Moparts

LCA / torsion bar install?

Posted By: cudaerik

LCA / torsion bar install? - 03/02/16 12:52 PM

I've been installing the QA1 Mopar (e body) tubular lower control arms this weekend and after I was done with the install on one side I feel that the lower control arm is pointing to far upwards.

Worked on the car again last night and I removed the UCA bump stop and pushed down the UCA / LCA assembly as far as I could get it before the UCA hit the frame rails / bumb stop bracket.
I was then able to rotate the torsion bar socket one notch before the torsion bar adjust leaver was hitting the crossbar / block for the adjustment bolt, reinstalled the torsion bar and added pressure to the torsion bar with the same amount revolutions on the adjustment bolt as before the first disassemble.

I guess the torsion bar adjustment bolt assembly has to be installed in the LCA but backed off all the way when I rotate the torsion bar socket to the right position?

Please see attached images. I still think I'm pretty close to the previous result, still the LCA have a very flat position with the thoughts to that the suspension is not under any load from the weight of the car.

I'm running 1970 Plymouth Cuda OEM drum brake spindles witch I assume should not cause any of the described issues?

My other concern is the torsion bars, I'm running Firm Feel Suspension 1.12 inch torsion bars. I have the bar marked LEFT on the left-hand side of the car but is there such thing as a front and back end on the torsion bar?

Please let me know if there is anything more to the torsion bar install than putting some grease on the ends and slide it through the crossmember hex socket, install dust boot and then into the LCA hex socket. And at last lock the bar in place with the rear locking clip.

Attached picture 001 (2).JPG
Attached picture 002.JPG
Attached picture 003.JPG
Posted By: 71rm23

Re: LCA / torsion bar install? - 03/02/16 01:19 PM

"I guess the torsion bar adjustment bolt assembly has to be installed in the LCA but backed off all the way when I rotate the torsion bar socket to the right position?"

Yes. Adjustment bolt needs to be backed off. I installed mine with a few threads showing.
Posted By: cudaerik

Re: LCA / torsion bar install? - 03/02/16 01:36 PM

The last picture of the adjustment bolt is after preload is added to the torsion bar.
Posted By: 71rm23

Re: LCA / torsion bar install? - 03/02/16 03:48 PM

The bars might need to be re-clocked then
Posted By: cudaerik

Re: LCA / torsion bar install? - 03/02/16 04:18 PM

the problem is that when I try to rotate the torsion bar hex socket more the leaver hit the square block of the torsion bar adjuster when the adjuster bolt is backer all the way out. The Upper control arm is pushed as far down as possible almost hitting frame rails and UPC arm bump stop.
any toughts are welcome:-))
Posted By: ruderunner

Re: LCA / torsion bar install? - 03/02/16 05:12 PM

Unbolt the spindle from the lower ball joint.
Posted By: AndyF

Re: LCA / torsion bar install? - 03/02/16 05:29 PM

You have a lot of aftermarket parts that you're trying to get to work together. In my experience once you start mixing and matching parts from various vendors you're on your own in getting it to work. The vendors do not all work from a common spec like they do in the high tech industry. These are old cars and there aren't any drawings or specs.

My guess is that the clocking is off on one of the parts but I don't know which. You'll just have to play with it and try different things. You might end up having to try different lower arms or different torsion bars before you'll find a combination that works.
Posted By: DAYCLONA

Re: LCA / torsion bar install? - 03/02/16 07:12 PM

Originally Posted By AndyF
You have a lot of aftermarket parts that you're trying to get to work together. In my experience once you start mixing and matching parts from various vendors you're on your own in getting it to work.




I'm glad you typed it Andy, so I didn't have too smile but my additional 2 cents for the OP is : What bars does QA1 suggest or recommend?
Posted By: AndyF

Re: LCA / torsion bar install? - 03/02/16 08:23 PM

A 1.12 bar is super stiff so there is a very small window for error in clocking. If the clocking isn't spot on then there isn't enough adjustment in the system to make up for it. When you use a small bar the bar gets twisted 40 or 50 degrees from bump to bump. A super stiff bar only twists a fraction of that amount.

If I'm building a pro touring type of car with a low ride height and stiff torsion bars I know that I'll most likely need to mock it all up and then order the torsion bars with the correct clocking. Firm Feel will clock the hexes anywhere you need them. If you just order the bars without talking about clocking then they take an educated guess on how heavy your car is and they assume that you're using stock lower control arms and they assume that your car has normal ride height.
Posted By: 6bblRoadrunner

Re: LCA / torsion bar install? - 03/03/16 03:47 AM

Have you tried removing the upper control arm bump stop? That might give you enough movement to slide the torsion bar in.
Posted By: screamindriver

Re: LCA / torsion bar install? - 03/03/16 04:13 AM

Originally Posted By cudaerik

Worked on the car again last night and I removed the UCA bump stop and pushed down the UCA / LCA assembly as far as I could get it before the UCA hit the frame rails / bumb stop bracket.
Posted By: cudaerik

Re: LCA / torsion bar install? - 03/03/16 09:18 AM

Thanks for the info guys. Talked to the guys at QA1 and Firm Feel and the parts should work together based on their specs. I have now done both sides and I will get the car of the jack stands and see how it sits with full load on the suspension.
Posted By: Evil Spirit

Re: LCA / torsion bar install? - 03/03/16 10:44 AM

Well, since nobody else mentioned it - has the trans crossmember had rust repair done to it? If so, the rear torsion bar anchors in it may not have been installed/clocked correctly. And remember, you shouldn't tighten the LCA anchor nuts until after you set the car down on the suspension to avoid pre-loading the LCA bushings.
Posted By: cudaerik

Re: LCA / torsion bar install? - 03/03/16 08:24 PM

Good points, car got no rust repairs in that area.
Posted By: TC@HP2

Re: LCA / torsion bar install? - 03/03/16 10:06 PM

Originally Posted By AndyF
A 1.12 bar is super stiff so there is a very small window for error in clocking. If the clocking isn't spot on then there isn't enough adjustment in the system to make up for it. When you use a small bar the bar gets twisted 40 or 50 degrees from bump to bump. A super stiff bar only twists a fraction of that amount.

If I'm building a pro touring type of car with a low ride height and stiff torsion bars I know that I'll most likely need to mock it all up and then order the torsion bars with the correct clocking. Firm Feel will clock the hexes anywhere you need them. If you just order the bars without talking about clocking then they take an educated guess on how heavy your car is and they assume that you're using stock lower control arms and they assume that your car has normal ride height.


Important info to note here.

As you step up t-bar size and start adding aftermarket components, the OEM methods aren't always in alignment. You may find you need to rotate the control arms UP before you get proper hex alignment to put it all together and create a reasonable ride height. Lower control arm clocking is the foundation of this and the area that it seems so many people get wrong.
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