Wheel shimmy
 

1970 BBC Nova. Need to eliminate wheel shimmy when touching down after small wheel stand. Currently have stock front suspension with Calvert 90/10, Santhuff springs and loose bushing bolts. Looking at Global West upper control arms instead of tricking up the factory control arms. They look like they have bump stops but not long threaded suspension limiters. You thoughts please.

Thanks for any help.

Re: Wheel shimmy
 

You didn't mention what class you run with your Nova or if it is a bracket car. Either way changing the upper A-arms won't fix the bump steer issue your having. Install a Bump Steer Kit and play with the adjustment until the lower A-arm and tie rod move in the same arch. I had the same problem on my Camaro and the kit solved the shimmy problem.

Re: Wheel shimmy
 

Toe out will cause wheel shimmy. My Camaro was doing the same thing. especially on the shut down if the brakes were applied to hard. I lowered my drag link to clear the pan which caused the bump steer issue and toe out condition. run your car up and down to see how much the toe changes. then make your adjustments.

Re: Wheel shimmy
 

This is a bracket car. I was told that changing the uppers really helped bump steer. Is the Baer kit good enough? It looks like the only one that Summit sells for my car.

Re: Wheel shimmy
 

here is what I am thinking and have i experienced the same thing ,, your car is launching wheels up and its not coming down hitting the both the front tires at the same time (right front hitting first then then the left ) causing that shimmy ,, the tires are not turning or stop turning when in the air ,just like an air plane landing ,, that's your shimmy ,it steers to the right then to the left but stays straight for the most part ,send a video or picture gmonde

Re: Wheel shimmy
 

To correct this you need to figure how high the chassis rises at launch and set your caster and camber to zero so that when the chassis settles back down it does not go from a toe in toe out condition which is causing the wheels to flutter back and forth--- more positive camber can correct that. the car will be a little harder to steer because of the camber but it will want to run straight without shimmying/fluttering but who cares its going straight--- pay attention when you back up BACK UP SLOW it might not back up straight it will want to go either left or right but if you go slowly you'll be OK--- get video and watch just the front end/ wheels motion and watch for the fluttering when the wheels touch you'll see what I mean

Re: Wheel shimmy
 

The reason changing the upper ball joints to the longer type helps bump steer is because it reduces camber change. Combine that with a bump steer kit and you'll solve the problem as much as you can without major modifications. When we put longer ball joints on the orange car, then added the Santhuff shocks, it calmed things down a ton. There is a video from the coverage of the GatorNationals a few years ago that shows the car before we made the changes, in slow motion. The car looks nothing like that now, even coming down from a wheelie bar bending moon shot.

Re: Wheel shimmy
 

Where do you buy longer ball joints ? Would they work on a 66-67 Chevy ll ?

Thank You Kenney Kelley

Re: Wheel shimmy
 

http://www.jegs.com/p/Specialty-Prod...33108/10002/-1

http://www.howeracing.com/c-560-howe...ll-joints.aspx

http://www.qa1.net/qa1_motorsports/c...ll-joints.html

Re: Wheel shimmy
 

Kenney, you need Eddie Rezac's stuff for the Chevy II, if you don't have it already. Not sure if there are long upper ball joints for the Chevy II like there are for F and A body cars, the early Chevy II is vastly different from everything else.

Re: Wheel shimmy
 

Long uppers would raise the front end height on a 1st gen. Chevy II, ...which you don't want.

Re: Wheel shimmy
 

Alan you are spot on when you say the early Nova front ends are different. The 68 and beyond are the same as a Camaro and that may give more options.

Re: Wheel shimmy
 

It seems to me that GM just copied Ford's better idea 60 Falcon

Re: Wheel shimmy
 

Thanks to everyone who took time to answer my questions . I didn't mean to take over the thread.
Thank You Kenney Kelley

Re: Wheel shimmy
 

If you have an early Chevy II, my kit will keep the toe exactly as you set it, all through its travel. Call me at, 402 443 8424 If I happen to not answer, please leave a message.
Eddie Rezac

Re: Wheel shimmy
 

Thanks for the replies. This still shot does show camber woes.
[IMG]http://i246.photobucket.com/albums/g...pse406fd43.jpg[/IMG]


Here's a short video that only shows the right side of the car. At about 25 seconds it goes slo mo and shows what's happening to the right side. I can't feel it when driving. I appreciate your thoughts.
[ame="http://www.youtube.com/watch?v=I3GIj3xdbnk"]Nova burnout and wheel stand at 75 and 80 dragway - YouTube[/ame]

Re: Wheel shimmy
 

We tried everything on my son Andrew's car and ended up having to put a steering damper on it. My car is just like his except he has wheelie bars and I don't. My car doesn't shimmy like his did. Both are 70-71 Camaros. The steering damper cured his car.

Re: Wheel shimmy
 

Have you guys checked that the steering box is set on center. When a box is off center the steering wheel will have an excess amount of play, and can cause a very severe shimmy. When it is dead on center, there is a high spot, in the box where it has "0" play. This applies to all vehicles, (street, race or otherwise) except those with rack and pinion steering.
A Chevy II of the 1968 and later can benefit from longer upper ball joints. The kit that I build is for the 1967, and older Chevy II. It is a completely bolt on kit, no bending, or modifying anything else, just follow my instruction sheet, and go racing.
Eddie Rezac 402 443 8424

Re: Wheel shimmy
 

The Global West control arms have standard BJ's. Is that because they're built in such a way that long ones aren't needed?

Re: Wheel shimmy
 

I don't think so. All you need are the Glodal West bushings and the 1-1/2" longer upper ball joints in stock A arms.

Re: Wheel shimmy
 

There are guys that say the Del-a-lum bushings are difficult to put in. Is that because the A-arms are a little off and that makes the holes in the bushings not concentric and that makes the shaft bind?

That's kinda the reason I was thinking about just replacing the whole arm. By the time I pay for shafts, bushings, ball joints and labor to press them in I'd be within 150 of their whole arm.

Re: Wheel shimmy
 

The GW A arms are not specifically built for drag racing, unlike the TRZ tubular A arms. The GW arms are just aftermarket tubular replacements and are heavier than the stock A arms too.

As has been said, you need longer ball joints at a minimum, maybe a steering box and wheel alignment at ride height too.

BTW, while the Del Alum bushings from a number of aftermarket suppliers are trick, the same result can be accomplished with aftermarket poly graphite bushings which is what my former car had, using emery cloth, a drill and 2 zerk fittings...

http://i381.photobucket.com/albums/o...scan0001-1.jpg