Technical Violent steering wobble at low speed

Ok, I took my 1963 Gasser Nova out today for the first time since winter and when I turned onto another street after stopping at a stop sign, I was pointed straight and really gave it the gas, broke the rear tires loose, hit the rev limiter (not hard to do since I lowered it to 5500 rpm) - it developed an incredibly violent steering wobble. I hit the brakes and brought the car to stop to get it to quit shaking violently and then after that it was fine. The only things I have done to the front end was lube all the fittings on the steering assembly and set the tire pressure at 34 psi a couple of psi higher than it was but it had bled down over winter time. Additional note: there is no steering stabilizer on the steering assembly. It has a Speedway gasser front end clip & a Vega steering box from Speedway it has what I consider to be a bit more play in the steering box than I like so I'm going to takeout the slack in the steering box (I also did tighten up the steering box a bit right after I got the Nova - so it appears the violent shaking loosened it up a bit again).
Is it a toe out mis-alignment issue ?
Loose rod end?
Wheel bearing gone bad?
When I aired up the front tires did I change caster enough to cause this?
Did the rear tires breaking loose in combination with the rev limiter going off combine to setup a harmonic vibration that started the wobble?

Anyone have any idea how to solve this problem so it never happens again?

 

one thing i would do without a doubt is put a dampner on it. took care of a problem i had, drove alot better.

 

Hit the search function and type in "death wobble". It will tell you all you wanted to know and more.

 

Had a friends gasser do the same thing. Checked the toe in and reset it. Wobble went away. Don't throw parts at it to mask a problem.

 

Add a few more psi to the tires first ( like 5 more each ) and check toe in as suggested. Gary

 

Bias ply tires? Could have been flat spotted from sitting.

 

post pics of your ride, and front/rear suspension

 

The spindles, are they Chevy type or Ford type? The king pin inclination on Chevys is more prone to these problems.

 

You mentioned "Speedway Vega Steering box", with slack. That's where the wobble can get started, a steering damper will sometimes serve as a cure. My 2 cents.

 

http://www.jalopyjournal.com/forum/forums/new-to-the-h-a-m-b-introduce-yourself-here.18/
Please also READ the inclosed link..You wanted our help.now give us yours

 

I would also remeasure your caster. Not enough will create a "shopping cart" affect.

Sent from my XT1585 using The H.A.M.B. mobile app

 

Op,
ALL OF THE ABOVE!!!!
Any unnecessary movement in a straight Axel can & will cause death wobble,
I worked on one ,made up a removable panbar to experiment with cure problem so I made it Permit ,Take notes test as you go.

 

All of the Vega boxes I've gotten from Speedway needed to be adjusted properly to remove the play. Do that first. Check the toe-in and check the caster angle. If there's toe out - that's an issue. If the caster is greater than 6-8 degrees, that can be a problem also. Grease everything.
Once you've adjusted that stuff and inspected for loose king pins, wheel bearings, or tie rod ends and all is good - THEN add a steering damper if you want to. Make sure you don't mask a mechanical problem that could get worse.
If it only happened once and all the front end parts are pretty new, it should be ok after the above check. Sometimes when they wobble often, it hurts parts like tie rod ends, king pins, etc.
Like 37hotrod said, search death wobble - lots of info on here. And do take the time to introduce yourself and post pics of your car.

 

If your shackles are not those weird long ones from the '70s and your bushings are good, look at caster and toe-in. I don't think a loose steering box is the problem. And I don't think a dampener helps much.

If the front tires are out of balance, alarming things can happen too.

 

On my 29 roadster I let my helper read the tape measure for 1/8 toe in and must of had about 25 lb in the tire, ran the car in the quarter 100 mph (its a flathead) all was OK next year prepping for the season I aired the front tires to 45 lb for less rolling resitance and to the strip I went. Car was OK under acelleration however had a VIOLENT wobble when you backed out of it. Home we went and I checked the toe in and it was 5/8 inch instead of 1/8 inch. I got by with this toe in until I aired the tires up. Reset the toe in to 1/8 in and all was OK. Also 5-7 deg of caster

 

63 gasser , did you ever get problem fixed, i am having same problem with speedway kit.?

 

This thread is over a year old, and the OP never got back to tell us what fixed it, or to thank the people who helped him fix it. So Sad.

 

Hey 1963,
A speed wobble like this one I filmed in 1964 at an All Gas Coupe and Sedan drag race day at Lions Dragstrip? It was K.S. Pittman in his lightweight, red, Willys Coupe ready to go against Big John Mazmanian. Something happened that sounds like a similar occurrence. BJM won this race by default.

Jnaki
Best guess, on-the-car tire balance and alignment.. Then you can blame something else if that does not work.

 

This wobble has been around as long as straight axles. It almost always occurs with straight axles and not A-frame suspensions. . Frist and foremost, check everything for wear and correct and balance the tires. Aline it to specs. If you still have the problem adjust the caster a few degrees either way till the wobble stops. This is a problem with a lot of ot four wheel drive diesel trucks on the highway today. Have solved their problems many times after they spent big money at other places and still had the problem. Don’t know why some trucks/ straight axle cars are prone to wobble and some are not, but we don’t live in a perfect world. Some times you just have to make adjustments. Putting a stabilizer on a wobble prone front end is not the solution. Bones

 

i got 7.5 degrees rake , i tried 3.5 same shake when i hit certain bumps in the road.

 

Try nine

 

Is the vega box setup for cross steer? If so it requires a panhard rod on the front axle .

 

Yep. A pet peeve. That sounds like a good starter for a thread. Opps, we got that already

Chris

 

Well apparently he figured it out and didn't think all the people that tried to help him were worth thanking, or he's dead.

"So it goes." ( Kurt Vonnegut)

 

I will let everyone know if i get this wobble thing fixed its bugging the %^&$ out of me. I ordered a vw steering damper to see if it helps , the sector shaft in the steering box was a little loose i tighten it up some . Here is my set up.
3100 lbs car
speedway 4inch drop axle kit.
chevy spindles and disc brakes
speedway leaf springs came with kit.
shackles set around 42 degrees.
15 x 5 chrome reverse rims 2 inch back space.
pro shocks 401 10 1/2 ride height
hoosier 23 inch drag tires 15x 5 32 p.s.i.
flaming river vega steering box.
2 inch drop pitman arm.
kingpin inclination set at 7.5 degrees.
are parts are new.

I can include what ever pictures are needed for your help.

 

Tow in? How much...

 

Like I said in an earlier post, putting a damper, on a system, is like putting a bandaid on a cut. You can’t see the cut, but it’s still there. Fix your problem, make your front end steer with out shimmy/ wobble. Then put a stableizer/ damper on for insurance. There are millions of straight axles going down the highway everyday with no damper and have no problems. If your font end shimmies/wobbles, change something till it stops. Specs are guide lines, sometimes you may have to adjust.

Bones

 

Im gonna throw this out there, as some food for thought. Some years back, I had a Sportster with a 35mm front end on it. One day it developed a wobble at 65 or so. Went home and started looking for wear anyplace I could find it. The only thing I could find wrong with it, was one side was down on fork oil, and not much at that. Filled it back up, and the wobble was gone. It happened again the following spring, low fork oil once again being the culprit. Changing fork oil became a monthly deal afterward, and I learned how important proper dampening really was.

 

It's an issue inherent with front beam axles.
From "Chassis Engineering" by Herb Adams

 

There you have it.

That diagram mentions coil springs, the wobble will happen on leaf springs too. That’s why I never understood the straight axle change over in “Gassers”. A wobble from a straight axle at 65 is bad enough, couldn’t imagine what it would be like at 130mph.