MX5 Donor, Using as a Donor/problems/solutions/advice Info

[HandyAndy]

A great suggestion has been put forward by forum member "Johno" to have a dedicated MX5 Donor page on the forum, as the Sierra is getting a little thin on the ground & as the current "Book" is written around using a Sierra then this thread will hopefully be a source of information for any current or future builders using the MX5 as a Donor.

There are currently some great builds in progress using the MX5 & all have their own "Build Threads" so, this thread will be a source of helpful tips / advice / solutions of using the MX5 which may hopefully help all current builders & hopefully encourage any future builders of a Roadster that may possibly think twice about a build due to a shortage of Sierra,s to take the plunge & build with an MX5.

So......Over to you guys who are or will be using this alternative Donor .

cheers
andy

[Johno]

Hi Andy,
Looks a bit quiet on here so I think I will start the ball rolling... (come on guys form an ordely que)...LOL
I asked Andy to put up a page to help out new members going down the MX5 route (plus ongoing builds) so lets not let him down.:D
Sometimes it's hard to pick out the info you need from this forum for specific related builds so lets put together information on this page for sound advice for new converts to the MX5.

Well here's my first two pence worth.
A good place for information regarding the MX5 for a Haynes/Locost build is Keith Tanners Seven build.

Just Google the above and you wil find over 1400 entries of all aspects of his build.
Well worth a look....:D

Johno

[Dualist]

Brilliant, can you sticky this then please.?
I'm going the mx5 route so will need all the help I can get and would need to find it easily. ;)

[PorkChop]

Some pointers about donor choice, or things to look out for if you're buying parts piecemeal rather than a complete donor.

All the 1600 and 1800 parts are interchangable to an extent. For example, you can run a 1600 engine and gearbox with a 1800 diff. You would need a 1800 prop and drive shafts to suit the diff. A 1600 engine will fit a 1800 gearbox.

Apparently (I don't know if this is true or not) but the 1600 gearboxes and diffs are slightly weaker than their 1800 counterparts.

A common upgrade for the 1600 engine (especially if tuned) is to fit the 1800 flywheel and clutch.

You can tell the 1600 and 1800 apart by looking at the cam cover - the 'Mazda 16V DOHC' lettering is raised on a 1800, sunk on a 1600. The 1800 has 'BP' cast into the block on the exhaust side.

The 1800 comes with bigger brakes as standard all round. Mark 2 Sport brakes are bigger still.

Early driveshafts are bolt on (and the PCD is different between the 1600 and 1800). Later driveshafts are push on (and I believe are still different between the 1600 and 1800).

There were several wiring revisions over the course of the mark 1's life.

Early 1600s ('short nose') engines had crank problems. Later long nose engines are fine. They can be identified by counting the number of slots on the crank pulley. The short nose has 4 slots, the long nose 8.

Any imported (Eunos) 1600 engine will be 115bhp, as are UK engines of the same era. The JDM 1600 was discontinued when the 1800 was introduced. The UK 1600 was then detuned to 88/90bhp at this time, so any later UK spec 1600 would be the 90bhp version.

The OEM alloys are very light for an OEM wheel. You would need to spend a significant amount of money to get lighter aftermarket ones.

A mark 3 MX5 gearbox will fit the Ford Duratec apparently :)

The mark 2 6 speed box is rumoured to be stronger than the mark 1 5 speed.

[Big Vern]

Some pointers about donor choice, or things to look out for if you're buying parts piecemeal rather than a complete donor.

All the 1600 and 1800 parts are interchangable to an extent. For example, you can run a 1600 engine and gearbox with a 1800 diff. You would need a 1800 prop and drive shafts to suit the diff. A 1600 engine will fit a 1800 gearbox.

Apparently (I don't know if this is true or not) but the 1600 gearboxes and diffs are slightly weaker than their 1800 counterparts.

A common upgrade for the 1600 engine (especially if tuned) is to fit the 1800 flywheel and clutch.

You can tell the 1600 and 1800 apart by looking at the cam cover - the 'Mazda 16V DOHC' lettering is raised on a 1800, sunk on a 1600. The 1800 has 'BP' cast into the block on the exhaust side.

The 1800 comes with bigger brakes as standard all round. Mark 2 Sport brakes are bigger still.

Early driveshafts are bolt on (and the PCD is different between the 1600 and 1800). Later driveshafts are push on (and I believe are still different between the 1600 and 1800).

There were several wiring revisions over the course of the mark 1's life.

Early 1600s ('short nose') engines had crank problems. Later long nose engines are fine. They can be identified by counting the number of slots on the crank pully. The short nose has 4 slots, the long nose 8.

Any imported (Eunos) 1600 engine will be 115bhp, as are UK engines of the same era. The JDM 1600 was discontinued when the 1800 was introduced. The UK 1600 was then detuned to 88/90bhp at this time, so any later UK spec 1600 would be the 90bhp version.

The OEM alloys are very light for an OEM wheel. You would need to spend a significant amount of money to get lighter aftermarket ones.

A mark 3 MX5 gearbox will fit the Ford Duratec apparently :)

The mark 2 6 speed box is rumoured to be stronger than the mark 1 5 speed.

Little can be swapped between 1600 and 1800 engines but they do both fit in the same 'hole' and fit on the same gearbox.

1600 diff up to 94 is 6" crown wheel from 94 all diffs 7" crown wheel and essentially the same as RX7.
7" naturally stronger than 6" but both are stout. 6" are open or the unpopular VLSD, 7" available as open or with Torsen type 1 or 2.
Three different types of driveshaft depending on the diff you have so get the driveshafts at the same time to go with the diff.

