Rear sway bar ?

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Re: Rear sway bar ?

by JCS » Mon Jan 24, 2022 11:50 am

Jim
My 1965 3.4 ltr “S” Type has the fully synchromesh gearbox and is fitted with 185 x 15 tyres.

I use the transmission in exactly the way it was intended, that is running in overdrive at cruising speed only to reduce engine RPM. If I meet other traffic and wish to overtake I drop out of overdrive and accelerate in 4th gear. I find adequate torque for that kind of use.

Obviously if you re-gear the axle in order to reduce engine speed, say from 3.77:1 to 3.31:1, then the car will lose some flexibility at lower speeds. In my case the original idea was to choose a ratio that would allow a good fuel range and easy cruising in Continental Europe, not particularly in England where I live. Unfortunately, two bouts of cancer put paid to very long Continental journeys, but Ireland and France are doable. In fact I conducted the initial shake down of the car with a 3.77:1 axle in both France and Ireland.

It is fairly easy to pick up second hand 3.31:1 gear sets in UK /Europe as they were original to E Type and those owners generally try to upgrade to 3.07:1. The standard E Types for North America had the 3.54:1 gearing, which would normally be my weapon of choice for an overdrive “S” Type car.

At the time I rebuilt the rear end on my car I had availability of a new 3.07:1 (still have), or a second hand 3.31:1 set. As I had all the hypoid gear ** **setting equipment and connections to lap the second-hand gears after I had fettled the teeth, I chose the 3.31:1 set. This was eventually fitted into a (LSD) limited slip differential, my original was none LSD………..don’t go there with the “S” type, use an LSD axle.

**In semi-retirement I had built up and owned the operation that rebuilt the majority of early post war Rolls-Royce Silver Cloud axles and some military hypoid drives. Although building hypoid axles were well within my pay grade, due to illness I had to get an acquaintance who specialised in Jaguar axles to rebuild mine with my supplied gear set.

Having chosen the 3.31:1 gear set it does work quite well in England, especially in my locality and I can drive, even around traffic islands in 4th and use the overdrive for the open road. The city here has the second largest collection of traffic islands in the UK, (hundreds) each demands a “give way” but not an actual “stop” as in the USA. These traffic islands can be negotiated in 4th gear with the 3.31:1 axle easily as engine is very tractable. If I need, fast away, or rapid overtaking I use the gearbox, that is its function. Country lanes are not a problem and the 3.4 ltr is a nice flexible unit and definitely enhanced with an LSD axle at the rear.

As I have tried to illustrate above much depends on “horses for courses”, the terrain and journey distances. If I were re-gearing an “S” Type overdrive model for use in England only I would use the 3.54:1, if it were for use in Scotland or Wales then I might consider leaving the 3.77:1 in situ to handle the terrain. In the case of the USA I think anyone travelling inter-state often may consider the 3.31:1 ratio.

The original ratio of 3.77:1 allowed good acceleration but demanded use of overdrive for even relaxed local driving, in short very under geared and very tedious to drive. We need to remember that road structures and gradients are much different from those when the cars were built and not everyone is interested in flat out acceleration or the resulting noise when that happens. I was trained in an environment where good automotive engineering was judged by the driver not knowing how fast he was travelling. Furthermore, I value the ride and roadholding more than shear acceleration.

Hopefully I will be able to attach here a chart showing all the other details you requested, I trust it may be helpful. Based on 82% series Michelin tyres at 785 rev per mile.

You might notice that the UK national speed limit is 70 mph and that speed in 4th gear drops right on the engine maximum torque at 3000 rpm with the 3.31:1 axle. Running at 70 mph in overdrive leaves the engine turning nicely near the bottom end of the useful torque band (2500-4000rpm) whilst disengaging overdrive places it exactly on maximum torque at 3000rpm.It is also within my self-imposed engine piston speed limit of 2500 ft per minute at 3594 rpm.
Jaguar axle full details.jpg
Jaguar axle full details.jpg (774.21 KiB) Viewed 1187 times
The only real down side is the need for slightly more clutch slip on take-off and in general a standing starts are mandatory in 1st gear, slightly moving starts can be performed easily in 2nd gear.

Re: Rear sway bar ?

by Bingo » Tue Jan 18, 2022 10:15 pm

Norman,


Why 3.3 and what are the relationships to rpms at typical speeds used in 4th as compared to the stock gearing ?

