approximate effect of torsion bar adjustment

[scudzuki]

I removed some new looking Calvert 90/10 front drag shocks from my 72 Swinger.
That helped decrease the unloading of the front end when accelerating which made the car not so fun to drive.
I replaced all the shocks with Rock Auto's best non-adjustable shocks for the car, KYB Gas-a-Justs, and it's firm, but goes down the road with confidence.
I remember the seller telling me he adjusted the torsion bars. I guess he was trying to make it into a drag car.
Personally I want it to be a good road car, and the front end sits too high for my liking; I think the car would look better (and would definitely have a lower CoG and thus less body roll) with the front dropped an inch and a half or so.

Has anybody ever noted how much one turn of the torsion adjustment screw changes the height at the axle?
I suppose I could get under there with a tape measure, estimate the ratio between the distances from the LCA pivot bolt to the torsion adj screw and axle, then measure the pitch of the screw, and estimate it, but...

Figured I'd ask first.

Now a shameless plug for a product, really an endorsement since I have no stake in the...
Jack Rod that turns a flook jack into a jack stand.
Money well spent. I use the crap out of mine.

Jack Rod – AGMProducts

Thanks in advance.

 

[TT5.9mag]

I’m guessing its not known because damn it’s so easy to just get in there with a 3/4” wrench and spin em both a turn. If it’s not low enough do it again. If it’s too low, turn em back. Seriously though, the size of the bars has an effect so without knowing what t-bars are in there it’s a guess at best. Just measure ride height, turn em one turn out, drive it a little, then measure again. Compare.

 

[scudzuki]

I’m guessing not it’s known because damn it’s so easy to just get in there with a 3/4” wrench and spin em both a turn. If it’s not low enough do it again. If it’s too low, turn em back. Seriously though, the size of the bars has an effect so without knowing what t-bars are in there it’s a guess at best. Just measure ride height, turn em one turn out, drive it a little, then measure again. Compare.

Yep.
When I'm troubleshooting an issue with a client's computer or network I've never seen before, I do a Google search because someone somewhere has seen and resolved it before, and I don't have to spend hours and hours trying different fixes. Once I find the solution (sometimes I have to create one myself) I make a knowledge base article so when I see it again in 3 years I'm not scratching my head 'cause I forgot WHICH "fix" fixed it.
Work smarter, not harder, that's my M.O.

Jacking the front end up, adjusting, dropping the front end, rolling the car back and forth, measuring, lather, rinse, repeat is not working smarter IMHO, but that's just me.

Thanks for the advice, though.

 

[TT5.9mag]

Jacking the front end up, adjusting, dropping the front end, rolling the car back and forth, measuring, lather, rinse, repeat is not working smarter IMHO, but that's just me

Me either. That’s why I didn't say any of that.

 

[1WildRT]

1.5" lower, I would start with five turns & see what you get.... Different torsion bars react differently but if the car is currently equal side to side the same number of turns side to side should keep it that way...

 

[Dana67Dart]

Jacking the front end up, adjusting, dropping the front end, rolling the car back and forth, measuring, lather, rinse, repeat is not working smarter IMHO, but that's just me

I have an idea....

Do what you posted and record your results.

Then it can be made a sticky and it will be there for others in the future.

I'm not being snarky, most of us old-timers did what you posted till we liked the result, mostly because there was no Internet to ask. So it would be nice to have some idea that 2 full turns gets you about 1 inch (or whatever it comes out to be)

 

[67Dart273]

Just pick a number. Let's say you turn each one 5 turns. It doesn't matter until later. Measure on some floor/ pad so you know where you started. Move it around, jounce it and drive it back into position. Try not to do so with the wheels just been cramped, etc, so that the suspension is not bound up. Relook, re-measure. If not enough, go 5 more. If too much split the diff and go back a couple turns. Easy.

 

[Kern Dog]

Yep.
When I'm troubleshooting an issue with a client's computer or network I've never seen before, I do a Google search because someone somewhere has seen and resolved it before, and I don't have to spend hours and hours trying different fixes. Once I find the solution (sometimes I have to create one myself) I make a knowledge base article so when I see it again in 3 years I'm not scratching my head 'cause I forgot WHICH "fix" fixed it.
Work smarter, not harder, that's my M.O.