MK2 gearboxes are 'better' than mk1 in that the mk1 is intentionally noisy but this proved unpopular and the leaky remote change was redesigned but both are equally stong as they came from the B1600 pick up.

Clutches - If running a tuned 1600 N/A engine then avoid the heavy 1800 flywheel better to use a H/D 1600 clutch. I'm using a 1600 flywheel and clutch on my nearly stock 1800 with no problems.
If turbo'ed then use the 1800 flywheel and MX6 clutch unless running mental amounts of power

5 speed boxes have better ratios that the 6 speed and in something like the haynes roadster first in the 6 speed would be pointless. Just extra weight to carry around and as its bigger, more of a squeeze on footwell space.

Brakes - Mk1 1800's have bigger front brakes, Mk2 1600 and 1800 had the MK1 1800 brakes and bigger rears, MK2.5 had bigger fronts again and then there were bigger rears for some special editions.

Wheels MK1 all 14" MK2 15" MK2.5 16" mk3 17"

Mk3 MX5 does indeed use the duratec engine as it was part developed by Ford and Mazda. (Well Ford does own part of Mazda)
So a Mondeo engine can be used but a mazda flywheel clutch and starter will be needed. I have a MK3 6speed if anyone wants to make me an offer?

MK1/2 parts Hardly anything interchanges with the MK3's. The MK3's all different, being based around the RX8.

[chrisponter]

The 1.6 inlet manifold is bigger making it harder to fit it under the bonnet, but people on here have managed it.

+1 on Johno's point about Keith Tanners book How to Build a Cheap Sports Car, it's just about how he managed to overcome all the problems in his build. And his contact details are in the back, there's not much he doesn't know about taking apart an MX-5 and he will answer you if you send him an email.

[HandyAndy]

Brilliant, can you sticky this then please.?



:) Consider it done :)

Great to see some very helpful info being posted, I,m sure this thread will be a great source for all MX5 donor builds....:cool:

cheers
andy

[Johno]

Hi all,
Some good info there guys...;) . Thanks for helping out with the page to get it going and thanks to Andy for making it a Sticky.
Well I'm going to keep it short and sweet. Here's a guy from the good old US doing a Haynes Roadster the American way.
http://www.locostusa.com/forums/viewtopic.php?f=35&t=8967

Some very interesting ideas there for a different approach to the car.
Have a look and see what you think...

Johno

[vmax1974]

Got the rear subframe dropped down to the floor today but the front subframe has got caught up on the threads

As far as I can tell all the groundwork to removing the subframe has been done

Have I missed anything why even bashing the subframe with a length of wood and a sledge hammer it just wont budge

[PorkChop]

Got the rear subframe dropped down to the floor today but the front subframe has got caught up on the threads

As far as I can tell all the groundwork to removing the subframe has been done

Have I missed anything why even bashing the subframe with a length of wood and a sledge hammer it just wont budge

Have you undone the 2 14mm bolts right at the rear of the subframe? There's 8 bolts to undo IIRC in total including the 4 around the strut tops.

Little can be swapped between 1600 and 1800 engines

That was the 'to an extent' bit that I mentioned ;)

[chrisponter]

Got the rear subframe dropped down to the floor today but the front subframe has got caught up on the threads

As far as I can tell all the groundwork to removing the subframe has been done

Have I missed anything why even bashing the subframe with a length of wood and a sledge hammer it just wont budge

The front is bolted on in 4 places I think, once on each side inline with the wishbones, then some more further back and in towards the middle of the car.

I did the back ones first, then held it up with a jack while I undid the fronts.

Can't remember if that rear bit uses 3 or 2 bolts though.

http://i1097.photobucket.com/albums/g348/superchickenlegs/FrontSubframe.jpg

Does that help?

[vmax1974]

Have you undone the 2 14mm bolts right at the rear of the subframe? There's 8 bolts to undo IIRC in total including the 4 around the strut tops.


Yes got the 2 rear most ones and 2 each side at the top of the subframe behind the strut that makes 6 where is the other 2

[alga]

+1 on Johno's point about Keith Tanners book How to Build a Cheap Sports Car, it's just about how he managed to overcome all the problems in his build.

His build log was my inspiration to start my own build! Sadly, the book is out of print and unavailable on the online booksellers for a reasonable price.

[PorkChop]

Have you undone the damper mountings? There's 2 bolts on each side. You won't be able to separate the shell from the subframe if you don't undo these.

[vmax1974]

Have you undone the damper mountings? There's 2 bolts on each side. You won't be able to separate the shell from the subframe if you don't undo these.

Yeah got them too spent most of the last 4 hours head scratching and double checking next step is going to be the gas axe I think

[PorkChop]

Yeah got them too spent most of the last 4 hours head scratching and double checking next step is going to be the gas axe I think

I know it's a bit late now, but it might help someone else - the bolts you mean are a bit hidden.

If you look at the front lower wishbone from the side of the car, you'll see an indentation in the bodyshell just slightly further back from the rearmost wishbone mounting. That's where the bolt is hidden, one on each side of the car.

These 2 bolts should be immediately obvious if you have either a pit or a lift.

[shh120m]

Solution to steering rack clearance issue. Turned alluminium tapered insert fitted into control arm on upright reamed to take standard ford rs2000 track rod ends from the top as opposed to underneath. Picture taken without rack in place but gives an idea how much clearance there is now. Its yet to be seen if there is any significant change to the amount of bump steer as the instant centre position is changed from the original setup, but either way its safer than having contact between rack and wishbone. I did toy with the idea of changing the upper wishbone to induce some negative castor, both to help lift the control arms and help with self centering, but it would be no consellation to those who have already made their wishbones so i think this is the best solution, although iirc talon was talking about using the bent bmw track rod ends- thats another solution well worth playing with, i dont know if hes tried it might be worth a mention.

