So after my 2001 MX-5 MK2.5 wont pass its MOT next year due to rusting sills (I could weld them but I needed an excuse to start a locost project) I started making my chassis.

Plans for the build;
Try to follow as close to the MA7DA racing series as possible, I'm undecided weather to go full roll-cage or leave it and install one later.
Build some sort of bench to build on.
Chassis - following Ron Champions £250 car, but using the MA7DA adjustments.
Engine - 1.8 VVT from my mx-5 - want to rebuild at some point - shall I go turbo/supercharge or go for high comp N/A build?
Electrics - depending on how skint I'm feeling I may just use the mx-5 wiring, but might splash on the emerald cpu or megasquirt.
Suspension/Axles - following MA7DA regs so Cortina mk3/4/5 uprights and escort Mk1/2 live rear axle.

That is the plan, however I may decide to scrap the MA7DA and just use my MX5 diff (which has a lsd in it) and uprights. my only concern is that the parts availability for new/aftermarket MX5 uprights isn't great. What does anyone think/have any experience?
Also I already have some 15x8j 4x100 wheels from my mx5 with AD08r's on them which I would like to use but unsure if they will fit the Cortina uprights/hubs or just use adaptors?

If anyone has any questions or pointers please post them.

Keen to hear if anyone has anything to comment on.

Pictures to come - I have made my bench and started the chassis already

I found an old 2.4x1.2m bit of plywood and some bits of 2x4, screwed them together to make my bench to work on.

Started cutting steel on the old band saw in the shed and used some small bits of wood I cut to clamp everything into place before welding.

After finishing the base - I checked the dimensions and checked them again, clamped it down and fully welded it. Not sure if I should have waited until I had made a bit more before welding it but its done now and pretty straight. Might be 3mm out max.

Please ignore the state of my garage, I have to work around my families stuff so there is not much I can do!

[Edited on 9/11/21 by rconey01]

Looks like a good project, keep the pics coming, questions too. This is the best place for help I think.

Looking at the bare chassis of these seven type cars, with the tapered front end, I always think it's going to be a speedboat......

Have a look at @Tools n track@ on You tube for a series of videos about building an MX5 based 7. There is a thread on here as well if you have a search for it. Very informative and humourous.

Have a look at Project 7 Up lower down this section as they are fantastic youtube stars showing them building the same type 7. It'll give you a fantastic head start !!

Thats the one I suggested as well!

http://www.locostbuilders.co.uk/forum/66/viewthread.php?tid=217361

Great to see a new project built up from scratch. Keep the updates coming!

Someone on here must have further good tips for an MX5 based Locost build, including if any chassis mods needed to the original Locost book chassis plans (or does everyone use the later Locost roadster Haynes book to use Sierra independent rear suspension in MX5 builds?).

The LocostUSA forum might be worth a look too and joining as they will have people using ‘Miata’ donors as more readily available than European Ford parts from MkII Escorts (engine, gearbox and rear axle) and MkV Cortina front hubs. See: https://www.locostusa.com/forums/viewforum.php?f=46&sid=ed7b092abe27a9c4c78052616c229e6b

Might be useful ideas from Westfield 7 builders too as IIRC you could get a single donor MX5 Westfield kit?
https://forum.wscc.co.uk/forum/

Cheers
Mike

[Edited on 10/11/21 by Mike Wood]

[Edited on 10/11/21 by Mike Wood]

[Edited on 10/11/21 by Mike Wood]

[Edited on 10/11/21 by Mike Wood]

Not a negative reply but you really need to clamp the frame down well and keep the build base and chassis rails as flat as possible. 3mm now is not a lot but when you start adding the verticals and then top rails you could be quite far out.

Exciting project and the pinnacle of kit car build.

Thanks chaps, really helpful!

Was having a look at escort rear axles and they seem like a very expensive option. Does anyone know best place to source a cheap one? Or should I scrap the ma7da regs and use my mx5 rear end?

quote:

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Originally posted by rconey01
Thanks chaps, really helpful!

Was having a look at escort rear axles and they seem like a very expensive option. Does anyone know best place to source a cheap one? Or should I scrap the ma7da regs and use my mx5 rear end?

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quote:

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Originally posted by nick205

quote:

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Originally posted by rconey01
Thanks chaps, really helpful!

Was having a look at escort rear axles and they seem like a very expensive option. Does anyone know best place to source a cheap one? Or should I scrap the ma7da regs and use my mx5 rear end?

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Not purchased/used an Escort rear axle myself, but I'd imagine they're expensive - even scruffy ones.

Do the ma7da regs give you any other options for the rear axle?

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An unfinished/wrongly registered old kit car might be a useful source of bits including an Escort axle. As long as you can get it cheap enough depending on how many of the bits you need for your build and others you can sell on.