Jacking the front end up, adjusting, dropping the front end, rolling the car back and forth, measuring, lather, rinse, repeat is not working smarter IMHO, but that's just me.

Thanks for the advice, though.

OR do what others have done and figure it out for yourself.
I can understand the desire to save time but people that jump in and figure things out are the guys that develop skills that stick with them. They are the guys that are not stuck on the side of the road unable to fix their car because the cell phone signal is bad.
If I am working on a car that is absolutely foreign to me, I'll do the research. Most of the time, I'm working on old Mopars. Even then, I only ask for help when I've already tried to figure it out and had trouble. People of my generation were independent and self reliant because we grew up before the internet came along.
Some will tell you that when you lower the car, you'll need to get it aligned. I used to dismiss that because for years, I'd make ride height changes and the car drove fine. Years ago, I saw this chart. Dive means below stock and the "-" mark means above stock height. 0.00 means the static ride height.

The toe in gets smaller as you lower the car, the caster increases too. Camber doesn't change a whole lot at first but it does a little. It changes a LOT about an inch under stock height.
As you raise the car though, the caster goes away fast!

 

[abodyjoe]

Has anybody ever noted how much one turn of the torsion adjustment screw changes the height at the axle?

it really depends on what bars are in it.. 6cyl bars will take more turns to raise it then say the 1.08 bars in our dart.

 

[matthon]

Turning the adjusters raises/lowers each size bar, each car, each side, differently per turn.

I just upgraded to bigger bars, needed less turns to get it back to where it was, but each side was adjusted slightly different.
I imagine weight plays a part, condition of car, my stupidity, etc.

 

[Ricks70Duster340]

It is a good idea to lift the front of the car to get the weight off of the adjusters before you start twisting them. Adjust them as mentioned, then roll the car back and then forward (or just drive it) and recheck the height.

 

[AJ/FormS]

A) When the camber changes, so will the toe-in, and then it starts to drive funny in a straight-line. Driving funny is like wandering, climbing ruts, tugging this way and that.
B) As you lose caster, the car loses straightline stability, the steering wheel stops self-centering;, and the changing camber....... well you know, see item A ..
C) Sooner or later, you'll have to fix these things. and it's gunna cost money.
D) when you get the K down to 5.5 off the deck, you'll be bouncing off speed bumps so, fabricate a skidplate sooner than later. I highly recommend a minimum of 6inches with 1.03 bars, and above the steering headers, lol.
E) if you get really low, yur gunna find "bump-steer" a whole new headache. more money to fix. if it even can be fixed.
You want a Camaro, buy a Camaro, or open up your wallet, wide.

 

[413]

Lift wheels off ground & place jack stands. Now lube threads and end of bolts. Go out about 7 turns then drive it and check it out for proper height.

One turn won't change a thing.

You will need to do an alignment your camber will be off enough to wear the tires.

Clean off rear of bars and tell us the numbers so we can try to figure out what bars are in there. If 6 cylinder bars the car won't handle that great.

 

[Kern Dog]

Camber itself isn't a major factor in tire wear, "413". Toe is.
Radial tires can tolerate some negative or positive camber.

 

[413]

Camber itself isn't a major factor in tire wear, "413". Toe is.
Radial tires can tolerate some negative or positive camber.

Hate to think I sat through auto college, alignment classe sand ASE tests to have a construction guy tell me how it's done. LOL just kidding on the last part, you know plenty about these cars.


I'm just letting him know now before he ruins his front tires, now he knows. Nobody else said a word.

I loaned some tires to a guy for his car, then he lowered it, ruined them in a few days. Thanks buddy!

 

[RogerRamRod]

@scudzuki , you may need to define “want it to be a good road car”, by that I mean, comfortable weekend cruiser, long highway trips, kind of spirited in the corners, or ripping some canyons. Drag racers usually use the lightest torsion bars to get the front end to rise quickly. Those bars pretty much suck for anything else.
How much weight you have up front (big or small block, slant, lots of aluminum, etc) will make a difference.