David bolam was asking about wingstays, if you make them like mine, just be sure to make sure the return angle at the bottom clears the wishbone plates at full hight of travel otherwise if there is any interference it could cause an accident whilst flying over the brow of a hill not being able to steer, probably best to use the dust cover holes as mounting points as suggested, something i never thought of duh




http://i97.photobucket.com/albums/l213/shh120m/SAM_1146-1.jpg

[garylomas]

Hi,Im joining you guys ,just bought an MX5 based chassis off a guy on e bay that was never started and came complete with all running gear,1800cc
need to start looking at the brackets necessarry for the sterrring column ,pedals etc
I think its a better choice than a sierra based model nowadays
cheers
Gary

[Johno]

Hi,Im joining you guys ,just bought an MX5 based chassis off a guy on e bay that was never started and came complete with all running gear,1800cc
need to start looking at the brackets necessarry for the sterrring column ,pedals etc
I think its a better choice than a sierra based model nowadays
cheers
Gary

Hi Gary welcome aboard....:)
Plenty of people on here more than welcome to help you out..
So don't hesitate to ask.....:D

[PorkChop]

Hi,Im joining you guys ,just bought an MX5 based chassis off a guy on e bay that was never started and came complete with all running gear,1800cc
need to start looking at the brackets necessarry for the sterrring column ,pedals etc
I think its a better choice than a sierra based model nowadays
cheers
Gary

Welcome Gary :)

Was this the chassis you bought? http://www.ebay.co.uk/itm/290779639242

[garylomas]

no the seller was Reading based
what caught my eye was the MX5 dodr option as I believe it has more character than traditional Sierra choices, and also the less availability of Sierra parts currently which will only get worse I guess
I am trying to go the route of clam shell wings as a preferance and wondered why most go cycle wings,hopefully this is personal choice rather than influenced by IVA approval!
cheers
Gary

[will_08]

Only prob is when you've built it you'll need to get a perm :p

I hope i never bump into Skov at any point! :)

[ozzy1]

I am trying to go the route of clam shell wings as a preferance and wondered why most go cycle wings

Clam shell wings are very "old skool" and cycle wings are more modern really but its personal choice .At the end of the day its your car do what you want V6,V8,turbo,nitrous,jet engine, whatever takes your fancy really :D

[Not Anumber]

Clamshell wings give an early, iconic look but are not regarded as very aerodynamic. Caterham started to fit them (mid 60's KAR120c etc ) but then changed back to cycle wings and stayed with them.
I may get a pair of clamshells sometime if some come up at the right price but would need to mount them so the car could be easilly swapped back for long trips etc

[alga]

Clam shells have a lot of lift at high speeds!

[skov]

Only prob is when you've built it you'll need to get a perm

I hope i never bump into Skov at any point!

oi!

https://lh6.googleusercontent.com/-0KNCWMHY5Bo/UHAxExhGceI/AAAAAAAAIsU/WoTN302pU4E/s601/big_silly_goose.JPG


Thinking about fitting a blower to mine post-IVA, not sure which one to go for though, this:

https://lh4.googleusercontent.com/-h0LiAzr_YNw/UHAxuYhuUKI/AAAAAAAAIsc/OYT7tZ0MteM/s640/T45.JPG

or this:

https://lh4.googleusercontent.com/-x8hnbsq9AFc/UHAxunMpp_I/AAAAAAAAIsg/XEIqhLDWato/s450/babyliss-pro-power-lite-pink-hairdryer-large.jpg

:D

[fangorn]

This is the way I will be going.I have the steel and a MX5 donor. Once I tidy up my work area and make a build table I'll be into it!! It is great to have a MX5 area.Sierras are Dodos here in New Zealand.

[vmax1974]

What size and grade bolts have people used to hang the diff

Need to know before going and ordering my nut and bolt set

Using the saturn plans and want to get the diff mocked up this week

[Talonmotorsport]

Can I ask how you are planning to mount the diff?

[Davidbolam]

I will pop some photos up of my modified mount in the next few days

I have made sure it won't budge

David

[PorkChop]

What size and grade bolts have people used to hang the diff

Need to know before going and ordering my nut and bolt set

Using the saturn plans and want to get the diff mocked up this week

Dunno about size, but you'll want 8.8 grade at the very least.

[PorkChop]

Solution to steering rack clearance issue. Turned alluminium tapered insert fitted into control arm on upright reamed to take standard ford rs2000 track rod ends from the top as opposed to underneath. Picture taken without rack in place but gives an idea how much clearance there is now. Its yet to be seen if there is any significant change to the amount of bump steer as the instant centre position is changed from the original setup, but either way its safer than having contact between rack and wishbone. I did toy with the idea of changing the upper wishbone to induce some negative castor, both to help lift the control arms and help with self centering, but it would be no consellation to those who have already made their wishbones so i think this is the best solution, although iirc talon was talking about using the bent bmw track rod ends- thats another solution well worth playing with, i dont know if hes tried it might be worth a mention.

David bolam was asking about wingstays, if you make them like mine, just be sure to make sure the return angle at the bottom clears the wishbone plates at full hight of travel otherwise if there is any interference it could cause an accident whilst flying over the brow of a hill not being able to steer, probably best to use the dust cover holes as mounting points as suggested, something i never thought of duh




http://i97.photobucket.com/albums/l213/shh120m/SAM_1146-1.jpg

Just to add to this; I've been researching both locostusa and Keith Tanner's build site.

The vast majority of people Stateside have had issues with the track rods fouling the lower wishbone. There are several reported ways of tackling this...

1 - straighten the steering arm so that it's horizontal, then ream to take a TRE from the top. Don't like the idea of this as you'll probably have to heat the arm, so the upright could be fatigued as a result of this.

