Midget Suspension Upgrades

[Timd]

I tried asking these questions in another thread, but received few replies. I have a 1970 MG Midget, and I intend to rebuild the front suspension this spring. I want to add a sway bar, get polyurethane bushings, new bearings and uprated springs. The reason for this, is that my car seems to have VERY loose suspension. Now, I've never driven another Midget, or even pushed down on one's fender, but I do believe mine is somewhat worn. I have decided to go with the 340lb/in springs, but what I want to know is:

-Does the VB swaybar kit include EVERYTHING you need to install a swaybar to a car not originally equipped with one? If not, is there one? What parts would I need to buy in addition? What parts are included?
-Since the 3/4in bar and 5/8in bar are the same price, which should I go for?

All I want is for the car to keep flat in the curves. ANY information you can give me on this would be a great help.

Thanks - Tim.

 

[spritenut]

Start with rebuilt shocks from Peter at World Wide auto Parts.
New A arm and trunion bushings and a sway bar.
I run a 3/4" bar, but I drive like I'm trying to outrun a nuclear blast /ubbthreads/images/graemlins/wink.gif The stock 9/16 bar is fine for daily driving, 5/8 or 3/4 will improve the curves but a 7/8 is overkill for the street.

 

[jollyroger]

I like the competition springs, 3/4 bar and stock bushes all around. 5/8 bar is good too. Shocks with competition valves and proper shock oil.

 

[adam70]

[ QUOTE ]
... but I drive like I'm trying to outrun a nuclear blast ...

[/ QUOTE ]

/ubbthreads/images/graemlins/lol.gif /ubbthreads/images/graemlins/lol.gif /ubbthreads/images/graemlins/lol.gif /ubbthreads/images/graemlins/lol.gif /ubbthreads/images/graemlins/lol.gif

nothing wrong with that.

 

[ChrisS]

I don't know if the VB kit is complete or not, but you can order them directly from Addco throught www.swaybars.com They supply it with links, mounts, and bushings. Your car should be set up to take it, but to check look for a tapped pad under each front frame extension, and the front edge of your control arm should have some mounting holes in it, 3/8" or so. I can get you a pic of mine if you need it.

 

[jollyroger]

I think the VB bars are Addco units and yes they do have all the stuff ya need. They will ask if your car has a bar or not. If your car has a stock bar on it now then buy the bar for the once they sell for cars with bars. It is different than the other one. My guess is your car has a bar on it now

 

[Timd]

My car currently does not have a bar, nor are the frame rails tapped. I figured it was common for people to have to do this themselves. My A-arms do have holes however. So if I order the performance 3/4 bar from VB (#5-984), you're certain everything is included to add it to a car not originally fitted with a bar? I find what is in the catalog is very hard to understand, and there is no mention of what is included in the kit. I usually order my parts online, but do you think if I call VB, that they would be able to tell me everything about it? I spoke to a women once on the phone there, and I don't think she knew a master cylinder from a brake pad.

 

[Matthew E. Herd]

Like the man said, Addco (the manufacturer) would probably be a better avenue for the swaybar. They'll be more familiar. Also, I run 400 lb/in springs, a 3/4" swaybar, and delrin (very hard) bushings in a slightly heavier 1500, and the ride is decidedly rough. I am actually thinking of changing back to the stock springs as I won't be autocrossing it this year. The added ride height is definitely a bonus.

If I were driving on the street only, I'd probably opt for a 5/8" bar, stock or 340 lb/in springs, and polyurethane bushings. That'd be a reasonable compromise to maintain comfort. Rebuilding the front suspension (new kingpin bushings, etc) will also help to make the ride a bit more confident. As an aside, it may be a good idea to put offset bushings in to increase camber. Since treadwear isn't really a concern on one of these cars, the extra negative camber (for only a few more dollars with the bushing kit) will make a nice difference.

 

[jcatnite]

Hey Tim, I don't think it is just the frame extension that is drilled and tapped. I think there is a couple of pads welded onto those rails. Looks like 1/4" plate, welded on, then drilled and tapped IIRC. Also, the sway bar will definitely help, but you won't know how much till you get the other parts working right. It would be easy to do the rebuild of the front suspension and shocks, and then add the sway bar after you feel it out a bit.
JC

 

[Matthew E. Herd]

I had a 3/8" or so plate added to the frame for extra support, but originally there was none. It can't hurt to have it added, though.