Did you find usable tourq while In OD in 4th ?

Do you find yourself in 3rd gear more often on backroads ?

Does your s type have the early (pre mid year 1964) rear and Moss box ?

Jim

Re: Rear sway bar ?

by JCS » Mon Jan 17, 2022 7:01 pm

Bingo
Is there anything specifically you want to know about the E Type axle ratio? For instance, why I chose that 3.3 ratio choice or the actual axle rebuild etc? Would I follow the same route again, any disadvantages etc.

I have had a lift and full workshop facilities for many years and although that makes my jobs easier it sometimes makes it more difficult to explain to someone the intricate details of completing the job without a lift.

I am pleased that you found the information helpful.

Norman

Re: Rear sway bar ?

by Bingo » Mon Jan 17, 2022 1:34 pm

Thank you.

Your analysis is very helpful. I am going to delay my effort until I have my lift working. At which point in time I will take the measurements you advised and mock up a sway bar to see what issues are present.

Would you elaborate on the the E Type 3.3:1 axle ratio ?

Jim

Re: Rear sway bar ?

by JCS » Sun Jan 16, 2022 12:37 pm

Jim,
“Will a rear sway bar for a series I or II XKE fit a 64 S type ?”

Sorry for the late reply, long term illness and other issues intervened.

I purchased my rear anti- roll bar from HBE Harvey Bailey Engineering in UK, usual disclaimers. Unfortunately, I have not been able to fit it at the present time and quite a few issues need sorting before that time arrives, including Corvid.

My understanding of the Jaguar rear anti-roll bars is that there are three variations to suit track widths approximately 50 inch, 54 inch and 58 inch, for E Type, S type and Mk X chassis types respectively. Therefore I cannot envisage an E Type bar fitting an S Type.

I visited HBE to look first hand at their operation…… for a very small company, I would say very impressive and very knowledgeable. I judge that against most of the smaller automotive operations which I have visited around the world. They have no connection now with the former Rolls-Royce Chief Engineer who formed the company and carried the name.

They are quite leaders in suspension technology and work for most F1 racing teams. Their equipment is the most up to date kit for testing suspension parts, particularly shock absorbers, that I have seen.

On my visit to HBE I learnt a few things about their bars. They advised me, in answer to my many questions, that they cold formed their anti-roll bars, and although they did not say, I would think they might de-stress them after forming.

Our discussions also brought forward another important point. They have come across two different widths between the rear frame section centres, to which the anti-roll bar is mounted, on the Jaguar S Type. In essence that means at least two different side to side distances between the threaded mounting holes. Possibly this was a result of Pressed Steel altering dies to aid body production. Nevertheless, it can, and does raise the need for the user to check the centre lines of the chassis threaded holes before ordering.

I would recommend anyone considering fitting a rear anti-roll bar to check out a few point beforehand, as follows…………

Although I did not fit my rear bar, I did offer it loosely into position. The right-hand side has a few obstructions to consider. The fuel line, brake line and rear brake hose could foul the ends and vertical link on the bar. If these parts have been replaced or re-routed it is even more important to check clearances. Similar fouling problems could just about occur if pattern exhaust silencers and tail pipes are fitted causing possible reworking of another component.

Many of these cars have the rear suspension lower or higher than standard and to adhere to clearances the bar need checking for a foul condition throughout the full suspension travel and full bump condition.

The chassis mounting points take the form of captured threads in the chassis box section, probably even a threaded plate. I do not know if all the S Types were fitted with these threaded mountings from commencement of production. It is worth checking if they are present and just as important rust free.

The anti-roll bar is “U” shaped in the centre to pass around the drive shaft rear coupling, I can see that this might be a hindrance if the axle pinion oil seal needed renewing. I would therefore suggest that the oil seal is replaced if there is any doubt about its integrity before fitting an anti-roll bar.

From memory only, I recollect that the actual head of the special bolt part no. C17149/1 that secures the rear wishbones to rear radius arms, can clash with the anti-roll bar drop link securing nut. In essence these two parts almost “butt heads together” in such a way that only one can be manoeuvred into position and the bolt head is nearly fully recessed…….at least that is my perspective of the arrangement.