2 - a mark 2 MX5 upright has raised steering arms compared to the mark 1 (7mm difference). The TRE would fit as OEM. There should be enough adjustment in the steering design to remove any bump steer that this might dial in. The 7mm may be enough to provide sufficient clearance. This is how Keith Tanner did it after trying rose joints on mark 1 uprights.

3 - remodel the front edge of the lower wishbone to clear the steering rack completely. This is how it is on a MX5.

Looking at the way Nathan has done it, I would be tempted to try a MX5 TRE instead of a Ford item in that situation. The cranked end of the TRE would bring the track rod down a bit, should still provide sufficient clearance for the lower wishbone and might reduce the amount of bump steer introduced by doing this.

Here's an article I found on bump steer - http://www.longacreracing.com/articles/art.asp?ARTID=13

Any thoughts?

[vmax1974]

Can I ask how you are planning to mount the diff?

Same way as the donor bolt through the mounts then rigidly mount the doughnut rubber to a plate welded to the diff cage

Then I was thinking about solid mounting the diff nose to take the place of the ppf on the donor was also going to work out a shield to protect me should the diff break

[Talonmotorsport]

Have you thought about making a bracket out of some 5mm plate that looks like this at all? Remove all the blocks/brackets around the nose fit some 3/4-19mm round stock with 12mm through holes in the 18-19mm holes in the nose and use M12 bolts.

http://i812.photobucket.com/albums/zz50/talonmotorsport/mx5diffnose_zpsdedbd948.jpg

[vmax1974]

That was the kind of thing I had in mind

Was worried about vibration from the diff till I remembered the book build diff is hard mounted to the chassis

[Talonmotorsport]

Just to add to this; I've been researching both locostusa and Keith Tanner's build site.

The vast majority of people Stateside have had issues with the track rods fouling the lower wishbone. There are several reported ways of tackling this...

1 - straighten the steering arm so that it's horizontal, then ream to take a TRE from the top. Don't like the idea of this as you'll probably have to heat the arm, so the upright could be fatigued as a result of this.

2 - a mark 2 MX5 upright has raised steering arms compared to the mark 1 (7mm difference). The TRE would fit as OEM. There should be enough adjustment in the steering design to remove any bump steer that this might dial in. The 7mm may be enough to provide sufficient clearance. This is how Keith Tanner did it after trying rose joints on mark 1 uprights.

3 - remodel the front edge of the lower wishbone to clear the steering rack completely. This is how it is on a MX5.

Looking at the way Nathan has done it, I would be tempted to try a MX5 TRE instead of a Ford item in that situation. The cranked end of the TRE would bring the track rod down a bit, should still provide sufficient clearance for the lower wishbone and might reduce the amount of bump steer introduced by doing this.

Here's an article I found on bump steer - http://www.longacreracing.com/articles/art.asp?ARTID=13

Any thoughts?

That seems like an a lot of machine work for a home builder to do why not just make the whole thing more simple like this:

http://i812.photobucket.com/albums/zz50/talonmotorsport/bentbones1-1_zps35ffc4c1.jpg

[PorkChop]

So there is an option 3 available :D; my problem is I've already got the front wishbones to SSC spec.

[Talonmotorsport]

I really don't like the SSC front lower wishbone design it realise on people's ability to weld those adjusters a little too much for my liking, they make the wishbones overly complicated with no apparent need for them as there is an adjustable drag link at the top.

[Davidbolam]

I've got the ssc ones and there is no fouling of the wishbones and steering arms. I have put a limit on the amount of lock available but there is still more than my passat has.

David

[PorkChop]

I've got the ssc ones and there is no fouling of the wishbones and steering arms. I have put a limit on the amount of lock available but there is still more than my passat has.

David

How much lock did you take off David (how thick were your stops?).

[Davidbolam]

Have a look at skov's build photos I did exactly the same

David

[skov]

Phoned up Mazda this week to ask for a proof of age letter for my donor/engine (needed at IVA to determine emissions levels, and hopefully avoid the need to fit a CAT!).

Here's what I did:

Phoned Mazda UK on 08457 484848 and got through to a very helpful chap named Adam (don't worry if you don't get Adam, he claims anyone there should be able to go through the process).

Rumour on the Westfield site has it that you need to talk to the homologations manager (Dean Armitage), I did try asking to talk to him directly, but apparently he doesn't take calls from the general public!

Adam took my personal details, and details of the donor car (vehicle reg, chassis number, and engine number), and filled in a form on his 'puter.
Because my donor is an import a few red warnings came up on his screen and he had to go away and talk to Dean to clarify.
He came back and said it wasn't a problem though!

I don't think their standard proof of vehicle age letter contains the engine number, so I asked if they could include it, after speaking to Dean again he said this shouldn't be a problem.
IVA emissions are based on engine age, so I think it's fairly important to get them to include it!

If you're the first owner of the vehicle there's no charge, otherwise it costs £35. You can pay by bank transfer or by cheque.

I was told I should receive the letter within 14 days of them receiving payment.

I'll update you when I do!

(P.S. Davidbolam gets the credit for digging up the details on how to do this!)

EDIT:

The letter turned up today, much quicker than the 14 days quoted!
Looks like it should convince IVA man not to do a CAT test :D

https://lh5.googleusercontent.com/-5jL-BqdU9bY/UQmT9cPiEkI/AAAAAAAAI9I/IcCr0JiPfYQ/s512/mazda_proof_of_age_letter_censored.jpg

[paul115]

Hey guys,
Moving to NZ in a couple of weeks. I started building the chassis here in the UK with sierra donor part, bit of research suggested that there isnt much point doing it round a sierra in NZ. So, MX-5 it is. I was in NZ for six months to test the water and got a job at a Mazda Car Wrechers and took a couple of MX-5's appart. I noticed that it basically comes on two subframes with a big alli bracer between the two. Has anyone used or thought of using the rear subframe complete, the brace and mounting it all complete to the chassis? Would only have to make the front end then. Or is there something really obvious I'm missing that just wouldnt allow this?

