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gearbox swap

PostPosted: Wed Jan 22, 2014 3:33 pm
by pauljones
Hi all,

Just by chance has any one fitted a gearbox from a Mk3 MX5. Its a 5 speed and im told it has the same mounts as a DURATEC. Im thinking more on the position of the gear lever and can it be moved as per type 9 style cut and weld.

Many thanks, , Paul

Re: gearbox swap

PostPosted: Thu Jan 23, 2014 3:23 pm
by Spyder fan
I think it will be a very slim chance that anyone has fitted one of those. here's a link to an Ebay auction for a Mk3 5 speed box

I bought a 6 speed version to try and fit it to my S4, yes it bolted straight on to the Duratec, but there was no easy way to move the gearlever without serious surgery. The box was huge as well and the position for the starter motor on the integral bellhousing was not in a very good place. I had to put it aside and use an MTX75 instead. you can see what I was up against on this Ebay advert for a Mk3 6 speed

The Neil Myers 6 speed conversion pictured below uses a MK 2.5 gearbox which is slimmer / more compact than the MK3, the bolt pattern isn't Duratec though. A neat bit of work is done to move the gear lever and some fettling of the integral bellhousing is done as well. There was a long queue of people for this conversion when I did my S4 and there was no chance of getting a special made to suit my car

Engine Gearbox.jpg and

Re: gearbox swap

PostPosted: Sat Jan 25, 2014 8:45 am
by pauljones
Thanks Spyder Fan.

I was thinking of trying to mate the box to a duratec for my spyder chassis.seems though the duratec from ford and the mazda box dont exactly mate. Is this correct?

Can you explain the mtx75 origins. And any fitting problems.

Thanks, Paul

Re: gearbox swap

PostPosted: Sat Jan 25, 2014 7:34 pm
by Spyder fan
Hi Paul
The MTX75 is a Ford MT75 gearbox that has been adapted by a company called Mitchell Cotts. They remove the integral bell housing to allow fitment of a separate type 9 bell housing so that you can match it to any motor. They also tweak the gear ratios to close ratio on 1st to 4th with a tall fifth for cruising.

Spyder use the Ford MT75 with a revised linkage for the gear lever on their normal Zetec conversions. therefore there is no issue with fitment of the Mitchell Cotts item in the chassis, providing its the Zetec chassis rather than the standard Spyder chassis.

there are various bell housings available from Raceline, Burton and some of the specialist retro ford converters (Anglias, Escorts etc), this is important as there is limited space for the starter motor unless you get a good mounting position on the bell housing , mine is at 7 o'clock ( viewing from the gearbox) and a little fettling is required to the chassis for clearance.

With regards to the mk3 Mazda boxes, I never got further than checking the bolt pattern which seemed fine, but the 6 speed was far too bulky to fit easily in the chassis, so was sold on. The mk 2.5 boxes are a better bet and should be doable with a bit of alteration for the gear lever as per the photo above, and sandwich plate for the bell housing.

No easy route, I'm afraid.



Re: gearbox swap

PostPosted: Sun Jan 26, 2014 9:04 am
by pauljones

The chassis I have is an early version but Spyder can bring this up to date so not a problem. I have various boxes from the Ford range to choose from, 4 and 5 speed but was looking at trying something new and different.
It does seem that trying to change from the norm posses a few problems for our Elans, but thats the joy of it I think.

Thanks. Paul

Alan, sorry. I forgot to mention I thought when you said MTX75 that I took it as being the transit box. Same designation. Apologies.