Replacing Torsion Bars

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Tony Fields

Tony Fields

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I know there is a right and left, but is there a front and rear to the bars?
Had a guy tell me they had a front end and rear end.

I'm replacing my /6 bars in the '67 Cuda with a set from a 340 Duster


Any info would be appreciated.
 
slant 6 bars are smaller in diameter and have a lower spring rate.
 
Sometimes there is no difference between left and right depending on the torsion bar. As far as front or back I always install them so the numbers are to the rear.

Chuck
 
DusterBoy15 said:
wanna sell your /6 ones?


whats the diff. between the /6 and 340 ones?
Click to expand...


Sure I'll sell them as I won't need them anymore.

$50.00 plus shipping......you could probably find these at
a local salvage yard for less money and no shipping charges,
after all I would be shipping to you from Columbus, Indiana


The /6 ones are around .840 in diameter (with my calipers)
and the 340 ones are around .890

I'm sure there is a std. size for these but I'm not sure
what the dimensions are.
 
340mopar said:
Sometimes there is no difference between left and right depending on the torsion bar. As far as front or back I always install them so the numbers are to the rear.

Chuck
Click to expand...


The 340 bars I have, have numbers on both ends. One end is a lot plainer to read....the other ends look like they may have been hammered on at
one time.
 
Tony, I'll bet the ends that have been beat on is the end facing the rear of the car. Well, that's assuming that the previous person put them in right!
 
all bars are left/right specific. they are so that the pass side is preloaded more than the drivers side. odd #'s on left, even #'s on right. they have about a 20* offset that mirrors the other side. put them on the wrong side and it will never sit right. end to end does not matter.
 
First off there is a right and left torsion bars as said being even number right,odd numbers left.And there is a front and rear to the torsion bar,and if you put it in the wrong way,it will sit with a funny stance and ride the wrong way and handle like crap,mrmopartech
[email protected]
 
Just a thought, if the bars are specific for each side with preloads built in then it would most deffinatly mater which end was the front. If there is a preload for one direction of twist, then if you flip the bar end for end the preload would be the wrong way. Unless the preload is just that the bar is alittle bigger in diameter, which i dont think is the case. So if they are side specific the they must be front to rear specific and if not then it should not mater which way that they go in.
 
Lets think of it this way,the right T/bar is made to twist in a downword motion to raise the car with the adjuster,and takes it own forum after awhile and has its own twist in the bar.That being said,if you switch the bars R-L,one side would have more preload than the other due to the twist that had forumed over the years and you would land up giving alot of adjustment on one side and very little on the other,never mind trying to install the bars.The T/bars do have a front and rear to them,the numbers on the end of the bars go in the anchor of the crossmember,and not the table end,this way you can read the numbers with a light and ID what you have through the anchor.Alot of handling problems are missed due to T/bars installed wrong and are very noticable in the driving,as the car goes great in one direction,the other is crap.If you want,I can supply you people as I have done in the past with a torsion bar chart so you can check what you have,mrmopartech
 
the bars were put in that way to see the part #. it CAN be installed either end front to rear since its 20* or so indexing will be the same looking from 1 end or the other. if installed with the part#'s in the lca anchor, it will not affect anything other than reading the part # with x ray vision.
 
Listen Red,If thats what you believe,so be it,I am not going to stand here and have a pissing war with you,you believe your story,I will go with whats written in my hard to find mopar books,topic is over,mrmopartech
 
i'd like to see what ehrenberg says. 2 of my books so far say that. "chrysler performance upgrades" by frank adkins page 42, and "performance handling for classic mopars" by tom condran page 27. but whatever. just going by what i learned.
 
Sorry people are getting pissed off!

I just wanted to get some help with a problem I'm having.

I'll figure it out the best way I can.
 
Tech Question
chris walker, ny, NY, 1966 plymouth belvedere 426

when installing torsion bars, how do you know which end is the front or rear? Which end is where the part number goes?

Thank you for your assistance, your magazine and help are great!
Chris

Chris, longitudinal torsion bars are handed but NOT directional.

Rick


the above was taken from the mopar action website from Richard Ehrenberg, SAE.

i am not here to step on toes nor to start a pissing war. but i have not found any info to suggest that i am wrong in what i am saying. i like to just simply put out info that i have found in numerous publications.

mrmopartech, scan in some of your data so we can see it, i am interested to see what you have.
 
Here's my figuring and reasoning FWIW.

1) Since the offset on the tbars is 20°, the left and right bars are not interchangeable.

Since the angle difference between the flats on a hexagon is 60° (360/6), a 20° offset would set the lower control arm angle incorrectly when installed. If the offset was 30°, then it would be correct regardless of the side installed on.

2) Installing the torsion bars front to rear, or rear to front would have no affect on the offset angle, therefore the lower control arm angle would be correct. However, the twisting motion would change from clockwise to counterclockwise on the bar (reverse on other side of car).

If there is an equal spring rate twisting in either direction then they should be able to be reversed front/rear. If they are designed to have a different spring rate in one direction from new, or if this occurs once the springs have been used, then they should be installed one way only,and reversing them would be incorrect.

Grant
 
you are correct. a bar is twisted at 30* or something like that in a clockwise motion for one side and a counterclockwise motion for the other side. having the weight of thecar on that bar continue that twist is what holds the weight of the car. going against that twist they cant hold the weight. bars are rated at about 10% of the front end weight, i.e. 180lbs for a 1800lb front end.

sorry, chuck i had no idea of those types of bars. i have never used them or installed them on customer cars since i don't build circle track cars. i guess i should say MOST bars are left/right specific.
 
Last night while in the "library", I was reading as always one of the million Mopar mags I have laying around. This from R.E. Mopar Action on a request by reader wanting to install MP 0.89" size tbars in a 68 Dart 270.

"T-bars do not have a front and back, only L and R."

Mopar Action - August 2002

LOL. According to this, it would seem there is no preload on the bars. I definitely think there is more to be investigated on this one.

Grant
 
When bars are new - I can see there wouldn't be an issue - but I have a used set and want to make sure I install them front/back as they were on the car they came from ("memory" in spring rate ?)- have no idea which end is front/back since they were painted. I do know that the factory blue mark is on the rear half of the right (passenger) bar when I've seen them.
 
The bar from Mopar that were larger than 1" typically did not have a left or right because they weren't clocked like the smaller bars.
 
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