[Talonmotorsport]

The idea of the Roadster is that is light and nimble, by adding a pressed steel sub frame to a light chassis it would seem to defeat the object of the design some what. There is a 7 design that uses the rear sub frame but the name escapes me at this point.
There is of course the MEV Exocet that uses the both the front and rear sub frames including the the back bone, a tubular frame is then dropped over the top but that is a different beast all together.

[paul115]

Knew there would be something obvious! lol

Next question then, does anyone know of any drawings for the differences? I found A pdf file from saturn sports car, is it that simple? imay have a few problems as I have more or less completed my chassis to sierra spec, but nothing a disk cutter and welder cant cure. :D

[paul115]

After having a look about there seems to be two options, Saturn Sports Car and Vodou. Has anyone got a copy of the Vodou plans? cant find them anywhere.

[Talonmotorsport]

If you remove the MX5 rear diff cover and the mounting arms you can make the MX5 diff fit where the Sierra one would go. You would just have to alter the wishbones to take the MX5 uprights.

http://i812.photobucket.com/albums/zz50/talonmotorsport/240720123451.jpg

http://i812.photobucket.com/albums/zz50/talonmotorsport/24072012338.jpg

[Stot]

Heres a tip. Having built a kit car before and being used to sub £10 ford parts.... Don't cut cables and hoses to remove parts from your donor. Mazda parts are not cheap.

£60 for a new set of rear handbrake cables. :eek:
£25+ for used ones... Which I cut a set of not 2 weeks ago. :o

Cheers
Stot

[Johno]

Heres a tip. Having built a kit car before and being used to sub £10 ford parts.... Don't cut cables and hoses to remove parts from your donor. Mazda parts are not cheap.

£60 for a new set of rear handbrake cables. :eek:
£25+ for used ones... Which I cut a set of not 2 weeks ago. :o

Cheers
Stot

I'll second that.....

[CTWV50]

Yep me too forgot the clutch flexi pipe when removing the engine £12 second hand!!

And also "I give up" where's that little thread/guide on adapting the mx5 fuel pump and sender for a SSC tank??

edit ok now got it.

http://www.haynes.co.uk/forums/showthread.php?p=68170&highlight=tank#post68170

[CTWV50]

If you remove the MX5 rear diff cover and the mounting arms you can make the MX5 diff fit where the Sierra one would go. You would just have to alter the wishbones to take the MX5 uprights.

http://i812.photobucket.com/albums/zz50/talonmotorsport/240720123451.jpg

http://i812.photobucket.com/albums/zz50/talonmotorsport/24072012338.jpg

Hi phil,

I've just discovered you absolutely can't use escort track rod ends with mx5 uprights.

http://www.haynes.co.uk/forums/showthread.php?t=12605

Just clicked on your shop link and noticed your selling extensions for mx5 steering balljoints. Is that right?



Cheers

Chris

[PorkChop]

Hi phil,

I've just discovered you absolutely can't use escort track rod ends with mx5 uprights.

http://www.haynes.co.uk/forums/showthread.php?t=12605

Just clicked on your shop link and noticed your selling extensions for mx5 steering balljoints. Is that right?



Cheers

Chris

Yes, it is Chris. I have a pair on order from Phil :)

[CTWV50]

So what kind of gearbox to prop flange clearance are people leaving? As there is no PPF anymore there is likely to be substantially more movement on the splined end of the prop. Any ideas?

[Talonmotorsport]

Hi phil,

I've just discovered you absolutely can't use escort track rod ends with mx5 uprights.

Cheers

Chris

Why would you use Escort track rod ends with MX5 front uprights? The Mazda track rod ends are kinked for use with the angled steering arms on the uprights, the rack extensions that I make for MX5 builds have M12 threads for Mazda rod ends.
There is a post on here some where from me about making the lower front wishbones bent so that the steering arms on the rack clear them.

http://i812.photobucket.com/albums/zz50/talonmotorsport/bentbones1-1_zps35ffc4c1.jpg (http://s812.photobucket.com/user/talonmotorsport/media/bentbones1-1_zps35ffc4c1.jpg.html)

[robo]

Is that kick in the lower wisbone a good idea? It has to be compromised in strength with the set in it and the angle of that tortured track rod end looks less than comfy. I am not knocking it but merely pointing out that from an engineering point of view its less than ideal. It might just be the angle of the shot.

Bob

[Talonmotorsport]

That's the correct MX5 track rod end for the MX5 upright although I don't think it had the top wishbone in place.
I take on board what your saying about the bend and it's been discussed before but it's done with a 25mm tube former so it's as clean as the bend can be.
I looked at the bend in the lower wishbone and came to these conclusions:
the chassis bracket is welded to a 1.5mm walled box section in some cases
the load acts on both ends of the wishbones not in the middle, if any load is transfered through the bend the pivots have siezed
if worried up the material to 3mm wall

[CTWV50]

Just thinking about this wishbone clearance issue. What about putting the lower wishbone chassis brackets beneath the Bottom rails rather than on top. How would that affect things? Might order 4 and try it out as an option.

How's that batch of mx5 steering rack extension coming Phil?

[Stot]

Just thinking about this wishbone clearance issue. What about putting the lower wishbone chassis brackets beneath the Bottom rails rather than on top. How would that affect things? Might order 4 and try it out as an option.

