Chassis for a dino
 

Hi

I'm looking to build a chassis with more up to date components for a dino build.
I currently have a rolling chassis built up with a dino 206 body fitted to it. (Deon GT)It's fitted with a cosworth v6 engine mated to the ford rs turbo box as per the dino build.
My reasons are that I want to remove the high cill sections present at the door openings, and remove the massive centre tunnel/backbone section. I also wish to upgrade the gearbox to either a ford focus mk2 st225/rs gearbox or toyota mr2 turbo one, to give me a better gearbox but also give me a cable change which will enable a better looking centre tunnel. My plan is then to fit a 246gt bodyshell.
Any input greatly recieved.

ian

Can the one you have be modified to get where you need to be?

chassis
 

Hi

I don't really want to cut and shut the one I have. The 246 dino has a slightly longer wheel base than the 206. I intend to use it as a starting point for a new chassis and alter it as I need. My plan being to sell on the deon at a later date.

ian

chassis
 

Hi

My current plan is to use a double wishbone front suspension set up similar to the deon, but using a modern billet alloy front upright with correct 5x108 bolt pattern so enabling the use of the correct cromadora wheels.These will be fitted with a 300mm vented disc and four pot calipers.I may use the mini rack as used on the deon as these are still available new.
At the rear is where the real work is needed. As stated by ross in another post on this forum fitting a V6 engine with the gearbox mounted end on, space issues mean that top wishbones end up very small.I know it's not strictly dino replication, but I'm looking at a macpherson strut arrangement on the rear with a bottom wishbone. This will allow me more room for the engine. Similar to the set up that is used on the Lancia stratos replica. Again using a billet upright with correct 5x108 hub,300mm vented disc and four pot calipers, along with a pair of brembo hand brake calipers.
My idea is to build a front chassis section with all suspension fitted,a rear section with engine/gearbox and suspension and join the two with the centre floor pan section. I intend to use 75mmx50mm out riggers with a smaller section to join the two.
What do others think?

ian

chassis
 

hi

just a quick pencil sketch but something like this. 50x50mm box section front and rear sections, 75 or 100mm x 50mm box section for perimeter of floor pan. I plan to have a bolt on structure to support the boot floor with bumper mounts at the rear,and a similar front structure for bumper and radiator mounts that bolts on at the front.

ian

Looks good to me

Good start Ian. A couple of points:
the 30mm brakes may not fit in cromodora wheels. Alfa 166 hubs are the right size (5x108mm and correct centre bore, unlike Ford 108 hubs)
Mazda Mx5 front, fitted with Alfa 166 hubs, is almost ideal.
Chassis triangulation is essential. If you think of a triangulated box you get the picture - it is rigid any way you look at it. Take away one face or one triangulation and you have a problem. Racing cars built around road cars have big diagonals across the doorways. If you want unrestricted cabin doorways and no centre tunnel then you are left with the original Ferrari-type design of an overly heavy floor (platform) that actually is not very stiff. Stiffness is needed for modern tyres and suspension geometry. In the good old days chassis twist was actually accepted and used as part of the geometry and the skinny tyres would give way long before the grip imposed too much force on the chassis. Now days it is different.....

http://roa.h-cdn.co/assets/cm/14/47/...r_1r1p1-lg.jpgThe Factory Five 818 is a good example of an interesting chassis. It isn't a replica though and sacrifices access in favour of rigidity:
http://www.roadandtrack.com/car-cult...rive/?zoomable

http://roa.h-cdn.co/assets/cm/14/47/...r_1r1p1-lg.jpg

I hope this picture link works - I'm not having much luck inserting them!
cheers
Ross

chassis
 

Hi
I'm looking to build a back end something like this. This is a stratos replica built using an alfa engine.
The front suspension would be along the lines of the old deon but using modern mechanicals.

chassis
 

Hi
Although this is an old picture, this is the front end of the deon. My plan is to shorten the front overhang and have a bolt on section to carry the radiator, bonnet hinges and front bumpers. This way the chassis around the suspension mounts/steering rack can have a larger build material than the bolt on section giving a stiffer structure.
Something else has come to mind regarding the large outer chassis rails.These could be swapped out for a double smaller rail using a triangulated arrangement that sits behind the dino's cill.