Keep an eye on evil bay for ‘kit cars’ like Locusts (not a typo), stalled Locost or Robin Hood builds, very tired Jago Jeeps and Duttons. Need a tape measure for axle width and info to make sure you are looking at Escort not the wider Capri or Cortina axles (or the unlikely to find narrow Anglia axle). I picked up a Locost rolling chassis (bare rolling chassis - no ali panels or fixed bodywork) and bits for about £800 a few years ago including installed Escort axle, Cortina hubs, steering rack and column, and a loose 1300 engine (unfortunately no engine number) and box, and some distinctly secondhand damaged bodywork.

Another option people talk of is a Freelander diff, but more expense in sorting the driveshafts to the wheels in an IRS set up, compared to welding brackets to an Escort axle for a live axle set up with trailing arms as per the original Locost book.

Good luck

Cheers
Mike

[Edited on 10/11/21 by Mike Wood]

[Edited on 10/11/21 by Mike Wood]

Since you have a Mazda diff etc I would go for that route the later model Haynes is wider than the original which fits the escort axle so I don't know if that takes you away from your original plan too much. My Mazda Haynes roadster was a hybrid where I used Sierra diff and running gear and everything else Mazda

Great to see another scratch build . Take your time and measure everything several times. Take photo's of everything as you go as you'll need that later and save every receipt in big folder.

I'd leave the MX5 totally complete and running until your actually needing it's parts. Even then I'd keep the engine and gearbox in and working right till the end rather than take it all apart at the start and have a huge heap of parts to get in the way.

[Edited on 11/11/21 by Mr Whippy]

Slow progress, only get time for an hour or 2 after work on some weekdays and weekends when im not busy.
Going up, hopefully start making wishbones before christmas.

Nice progress.

An example of a part built Locost project that pops up for sale: https://www.ebay.co.uk/itm/185157700797?hash=item2b1c424cbd:g:kFIAAOSwKKhhjNvk interestingly with an Atlas not an English axle.

Also picture of Mazda diff in a Westfield chassis: https://forum.wscc.co.uk/forum/topic/104326-identifying-different-types-of-rear-suspension-and-diffs/

Cheers
Mike

[Edited on 12/11/21 by Mike Wood]

Had a good run at the chassis this weekend, got the main chassis done, minus the trans tunnel and some bracing as I dont have any 19mm box or tube in. Got this all welded and its properly straight and solid now. Looking at it, unsure if the engine will fit haha, must do though as thats how the ma7da lot build it

Just the rear section to figure out now, I think I will stick to the Haynes rear end and mod it to fit the mx-5 diff as thats what most people seem to find the easiest.
I'm going to put a full roll cage in, anyone know anywhere that will fit one, I understand that procomp offer a roll cage fitting, are there any others?

Wow, that is some great progress.

You can buy ready made wishbones if you want from Rally Design or MK:
https://www.rallydesign.co.uk/advanced_search_result.php?search_in_description=1&keywords=Locost&x=20&y=11&osCsid=c18dq8u7ccuk2j5lr5je b5smn0

http://www.mksportscars.com/parts/locost.html

Cheers
Mike

[Edited on 15/11/21 by Mike Wood]

Thanks Mike,

Think I'm going to make my wishbones, they're a bit expensive to buy, especially if they're standard and not specific to the setup you want.

Enjoying your build thread and DIY approach.

You ask about roll over protection systems (ROPS). Best to work out what you want to do with the car so if you do decide to sprint or hillclimb it the rear rollover bar/full rollcage conforms with the correct rules for cage design and tube specification, see Section K1 and Section S of: https://www.motorsportuk.org/wp-content/uploads/2021/08/2021-09-02-motorsport-uk-yearbook-2021.pdf
(worth checking on this forum with those who compete with their cars as well as the Uphillracers forum). And keep an eye on how these regs change and for any championship supplementary regulations. I know I am jumping ahead, but you will not want to build the cage twice if you decide to compete in the car. Also think about rear harness mounts, how any seat will fit and if harness mounting is compatible with a head restraint system (HANS) in association with a suitable race harness, if HANS is a requirement or preference. And also you can get the car through IVA.

In addition to Procomp as a possible rollcage supplier and fitter - http://www.procomp.co.uk/rollcage.html - someone on the Westfield forum had a recommendation for a company in Essex (MJS Fabrications in Malden)that built them a rear roll bar for a Westfield Eleven that they used for competition, see: https://forum.wscc.co.uk/forum/topic/122870-building-my-eleven/page/6/

If you go DIY, suitable tube can be supplied bent, e.g. by: https://tube-bender.co.uk/hoops.html

Have you got a copy of Allan Staniforth’s ‘Race & Rally Car Sourcebook’ as has some handy info? Should be available secondhand.

