Vitesse Mk2 - acceptable chassis flex?

[Phil C]

Evening all,

What level of flex/bend is to be expected with a Mk2 Chassis in good condition?

My chassis has been supported by four stands each mid way along the front and rear outriggers (all newly replaced) for a couple of years as the car has slowly been rebuilt. It now is almost complete with the four supports taking the full weight of the car. 

Not really thinking it through I had sorted all the panel gaps whilst supported like this too.

Today I lowered the car on to its wheels and the B post door gaps closed up by around 4mm making the doors almost impossible to open.

I can redo the gaps with the car on its wheels but was alarmed at the amount of flex witnessed and how this might cause future difficulties say when changing a wheel.  Should I be concerned or is this normal??

I had the chassis blasted and, apart from the outriggers/rails which were replaced, it appeared to be in solid condition.

Thanks 

 

[JohnD]

Phil, 

There is a HUGE amount of body flex, compared with a monocoque car!

My first race Vitesse had a full roll cage, but the front and back hoops were joined by bars whose joints could rotate around them.  And they did!   If I drove over an obstacle, a kerb say, I could hear them squeaking!

A body that is bolted on with the rubber mounts will not improve this.   Leave out the rubber if you don't mind a lot more road noise.    A roll cage with tight/welded joints will add an enormous amount of stiffness.

There are other ways, see an old article in the TSSC's Courier (search their Technical Index) or I think there was one here. search also.

Good luck!

John

 

[Pete Lewis]

i woukd say doing any body settings on stands rather than on wheels is a route for some variable gaps to appear  

and a CV distorts more than a saloon  hence the need for hasp and staple door controls 

when jacking it will be fine  best keep the doors shut 

and with these old chassis  not many would jack as the book on the end of the outriggers but on a more solid centre  crossmember  or similar 

Pete

[PeteH]

Hmmm?. Food for thought here, the 13/60 is currently supported on axle stands under the main chassis, makes work less back aching!!. The gaps are coming together after months of "adjusting". Now?, do I put it on the wheels to check?, if so, better before I paint it I guess?.

Looking at the structure of the outrigger/side rail, even in as new condition, I would be reluctant to jack or support on them, I suppose a (quick?) wheel change might be OK?, but nothing else?.

Pete

[NonMember]

43 minutes ago, PeteH said:

the 13/60 is currently supported on axle stands under the main chassis,

I would have thought that if you place the stands under the front suspension turrets and the rear saddle, then they're as close as possible to where the weight is supported on the suspension, so you shouldn't get distortion. Or, perhaps more accurately, you should have the same distortion as in road conditions, so it's OK to fit up the doors like that.

[Phil C]

Thanks all for your input.

May be I have "normal" flex but I was very surprised as to the extent. 

15 hours ago, JohnD said:

A body that is bolted on with the rubber mounts will not improve this

I did feel the rubber mounts supplied were overly soft which made aligning the gaps very difficult as they would distort a little when tightened.

3 hours ago, PeteH said:

Now?, do I put it on the wheels to check?

I would be very interested to compare notes if/when you do? A similar movement would be reassuring for me - but a pain for you ☹️

2 hours ago, NonMember said:

I would have thought that if you place the stands under the front suspension turrets and the rear saddle

I think this makes sense. In my case the engine cantilevered over the front support and the axle/drive shafts over the back. This obviously opened the top of the B post gap which then closed as the wheels take the weight.

3 hours ago, Pete Lewis said:

i woukd say doing any body settings on stands rather than on wheels is a route for some variable gaps to appear 

I am going to re-gap everything with the car on its wheels  😩 and rearrange the support points...and keep the doors closed whilst elevated!!

