Anyone used a mazda engine and box in a standard roadster chassis. I'll be keeping the sierra diff so will need to match ratios but I like a challenge.

Try on the Haynes forum, a few people have used this combo including stot. Hth

I don't see why not, the chassis changes aren't huge and are mainly concentrated at the back to accommodate the MX5 diff. If you're staying Sierra for the rear end then it would probably make things easier.

The connection between gearbox and diff will probably be the most complex thing, but I guess just take the two propshafts (one Sierra and one MX5) to an engineer and get them to stick them together?

Search function is sh1t on there. I have found a guy in america fitted the engine and box in a caterham with a sierra diff.

Research so far shows the NB8B 1.8 6 speed is the one to go for. Better ratios than the type 9 and matches the diff ratio nicely.

cant see any problems with that. you will just need different engine mounts then get someone like dunning and fairbank to make you a new prop, mazda one end ford the other. im running a sierra hubs and diff with a saab engine and omega gearbox in my haynes so almost anything is possible if you can get it to physically fit

the better option may be to go for a 2.0 with the 6 speed out of a late car as you are not really inhibited by the diff and other bits from the later cars and may pick up a deal.

[Edited on 20/11/2013 by ashg]

don't get too hung up on making the ratio's the same as the MX5 - even just using a different tyre size will change your overall ratio

besides who says the MX5 has the perfect ratio fir the way you want to drive the car ?

I have used MK2 MX5 engine, 6 speed gearbox, steering column and wiring loom.

To get the engine back far enough I had to alter the front of the tunnel a little and the drivers foot well for the clutch arm.

I currently have a Sierra 3.62 diff that was great with the supercharger but as I have destroyed that I will be going to a 3.92 this winter.

Having said that it depends what you will use it for. Mine is mostly for track.

Have a look here for build details

http://www.thruxtongt.co.uk/joomla16/index.php/rogers-build-diary

I forgot to say I also cut the RTF mounts off the box to make some room.

[Edited on 20/11/13 by rdodger]

[Edited on 20/11/13 by rdodger]

Thanks for the info. I'll keep you informed how I get on.

Mine will mostly be for road use with occasional track use. I suppose it's easier to change the diff ratio later on to get the right drive so I'll stick with what I have for now and see what it's like once on the road.