Is your chassis a copy of an original or specific to the kit it's fitted to

If you wanted a different style chassis I believe the "cascu" chassis Is better suited

chassis
 

Hi
The cascu chassis is an exact copy of the original dino and as such requires dino suspension components. These can come from a 308dino or an original 246dino.
Nobody would scrap an original 246dino to build a recreation 246, with the price they fetch it would be restored. Similar story with the 308dino/gt4. These are rapidly going up in price and it wouldn't be worth it to scrap one justt to source the components needed.
There are other problems too, the main one being the engine bay, It's designed around the ferrari engine and gearbox-with the gearbox being underneath the engine, not for an end on gearbox fitment.
I want a more bespoke chassis built with more up to date mechanicals,not with an aging 30 year plus donor. I have a new crate V6 engine and I'm hoping to mate it to a modern Ford Focus RS gearbox. The engine cradle/bay is to be my starting point.

Hi Ian, the Stratos replicas are very interesting - Lister Bell's in particular. This link is to a Lotus Europa scratch built chassis project which I find interesting for its smaller tube triangulation and use of Mazda MX5 components:
http://fortinimillwork.com/car.htm
cheers
Ross

I just found this website. It has very useful info on designing a sports car (or racing car) from scratch, including links to free software:
http://www.buildyourownracecar.com/r...esign-process/
cheers
Ross

I learned something about triangulation - the difference in strength between compression and tension - in the first paragraph of reading this! http://www.buildyourownracecar.com/r...cs-and-design/
cheers
Ross

chassis
 

Hi

Funny I had been reading these pages myself recently! It was actually the guys at LB who suggested the macpherson strut arrangement at the back. They use it in heir stratos replica to very good effect. It'll give you more room for an end on transmission too.Front steering and suspension is very similar to the deon just modern donor parts but all purchased new. He has invited me up with my 16" cromadora wheels to see if they fit his set set up using 300mm discs, so I could possibly use his mechanicals in my build.Also looking at an engine cradle similar to his as a starting point to.

ian

Stratos vs Dino 246. Before getting too excited about the Stratos and chapman strut type suspension do a quick measurement of the available space in a Dino body. I once thought a Toyota MR2 rear strut would work before I discovered it was over two inches too high for the bodywork. It'd be a great solution if it fits!

chassis
 

Hi
Funny that! I was thinking the same thing about height issues. LB have all their suspension components made to measure, so to speak, so I'm guessing the struts and springs could be made shorter? The top mount could be lowered to fit under the dino's body.
I know with the Toyota MR2 they fit lowering struts and springs thus lowering the whole car to the ground. I'm guessing if you lowered the top mounting points and fitted the lowered suspension the car would keep the normal ride height?
Alternately there must be some cars out there riding on mcpherson struts with a lower bonnet line? the MX5 springs to mind? I myself do think it would be a better solution to an end on transmission fitment.
ian

strut rear suspension
 

The DGT/Deon is a strut front suspension but with the actual strut replaced with wishbones and coilover. You could try the actual suspension from the car you've sourced your engine/transaxle from. This will require complete rethink of geometry though which is way beyond me! Or you could look at MGF. Someone on here already went down that route with an Alfa 166 hub adapted to it.