[Pete Lewis]

I remember many years back i used to service my bank managers car  it was a Standard 10  the jack point is inside the car next to the B post ,you hook a jack 

in through the hole in the floor and yes  lift the floor   the rest of tha car stayed on the ground,  now the doors have no hope of closing 

i think it got scrapped in the end  , not a rusty car but some underpinnings were shot 

Pete

[Mark B]

Yup, the Vitesse convertible is as floppy as a wet lettuce. I rebuilt my Vitesse several years ago, started with an excellent solid chassis. I reinforced and boxed in all the outriggers, added extra support where the outriggers join the main rails. I added additional supports to the boot floor from the boot outriggers as were fitted to the earlier Heralds. I used all solid aluminium spacers, no rubber anywhere. The complete restoration was finished a few years ago, and the car feels more solid than previously. But still, if jacked up on the side rail/rear outrigger corner you can see the door gap open slightly at the top. I've looked a loads of cars at shows when trying to stiffen the Vitesse up, and out of curiosity asked the owners to press down on the end of the rear wing on a  Vitesse/ Herald convetible's on each occassion the door gap opened slightly at the top, to their surprise. I keep the doors closed when jacking the car up. I did all the panel alignment with the car on its wheels on a flat surface.

[PeteH]

7 hours ago, NonMember said:

I would have thought that if you place the stands under the front suspension turrets and the rear saddle, then they're as close as possible to where the weight is supported on the suspension, so you shouldn't get distortion. Or, perhaps more accurately, you should have the same distortion as in road conditions, so it's OK to fit up the doors like that.

I`m not going to say I had thought that through prior, but thinking after I posted I do wonder?. The stands are as close to the Turrets and rear saddle/cross beam as possible to get. But as yet the Engine/Gearbox have to go in, how much if any difference that will make is another imponderable. I`ve already had to "adjust" the Tub width wise to make it line up with door as accurately as possble.

Pete

[ahebron]

This should give you the info on the Vitesse chassis.

https://pearl.plymouth.ac.uk/bitstream/handle/10026.1/17331/TPSS-2021-Vol14n1_246-285Jones.pdf?sequence=1&isAllowed=y

I think the most practical fix is a t shirt plate similar to the TR6 one in front of the diff on the underside of the chassis

[Colin Lindsay]

On 25/08/2022 at 12:10, Mark B said:

Yup, the Vitesse convertible is as floppy as a wet lettuce. 

Bit extreme, Mark - given that you say when you jack up one corner you see the gaps open slightly at the top. Slightly??? Hardly wet lettuce standard. I've been driving a Herald convertible a lot recently, the bonnet squeaks a bit as it's a terrible fit but there's no noise from the tub at all when driving so I assume it's not moving about. I nipped out to the garage and tried pressing the rear wing down just now and the door gaps don't open at all, in fact the horseshoe trim came off... so possibly it's down to poor body mountings, or wear? 

[trigolf]

I think it's well known that Vit DHC suffer more from scuttle shake than a Herald DHC. I guess it's because of the heavier lump up front. 😟

[Colin Lindsay]

1 hour ago, trigolf said:

I think it's well known that Vit DHC suffer more from scuttle shake than a Herald DHC. I guess it's because of the heavier lump up front. 😟

Probably right, there is an enormous weight difference so I hope Mark will forgive my nit-picking. Someone has to stand up for them!

[johny]

yes Herald makes more sense really unless Triumph had come up with a lovely aluminium straight 6😒 

[Mark B]

3 hours ago, Colin Lindsay said:

Probably right, there is an enormous weight difference so I hope Mark will forgive my nit-picking. Someone has to stand up for them!

Hi Collin, I've had a couple of Herald convertibles I love them, wish I still had mine. Much lighter on their toes and with a tuned small crank 1360 would give a Vitesse a run for its money. I am sure the extra weight of the Vitesse runing gear, engine etc. all much heavier, makes the chassis/tub flex much more noticeable. Yes, the door gaps still opens slightly when jacking up my car, but that's despite an excellent chassis, solid mounted tub and the other mods mentioned above. I still wouldnt leave the doors open when jacking up though. This is the fourth Vitesse I have owned and by far the most solid. Vitesse Saloons are noticeably more solid.