How's that batch of mx5 steering rack extension coming Phil?

Don't think that will be possible.
You would need quite a steep upward angle to keep the upright in the correct place and this would foul the chassis on bump.
The Wishbone would need to be longer.
The lower ball joint would be canted all the way over, locking out on bump.
Also there's no where to put the forward mount on the bottom as its mounted to the angled FF members.

https://lh5.googleusercontent.com/-iX5fdXfVQTM/UXonVkNLkxI/AAAAAAAAExk/lqarEs2f6ds/w600-h648/wishbonemove.jpg

Cheers
Stot

[CTWV50]

Oh yes! :D Not one of my better ideas. lol!

[vmax1974]

Just about to move onto mounting the engine into the chassis what height have people mounted there engines to allow for clearance of steering

I am using the 1.6 engine

All advice greatly appreciated

[skov]

Just about to move onto mounting the engine into the chassis what height have people mounted there engines to allow for clearance of steering

I am using the 1.6 engine

All advice greatly appreciated

I think I've got my sump 40mm below the bottom chassis rails.
Try to get it as far back as you can without the clutch slave hitting the chassis.
Have you got your bodywork yet? I had to shift my engine 25mm towards the passenger side to get the intake manifold to clear my Saturn bonnet.

[vmax1974]

No not got bodywork yet may try and get hold of spud to see if I could borrow some seconds if he has any

[Davidbolam]

No not got bodywork yet may try and get hold of spud to see if I could borrow some seconds if he has any

Good to hear that you are working away on your build. Any pictures you can load up??

David

[Johno]

Hi David,
I fitted the engine in the same place as Skov and Davidbolam but I have the AGM body kit and have no problem with the throttle bracket hitting the GRP.
;)

Post some photos of your car for an update....:)

[Davidbolam]

Hi David,
I fitted the engine in the same place as Skov and Davidbolam but I have the AGM body kit and have no problem with the throttle bracket hitting the GRP.
;)

Post some photos of your car for an update....:)

Johno,

I really like the look of the agm bodywork and have my engine as far back as possible. When I looked at their measurements of their kit I'm not sure it will kit.
Can you tell me how far your engine is from the front member?

[Johno]

Johno,

I really like the look of the agm bodywork and have my engine as far back as possible. When I looked at their measurements of their kit I'm not sure it will kit.
Can you tell me how far your engine is from the front member?

Hi David,
Will check measurement tomorrow. I'm very happy with the AGM kit, sure there are a few imperfections but nothing that can't be sorted. :D

[jason 82]

What drag links are to be used on the mx5 roadster please ? Any help would be really appreciated. Oh by the way, I bought a crash repairable mx5 over the weekend for £300. There are loads of them around in scrap yards, and you get all of the paperwork that goes with it, but without the guilt of wriping apart a clean car.

[PorkChop]

They're BMW 5 series ones; Motaquip part number is VTR325 (BMW E34 5 series saloon, 1988-1996).

HTH.

[jason 82]

Thanks for that Pork chop, you are a star. I have got the Gillham online manual, but it seems really vague.

[Stot]

Those have a different thread to the Transit ones , 16mm vs 18mm IIRC so make sure your wishbones are made with the right thread,

Cheers
Stot

[jason 82]

Brilliant, thank you very much for that. I will get hold of Talon Phil a bit quick.

[skov]

The other option is to use the Transit drag links and ream out the holes in the uprights to match.

[Johno]

Johno,

I really like the look of the agm bodywork and have my engine as far back as possible. When I looked at their measurements of their kit I'm not sure it will kit.
Can you tell me how far your engine is from the front member?

Hi David,
I measured from the front of the water pump pulley to the front cross member and it's approximately 300mm. I wish I moved the engine back a little more though as the cam cover just catches the bonnet right at the front. Not too much of a problem though as I plan to fit a bonnet scoop anyway..:D

[Davidbolam]

Hi David,
I measured from the front of the water pump pulley to the front cross member and it's approximately 300mm. I wish I moved the engine back a little more though as the cam cover just catches the bonnet right at the front. Not too much of a problem though as I plan to fit a bonnet scoop anyway..:D

Johno I have just measured mine and its 285 mm (to the back of the front cross member). I don't know how the engine could go any further back.

I might wait until you have chopped your bonnet to see that is like.

If you removed the flange without cutting the top would it fit?

David

[Stot]

Johno I have just measured mine and its 285 mm (to the back of the front cross member). I don't know how the engine could go any further back.

I might wait until you have chopped your bonnet to see that is like.

If you removed the flange without cutting the top would it fit?

David

I dont know the measurements because I stripped back to the chassis yesterday for painting but this photo shows how far back my engine is. The clutch rubber is in line with the upright.

https://lh4.googleusercontent.com/-EB-vi0ZYmUE/UZeDiXfrXSI/AAAAAAAAE-w/E28NP68AwB8/w800/engineposition6.JPG

I have my engine a bit further to the passenger side which gives me steering rack and inlet clearance. I'm using the Equinox bonnet and it fits without cutouts.

https://lh3.googleusercontent.com/-DnC7mIO2O0Q/UZeDgyncILI/AAAAAAAAE-k/dQc13aSwrpE/w800/engineposition4.JPG

Cheers
Stot

[Johno]

Johno I have just measured mine and its 285 mm (to the back of the front cross member). I don't know how the engine could go any further back.

I might wait until you have chopped your bonnet to see that is like.

If you removed the flange without cutting the top would it fit?

David

I measured mine to the front face of the crossmember...:)
So in fact yours is further back...

[Davidbolam]

I measured mine to the front face of the crossmember...:)
So in fact yours is further back...

Thanks Johno that has made my day!