Modern suspensions tend to have different offsets to the cromodora wheel though.

like this:
http://pictures.topspeed.com/IMG/cro...-22_600x0w.jpg

chassis
 

Hi
Yes similar. The LB has the struts in a more upright position rather than inclined inwards as on the mgf.
I've started on mounting my focus rs box to my spare cosworth v6. I've upended the v6 engine and machined a spigot bearing that fits in to the v6 crankshaft. I will now bore this to fit the input shaft on the focus box thus centring it ready to mark out my adaptor plate.
Ian

chassis
 

Hi
I've turned the other end of the spigot jig and fitted to the gearbox. I now need to mate the two together and start on the adaptor plate.
ian

chassis
 

hi

With the jig pressed into the end of the V6's crank I've lowered the M66 gearbox via the splined input shaft onto the engine. this will centralise engine and gearbox.Looks like everything will work. Now on to plot the mounting holes for the adaptor plate. I have the bolt pattern for the v6 block but I can't find the bolt pattern sizes for the Volvo/Ford M66 box anywhere. Anyone have any idea's?

Ian

chassis
 

Hi all

Does anyone who reads this know much about the Vw/audi 02m 6 speed box?
As fitted to the RS3 and cupra.
Been told these can handle more power than the ford focus st/rs box and they are easier to get hold of. Plus spares and LSD's are much cheaper.
I also like that the starter is bolted through the gearbox rather than from the engine side.And it's cable operated like the ford box too.

ian:icon_razz:

Re-reading this I remembered that Hondas of the 80s and 90s used to have very low bonnet lines - and so shorter strut (or wishbone/strut) front suspensions. Nowadays cars have higher bonnet lines to add a couple of inches of crumple for the poor pedestrians who get hit.
I'm no suspension expert but you do get the geometry by drawing a line from the top of the strut and intersecting it with the line created by the bottom wishbone. So I guess just shortening the strut would have an effect on geometry.
http://www.rqriley.com/images/fig-14.gif

chassis
 

Hi

I've seen this diagram before. I would guess if the strut is shortened along the same radius it would still be ok? Looking at the photos I've attached LB's struts look almost vertical.

Ian

shortening struts
 

If you take 2" off this strut and redraw the diagram you can see a big change in the roll centre height and the virtual reaction point.

chassis
 

Hi

You're showing a drawing here of the front suspension. I'm going to copy the front suspension from my deon and it will be the same just new hub carriers.
It's the rear suspension I'm looking at altering. I know that just loping of 2" off will alter the swing radius as you say,this is must be why the LB struts are more upright.To Keep the virtual radius with a shorter strut the same moving the top mounting point out then will surely bring it back in line?
I'm hoping to get my adaptor plate cnc'd either this/next week and will start by building the engine cradle/suspension. I want to keep as close to the deon as possible.

Ian

Hi, by the way - please take my comments about engineering and suspension with a pinch of salt! I don't pretend to know much about either. If you want knowledgable feedback and people aren't answering on here then maybe posting some questions on the middy section of the locust site would get you useful responses. I'm following the discussion with interest.
cheers
Ross

Lancia Montecarlo Scorpion rear suspension
 

Hi, here's the strut rear suspension from a Lancia Mid engine Montecarlo for reference
http://www.motorlegend.com/images-vo...-2-0-45976.jpg

Much the same design as the Montecarlo is the Fiat X1/9. It uses the same uprights, a very wide lower wishbone and a type of adjustable tie rod to give lateral location. In the X1/9 the top of the strut is 790mm high.
http://www.midwest-bayless.com/image...e/17521_2_.jpg

http://www.spiderroadster.com/X39a.jpg

http://www.midwest-bayless.com/image...arge/16862.jpg

chassis
 

Hi

The X19 uprights you show look very similar to the ones I had on a fiat 128 coupe years ago. The 128 coupe was front wheel drive so these arms were bolted to the steering rack. As they were transferred to the back in the mid-engine X19 a fixed stay must have been incorporated to stop rear wheel steer.
The deon uses a lancia beta front upright at the rear with a fixed location built into the rear top wishbone. Metal brackets then bolt to the strut mounting holes to attach the top suspension.
The deon front ones were taken from a fiat 124,and later a lada riva. And unbelievably still available new from lada complete with hub/bearings and brake discs!!
ian