An inch & 1/2 is going to require an alignment, then you might (probably) find that you want bigger bars, better shocks, then you’re back to the alignment shop (if you get in that far, good chance you’ll be doing some other items as well- unless previous owners already addressed)

 

[RustyRatRod]

The approximate effect of the torsion bar adjusters is, turn them clockwise and it raises the front of the car. Turn them counter clockwise and it lowers the front of the car. That's about all the approximating you can do. As to "how much" is anyone's guess.

 

[junkyardhero]

before you go twistin' them bolts to and fro, loosen the lower control arm pivot nut.

failure to do so will absolutely destroy factory/rubber lower control arm bushings.

once you have established your desired ride height, torque back to factory spec.

 

[Kern Dog]

Hate to think I sat through auto college, alignment classe sand ASE tests to have a construction guy tell me how it's done. LOL just kidding on the last part, you know plenty about these cars.


I'm just letting him know now before he ruins his front tires, now he knows. Nobody else said a word.

I loaned some tires to a guy for his car, then he lowered it, ruined them in a few days. Thanks buddy!

Maybe all that training was before radial tires came along. (Kidding)
My point is valid though. I've ran up to 1 degree of negative camber in my Charger for a long time. My 412,000 mile Dodge truck has had negative camber since new. They don't have accelerated wear on the inside edges because the toe settings are always IN.
Logic would have us think that negative camber would result in excessive wear on the inner edges but the way that radial tires flex, that is not the case anymore.

 

[MOPAROFFICIAL]

You're going to need to realign the car every time you mess with the right height Adjusters. If you lower it enough, you'll have a bunch of toe out, and vice versa.

 

[Kern Dog]

You're going to need to realign the car every time you mess with the right height Adjusters. If you lower it enough, you'll have a bunch of toe out, and vice versa.

Have you ever looked at this chart?

Lowering the car 2 1/4" and you lose a whopping .018" of toe !

 

[Kendog 170]

before you go twistin' them bolts to and fro, loosen the lower control arm pivot nut.

failure to do so will absolutely destroy factory/rubber lower control arm bushings.

once you have established your desired ride height, torque back to factory spec.

How many turns is your choice. I'd go 2 turns at a time if you're going to do a Sticky as Dana mentioned. I agree with junkyardhero about loosening the control arm just make sure you retighten with the weight of the car on them (loaded). I know it's said to make an adjustment and drive the car but sometimes I just bounce the car pushing on the bumper a few times and repeat until I think I'm close. Then I take it for ride to be sure I like where I'm at. Just a time saver thing for me.
Good luck.

 

[MOPAROFFICIAL]

Have you ever looked at this chart?

View attachment 1716433803

Lowering the car 2 1/4" and you lose a whopping .018" of toe !

View attachment 1716433804

I see the chart, but real life had my toe in to detriment. I was an alignment tech for 4 years. Very little adjustment, especially varying side to side, causes pull.
Have you ever raised/lower the car 2.225 and driven it getting go of the wheel..?

 

[scudzuki]

Me either. That’s why I didn't say any of that.

So I guess you'd just skip those steps?
Just because you don't know doesn't mean someone else doesn't.
If you had nothing to contribute why did you respond at all?

Obviously I can randomly twist the adjuster until I get it where I want it, but I don't go into any job with at least a few questions answered.

The engineers who designed the torsion bar suspension knew exactly the effect of one turn of the adjuster.

Anyone who has adjusted then readjusted theirs knows how much one turn of the adjuster changes the height at the axle.
They make an adjustment, let the car settle, measure the change in ride height, do a little math, then make another adjustment based on the results of the math.

Do you have some aversion to learning things?

 

[scudzuki]

before you go twistin' them bolts to and fro, loosen the lower control arm pivot nut.

failure to do so will absolutely destroy factory/rubber lower control arm bushings.

once you have established your desired ride height, torque back to factory spec.

Yep, I planned on it.