 

[jollyroger]

As I recall you can order a bar for a car that did not come with a bar. It will come with a square shaped sorta U-bolt and a piece of 1/4" plate with pre-drilled holes. You will need to drill matching holes(using the plate as a template) in the frame. Then you snake the square sorta U-bolt through the holes in the frame, in one hole and back out the other hole so you have something to bolt the sway bar to. Slide the plate over the protruding threads and shank then the sway bar and mounting hardware. Works great and all ya need is a drill and a 3/8" bit.
Too much sway bar can be bad. In hard driving the sheet metal frame will tear apart. I now lean toward the competition springs and smaller sway bar, say max 3/4"( the factory Sebring Sprites came with 5/8" bars). The bugeye that I race has the stock bar and competition springs. It is the best handling car I have ever driven...period. I can't take credit for the set-up. A friend who is no longer with us, who raced sprites since 1960 set the car up. I have yet to improve on the performance of this car. I leave it alone and experiment on other cars. I have found that I can equal the performance but not the feel.

 

[Dave Russell]

[ QUOTE ]
I had a 3/8" or so plate added to the frame for extra support, but originally there was none. It can't hurt to have it added, though.

[/ QUOTE ]
As a matter of interest, the stiffness, resistance to twisting, of a sway bar, anti roll bar, varies with the fourth power of the bar's diameter. ie. doubling the diameter of a bar would result in having a bar that is 2x2x2x2 or 16 times as stiff as the original bar.

Compared to a 1/2" bar, a 5/8" bar would be 2.4 times as stiff. A 3/4" bar, 5 times, a 7/8" bar 9 times, & a 1" bar 16 times as stiff as the 1/2" bar.

This additional stiffness puts proportionally greater stress on the bar attaching points & links & on many cars that are not structurally designed for the increased stress, the attaching points can tear out. Most factory mounts can likely withstand a 3X increase in stiffness without damage. Beyond this, reinforced mounts are definitely advisable.
D

 

[jlaird]

Wow, I for one found that intresting. Thanks

 

[vping]

What is the consensus on urethane bushings. Are they worth it or are stock bushings fine.

 

[jcatnite]

Man, I love it when Dave jumps in and puts science to our supposition. Seems that I learn something from everything you write Dave. As far as the urethane bushings, I like them for the sway bar but found that for normal driving, the rubber bushings gave a better balance of ride and performance than the urethane...just a personal opinion though. Urethane bushings in the suspension will definitely stiffen up the ride, used to put them in the large American cars I hopped up as part of the default setup. But the "tanks" I used to mess with couldn't dream of handling the way my midget did the day I bought it, worn out bushings and all.
JC

 

[Timd]

[ QUOTE ]
Hey Tim, I don't think it is just the frame extension that is drilled and tapped. I think there is a couple of pads welded onto those rails. Looks like 1/4" plate, welded on, then drilled and tapped IIRC. Also, the sway bar will definitely help, but you won't know how much till you get the other parts working right. It would be easy to do the rebuild of the front suspension and shocks, and then add the sway bar after you feel it out a bit.
JC

[/ QUOTE ]

My rails do have the small plates of metal in them, they're not tapped though. I suppose I will call VB and ask if their kit includes everything. The only reason I would prefer get it from VB rather than anywhere else, is only for simplicity and saving on shipping, since all my other parts will be coming from there.

 

[jollyroger]

I will use a mix urethane and rubber on the end links to dial in a car at the track. I do then to lean toward softer settings. If I need a really stiffen the set-up I will go up in spring rating first. Then I will go to the sway bar to tinker with the settings.

 

[Timd]

Ok, I called VB today, and as far as I could tell, everything is included in the kit except endlinks, which I'll get from VB aswell. So now is the question, what size? I'm not an older gentleman who enjoys a smooth quite ride... More of a younger (19) gentlemen who enjoys a 'spirited' ride. I'm stuck between the 5/8 and 3/4 bar, both are same price. I WOULD prefer the stiffer ride, however I'd like to hear your opinions on the subject.

Note: I'm going with the 340lb/inch springs and polyurethane bushings.

 

[jollyroger]

Try the 5/8th bar and if it is still not stiff enough cut a half of an active coil off the springs with a cut off wheel. then try it. This will lower it a bit and stiffen the front.

 

[jcatnite]

Jolly,
I've always wondered about cutting coil springs. When you cut 1/2 a coil off, you end up removing the portion that has been flattened to sit in the spring pan. Do you have to grind the new "bottom" part of the spring flat again? Things you always wanted to know but were afraid to ask.
JC