MX5 diff casing

[Talonmotorsport]

During todays mid morning coffee break I put an MX5 diff in front of us and we had a little discussion as to how to mount it properly. The weakest part of the diff as others have found even used in anger in the donor is the cover/rear mounting arms. Given that it appears to be made of low grade cast ali we came to the conclusion that the rear casting is too brittle to use as is. Out came the impact gun and the casting was removed for a better look, all the rear casting does in terms of the workings of the diff is hold the oil seals in place around the drive shafts. So keep an eye out for a new product from us that will solve the problem in the form of a very strong fabricated bolt on replacement part.

[MarkB]

Well done Phil, Test it and prove it works and you will be onto a winner especially if you can keep original mounting points as Mx5 owners might just want them to...

[PorkChop]

What sort of money do you think it'll be priced at?

[Big Vern]

Oh Boy here we go again
I thought we'd cleared this one up but it appears not!
The diff needs to be constrained properly to avoid failure. The ally casting is up to the job it was intended to do. It's when its not used as intended there are problems. So long as the diff nose is correctly constrained in the Z axis there shouldn't be any problems. I have first hand experience of this and many years of experience working with Mazda power plant frame cars.
The fabricated cover you have designed may make the diff more usable in varying installations so long as the diff nose is suitably constrained.
Does seem like a sledgehammer to crack a nut though.
£95 seems mighty cheap considering the work that will be required to produce it, but then I guess you know your business Phil

[MarkB]

Originally Posted by Big Vern

Oh Boy here we go again
I thought we'd cleared this one up but it appears not!
The diff needs to be constrained properly to avoid failure. The ally casting is up to the job it was intended to do. It's when its not used as intended there are problems. So long as the diff nose is correctly constrained in the Z axis there shouldn't be any problems. I have first hand experience of this and many years of experience working with Mazda power plant frame cars.
The fabricated cover you have designed may make the diff more usable in varying installations so long as the diff nose is suitably constrained.
Does seem like a sledgehammer to crack a nut though.
£95 seems mighty cheap considering the work that will be required to produce it, but then I guess you know your business Phil

You said it yourself there....."not being used as intended"

But what Phil is doing is making the best of a bad job as Sierra stuff is drying up now and the Mazda diff obviously doesn't like being in anything but a Mazda.....perhaps

[Davey]

Can you anodise steel? I thought that was a process that gave a hardened, corrosion resistant surface to aluminium, I could be wrong though.

D.

[MarkB]

Originally Posted by Talonmotorsport

sorry I ment electro plated I just know it as being zinc and pas. but thought that would confuse every body.

Nope Zinc&pass doesn't confuse me, the arm chair experts do though

[K4KEV]

Originally Posted by Talonmotorsport

sorry I ment electro plated I just know it as being zinc and pas. but thought that would confuse every body.

I am confused Phil.....do you mean the part is fabricated, welded prepped then elctroplated in a zinc salts bath or passivated first in a acid solution and then into a passivate solution.!
Most components that are open to the elements would need galvanizing which is
requires the part to be passed through a vat of molten zinc (hot dip)
zinc plating would be of no use as the coating is way too thin to be of any use.
As I said above to passivate you would have to 1st dip in a strong acid solution to cleanse and degrease then rinse in de-mineralised water and then dip into a passivate......would appreciate clarification

[robo]

Originally Posted by Big Vern

Oh Boy here we go again
I thought we'd cleared this one up but it appears not!
The diff needs to be constrained properly to avoid failure. The ally casting is up to the job it was intended to do. It's when its not used as intended there are problems. So long as the diff nose is correctly constrained in the Z axis there shouldn't be any problems. I have first hand experience of this and many years of experience working with Mazda power plant frame cars.
The fabricated cover you have designed may make the diff more usable in varying installations so long as the diff nose is suitably constrained.
Does seem like a sledgehammer to crack a nut though.
£95 seems mighty cheap considering the work that will be required to produce it, but then I guess you know your business Phil

This is my take on the whole thing for what its worth. To try and restrain the diff from that close to the center of the diff is impossible. There is no room on the drivers side to run a torque control arm forward but there is on the nearside. So why not design a control arm that picks up the original holes on the diff and take an arm off of that up the gear tunnel as far as poss, maybe even up to the gearbox mount. I would consider that the problem solved with the minimum of fuss.

Old and stupid Bob

[TSM Locost]

Using the internet and looking at what they do across the pond with their MX5 locosts makes sense to me.

Try here www.locostusa.com/forums/index.php or www.cheapsportscar.net by Keith Tanner who wrote the book " How to build a cheap sports car " Like Big Vern he has Mazda experience, it's free information, simples.

Assemble the diff as Mazda intended filling the holes in the outer rubber mountings with shoe goo ( available in the uk on ebay £6 posted ) to stiffen the mounts. At the front they use a small metalastic bush to locate the nose and keep the whole unit flexible and control vertical movement.

I am not an arm chair expert just an engineer for over 35 years using common sense and information that is already available, Hey but what do i know

Happy Days ................when it stops raining.