[PeteH]

On 18/09/2022 at 15:08, johny said:

yes Herald makes more sense really unless Triumph had come up with a lovely aluminium straight 6😒 

They did, Well actually BL Did, but it was a V8 and finished up in the Rover. Curtesy of Buick I believe.

Interestingly The 1600-6 max power was listed as 70BHP, the 2000 as 95BHP. The 13/60. is around 58 I understand?

Pete.

[johny]

Hmmm a V8 doesnt really lend itself to fitting well in the Triumph small chassis and then a 3.5L is just too big anyway. No I think it should have been a 2L OHC six but maybe with the cylinders slightly off the centreline to keep it shorter and of course with aluminium block and head👍Course a new gearbox would have been nice as well!

[KevinR]

On 18/09/2022 at 11:49, ahebron said:

This should give you the info on the Vitesse chassis.

https://pearl.plymouth.ac.uk/bitstream/handle/10026.1/17331/TPSS-2021-Vol14n1_246-285Jones.pdf?sequence=1&isAllowed=y

I think the most practical fix is a t shirt plate similar to the TR6 one in front of the diff on the underside of the chassis

Fascinating read

[Clive]

Chris Jones did a proper thesis of the vitesse chassis. The article was the sept 2020 CT magazine. 

Nick (his dad) has carried some chassis mods accordingly. 

[Nick Jones]

On 19/09/2022 at 18:38, clive said:

Chris Jones did a proper thesis of the vitesse chassis. The article was the sept 2020 CT magazine. 

Nick (his dad) has carried some chassis mods accordingly. 

Adrian’s link is to Chris’s full dissertation. Well found - we didn’t know it was there!

My mk2-ish CV was the test victim. I’ve got some fairly scary video clips.

Bit more here

https://sideways-technologies.co.uk/forums/index.php?/topic/5220-nicks-vitesse/page/5/#comments

bottom of that page and the next couple.

At “some point” I may add a H-frame, which will mean adding some structure to the bulkhead to pick up on.

Nick

 

[Nick Jones]

On 18/09/2022 at 11:49, ahebron said:

I think the most practical fix is a t shirt plate similar to the TR6 one in front of the diff on the underside of the chassis

Good luck finding a T-shirt plate position that allows you a propshaft and exhaust. Also note the the FEA analysis didn’t rate a single T-shirt plate as a worthwhile addition.  A double (top and bottom of the main rails) T-shirt does better, but is utterly impractical.

Nick

[ahebron]

9 hours ago, Nick Jones said:

Good luck finding a T-shirt plate position that allows you a propshaft and exhaust. Also note the the FEA analysis didn’t rate a single T-shirt plate as a worthwhile addition.  A double (top and bottom of the main rails) T-shirt does better, but is utterly impractical.

Nick

I stand corrected.

Nick are you referring to a similar H frame as the Spitfire /GT6

[Nick Jones]

On 22/09/2022 at 08:00, ahebron said:

Nick are you referring to a similar H frame as the Spitfire /GT6

Yes. Problem is that there is nothing structural on the bulkhead to attach to, so something has to be created. Maybe this winter…..

[Wagger]

I cannot find the link now but there was a feature some years ago that demonstrated  how to make the Vitesse chassis less flexible. It involved making the outer rails full box sections and a bit more welding.

It, probably, is no more flexible than a old Morgan with a wooden chassis.

It is alway best to adjust gaps with the vehicle riding on its wheels after rolling it back and forth to allow the rear spring to settle etc.

I restored a Morris Traveller 12 years ago and manged to adjust gaps of over 1/2 in using studding to hold bits in place bfore bolting everything up. Some monocoques are  almost as bad!

[PeteH]

After weeks of "adjusting", the gaps and lines are looking a bit more even. But the chance of getting them much closer is not very encouraging.

Pete