Well i'm pulling my hair out on this one,

We've got a Fiesta ST150 Duratec engine with the solid flywheel and then I believe a 1.8 5 Speed MX5 gearbox that is the correct bolt pattern for the Duratec engine.

Unfortunately the Clutch plate that came with the engine doesn't fit the Mazda gearbox splines so we bought an MX5 clutch plate and everything bolted up nicely.. put all the engine in, had it running but couldn't dis-engage the clutch
Took it all back out again only to find that a ring on the pressure plate center fouls on the clutch plate when the clutch is pressed in not allowing the clutch plate to seperate.

So ordered a replcement pressure plate (which we now notice is a different design from the FWD Ford one with no center ring)..... now while all the inner splines and friction plates etc are correct, the pressure plate is bigger on its outer diameter than the Ford Flywheel and thus doesn't fit on the dowels and won't bolt on.

Why the hell did I think this engines and gearbox would fit together so easily using common parts!..

Has anybody else gone through this, and can confirm what parts fit where and if now ordering the MX5 Flywheel everything will finally fit?

What diameter is the Mazda Friction Plate.

As I understand it the MX5 1.8 has a 215mm plate which would fit inside an RS Turbo clutch pressure plate, which does fit the ST150 flywheel, like mine below.

The fingers needed shortening to work with a hydraulic clutch but that was sorted easily with a Dremel and cutting disc.


[img]
RS Turbo clutch Duratec [/img]

[Edited on 4/5/11 by big-vee-twin]

Yeh the MX5 clutch plate we bough is 215mm the same as the ST150 one that came with the engine, but ofcause has the correct splines to fit the gearbox.

The ST150 Pressure plate fits fine with this clutch and obviousley bolts upto the flywheel,
only part of the clutch spring mechanism on the pressure plate fowls the clutch plate itself not allowing it to disengage.. so it sounds like similar to you we've ground off this spider looking bit off that fowls and it appears to seperate whilst testing it out of the car. Were still using the MX5 lever arm with the external slave cylinder etc.

The MX5 flywheel must be of a different design with the dowels and pressure plate mounting holes right on the edge near the ring gear to allow the larger diameter MX5 pressure plate to fit... I didn't think they'd bother making a different flywheel and clutch setup and the ford/mazda parts would have beein interchangable.

Just hopeing the ST150 pressure plate etc is going to be strong enough now (espescially as we've modified it) as the mazda one does look abit beefier.

The pressure plate I have is the RS Turbo which in standard format its good for about 130 hp, the one I fitted is uprated to do 300hp, my engine will eventually get to 180-200hp.

There wasnt any spring to grind off I just shortened the length of each finger by 2-3mm to allow the guide shaft of the hydraulic clutch to fit just inside the fingers.

The clutch plate I have is manufactured by Techniclutch you can find them on ebay, if you need to do something different.

Your standard plate will probabily be ok as you car will weigh a fraction of the original fiesta.

I only fitted a HD clutch as I didnt have any donor parts so had to buy one.

Better late than never, got it all to fit in the end!.

To say they share the same engine etc the clutch and flywheel setup etc are totally different.

To get the ST150 engine to fit the MX5 you need the following from the MX5

Flywheel
Starter motor
Pressure plate
Friction plate

But boy was it worth it!

quote:

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Originally posted by MkIndy7
Better late than never, got it all to fit in the end!.

To say they share the same engine etc the clutch and flywheel setup etc are totally different.

To get the ST150 engine to fit the MX5 you need the following from the MX5

Flywheel
Starter motor
Pressure plate
Friction plate

But boy was it worth it!

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My I ask what year MX5 gearbox are you using please as im looking for a gearbox for my Duratec.
Many Thanks
Mark

The Mazda flywheel bolts straight upto the ST150 crank no problems,
It is a larger diameter tho so the standard ST150 starter motor won't engage, I believe the Duel mass flywheel type starters are different so these may fit the Mx5 flywheel, otherwise you'll need the MX5 starter aswell.

Its the later Mk3 Mx5 the very rounded shape ones that fit onto the Duratec... 2005? onwards?, ours was a 2007 so defiantely into the correct age. (Known as an N7 gearbox I believe)

The MX5 gearbox does incline the engine over towards the drivers side of the car I presume to try and get the larger side of the camshaft cover lower.

This may have implications as which sump to use as the aftermarket RWD ones may be designed for the engine to be stood upright and have extra wings on the side to maintain capacity.. with the engine leaned over these wings may make the sump even lower (guess who found this out the hard way and had to watch the best part of £30's worth of fully synth dribble down the road )

Thanks for getting back to me, gives me another option to look at