Front frame rail help

Moderator: Moderators

Front frame rail help

Postby RockDaddy » Mon Sep 27, 2010 10:31 am

Well as most know I have been really working my car this year which includes a ton of large wheelies and a few were rear bumper hitters that came down hard.

I used to use my limiters and have a couple of people help push the front suspension down so I could get the limiters to click in and held it down at that level but now the car just sites naturally in that position.

Front tires look crooked with top of the tires pointed in and bottoms out. Car is so low in the front naturally now that on side is less than a finger width from hitting the fender. I see the front of the frame rail on one side must have had some plates welded in like it was being reinforced and the spot welds popped and you can tell seam is sight at the top and spread about a half inch at the bottom type thing.

One time at the races a Vega guy was talking to me about it and how weak some parts are and how all Vegas end up in this stance.

If anyone knows the weak points or where I should be looking and spending my $ on please shoot me some info. I don't know if I'm bending frame rails or suspension parts or what.

Any info for a starting point would be great!
Image;Image

Thx to Billy Briggs and the guys at http://www.motorcityspeedonline.com
RockDaddy
 
Posts: 322
Joined: Thu Feb 07, 2008 9:17 pm
Location: Michigan

1972 Chevrolet Vega


Re: Front frame rail help

Postby Kenova » Mon Sep 27, 2010 4:25 pm

You most likely have a bad case of the dreaded "frame spread".
The factory crossmember is bolted in and the holes are slotted. This would allow the frame rails to spread when you land one of those wheelies. It is also possible that your upper control arm mounts have been pushed inward, indicating a slight twist in your frame rails.
Here are a couple of threads that may be of some help:
viewtopic.php?f=10&t=874&start=0&st=0&sk=t&sd=a
viewtopic.php?f=10&t=24784&p=121922&hilit=frame+spread#p121922
Considering your Vega's penchant for altitude, you may very well be looking at a tube front clip in the near future.

Ken
My other car is a Nova.
User avatar
Kenova
 
Posts: 1641
Joined: Sun Jul 02, 2006 9:46 pm
Location: Ontario, Canada

Re: Front frame rail help

Postby RockDaddy » Mon Sep 27, 2010 7:11 pm

I haven't really looked at it yet but with my motor plate holding the frame rails together in the front I bet I'm bending it. One side fender wont let the door open so I have to move it a bit. I'll have to give it a good look over though. Season is almost over so I hope she makes it!
Image;Image

Thx to Billy Briggs and the guys at http://www.motorcityspeedonline.com
RockDaddy
 
Posts: 322
Joined: Thu Feb 07, 2008 9:17 pm
Location: Michigan

1972 Chevrolet Vega

Re: Front frame rail help

Postby megavega » Thu Sep 30, 2010 12:09 am

I would say your bending the rails in at the top. I would have the car put on a frame machine and pull the frame back from the bottom to the stock specs, then I would add reinforcing tubes to the cage and front end. Most 10-12pt cages have 2 bars that go to the frame ends(front) and your engine plate may be tied to these. What I have done in the past is to put tubes going down from these bars in between the top a arm mounting points. You can also if you have the room make a removeable side to side tubing brace that connects the 2 frame bars from left to right,across the top of the engine. I would also make a solid mount crossmember from 1 5/8 tubing and bolt the bottom together.
1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....

1973 vega wagon-under the blue flame knife.
User avatar
megavega
 
Posts: 1282
Joined: Mon Jun 25, 2007 12:32 am
Location: Ohio

1972 Chevrolet Vega Hatchback

Re: Front frame rail help

Postby megavega » Thu Sep 30, 2010 12:15 am

In this pic, you can see where I am talking about, (except this car still has the brace for the upper a arm plate), if yours is removed, then the tube will go down between the mounting bolts, its a flat surface to connect to. also the small rear diagnol brace by the curve is a good one to add (ties to your cage windshield down tubes)also to keep from twisting the rails.
You do not have the required permissions to view the files attached to this post.
1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....

1973 vega wagon-under the blue flame knife.
User avatar
megavega
 
Posts: 1282
Joined: Mon Jun 25, 2007 12:32 am
Location: Ohio

1972 Chevrolet Vega Hatchback

Re: Front frame rail help

Postby RockDaddy » Mon Oct 11, 2010 5:48 pm

Hey guys thx for the responses. I'll see if I can get some pics tonight of my setup and get some more insight from you guys.
Image;Image

Thx to Billy Briggs and the guys at http://www.motorcityspeedonline.com
RockDaddy
 
Posts: 322
Joined: Thu Feb 07, 2008 9:17 pm
Location: Michigan

1972 Chevrolet Vega

Re: Front frame rail help

Postby RockDaddy » Mon Oct 11, 2010 6:29 pm

Ok check it out. 2 Videos that tour my bent car. Let me know what you guys think.

All frame rail? Suspension parts? Both?