In fact, anyone replacing the rear radius arms or bushes may perceive this situation when trying to tighten the self-locking nut on the C17149/1 special bolt. Fortunately, when I had my subframe parts dismantled I found the Jaguar bolt / nut could not be held against rotation. Furthermore, the bolt could be impossible to hold if removal was required with the sub frame in situ.

I overcame that situation by using a top grade 0.5 inch? cap head bolt with some machining to reduce the depth of the internal hexagon. This meant I could hold the bolt head with an allen key and use a wrench on the nut. I mention this arrangement as it would also allow the anti-roll bar link to be attached more easily to the radius arm.

On my car, the right-side chassis section has been repaired at some point in its life, a very good repair it is, but unfortunately the repairer did not reinstate the threaded points for an anti-roll bar mounting. I am very guarded about trying to reinstate any form of mounting in that location, as without very major surgery it will be impossible to reinforce the area sufficient to handle the forces involved.

As I have replaced all the main components on the rear end of my car, including using an E Type 3.3:1 axle ratio, the ride which I value highly is superb and the body roll I can accept for the way I use the car. I initially contemplated fitting the rear anti roll bar out of curiosity rather than necessity, so aborting the fitting is of no great consequent. At the moment outside influences are pointing towards someone in the UK buying a cheap anti roll bar from me, however I hope these notes may help someone who may be contemplating the job.

Re: Rear sway bar ?

by Glyn Ruck » Fri Dec 24, 2021 1:12 pm

Norman (JCS) is the authority on rear sway bars for S Types. Shoot him a PM. They are available. Not sure if he's fitted his yet. Their size is intermediate to MkX & E Type. All the mounting points are there. Radius arms & body with a plug in them.

Re: Rear sway bar ?

by John Quilter » Fri Dec 24, 2021 5:47 am

And many an American hot rod used a version of this Jaguar independent rear suspension but not sure which width was common. Often extra effort was made to chrome plate each and every part of it for show bling!

Re: Rear sway bar ?

by cass3958 » Thu Dec 23, 2021 11:06 pm

As I understand it the rear suspension on the S Type although derived from the E Type and Mk10 was slightly narrower in width. Not sure but I think the XJ6 again was slightly wider than the S Type. The slightly narrower rear of the S Type was stolen sorry used in the Cobra and Cougar kits due to its width.
That said the sway bar or antiroll bar from the E Type or XJ6 might fit but it would have to be offered up for size to make sure there is no interference with the inside of the rear wheels. Someone must have tried it out before and I am sure others will know more than me.

Re: Rear sway bar ?

by Bingo » Thu Dec 23, 2021 10:08 pm

Bingo wrote: Thu Dec 23, 2021 10:07 pm
Bingo wrote: Thu Dec 23, 2021 9:15 pm Will a rear sway bar for a series I or II XKE fit a 64 S type ?


Found this….

A key element of the Mark X that Jaguar wanted to include in the S-Type was its sophisticated, and by then widely acclaimed, Jaguar independent rear suspension. The suspension was a revelation at the time of its introduction, and remained the benchmark against which others were judged until the 1980s. Essentially a double wishbone setup, it uses the driveshaft as the upper wishbone. It carries the drive, braking, suspension and damping units in a single fabricated steel crossbridge, which is isolated from the bodyshell by rubber blocks. Including this suspension in the S-Type necessitated the development of a new crossbridge suitable for its 54 inches (140 cm) track, coming as it did between the 58 inches (150 cm) track of the Mark X and 50" track of the E-Type.
The S-Type used the same subframe mounted, coil sprung, twin wishbone front suspension as the Mark 2.



Thanks,
Jim

Re: Rear sway bar ?

by Bingo » Thu Dec 23, 2021 10:07 pm

Bingo wrote: Thu Dec 23, 2021 9:15 pm Will a rear sway bar for a series I or II XKE fit a 64 S type ?


Found this….

A key element of the Mark X that Jaguar wanted to include in the S-Type was its sophisticated, and by then widely acclaimed, Jaguar independent rear suspension. The suspension was a revelation at the time of its introduction, and remained the benchmark against which others were judged until the 1980s. Essentially a double wishbone setup, it uses the driveshaft as the upper wishbone. It carries the drive, braking, suspension and damping units in a single fabricated steel crossbridge, which is isolated from the bodyshell by rubber blocks. Including this suspension in the S-Type necessitated the development of a new.



Thanks,
Jim

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