David

[jason 82]

After stressing about which direction I want to take my mx5 build, the broken diff nose issue keeps arising. Off work with a broken leg, so I am bored and decided to look into it. My local mazda dealer said that it was an issue on the 1.6 mx5, but the 1.8 diff is a lot stronger. I googled it, and can't find any 1.8 diff failures, only 1.6. Are we all worrying about nothing? Or is there a genuine problem, not that well publicised. If my car was a 1.6, I would drop the 1.8 in as a matter of course. But my car is a 1.8, so do I risk it ? Or look into better support ? Just thinking about trying to keep the weight down, and don't want to over complicate the build if I can help it.

[Davidbolam]

After stressing about which direction I want to take my mx5 build, the broken diff nose issue keeps arising. Off work with a broken leg, so I am bored and decided to look into it. My local mazda dealer said that it was an issue on the 1.6 mx5, but the 1.8 diff is a lot stronger. I googled it, and can't find any 1.8 diff failures, only 1.6. Are we all worrying about nothing? Or is there a genuine problem, not that well publicised. If my car was a 1.6, I would drop the 1.8 in as a matter of course. But my car is a 1.8, so do I risk it ? Or look into better support ? Just thinking about trying to keep the weight down, and don't want to over complicate the build if I can help it.

Without opening a can of worms the diff only broke on the saturn nts car as it wasn't bolted on properly. Most people have also beefed up he front mount.

The Saturn nts car was an 1800 engined car.

David

[jason 82]

Thanks for that. I noticed last night that the mk3 diff is mounted from the top. It would be a breeze to fit to the chassis, but I am not sure if its compatible with mk 1 and mk 2 models ?

[Johno]

Ohh the dreaded diff problem....:eek: :eek:
As David said Nathan (NTS) made the mistake of not bolting the diff up correctly.
There seems to be many options as to how to mount this correctly, just check out the Locost USA forums for a starter.
Even the main kit car 7 suppliers have their unique way of installing the diff so there is no one hard rule.
I believe the main concern is containing the torque on the nose of the diff.
Have a look at all the options (check out Keith Tanners problem with this) and see what you can come up with?
I believe Skov is the nearest to getting his car on the road and seems to have the nose of the diff under control with rubber mounts.
Some ppl go for the solid mount option but this may lead to fatigue problems in the future....

Just my observations but I'm sure there are more people out there more knowledgeable than me.:) :)

[CTWV50]

Anyone need any bodywork?

http://www.haynes.co.uk/forums/showthread.php?t=12782

[Stot]

Hi,

I'm getting some questions about my solid diff mounts I made.

https://lh5.googleusercontent.com/-Vo1vE0f1_LU/UfDBhV5Ls8I/AAAAAAAAGdE/1udHmQrLbns/w640/DiffBush3.JPG

Skov and PorkChop asked me a while ago If I could make them some when I did mine to share the cost of the aluminium but I cant make them for others I'm afraid. I'm sure Phil or someone could make them up if asked nicely.

The bushes slip fit as the clamping action will be providing the support hence the thick lugs.

https://lh4.googleusercontent.com/-1XegzETBD6k/UfuDSTRp6wI/AAAAAAAAG5Y/HUyXNdt3gKo/w640/DiffBush.jpg

I made them from 3.5" stock which is the perfect size, I didnt even bother turning down the outside surface.

I chose 40mm and 20mm long because I was able to buy offcuts this size to save further on materials. It gives about a 10mm gap between the two halves when fitted so you can play with the individual lengths really as long as the lug parts are 12.5mm and you leave a gap so they can clamp on the diff ears when bolted up.

Biggest problem I had was getting the old bushes out! A 3 jaw puller makes the job easy and theres some guides on the MX5 forums. I didnt have one of those so used a hammer and chisel to bend the outer bush casing in a bit then pushed them out with a 12 ton press. :eek:

HTH

Cheers
Stot

[jason 82]

Thanks for popping up the dimensions stot. It must be really hard sharing one of your ideas. They are really appreciated. :cool:

[Stot]

It must be really hard sharing one of your ideas. They are really appreciated. :cool:

Not at all mate, I just didnt think to! Hope they help and one of the fabricators can pick them up.

I would have considered making them if

I didnt have a full time job.
I didnt have an app on Android, iOS and PC im trying to maintain in my spare time.
I wasnt building a car in my spare time.
I didnt have a wife (in my spare time)
There wasnt already fabricators who could probably do with the business. ;)

Cheers
Stot

[PorkChop]

And nicely done they are too Stot - thanks very much, I'm very pleased with them :)

[skov]

Very happy with mine too - thanks Stot!

Regarding the original bushes, mine came out fairly easily.
I started off by drilling a load of holes in the rubber then pushed the centre bush and most of the rubber out.
I then set to work on the outer metal bushes with a hammer and screwdriver.
The outer bushes are in two halfs and the trick is to bend one half inwards along the join.
As soon as the two halfs of the metal bush aren't touching the pressure holding them in is released and they pretty much just pop out :D

[PorkChop]

I've posted the SSC coilover specs a few times throughout the forum, but never on this thread...


Front

13" open 9" closed 1.9" ID dampers, with 350lb springs - 8" open x 1.9" ID.

Rear

12" open 8" closed 1.9" ID dampers, with 250lb springs - 7" open x 1.9" ID.

EDIT: AFAIK the front suspension mountings are the same spec as the book Sierra build, so the 13" +1" extension dampers should also fit the front.

[skov]

I've posted the SSC coilover specs a few times throughout the forum, but never on this thread...


Front

13" open 9" closed 1.9" ID dampers, with 350lb springs - 8" open x 1.9" ID.

Rear

12" open 8" closed 1.9" ID dampers, with 250lb springs - 7" open x 1.9" ID.

