Scuttle Shshshshaake
Posted By : John Davies, 20-Jun-2007, 09:38pm
David,
The front suspension turrets have two bolt holes above the inner ends of each upper wishbone . I think all they are used for is to attach the inner engine bay valances.
Make up a strut to run betwen the rear one and the front of the bulkhead, somewhere, probably the shelf edge, where it will be stiff.
That should help brace the bulkhead better than a load of extra weight down on the outriggers.
Nothing heavy, a length of alloy tube, flattened at the ends might do.
John
The front suspension turrets have two bolt holes above the inner ends of each upper wishbone . I think all they are used for is to attach the inner engine bay valances.
Make up a strut to run betwen the rear one and the front of the bulkhead, somewhere, probably the shelf edge, where it will be stiff.
That should help brace the bulkhead better than a load of extra weight down on the outriggers.
Nothing heavy, a length of alloy tube, flattened at the ends might do.
John
Scuttle Shshshshaake
Posted By : Calvin Andrew, 20-Jun-2007, 10:01pm
David,
Fit a multi point roll cage?
Calvin
ps Will look really cool too
Fit a multi point roll cage?
Calvin
ps Will look really cool too
Scuttle Shshshshaake
Posted By : Chris Taylor, 20-Jun-2007, 10:03pm
Fit a hardtop.............
Any decent restorer should be able to rip off the existing outriggers and fit stronger ones for a reasonable price; if the rest of the car is good and clean, and body mounting bolts come straight out, it's not too difficult or long a job. Just make sure they weld the TOPS of the rear riggers under the rear seat. This would mean either cutting a hole in the rear seat pan or lengthing the upper face of the rigger and welding the edge from the propshaft side. (For those who consider this a bodge, it's an official Triumph bodge, one service manual even detailing the size of plate to fix to the outrigger).
Similarly any restorer or experienced chassis welder could box in the siderails or replace same with steel box section. (Boxing in is easier perhaps, but steel tube will be stiffer as it has thicker walls.
The rear body shell can be stiffened by wleding or even rivetting (yes, decent quality pop-rivetting in tight fitting holes will do) a steel or alloy plate across the hole between boot and rear seat. Fitting a roll cage will do similar. I've not seen any similar mod for the bulkhead though. It's worth checking that all body mounting bolts are done up tight (there may have been some settling since the restoration as everything beds in), that the dashboard frame is tightly bolted to the A posts, the strut from the rearmost steering column support to the windscreen surround next to the wiper wheelbox is there, and that the lower column support bracket is there too.
Making sure the bonnet support cones and bonnet catches are properly adjusted may help as rattling of the bonnet will make any scuttle shake sound even worse.
Any decent restorer should be able to rip off the existing outriggers and fit stronger ones for a reasonable price; if the rest of the car is good and clean, and body mounting bolts come straight out, it's not too difficult or long a job. Just make sure they weld the TOPS of the rear riggers under the rear seat. This would mean either cutting a hole in the rear seat pan or lengthing the upper face of the rigger and welding the edge from the propshaft side. (For those who consider this a bodge, it's an official Triumph bodge, one service manual even detailing the size of plate to fix to the outrigger).
Similarly any restorer or experienced chassis welder could box in the siderails or replace same with steel box section. (Boxing in is easier perhaps, but steel tube will be stiffer as it has thicker walls.
The rear body shell can be stiffened by wleding or even rivetting (yes, decent quality pop-rivetting in tight fitting holes will do) a steel or alloy plate across the hole between boot and rear seat. Fitting a roll cage will do similar. I've not seen any similar mod for the bulkhead though. It's worth checking that all body mounting bolts are done up tight (there may have been some settling since the restoration as everything beds in), that the dashboard frame is tightly bolted to the A posts, the strut from the rearmost steering column support to the windscreen surround next to the wiper wheelbox is there, and that the lower column support bracket is there too.
Making sure the bonnet support cones and bonnet catches are properly adjusted may help as rattling of the bonnet will make any scuttle shake sound even worse.
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Scuttle Shshshshaake
Posted By : Paul Carter, 21-Jun-2007, 00:44am
don't forget that the chassis design was down to a price.the main problem is that the two main rails that run front to rear actually go very close together along the middle of the car which goes against all sound engineering principles in as much that it allows the whole car to rotate around this point.it was adequate for what it was designed for and was suited for the other components which were fitted to the car as standard at the time.as NJoH has stated, by fitting bars from the turrets to the outriggers can make quite a substantial difference to the stiffness of the front end.it all comes down to TRIANGULATION of the chassis,as forces travel in a straight line you have to install struts or braces along these lines to counter the scuttle shake.i also have fitted braces between said items and it made a hell of a difference.a couple of years ago i had a knocking coming from what i thought to be the passenger door somewhere but after much detection it turned out that the bolts i fitted in the bar that bolted to the front out rigger were loose,after tightening them the noise dissapeared.so it goes to show that there is quite a substantial amount of movement within the chassis.my next step was to make and fit a custom cage around the complete bodyshell going from front to rear and across the front bulkhead.im running 400lb springs up front and 40series tyres and my scuttle shake is hardly noticable now.in fact i've been in new covertibles that are worse than my car!-
Scuttle Shshshshaake
Posted By : Jonathan Binnington, 21-Jun-2007, 07:20am
as a further, I have a full cage in my car, running from the front outriggers, through the front bulkhead and down to the rear chassis mounts
t'bugger doesn't shake - although it is an incontrovertibe convertible...
j -
Scuttle Shshshshaake
Posted By : David Freeman, 21-Jun-2007, 07:23am
Lots to think about, gentlemen. I shall put these to action soon. It disturbs me that the door gaps change even when pushing the car over some undulating ground i.e the car is moving slowly and I am outside the car walking along seeing/feeling the door gaps change!!