Video #1
http://www.youtube.com/watch?v=OjYSlNPbdrg

Video #2
http://www.youtube.com/watch?v=Cb5iBdH_E6k
Image;Image

Thx to Billy Briggs and the guys at http://www.motorcityspeedonline.com
RockDaddy
 
Posts: 322
Joined: Thu Feb 07, 2008 9:17 pm
Location: Michigan

1972 Chevrolet Vega

Re: Front frame rail help

Postby megavega » Fri Oct 15, 2010 1:54 pm

I found a couple pics in your build journal and in my opinion, who ever built the cage made the front strut support bars too high and too far out to help anything. With having the wheel well brace removed your simply tweaking the frame between the firewall and the front strut bars attachment point. It also looks like you still have the stock stamped sheetmetal crossmember in it(under engine),should replace that with a peice of 1 5/8 round tube solid rigid mounted,or welded in AFTER you have the frame pulled back on a frame machine. I would then weld all the seams on the stock front frame rails after the frame is pulled back, then add these reinforcing tubes.
The pic I posted earlier would be what you need to duplicate,and with the brace for the a arms removed, the bar from the strut tube will go down between the top a arm mounting bolts, its flat there. A good thing would be to weld a peiece of 1/8" thick plate to it(stock vega frame), then attach the tube to it then the strut bar. Add the diagnol at the curve to your windshield down tubes,I assume you already have a crossbar on the cage under the dash. mid mount plate with the same kind of mounts in the pic I posted will help as well for the curve of the frame rail.

Any and all race cars get thier strength from triangles, so you need to triangulate the front brace bars to gain any strength.
1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....

1973 vega wagon-under the blue flame knife.
User avatar
megavega
 
Posts: 1282
Joined: Mon Jun 25, 2007 12:32 am
Location: Ohio

1972 Chevrolet Vega Hatchback

Re: Front frame rail help

Postby megavega » Fri Oct 15, 2010 2:06 pm

here is the same pic and i used some color referances to help explain:

green: cut the strut tube and section it back towards rear of car.

Red: down brace tube you add after moving strut tube back

orange: motorplate bracket should touch strut tube bar, also weld tubular crossmemebr like shown(arrow)

light blue-should be what your cage looks like behind firewall

dark blue: is the vega rockerpanel, or 2x3 box tubing added to vega floor. the midmount plate will tie into this

yellow dashes:- are wehre you need to weld the stock vega frame, both inside and outside-AFTER you get it pulled back on frame machine.
You do not have the required permissions to view the files attached to this post.
1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....

1973 vega wagon-under the blue flame knife.
User avatar
megavega
 
Posts: 1282
Joined: Mon Jun 25, 2007 12:32 am
Location: Ohio

1972 Chevrolet Vega Hatchback

Re: Front frame rail help

Postby RockDaddy » Fri Oct 15, 2010 2:23 pm

Hey thx for all the info. The cage and so on was built before I owned it and it was running 11.0 so it doesn't surprise me it isn't handling what I'm putting it through now. I will totally address these issues this winter but I'm not a chassis guy and a Vega is not the most common setup at the race shops around here.

Thx again. I'll look all this over and post any Q's I might have.
Image;Image

Thx to Billy Briggs and the guys at http://www.motorcityspeedonline.com
RockDaddy
 
Posts: 322
Joined: Thu Feb 07, 2008 9:17 pm
Location: Michigan

1972 Chevrolet Vega

Re: Front frame rail help

Postby chevy art » Fri Oct 15, 2010 5:49 pm

hey rockdaddy any good chassis guy that builds nhra certified chassis guys will be able to fix your chassis for an 8-second ride. maybe get some references at the track from guys that have real fast cars and probably have a good chassis builder good luck art
chevy art
 
Posts: 1124
Joined: Fri Feb 26, 2010 11:33 pm

Re: Front frame rail help

Postby Sirshredalot » Wed Oct 20, 2010 12:54 pm

The vega style chassis is very similar to other style chassis...Any good fab/chassis shop should have not problem getting you stiff...lol.
If find it hard to believe that chassis shops find the vega a rarity...There are about 10-15 at our local track on an average friday/saturday night.

God bless
-Shred

PS: Looking at the that picture of your engine gives me a boner....not that you care though.
User avatar
Sirshredalot
 
Posts: 1384
Joined: Wed Aug 23, 2006 3:12 pm
Location: Muncie, Indiana

1980 Chevrolet Monza Spyder

Re: Front frame rail help

Postby RockDaddy » Wed Oct 20, 2010 2:21 pm

Engine will be fore sale complete very soon here. Save your pennies!
Image;Image

Thx to Billy Briggs and the guys at http://www.motorcityspeedonline.com
RockDaddy
 
Posts: 322
Joined: Thu Feb 07, 2008 9:17 pm
Location: Michigan

1972 Chevrolet Vega


Return to Racing Chassis

Who is online

Users browsing this forum: No registered users and 5 guests