Front ride height/Torsion bars and tool

Talk about the E-Type Series 3
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vee12eman
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#1 Front ride height/Torsion bars and tool

Post by vee12eman » Sun Sep 04, 2016 9:50 pm

Hi,

Measured the front ride height of the car at the weekend, and found it a little low, this is despite the fact the snail cam adjusters were virtually at their upper limit (just to be clear, this is a Series 3 car with the adjustment capability from new).

I understand the way in which you can load up the torsion bars and have followed the setting guide in the manual, at least as far as I can. The manual refers to a torsion bar tool JD 43 and I understand how this is used to tension the torsion bars by using a turnbuckle, but of course I don't have one of these tools or access to one. I did manage to put some tension into the bars some years ago on initial set up, but this was pretty difficult without the tool and it appears that maybe I didn't get enough pre-tension into them.

Anyone got any bright ideas how I can tension the bars more and increase the ride height that way (without the special tool)? I need at least one spline past the "resting" position and would prefer a little more if possible. Alternatively (and probably preferably) anyone know of a source of the JD 43 tool - remember I can't just hire it from Jaguar Enthusiasts Club as I live in Australia... I could I guess make one from two torsion bar fittings, but they don't seem to be available from the usuals, anyone got a pair of Torsion Bar Brackets Pt number C36107 they are willing to sell?

Regards,

Simon
Simon S-Y
Series III FHC

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MLBS3V12
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#2 Re: Front ride height/Torsion bars and tool

Post by MLBS3V12 » Sat Sep 10, 2016 8:18 am

Hi Simon

I understand that you have to move somewhere 1 spline. 2 parts on the torsion barre are used as reaction brackets. At the front there are 24 splines and at the rear 25. I would move one of the bracket to gain 1 spline and then be able to fine tune the height of the car with the cam adjuster on the lower wishbone. Of course this way means to dismantle almost all the suspension. It means a few time for sure!
:hammerdrill:
Le chemin sera long!...

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Whitact
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#3 Re: Front ride height/Torsion bars and tool

Post by Whitact » Sun Sep 11, 2016 8:29 am

Simon,
Rich Mozzetta has posted an ingenious solution to this on Jag Lovers. It involves loose fitting one end of the rear reaction plate then using a jack to raise the other end to add tension and complete the process.
I can send details of the JD43 tool if you decide to go the route of making one up.
Cheers
Adrian Turner
S3 OTS & FHC
S1 FHC
XK140 FHC

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MarekH
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#4 Re: Front ride height/Torsion bars and tool

Post by MarekH » Sun Sep 11, 2016 10:51 am

That's exactly right and may involve putting quite a lot of tension into the bar than you might have thought.

1/ Raise the front of the car via the picture frame.
2/ Pop the top ball joint and undo top shock mount.
3/ Place a jack under the lower wishbone and then remove the wheel.
4/ Wind the tension out of the bar by taking the jack down.

This may not be fun as it'll want to twist a long way and snap out on you if it can. Don't put your hands in the way.

5/ Consider loosening or fitting longer bolts onto the lower wishbone to frame joints. This is because to you may need to offset the torsion bar laterally to be able to get the amount of tension you need into it and having something which has no degrees of freedom to move may not allow you the leeway to get enough of the lower wishbone aligned with more tension in the bar than before at an angle that lets you do any jacking safely. In other words, you don't have to have the lower wishbone tightly assembled into the engine frames to achieve a result here but do remember safety first.

6/ Mark the two end of the bar and then wind in one click at one end and wind out one click at the other end such that you'll be under more tension.

When the bar is loose without tension, it is easy to do and undo the bolts at the back holding it into the body. With any tension don't even try, it'll totally strip the threads and snap out on you. This is what the JD tool does for you - when it works.

Reset your cam adjusters whilst it is easy to do.

7/ Jack it back up and wind the lower wishbone to frame bolts back in bit by bit (having undone as little of that as was necessary to disassemble).

8/ Return the top balljoint.

9/ You want the castellated nuts to be done up when the car is properly loaded and suspension settled.

If you have the right ride height, then the wishbones will be horizontal.

An alternative variation might be to use the car's own weight as the safety feature. Undo the relevant bits first and then keep jacking the car up to reduce the tension in the bar. Eventually, the wishbone will want to swing to ~90' if it has the space to. Having various length metal bars in place of the front shock is an obvious way to safely have staging points for relieving the tension.

kind regards
Marek

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vee12eman
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#5 Re: Front ride height/Torsion bars and tool

Post by vee12eman » Sun Sep 11, 2016 10:54 am

Many thanks for all the answers.