EDIT: AFAIK the front suspension mountings are the same spec as the book Sierra build, so the 13" +1" extension dampers should also fit the front.


Those shock lengths are fine, but I wouldn't take the spring rates as gospel.

Nathen had started supplying 400lb springs for the front as he thought it rolled too much, which is what I ended up with.
From my experience that's a recipe for massive understeer. It also gives a horrible jolty ride on bumpy roads as the rear can't react fast enough to catch up with the front.
I'm not convinced Saturn's original values would be much better either.

Having done some calculations (albeit full of assumptions/guestimates/errors) I came to the conclusion that the rear needs to be around 100lbs harder than the front, and that 300 front / 400 rear would be a good starting point.

As a quick test I swapped mine over and put my 250lb springs on the front and my 400lb springs on the rear and went out for a drive.
Have to say it's transformed the car!
The ride is far more composed on bumpy roads, and I've got shed loads of front grip.
It's possibly gone a little too far the other way, as it's ever so slightly tail happy now. It is however nicely controllable and much more fun that way :)
I'll get some 300lb springs for the front and report back at somepoint.

[jason 82]

Cheers for that. Your help is really appreciated. It feels like my first drive is a million years away ! Can't wait to go and burn a little rubber. :D

[PorkChop]

Those shock lengths are fine, but I wouldn't take the spring rates as gospel.

Nathen had started supplying 400lb springs for the front as he thought it rolled too much, which is what I ended up with.
From my experience that's a recipe for massive understeer. It also gives a horrible jolty ride on bumpy roads as the rear can't react fast enough to catch up with the front.
I'm not convinced Saturn's original values would be much better either.

Having done some calculations (albeit full of assumptions/guestimates/errors) I came to the conclusion that the rear needs to be around 100lbs harder than the front, and that 300 front / 400 rear would be a good starting point.

As a quick test I swapped mine over and put my 250lb springs on the front and my 400lb springs on the rear and went out for a drive.
Have to say it's transformed the car!
The ride is far more composed on bumpy roads, and I've got shed loads of front grip.
It's possibly gone a little too far the other way, as it's ever so slightly tail happy now. It is however nicely controllable and much more fun that way :)
I'll get some 300lb springs for the front and report back at somepoint.

Ah, didn't know that Nathan had changed the specs John - I copied them off the website when Nathan announced he was going to shut up shop, because they weren't in the build guide.

I don't know the spring rates used, but Spud's car seemed fine to me WRT suspension set up when I've been out in it. I'm guessing Spud used his car as a starting point for speccing the MX5 build.

I need to buy rear dampers and springs for my build (I already have Protech front dampers, which funnily enough are Sierra spec rear dampers and 250lb springs). I've been impressed by the reviews Procomp have got so I was planning to source the rear dampers through them and hopefully get their opinion on spring rates etc to start with.

[skov]

I don't know the spring rates used, but Spud's car seemed fine to me WRT suspension set up when I've been out in it. I'm guessing Spud used his car as a starting point for speccing the MX5 build.


That was my guess too. The thing is, Spud's car was Sierra based which has a very different rear geometry.

Talking to procomp sounds like a good idea, let us know what they recommend!

[jason 82]

I don't mean to be thick, but if the coilovers we require is 13inch + a 1 inch extention, why don't they specify 14 inch coilovers ? Or am I missing something ? :confused:

[Stot]

I don't mean to be thick, but if the coilovers we require is 13inch + a 1 inch extention, why don't they specify 14 inch coilovers ? Or am I missing something ? :confused:

I would say they said 13" + 1" as they thought people who had already built and or purchased shocks could add an inch extension to their build and carry on but theres no reason not to go straight for 14" if you are buyng new.

I'm using standard GAZ 14" at the front no problem.

Cheers
Stot

[jason 82]

Cheers for that stot. :D

[CTWV50]

Those shock lengths are fine, but I wouldn't take the spring rates as gospel.

Nathen had started supplying 400lb springs for the front as he thought it rolled too much, which is what I ended up with.
From my experience that's a recipe for massive understeer. It also gives a horrible jolty ride on bumpy roads as the rear can't react fast enough to catch up with the front.
I'm not convinced Saturn's original values would be much better either.

Having done some calculations (albeit full of assumptions/guestimates/errors) I came to the conclusion that the rear needs to be around 100lbs harder than the front, and that 300 front / 400 rear would be a good starting point.

As a quick test I swapped mine over and put my 250lb springs on the front and my 400lb springs on the rear and went out for a drive.
Have to say it's transformed the car!
The ride is far more composed on bumpy roads, and I've got shed loads of front grip.
It's possibly gone a little too far the other way, as it's ever so slightly tail happy now. It is however nicely controllable and much more fun that way :)
I'll get some 300lb springs for the front and report back at somepoint.

Cool I'll swap my 250lb and 400lb around during the final build.

[Davidbolam]

Cool I'll swap my 250lb and 400lb around during the final build.

I've gone for the rear springs at 250lb and the front 375.

Will give it a go and maybe swap them around see what the difference is.

Hopefully I will get to test it on an airfield before the road and iva anyway as a shakedown

David

[CTWV50]

Hopefully I will get to test it on an airfield before the road and iva anyway as a shakedown

David

That's Handy! :)

[Stot]

I bought a Haynes Manual for the wiring diagrams on Friday only to find the diagrams didn't really match my car too well.

A bit of hunting turned up this page with LOADS of MX5 service manuals.

http://www.mellens.net/mazda/

Really useful to an MX5 builder.

Cheers
Stot

[CTWV50]

Some more info on mx5 donor front suspension and experimentation....

http://www.haynes.co.uk/forums/showthread.php?t=6206&page=31