73 911 Rear Torsion Bar Adjustment help

[klober23]

I have adjusted the stance on many 911's, but having a hard time with this one. Its a 73.5 911. The torsion bars were removed before the car came my way, so I have no true index mark from their orientation prior to removal. The bars cosmetically appear to be in good shape. My issue is the car seems to be fully lowered in the rear and I am unable to get the car to raise to the correct height.

A little info - everything is mostly new on the rear end, refurbished swing arms, new bushings, new Blistein, new rotors, new radius arm / torsion hole bushings in and out, etc. I assume the torsion bars are stock, but I have not measured.

The torsion bars are installed correctly, I have the R & L on the correct sides with the 40 splines inside, and the 44 splines on the outside. The torsion bars are correctly lubricated, and I can feel them slide in and grab on the splines. They feel to be fully and easily seated inside, once seated, I cannot spin them. The issue is, even with the radius arm for example at 30 degrees, the car will still "bottom out" in the rear. The tires do not rub, but are very much seated up into the rear fender. I have tried flipping the torsion bar 180 degree rotation and other subtle degrees of adjustments with the same result. I have played with multiple radius arm / torsion adjustments and still no luck. Any thoughts? Am I missing something? I know the torsion bars are pre stressed per R & L side, but will rotation of the torsion bar alone create more / less torsion depending on how the bar is oriented without the radius arm? When you index new bars, is there a specific orientation marked on the bar to achieve the greatest twist? Thanks in advance, just trying to fully understand as I have never had this issue.

Thanks

[Flieger]

Measure the bars. If 23mm stock then you should have a setting of 32 degrees or more measured from the door sills. My car is low and weighs 2000 pounds. With 23mm torsion bars I calculate I would need 32 degrees (I have 31mm bars though so run a lot less). You've got rubber bushings though which add spring rate.

[klober23]

Thanks for the reply. With the spring plate in the farthest down position where the bolts will still tighten up it still bottoms out. There is no more adjustment in degrees moving down

[Porboynz]

I have a 72 so assuming very similar, my method is to have the spring plates such that the bottom bolt hole with the removable sleeve is just obscured. (in line with the opposite side of the hole) I then use a jack to push on the spring plate so the bolt can be refitted with the sleeve. This gives me about the right ride height with minor alterations thereafter using the adjustable spring plates.

[Flieger]

Originally Posted by klober23

Thanks for the reply. With the spring plate in the farthest down position where the bolts will still tighten up it still bottoms out. There is no more adjustment in degrees moving down

With soft bars you will need to push up on the spring plate to get the last bolt in. You may also need to disconnect the damper until the spring plate has weight on it as well.

With my stiff bars neither problem was encountered because there is so much less droop.