Frame flexing maybe? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 01-31-2007, 06:21 PM
Registered User
 
Join Date: Jan 2007
Location: pocono mtns,PA
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Frame flexing maybe?

I started a 47 chevy pick up project 11 years ago and got it on the road then had kids,new house ,yada,yada,yada. Well I have a question. I am running a 406 sbc that dynoed at 436hp & 459 ft.# torque. built turbo 350 trans & ford 9" 390 gears. Runs like a bear & a fast one.
I have an RB'S bolt in mustang 2 kit and a tranny crossmember. Other then that it is a stock frame. ( not boxed )
When I jump on it it feels as if the frame may be flexing under the torque ( to the passengers side) causing the truck to go left. I am not sure if this is from frame flex or if the rear is causing it ?
any ideas?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 01-31-2007, 07:27 PM
Registered User
 
Join Date: Jan 2007
Location: Mar del Plata, Argentina
Posts: 35
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Flex...........

Ye gods a 47' Chev pickup with that much power......of course its' flexing especially if your getting some stick from the rearend off the line.
Have somebody else drive her for ya & observe for yourself.....You have probably seen it several times at the drags....one front tire is still in contact with the pavement, the other has ten inches under it!
Have it boxed & braced....can't hurt it & you'll probable feel the difference off the line first time.
______________________________________________Rick ............
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 01-31-2007, 08:43 PM
opinionated old fart
 

Last journal entry: Sheetmetal
Last photo:
Join Date: Jan 2007
Location: Round Rock, Tx
Posts: 65
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The frames on the AD trucks are weak and flexable, and over time the rivits in the cross members work loose, before we redid mine you could lift one corner of the frame 3 inches before the other side moved. Box and brace the frame, here is how we did mine.
Larry
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 01-31-2007, 10:15 PM
Member
 
Join Date: Oct 2002
Location: The Lone Star State (Houston area)
Posts: 1,189
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Is that a 1st Series 47 Pickup with the rollout windshield, waterfall grille and headlamps on top of the fenders
OR
2nd Series 47 Pickup with fixed windshield, venetian blind grille, and headlamps in the fenders?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 02-01-2007, 06:22 AM
Registered User
 
Join Date: Jan 2007
Location: pocono mtns,PA
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thank you for your answers. The picture is great, that was my next question.
It is a 2nd series title says 1947 but I think it is a 48 or 49. Same body style as through 54.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 02-01-2007, 09:26 AM
Member
 
Join Date: Oct 2002
Location: The Lone Star State (Houston area)
Posts: 1,189
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The 2nd 47 trucks have one-piece door glasses and pull-down outside door handles.
The 51-up trucks have vent windows in the doors and pushbutton outside handles.
The 54-1st 55 have a curved glass one-piece windshield and a different grille.
The earlier trucks have a cowl vent that opens on the side of the cab, the later ones have a louvered panel for air intake.

Last edited by pasadenahotrod; 02-01-2007 at 02:04 PM.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 02-01-2007, 12:36 PM
Registered User
 
Join Date: Jan 2007
Location: pocono mtns,PA
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
yea the 47 gas tank is under the cab 48 they moved it to inside behind the seat. The 47 & 48 us a molding to secure the windlace to the cab 49's have channel the windlace fits in.
My trucks title is 47, but the gas tank is behind seat & has the channel for the windlace. so its any bodies guess.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 02-01-2007, 12:38 PM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
It is easy to blame the frame as twisting, and worth checking, but more than one factor enters into this.

Most likely you have a common case of "roll steer".

As the chassis torques to the right the "bump steer" toe in change of the front suspension causes the vehicle to steer to one side. Yes even on an independent suspension. Did you measure your bump steer at zero? I bet you didn't measure it at all. You just put the suspension in..... not all are good. (caster also alters bumpsteer. The more caster the worse the bumpsteer.)

With a leaf spring rear, roll steer is also caused when the right side squats under torque that spring arc gets longer and the left one gets shorter.... by a significant amount. That steers the rear to the right making the vehicle steer to the left.

You could also have too soft of rear spring eye bushings that are allowing the rear end to shift to an angle.

Tracking down this situation takes considerable effort. Making it all the more important to have done it correctly in the first place.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 02-01-2007, 12:40 PM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by CptKaos

So you liked that movie, huh??
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 02-01-2007, 12:41 PM
Registered User
 
Join Date: Jan 2007
Location: pocono mtns,PA
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I think it would be easier to change the drive train instead of trying to box the frame now with every thing else done.
Can the stock 47,48,49 frame handle a stock 350 250/275 hp engine?? the frame is boxed from the front horns to after the engine mounts.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 02-01-2007, 12:49 PM
Registered User
 
Join Date: Jan 2007
Location: pocono mtns,PA
Posts: 6
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
hey xntrik.
Sure wish I would have talked to you before I did this project. I think I will check the bump steer first. The rear suspension is from a 69 ford galaxy 9". I will also have Posies look at that set up. Thanks for the advice.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 02-07-2007, 02:45 PM
xntrik's Avatar
Save a horse, Ride a Cowboy.
 
Last photo:
Join Date: Jul 2005
Location: Arkansas
Posts: 5,131
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by timwarren1@msn.com
hey xntrik.
Sure wish I would have talked to you before I did this project. I think I will check the bump steer first. The rear suspension is from a 69 ford galaxy 9". I will also have Posies look at that set up. Thanks for the advice.
You're welcome.

In #8 I said spring ARC, I meant spring RADIUS, since the leaf spring straightens out and gets longer the radius increases, and the other side shorter. 1/8 inch on each side is common.

If you need more help, you can PM me in case I miss a thread. (just like now a few days late)

Urethane bushings in the rear spring eyes and shackles will help tremendously and are NOT noticeably noisy or stiff.
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




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

Posting Rules
You may post new threads
You may 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


Similar Threads
Thread Thread Starter Forum Replies Last Post
59 Chevy pickup frame woes! Li'l Pine Suspension - Brakes - Steering 33 07-08-2009 08:24 PM
Frame question Rufus_2 Suspension - Brakes - Steering 2 01-30-2007 09:52 AM
Critique My Frame STATUTORY GRAPE Suspension - Brakes - Steering 23 12-21-2005 08:51 PM
Cantilever system for air bags 53LEDSLED Suspension - Brakes - Steering 17 12-05-2004 03:26 PM
Body & Frame question ruiner808 General Rodding Tech 7 09-14-2003 05:54 AM


All times are GMT -6. The time now is 09:33 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.