Torsion bar adjustment question...

[StockMan]

In order to get acceptable front end height (68 charger-383) I need to screw the torsion bar adjustment bolt in approx 90% of the threads.  Would there be a problem operating the car like this, are they designed to work safely like this?  I doesn't appear that I can make any other adjustments to compensate for this.  I suppose this means my bars are a bit tired.

Any ideas, comments?

Thanks

[Mike DC]

 
It shouldn't take that much threading to get the stock height up.  The T-bars are clearly worn out. 



--  You asked, "Is it safe to run the T-bars this way?"

Well, you can probably picture the relative safety of keeping a set of totally worn-out rear leaf springs.  This is the same thing that you're doing in front.  It's gonna have little or no front body roll resistance depending on the sway bar situation.  And when street driving, it's probably gonna bottom out the front end onto the bumpstops more often than it should.


The torsion bar adjustment bolt is the equivalent of running a longer/shorter set of shackles on the rear leaf springs.   Purely a height adjustment, no change in the springs' leverage on the vehicle weight or anything.


--------------------------------------------------------------------------------
   

It's 2008, and these cars generally need all four springs replaced at least once since they were orignally built.  If you're gonna mismatch them and not get all four wheels at once, then leaving the front weaker is probably a little safer than the rear.  I'm not exactly advocating this idea or anything, but at least that promotes understeer instead of oversteer. 

   

[StockMan]

Thanks for your reply.  I'll should probably look around for a new set.

[Rolling_Thunder]

have you recently reinstalled your torsion bars ?   I had this problem with i installed mine on the incorrect side   

[Ghoste]

When you say "acceptable" ride height, do you mean by eye or by the fsm measurements?

[375instroke]

Torsions don't wear out by getting softer.  They maintain the same spring rate they had when new, which was originally very soft.  The threads are fine.  It's going the other way with fewer than all the threads engaged that is bad.  If you just want stiffer torsions, then get them, but don't get new ones the same size as what you already have and expect them to ge stiffer.  Leaf springs are a different story when talking about wearing out and getting softer.  The leafs rub against each other and they get thinner, thus reducing stiffness and spring rate.  I have a set that you can clearly see the wear pattern and reduced thickness on.

[Mike DC]

               
I beg to differ. 


I'm not a spring expert. 
But the bottom line is that as the bars really begin to wear out, it ends up taking more and more threading of the adjuster bolt to get the same height achieved.  I've seen this too often to doubt it.  And as for leaf springs, they do wear the leaves themselves, but I don't think they lose enough leaf-thickness to account for the sagging they undergo over time. 

Could it be that the installed functioning spring rate is the same, but the native  height of the springs is sagging over time?   I'd sooner buy this idea. 




Either way, most of the Mopar hobby agrees that the factory front torsion bars were all a little too soft by modern standards.  Not WAY too soft, but enough that it's worth it to buy a notch thicker. 

 
         

[375instroke]

What I'm saying is that even though the torsions may be sagging, the spring rate isn't decreasing.

[StockMan]

Thanks for all the correspondence.  I do have the bars installed on the correct sides as stamped on the units.  Front to back doesn't matter I'm told.  As far as the height I'm trying to achieve, it is eye-ball and not measured at this time.  I do have approx 1/2 inch or so of thread left at the height I like (so aduster is around 90% threaded in).  My concern is that I was told that it is not good to operate the vehicle with the adjusters threaded in that far, not sure I understand why.

[Mike DC]

 
I don't know if the adjusters are any real threat to breaking.  Never heard of it happening.  Just the springs themselves.


I once parked my Charger at school in the morning, and came out to find the RF torsion bar broken at 3:00 that afternoon.  It had literally snapped in half while the car was parked that day.  There had been no warning signs when driving the car beforehand. 




The factory "stock" height is higher than most people ever want to see these cars anymore.  If you put your front end up to the true stock height and took it to a Mopar cruise, you might even get asked why you "jacked it up" like that. 

 

[Chryco Psycho]

I would swap in a larger set of bars , they are not that expensive

[StockMan]

I was told the thicker bars, like the RT ones, make for a rough ride...

[craigandlynda]

thicker bars are stiffer, can handle more weight, and actually have less "travel" (twisting movement)...if going from a slant six to a big block, you need to upgrade the bars for street use...however, old racers trick, if dragging a big block car, put in six cylinder bars and 90/10 shocks.When you dump the clutch, the front end will really wump upwards, giving better weight transfer...

saw the post about the bar that snapped while car sat for a while....was standing next to a 68 cuda when one went. sounded like a rifle shot, loud, fast and sharp BANG. turned around and saw fender down almost on front tire.

[craigandlynda]

btw, do NOT try the 6 cylider bar trick on a street machine...not only will you risk snapping the bar on potholes and other hazards, but you will lose much in the way of control on cornering...that is a drag race trick ONLY. 

[StockMan]

I'm looking for the same ride this car would have had from the factory so I'll likely stick with the .92 383 bars.

[Chryco Psycho]

I would go up to at lest the .96 bars

[375instroke]

btw, do NOT try the 6 cylider bar trick on a street machine...not only will you risk snapping the bar on potholes and other hazards, but you will lose much in the way of control on cornering...that is a drag race trick ONLY. 

And don't run with scissors.  I've driven /6 bars and 90/10 shocks on the street in a 440 Dart, and it's no big deal.  The car was slammed on the ground, so that was more of a problem with dips and speed bumps than just the soft front end.  An oversteering car, one with torsions too big and a rear sway bar too big is much more dangerous.

[craigandlynda]

which brings us back to, trust the engineers, and don't stray too far from original for best overall street service....

[Mike DC]

             
BTW, I think even Mopar itself is saying that the stock muscle-era sway bars are softer than they would recommend now.  I think I remember something about them giving advice to start at the R/T level. 



Of course, that may be a concession to the fact that their stock R/T leaf springs were bone-jarringly stiff even for that era. 

I think I'd rather run some front torsion bars that are still near the stock R/T diameter, and then shrink the stock R/T rear leaf springs down a leaf or two.  And add a pretty small rear sway bar. 

                     

[StockMan]

I'm able to get the correct height from these original bars so I think I'll stick with them for now.  After 5 years of restoration on this car I still have never driven it.  So, these bars might just be acceptable for the meantime.  I do plan on a new set of poly-glass tires to get the real effect of the late sixties era, despite the comments I hear about them.  I'm told by some that they aren't so bad.

Thanks for all the feedback.

[375instroke]

Wonder why they can't or don't make radials with the bias look, that is the square sides on the tread.  Modern lo pro tires on 18s may handle well, but they aren't going on my cars.

[Mike DC]

I think the "rolled" shoulders on the radial treads is integral to their smoother breakaway at the limit of traction. 

[StockMan]

The radial tire would certainly be a better handling tire.  In the late 80s I had another 68 charger with bias ply and it was very drivable with those tires.  The thing I can recall is that it steered around a bit on grainy type ashfault surfaces.  If the car never sees radials I won't see the difference.

Where can a person get some Goodyear polyglass for a reasonable price?  There is Coker for 180.00 per tire, to my door, which is kind of steep.

[Mike DC]

         
Every street car I have is only gonna wear radials.  The difference is more obvious when you get into trouble than when you're just cruising easy. 

[1969chargerrtse]

I was told the thicker bars, like the RT ones, make for a rough ride...

My stock R/T bars ride just fine.  I don't find them hard.