Hi,
yes the Deon (and before that the DGT) were, if magazine articles are correct, fine tuned by a company called Geoscan.
It would be incredibly helpful if someone could do a drawing or simply list all the mesurements of the complete Deon suspension system. From all accounts it is very good.
Of course tyre profiles and engine weights have moved on from the 80s but it is a good starting point.
here are a couple from the Locost site as an example of what I mean:

http://www.locostbuilders.co.uk/gall...cost%20sus.JPG

https://d2t1xqejof9utc.cloudfront.ne...df67/large.jpg

[IMG]https://www.google.co.nz/search?q=locost+suspension+drawing+-+mazda+mx+5&client=firefox-b&sa=X&biw=1440&bih=728&tbm=isch&tbo=u&source=univ &ved=0ahUKEwiM0siDsrHSAhXCH5QKHWaVCHIQsAQIFw#tbm=i sch&q=locost+suspension+drawing+&*&imgdii=r4cVw4yx Y09UuM:&imgrc=KafhWiBCsdZYaM:[/IMG]

http://s46.photobucket.com/user/monk...3copy.jpg.html

chassis
 

Hi

This is a diagram of the deon front suspension. Unlike the locost wishbone where the ball joint screws in or out, the deon ones have the adjustment on both the inner arms where the wishbones bolts to the chassis rather than at the upright. The ball joints were bolted in securely. I guess this allows fine tuning of the upright angle? Both top and bottom wishbones have this arrangement.
The rear wishbones on earlier JHC cars also had this adjustment on both upper and lower wishbones ,but later deon cars had a fixed upper wishbone.
When I come to make my chassis I can draw a diagram and add sizes if anyone is interested.
You're right about the deon/jhc chassis being fine tuned by geoscan.It was said to have been tested at castle combe circuit.

ian

chassis
 

What site are you on for this-might be worth a read-ian

These images were just grabbed randomly via google image search to show how other people had sketched dimensions. However the Locost community in general have lots of discussion about suspension design as they tend to customise their DIY, built from scratch designs using a variety of donor parts.

http://www.locostbuilders.co.uk

https://www.locostusa.com/forums/ (although often the donor parts are USA specific, except for Mazda MX5)

http://sevenesque.com/plans/ (McSorley's site has lots of plans and DIY suspension fine tuning without all the maths advice)

http://www.super7thheaven.co.uk (lots of engine fitment, radically different ideas)

cheers
Ross

chassis
 

Hi

how about this? some guy on FB is designing a chassis for a ferrari on cad/system works. looks similar to the dino one.

ian

An interesting start to a design. Do you have a link to it on FB? At present it just looks like a version of the 1960s Dino design - which was essentially a platform design without much triangulation. It relied on some heavy big tubes and a few basic upright frames. The sports racing Dino 206sp chassis - multi tubular, small tube, augmented by riveted aluminium sheet is a far more advanced design than the road-going Dino 246http://homepages.paradise.net.nz/aca...205chassis.jpg. This is a replica one I saw being built in Invercargill NZ in the '90s.Its a bit like comparing a Dutton to an Ultima.

chassis
 

Hi there

The chassis design he posted was a project for a ferrari f40 he was constructing. The fb page is just titled 'kit cars' and the post show various stages from chassis design and sizes up to a complete car. There are some nice photo's. Check out 'nitescu lon laurentiu'

ian

Ferrari F40 replica
 

Some more F40 links for fun.

here's an F40 replica with twin turbo Toyota V8 - 700BHP made in my home town:
https://www.youtube.com/watch?v=SmZR9ynRPio

the last couple of pages of the factory F40 manual have chassis drawings and dimensions (and suspension views too):
http://axisofoversteer.com/blog/docu...0_USA_1992.pdf