, but also very cool that your engine has such a power that it would break a torque bar!!

What engine did this?

Thanks for sharing
__________________
'75 Super.
...because race car!
Reply With Quote
  #5  
Old May 18th 2005, 14:06
SilverBullet SilverBullet is offline
Registered User
 
Join Date: Jul 2002
Posts: 428
Wally, I dont think its my engine which snapped the bar, but most likely my style of driving. I enter and exit coners at high speed till the tyres start screeming. I guess that plus very hard setting of the rear dampers could be also facts contributing to the failure!
Btw its a small engine 88x69 w110 44 heads stock carb, bas exhaust. .
But animal is being chained till next month. T4 103x80 schl.340 48x40, 48idfs,remmele's exhaust.
__________________
T4 2666 1303s
Reply With Quote
  #6  
Old May 18th 2005, 14:30
Wally's Avatar
Wally Wally is offline
Registered User
 
Join Date: Nov 2002
Location: The Netherlands
Posts: 2,528
Quote:
Originally Posted by SilverBullet
T4 103x80 schl.340 48x40, 48idfs,remmele's exhaust.
Now, you are talking

OTOH, its still very weird that the bar snapped. The load is supposedly along the axis of the bar. Breaking it that way is very very difficult. I would suspect a less than ideal installation.
Way more powerfull cars with way harder suspension have used these bars with drag race starts many times over without failure, so it is hard to believe its a design fault...
Welding the taps straigth towards the direction to which the bar attaches to is critical to avoid lateral stresses. The bar is not designed to take lateral forces.

Anyway, please, do show pics and specs of your future engine Sounds spectaculair!

Thanks,
Walter
__________________
'75 Super.
...because race car!
Reply With Quote
  #7  
Old May 18th 2005, 16:37
starmember's Avatar
starmember starmember is offline
Registered User
 
Join Date: Aug 2003
Location: De Wilp Groningen
Posts: 135
i heard it before that the csp tourque bar snapt under a little stress for a long time. thats wy i didnt buy one.
__________________
90 in to te corner.
Reply With Quote
  #8  
Old May 19th 2005, 02:38
Richie's Avatar
Richie Richie is offline
Registered User
 
Join Date: Dec 2002
Location: The Netherlands
Posts: 100
Hello,

This brace was developed and used by a lot of German KaeferCup racers, so high cornerspeeds shouldn't be the reason for breaking.
I think the bar has been preloaded when the wheels were off the ground.
Another possibility could be that there has been some misalignment in the mounting of the bar, but my guess is preload.

Cheers,
Richard
Reply With Quote
  #9  
Old May 19th 2005, 11:11
puma-Alex puma-Alex is offline
Registered User
 
Join Date: Sep 2004
Location: Norway
Posts: 6
Just have to ask a dumb questione as im mounting mine soon : You meen preload as when in a driving situatione , or by having the car on stands with no weight on the frame during mounting etc .
Regards

Puma-alex
Reply With Quote
  #10  
Old May 20th 2005, 02:39
Richie's Avatar
Richie Richie is offline
Registered User
 
Join Date: Dec 2002
Location: The Netherlands
Posts: 100
Hello,

I meant (too much) preload on the bar during installation. After putting the car on its wheels, the load on the bar is even more so this could be the reason for breaking. But, as said, it's my guess, I would mount it "loose" and turn the bars to a snug fit after putting the car on its wheels.

Cheers,
Richard
Reply With Quote
  #11  
Old May 20th 2005, 23:36
SilverBullet SilverBullet is offline
Registered User
 
Join Date: Jul 2002
Posts: 428
Any of the possibilities could have caused the failure, but its about more that a year and half before the failure since the installation. AS I'm out of town now, and according to my mechanic, he said that looking at the cross-section of the bar, 2 different shear marks, meaning that an earlier hairline crack/fracture might have been the start of the failure and was at the thread end. Anyway its been welded back and going into the car.
__________________
T4 2666 1303s
Reply With Quote
  #12  
Old May 24th 2005, 19:06
MattKab's Avatar
MattKab MattKab is offline
Registered User
 
Join Date: Jul 2002
Location: NW UK
Posts: 371
Sorry to hear the Beetle is sick.

Do you have a close up pic of the break? That will tell how and why it failed. There is a few scenarios that can be pin-pointed. Fracture mechanics was one of my hot subjects at University.

I've not seen a 'bolt-on Kafer-bar' set up yet that impresses me, even the new Bugpack piece looks medioka. The CSP looks alright, if it wasn't for the cantilever tabs, which result in improper triangulation. I don't believe this'll be the first failure of this type when using monoball. Are you concerned about the amount of strain you're seeing? It sounds like a tensile fatigue failure brought on by flexing of the rest of the car, not any of the 3 torque bar links. I would have the diagonals copied in steel.

Matt
__________________
'79 Karmann, Nrburgring or bust...
Reply With Quote
  #13  
Old May 25th 2005, 11:07
SilverBullet SilverBullet is offline
Registered User
 
Join Date: Jul 2002
Posts: 428
Ok here is the fault we found, we most certain of it, the welded tabs are not inline with each other thus causing a twisting force/stress on the bar, thus it snapped! Got the bar welded back anf will have to reweld the tabs.
__________________
T4 2666 1303s
Reply With Quote
  #14  
Old May 25th 2005, 12:27
Wally's Avatar
Wally Wally is offline
Registered User
 
Join Date: Nov 2002
Location: The Netherlands
Posts: 2,528
Quote:
Originally Posted by Wally
Welding the taps straigth towards the direction to which the bar attaches to is critical to avoid lateral stresses. The bar is not designed to take lateral forces.

Walter
I won't tell you 'I told you so', but...I told you so haha
__________________
'75 Super.
...because race car!
Reply With Quote
  #15  
Old May 26th 2005, 08:37
SilverBullet SilverBullet is offline
Registered User
 
Join Date: Jul 2002
Posts: 428
May the force be with me.
__________________
T4 2666 1303s
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:49.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
© www.GermanLook.net 2002-2017. All Rights Reserved