Has anyone any photos of these mods you discuss? I am now very keen to sort this...
DF -
Scuttle Shshshshaake
Posted By : John Davies, 21-Jun-2007, 08:54am
A chassis with a central 'spine' is not necessarily bad engineering.
See below, a Lotus Europa chassis.
The point that makes the Lotus extremely stiff (until it rusts away) is that it is totally enclosed, so that torsion loads are spread and resisted, rather than allowed to concentrate on small areas. Enclosing the space between the rails would go a long way towards stiffening the Triumph, even if the ends were left open for the propshaft. But that is theory, I've never done it and it would not be simple to do!
John Thomason wrote some years ago in the Courier on this problem. He passed on a solution that had been worked out in a engineering school and tested on a torsion rig. A three strut pyramid approximately in the passenger seat area that could work well for a race car. I have to say I've not seent hat installed in the Silver bullet, so maybe that has installation problems too!
A roll cage does the trick. IMHO, open Triumphs are not safe on modern roads without a roll-over bar. Indeed they were not safe when they were built, but safety design has moved on. The addition of a front hoop connected to the rear will solve all these problems, without compromising daily use.
JOhn
Scuttle Shshshshaake-
Scuttle Shshshshaake
Posted By : Chris Taylor, 21-Jun-2007, 09:59am
The difference with the Lotus design is that the spine is much deeper. You could get similar benefits by making it wide and shallow, but that's not fully feasible with the Triumph chassis as floorpans get in the way, and the propshaft being at such a shallow angle means that there is a very limited length over which you can connect the main rails at both top and bottom flanges. Has anyone tried an undertray from main rails, UNDER the floorpans and across to the siderails? Would probably help aerodynamics as well, but weight, gearbox cooling and drainage of water might be issues!
Interesting that Triumph's solution to this "problem" (if it was perceived as such at the time!) with the Spitfire was to make the body more rigid rather than the chassis. It's also noticeable that the Herald saloon, despite its thin pillars and bolted construction, is (or at least feels!) a fair bit stiffer than the convertible.
As for these cars being "unsafe", I would suggest that they are as safe as any convertible that does not have a roll cage. By the standards of the day, their impact resistance from front and rear was pretty good. I would not want to experience a direct side impact, but then I would not want to in a Mini or Ford Anglia either!
The bracing of the front suspension towers is interesting and sounds effective. Has anyone any pictures of this?-
Scuttle Shshshshaake
Posted By : Nigel Gibbins, 21-Jun-2007, 11:32am
I think a GT6 / Spitfire would score a 4 on euro encap ratings... this is from my own experience of being rear ended @ 50 mph in to the car in front in a GT6 - doors were difficult to open (due to bonnet moving back) but passenger compartment was untouched. And the spitfire went into a tyre wall at 50mph (approx) at a slight angle so took all the force in the suspenion (GRP bonnet) and only a minor incursion into the footwell (by front wheel) was noticed in the passenger compartment.
Not bad for a 40+ design...
So they are IMHO pretty safe cars front to back... not sure about side impact though-
Scuttle Shshshshaake
Posted By : John Davies, 21-Jun-2007, 01:13pm
Sorry, should have been more specific.
It's the rollover accident in which old cars like ours are unsafe.
Doesn't happen often; as Nigel says, the cars can perform well if front or rear ended.
I had the former in my old Vitesse and stepped out, but it did have a full cage.
Modern convertibles are built with massive A-post strength - Triumph didn't
If the car rolls, the windscreen surround has no strength at all.
I did not let my son drive his Spitfire until we fitted a rollover bar and I recommend them to anyone else.
Jon Wolfe used to have an extension from his Spitfire's roll cage to the front turrets.
That was a length of 2 1/4" diam. steel tube, but to improve scuttle shake something much less robust would suffice.
John
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Scuttle Shshshshaake
Posted By : Leon Guyot, 21-Jun-2007, 04:13pm
John wrote:
A roll cage does the trick. IMHO, open Triumphs are not safe on modern roads without a roll-over bar. Indeed they were not safe when they were built, but safety design has moved on. The addition of a front hoop connected to the rear will solve all these problems, without compromising daily use.
I must partly disagree with this. I have been driving convertible Heralds and Vitesse for 26 years without roll cages, and have never felt unsafe, in normal driving conditions. And believe me, I have made a few mistakes!
The cars are very stable on the road, and they are even fairly safe during a side impact, which is somewhat surprising, given the lack of a side impact bar!
I have been driven into from behind twice, whilst not moving, and once had a Ford Fiesta drive into my drivers door! (just after a lengthy restoration).
Back in the day, the Herald was regarded as being one of the safest cars on the road, as period insurance adverts testify.
Herald and Vitesse Saloons are no safer than the Convertibles, as the roofs are not really stress bearing and only attached with a few small bolts.
I have also seen roll cages poorly installed, as they were simply bolted to the floorpan, which offers little in the way of strength, should the car roll, and indeed such an installation would do little more than potentially instill a misplaced sense of safety, possibly causing the driver to do something that he would not do without said cage in place?
I admit that our 1960's cars cannot be as safe as the cocoon that modern cars have become, with their highly engineered 'safety capsule' to protect the occupants.
But it's horses for courses, if you drive accordingly, you should be perfectly safe.
Rgds
L&195;&169;on
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