I have actually discovered that no tricks or special tools are required. Firstly wind off all tension at the cams. Set up the torsion bar with the spacer (home made, fits in place of the damper and two holes 19.25" apart) and by trial and error insert the bar until (turning one spline at a time), the bolts freely enter aligning the torsion bar bracket to the holes in the reaction plate. Next release the tension using a jack and remove the spacer from the damper mounts. Lower the jack, you will need the anti roll bar, upper ball joint and steering arm ball joint disconnected for full range. Now, with tension removed you can slide the torsion bar bracket and carefully rotate one spline in the direction to apply more tension when secured and also ensure the small location bolt at the forward end of the bar is inserted. Now, with the lower wishbone hanging it is possible to carefully lever a little extra tension into the bar bracket and push the bolts home. Reassemble, then adjust the ride height using the cams. A tip here is to wind the cams up fully for height before lowering the car as it is much easier to wind tension off the cams, lowering the car, than it is to wind tension on, with the full weight of the engine resisting the action.

Hopefully this will help someone else, just to add a proviso however, there is a lot of tension involved, go very carefully and keep clear when applying or releasing tension. Don't try this without a good jack and remember, my advice is merely the way I achieved the result I wanted, not a definitive method for you to follow. Proceed at your own discretion and with caution.

Regards,
Simon S-Y
Series III FHC

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jivili
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#6 Re: Front ride height/Torsion bars and tool

Post by jivili » Fri Sep 23, 2016 11:49 pm

Just followed the instructions above as my ride height was a little low.
I would add that you need to jack up the front to min 350mm above picture rail height and then you can get the extra set on the torsion bars without too much difficulty.
By setting as per manual I would never have achieved the correct ride height..
Thank you Simon & Marek

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colin gray
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#7 Re: Front ride height/Torsion bars and tool

Post by colin gray » Sat Oct 15, 2016 4:39 pm

vee12eman wrote:Hi,

Measured the front ride height of the car at the weekend, and found it a little low, this is despite the fact the snail cam adjusters were virtually at their upper limit (just to be clear, this is a Series 3 car with the adjustment capability from new).

I understand the way in which you can load up the torsion bars and have followed the setting guide in the manual, at least as far as I can. The manual refers to a torsion bar tool JD 43 and I understand how this is used to tension the torsion bars by using a turnbuckle, but of course I don't have one of these tools or access to one. I did manage to put some tension into the bars some years ago on initial set up, but this was pretty difficult without the tool and it appears that maybe I didn't get enough pre-tension into them.

Anyone got any bright ideas how I can tension the bars more and increase the ride height that way (without the special tool)? I need at least one spline past the "resting" position and would prefer a little more if possible. Alternatively (and probably preferably) anyone know of a source of the JD 43 tool - remember I can't just hire it from Jaguar Enthusiasts Club as I live in Australia... I could I guess make one from two torsion bar fittings, but they don't seem to be available from the usuals, anyone got a pair of Torsion Bar Brackets Pt number C36107 they are willing to sell?

Regards,

Simon
For anyone just reading this topic due to torsion bar issues, I have only just done mine on my 1973 series 3 2+2. My car is a later series 3 and they are adjusted slightly different to the earlier models in the production run. What I can say is follow the Jaguar series 3 manual to the letter and you should not go far wrong. On my car I made a bar to the exact length as stated in the manual and then fitted it as described, after this I rotated my torsion bars in the splines (front one at a time and rear the same) until the holes in the reaction bracket and clamp lined up perfectly. I then marked the spline and bracket and using the Jaguar tool added tension to the torsion bar 1 spline on the rears until the holes lined up completely again. Note this is all done with the front snail adjuster set at its lowest point.
When I let my car down it was an inch and 3/4 too low, this suited me as I want my car to be roughly level as the rear is slightly low due to age. I then adjusted the snail adjusters to about 1/3 the way round with extra tension which brought my car to 5 1/4 inches which is about 1 inch lower than spec but my car now looks right and while driving the front is not going light and losing what little feel a series 3 has at higher speeds. This had been a problem at 6 1/4 inches front ride height. I would say that if I adjusted my snail adjuster to max I would have been about or just over the proper ride height however I feel it is a falsehood to seek the proper standard ride height on an old car as it can become unsafe if the rear has sagged like mine. You may be better off (in my opinion only) to seek a sensible stance for your car that will improve stability and safety.
I finally ended up measuring the rear of my sills compared to the front along the flat edge and concluded that the 1/4 inch lower stance at the front edge was appropriate as that is how we try to run our club entry level competition cars, for us this is the best turn in and stability compromise. Additionally we do run some negative camber front and rear and almost an inch drop front to rear depending on the event. These are also not Jaguars but it should still cross over to a degree. I am only putting my experience out there to try and help, so please use your own common sense and judgement as well and seek some appropriate advice there are lots of sensible experts in the club to ask.
It depends on the chassis number as you will need the tool after a certain number for sure. I have some series three clamps and I am thinking of making a tool but I live in the UK so that is no good to you I am afraid. Before I got my spare brackets I was going to take my originals to a machine shop to copy the spline pattern and make a tool that way.
Good Luck

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BOBLOEB
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#8 Re: Front ride height/Torsion bars and tool

Post by BOBLOEB » Wed Jul 15, 2020 6:32 am

My 1973 Series 3 Roadster is running with only 3.5" clearance on the front
box frame. I am out of adjustment on the cams. Does anyone know how
many inches lift I get for each spline shift in the rear of the trosion bars?
I am hoping to only have to shift them once.

Thanks,

Bob

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