SIII Torsion Bar Fitting SNAFU


(Steve Dinse) #1

Has anyone else run into this? I am refitting my uprated torsion bars since they have taken on a set that leaves the front end a bit too low. They were installed new when the car underwent restoration some years ago. I’m not sure how they did it, but I am trying to follow the manual. I have the shock bolt centers set to 19.25" per the manual and the adjustment ramps at their lowest. When I try to fit the torsion bar to the front, it comes into contact with the rear lower control arm support before I can get it to align with the front fitting. The bars are specified at 0.900 and came with a rather thick powder coat that had to be sanded down to allow the reaction brackets to rotate when pushed past the splines.

Are these bars just too thick to be installed according to the manual? Would they need a smaller dimension for the shock bolt center to center setting? Looking for clues here. :slight_frown:

Thanks


(Doug) #2

I would suggest that the uprated torsion bars would require a shock setting LESS than 19.25" to achieve the proper ride height as they are stiffer. Did you measure this prior to removal? This may give you room to fit this back in.


(Steve Dinse) #3

Thanks skiracer,
No I did not, since they were obviously set wrong. The front end has always been low and I finally ran out of adjustment with the adjustment cams as time went on. I think you are correct in that a stiffer torsion bar should have a smaller setting to achieve the stock ride height. Something else in the back of my mind comes from searching the archives and hearing about how the result of using the factory manual procedure usually results in a somewhat low ride height (stock torsion bars) and necessitates adjusting the cams to their max to get the proper height.

It seems to me that I will be forced to use a lower setting tool dimension if I’m ever going to get the torsion bars back in. I’m just wondering how much preload I should use to get the normal ride height.


(Steve Dinse) #4

Does anyone know what dimension setting tool should be used for uprated torsion bars? Surely, I can’t be the first to fit these.


(Steve Dinse) #5

Update!

Just for the record, I had to close up the setting tool dimension to 17.5 inches before I was able to insert the torsion bars on both sides. Once they were in and indexed, I set the preload to 1 spline using the JD43 tool as directed in the procedure. Trial and error here so I’ll know if this works out once I get it back down off the jackstands.


(Ole Würtz) #6

Hi Steve, as I posted to your question on the UK forum, the setting distance has to be shortened. And to your comment about the TB fouling the lower control arm mounting, yes mine did too. Once the TB is fitted and the car is on the ground, they don’t, but it’s very close. I wrapped my powder coated TB with black tape to cover the scratch. Low tech, but no one notices and I mostly forget.
FYI: I measured my TBs at one point for comparison. Original=19mm, uprated=23mm.
Cheers … Ole


(Steve Dinse) #7

Thank you Ole, for the detailed drawing and the time & effort it took to create it. Very informative, a real keeper! I’ve yet to get the car down to check the results, but perhaps in the next couple of days. Life is what happens when you’re busy making other plans, you know. :wink:

Steve


(Ole Würtz) #8

Steve,
Indeed. My works also seem to interfere severely with my daily life :joy:.
Once you get your car back on it’s wheels, it will have to be rolled a few tire rotations back and forth to let the suspension settle and you can measure the ride height. Alternatively place some magazines (shiny pages) one under each front wheel, to lower the car onto, it will allow the wheels to move sideways and the suspension to settle on the spot.


(Steve Dinse) #9

Update!

After getting the car off the jack stands and on to the street I have found that even with about 10 miles of driving with the adjustment cams at their lowest setting, the front height is about an inch too high.

I’m thinking that the jacking points I used at the time may have had something to do with the interference issue. I was supporting the front at the jacking points and I noticed that in the manual they specify placing the jack stand under the “lower wishbone fulcrum support bracket”. If there is any amount of body/frame flex, that difference may account for the torsion bar hitting the lower wishbone mount bolt at such a low shock setting dimension.

I also have come to the conclusion that all the different dimensions I’ve heard for the setting tool (18, 18.5, 19) were all set without using the JD43 tool to preload the torsion bars by 1 spline.

Mathematics says that 1 spline SHOULD account for a 2 inch difference in ride height. So if I took out the preload, I should be about 1 inch too low with the adjustment cams at their current low setting. If the adjustment cams can give me 1 inch up at the highest setting I should be OK without having to actually remove the torsion bars again. We’ll see! If not, then I am definitely changing how I support the front end when I have to do it all over again to get it right!


(Steve Dinse) #10

Final Update!

As I mentioned in a previous post, where the jackstands are placed DOES have an effect on the clearance issue that was the initial problem. Simply relieving the 1 spline preload on the torsion bars installed at 17.5 inches left the ride height too low. Looking at Ole’s drawing and doing some math I came to the conclusion that 18.5 inches on the setting tool(turnbuckles in my case) should put it all in a reasonable range.

With the jackstands directly under the rear lower wishbone at the crossbar mounting I was able to get set the shock bolt centers at just over 18.5 inches before there was interference, so 18.5 was the setting I used. With the cams at their highest setting and the car back on the ground, the ride height measured around 7 inches after running the car back and forth on the driveway a half a dozen times then back into the garage. Setting the cams back down to the lowest setting resulted in 5.75 inches. WAHOO! :smiley: A normal ride height was within range. After 3 tries at fine tuning the adjustment cams positions I was able to get the ride height spot on.

Moral of the story: follow the manual PRECISELY!

Thanks to all for the many suggestions!