mikey p
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| posted on 25/3/12 at 11:24 AM |
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mk3 mx5 gearbox
How easy are these to fit and sort clutch etc? mating to duratec.
is it just a case of running mx5 clutch and flywheel, modified prop? and custom gearbox mounts.
anyone done this and what were the associated costs?
Thanks
Mike
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Furyous
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| posted on 26/3/12 at 07:26 AM |
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I'm using an MX5 gearbox in my Duratec install. You will need an MX5 clutch, pressure plate, flywheel, and starter. They all bolt straight on. I
think I weighed the MX5 flywheel at 7.3KG which is a reasonable saving over the dual mass flywheel of the Duratec at something around 10-12kg. The
spigot bearing is the standard Duratec with a 15mm internal diameter. I'm going to use a standard MX5 clutch but I don't know if I should
use an uprated one. The standard MX5 makes something like 160-170bhp so I'm guessing it should be ok with around 190bhp and a lighter car.
It's replacing a Type 9 box but it's a bit bigger. The bell housing is quite wide, so it's a bit of a squeeze in the transmission
tunnel. I had to chop off a few bits like mounts to make it fit more comfortably. The bigger bell housing also means it hangs quite low. A 75mm
shortened sump would be about 10mm above the bottom of the bell housing. It's fairly high at the back as well. The top of the gear stick mount
is level with the top of the tunnel in my Fury, while the mounts at the bottom are level with the floor pan. I had been considering shaving a little
off the bottom of the mount to be able to drop it down maybe 10mm but I need to take a good look at it first.
The 6 speed is apparently bigger, so I think I would have struggled to make it fit without modifying the chassis.
I'm not entirely happy with the way I've mounted it but I'll sort it out properly when I'm back home. I've taken the
Type 9 mount with its horizontal slot and mounted it 90 degrees around, so that the slot runs lengthways. But the slot isn't wide enough to fit
the mount in properly. The trouble I had coming up with a mount is the height. If I use rubber bobbins underneath they will either hang below the
floor pan or lift the box too high.
I've got some photos in my archive but I don't remember what exactly they show.
The MX5 box tips the engine over 10* towards the exhaust, or driver's side. I had visions of it leaning so far that it would foul chassis rails
but it's really not much of a lean. It almost levels off the uneven cam covers. I'm pretty sure it's saved me about an inch in
height but I haven't actually measured.
I got lucky buying the gearbox and snagged one just before Christmas for £125. I was the only bidder on the ebay auction. Only about 5 miles from
home, as well! I've seen a couple around £250 BIN but most seem to be £400-500 BIN with no one buying them. I bought the clutch/flywheel/starter
used. Clutch - £30. Flywheel - £30. Starter - £50.
You should get a 10* angled sump to go with it. I was planning on buying a Raceline sump but the 10* one is over £100 more than the flat one. I might
modify the Ford sump myself.
[Edited on 26/3/12 by Furyous]
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mikey p
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| posted on 17/7/12 at 10:43 PM |
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Thanks and sorry for late reply. only just started thinking about this again....
Yeah sounds OK.....and possible to do it cheaper than the bell housing and flywheel/clutch for a type 9...
What prop shaft are you using?
I would be fitting it in a Westfield SEiW with a type 9 and sierra diff currently fitted.
Anyone fitted the 6 speed in a Westfield?
Thanks Mike
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mikey p
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| posted on 20/7/12 at 09:05 AM |
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Does the old mk1 and mk2 mx5 engine share the same bolt pattern as the later mzr engine'd cars?
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chillis
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| posted on 20/7/12 at 09:13 AM |
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quote:
Originally posted by mikey p
Does the old mk1 and mk2 mx5 engine share the same bolt pattern as the later mzr engine'd cars?
Afraid not. The bellhousing/front gearcase is different to match up to the duratec engine and the powerplant frame mounts on the opposing side.
I have a MK3 6speed just 5000mile if anyone wants to make me a sensible offer.
[Edited on 20/7/12 by chillis]
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