V12 Torsion Bars

[PoB]

I'm Starting to get my 1974 V12 2+2 ready for the summer. I'll have to take the engine out as the rear exhaust manifold is cracked. While I'm at it I'll probably do the clutch as well.

The car is currently 2-3 inches lower at the front than it should be. The manual says that height can be adjusted using the cams. But I can't see me getting that much adjustment from the cams alone. Also, As the ride height must be set with the engine in place and thecar on level ground, how will the cams lift all that weight?

Any advice welcome.

Cheers

Pat

[TriQpilot]

Hi
It is sometime since you posted your message regarding your V12 ride height and I see that no one responded.
I have exactly the same problem on my '72 V12 and would like to know how you resolved the issue.

The front end of my car, which has only covered 31k mls and which I have owned since '74, has been completely dismantled, parts refurbished or replaced, and then reassembled with poly bushes.
The drive height should be between 6 and 6.5 inches, but I cannot adjust it to more than 4.25 inches.
I have used the setting tool as described in the workshop manual, but to no avail.
Am I missing something or do I need two new, and expensive, torsion bars?

All and any help/advice would be appreciated, especially from someone with previous experience of this problem.

[jagman723]

I too have this problem. Is there anyone out there who can help please?

[piman]

Hello all,

If the E-Type torsion bars are the same as other cars the adjusting arms and the front suspension arm is fitted to the spring on splines. The usual method if you have not sufficient adjustment is to remove one or the other and rotate by one spline. The hard part is uncoupling the front suspension to safely release all the pressure in the spring.

Alec

[oldtimer]

Alec,
You are so right, releasing the load off the Torsion Bar / Spring is the dodgy bit.
Just had a look in my Mk 7 manual as a reminder, donkeys years ago since I had one.
Not familiar with the E type arrangement but it will be a similar to Mk 7 8 & 9. in principal.

Careful consideration must be given as to how the load is released - we don't want any accidents

All height adjustments are made with the vehicle lifted and on proper axle stands on concrete.

[stmh]

Hi had exactly this issue with my series 3 roadster, caused issue with insufficient travel. Ultimately had the suspension completely dismantled, torsion bars rotated by spline, not looks much better and rides / handles as it should.....

[colingray]

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.

[stuarthardy]

Hi Colin

I understand your reasoning for setting your car to a non-standard ride height but would urge caution in compounding the error at the rear caused by suspension sag. Accepting the incorrect rear ride height means that you are also accepting a loss in suspension travel with the risk of bottoming out over rough roads and, along with it, incorrect rear suspension geometry.

I would replace the worn springs and shock absorbers at the rear with some good quality aftermarket items, perhaps GAZ shocks with adjustable spring platforms. its one of the easier jobs on an E-Type. That way, if you want your car to look lower than standard then you can get the look you want along with improved springing and damping. It is also wise to re-set the rear suspension geometry to suit.

Regards