Cheers
Mike

[Edited on 20/11/21 by Mike Wood]

[Edited on 20/11/21 by Mike Wood]

[Edited on 20/11/21 by Mike Wood]

[Edited on 20/11/21 by Mike Wood]

[Edited on 20/11/21 by Mike Wood]

[Edited on 20/11/21 by Mike Wood]

[Edited on 20/11/21 by Mike Wood]

[Edited on 20/11/21 by Mike Wood]

Slow progress, custom rear end to fit the mx5 diff as I dont have the saturn plans. More steel arrived so I can crack on with the bracing and trans tunnel soon. Lucky that work have a plasma cutter so I can get all my plate cut soon.
Plan on getting a pipe bender to do my roll cage in parts then i'll assemble it/weld it in.

Work on the transmition tunnel has started, didnt buy enough 3/4" box so need to order some more. Also I got work to plasma cut out some of the plates I need, mainly 3mm but a couple 6mm for the diff mountings.

Nice to see another one starting from scratch and an impressive pace of getting the frame knocked together.

Have you done any destructive tests of your welded joints?

A lot of the welds look to have quite a high crown so might be lacking penetration, but if they need any rework, now is the time to do it while you can get at most of them.

Cutting a joint perpendicular to the weld and seeing how much penetration you have is probably the most illuminating method rather than just smacking a T joint with a hammer to see what breaks first. A high crown might give you enough strength as laid but anywhere you need to linish it back flat might cause issues.

Good luck, keep the momentum going!

Thanks for your concern on my welds haha, I do plan to grind and weld again any welds that look a bit suspect.

Looking good.

This might be a useful picture, albeit of a Roadster MX5 build: https://completekitcar.co.uk/2021/07/05/haynes-roadster-rolling-chassis/

Cheers
Mike

[Edited on 30/11/21 by Mike Wood]

Hi

I have you seen this - looks like a very handy MK Indy donor - still plenty of building to do. Keep you chassis as a spare/track project in future…
https://www.ebay.co.uk/itm/265432769288?mkevt=1&mkpid=0&emsid=e11021.m43.l1120&mkcid=7&ch=osgood&euid=92e7de84782844e9a48f4256010d 4f8e&bu=42986122776&ut=RU&osub=-1%7E1&crd=20211202081009&segname=11021&sojTags=ch%3Dch%2Cbu%3Dbu%2Cut%3Dut%2Cosub%3Dosub%2Ccrd %3Dcrd%2Csegname%3Dsegname%2Cchnl%3Dmkcid

Cheers
Mike

quote:

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Originally posted by Mike Wood
Hi

I have you seen this - looks like a very handy MK Indy donor - still plenty of building to do. Keep you chassis as a spare/track project in future…
https://www.ebay.co.uk/itm/265432769288?mkevt=1&mkpid=0&emsid=e11021.m43.l1120&mkcid=7&ch=osgood&euid=92e7de84782844e9a48f4256010d 4f8e&bu=42986122776&ut=RU&osub=-1%7E1&crd=20211202081009&segname=11021&sojTags=ch%3Dch%2Cbu%3Dbu%2Cut%3Dut%2Cosub%3Dosub%2Ccrd %3Dcrd%2Csegname%3Dsegname%2Cchnl%3Dmkcid

Cheers
Mike

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Slow progress at the moment, being caught up in University assignments is a pain. Will be finishing the trans tunnel, bracing and rear frame shortly as I've got some more time on my hands now. Then its time to strip the mx-5.

I've been looking to get an engine crane, does anyone have one for sale/borrow?

[Edited on 15/12/21 by rconey01]

Where are you located? I have an engine crane not doing much at the moment but will probably use it end of Feb-March. I'm just north of Bristol. Fits in an estate car if dismantled

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Originally posted by Sanzomat
Where are you located? I have an engine crane not doing much at the moment but will probably use it end of Feb-March. I'm just north of Bristol. Fits in an estate car if dismantled

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Update, Trans tunnel finished and diff mountings in, a couple of the side bracings are also in. Also welded up quite a few bits and tidied up some welds and ground down some areas. Next to finish the rear end and try to bend some pipes.

I hung the diff and possitioned the plates while the diff was in-situe to weld them so I knew it would be in the right position.

Does anyone know if a £40 15/22mm pipe bender from screw fix will be any good for 19mm pipe? If not I will have to make a jig out of wood and bend it around that.

quote:

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Originally posted by rconey01

Does anyone know if a £40 15/22mm pipe bender from screw fix will be any good for 19mm pipe? If not I will have to make a jig out of wood and bend it around that.

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