Lotus Elan

Fitting a MT75 box to a std elan chassis

PostPost by: worzel » Fri Mar 04, 2011 1:55 pm

Hi

Apologies since this has been flogged to death somewhat but I'm trying to get a definitive lowdown before I start something I'll regret.

I've managed to get hold of an excellent early spyder stressed skin chassis plus a body much in need of repair.

Since this would otherwise probably end up as a breaker I'm thinking of making a "bitsa" car. I definitely want to put a 5 speed box into it but don't want to either modify a box myself- I've done it before but it takes too much time/fiddling so I'm thinking of using a MT75 or rather a MCT75 box and mating it to a modified RS2000 alloy bellhousing.

My problem is that before I commit to buying the box (pricey) I need to determine if it will actually fit without butchering the chassis.

As I understand it the std MT75 box won't fit because of bellhousing difficulties- starter position etc but a MCt75 box might.

Can anybody out there who has either managed to fit a std MT75 box or has used a MCT75 one in a STANDARD chassis clue me in on its feasibility or otherwise.

Regards and thanks (in anticipation)

John
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PostPost by: GrUmPyBoDgEr » Fri Mar 04, 2011 2:37 pm

I don't know anything about the McT75 gearbox but the MT75 box will fit into a stressed skin Lotus sub-frame.
If the Spyder frame is the same then the same rules should apply.
The problems arise if you try to fit an MT75 box into an early Spyder tubular chassis.
The tubing reduces the amount of space & the MT75 box is to fat to fit without significant changes to the frame (which can be made).

Good luck
John

PS be sure to buy an MT75 box where the starter motor is located on the intake side of the engine!
There's no space on the exhaust side, due to the manifold etc. being there.
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PostPost by: worzel » Fri Mar 04, 2011 3:02 pm

Hi

You're quick- thanks.

I've looked at a std MT75 box and thought it might well go in but wasn't sure. My only reason for possibly using a MCt75 box is that it is identical in all respects except that it takes a separate bellhousing. In my case I have a Ford RS2000 bellhousing that bolts straight to the MCT box and the elan block(same fixing patterns) but needs modifying to permit a hydraulic clutch (not really too big an issue I believe).

That's a big help- thanks.

Regards

John
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PostPost by: AussieJohn » Fri Mar 04, 2011 3:19 pm

As long as you choose an mt75 from a 16v scorpio then the starter is on the correct side. A friend of mine has a design for moving the gearlever to the original position. I think that you need to use a transit output flange and maybe a crossflow flywheel. If you need more info. mail me and I will put you in contact with my mate who has a lot of the answers, cheers, John.
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PostPost by: worzel » Fri Mar 04, 2011 7:36 pm

Hi Aussie John

That's more useful info. I imagine there aren't too many Scorpio's left now so might be a problem. i'm not clear why the flywheel might need to be replaced as you suggest. Do you have a link to your "guru" friend/

Regards and thanks

John
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PostPost by: AussieJohn » Fri Mar 04, 2011 9:29 pm

There are a few scorpios still around, I have a feeling that the ring gear to match the pre-engaged type startermotor has a slightly larger internal diameter needing a different flywheel or a spacer ring of some sort. I think my friend goes as " Hawkins" on this site but he rarely posts, if you cant find him I will mail you his phone or email address, cheers, John.
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PostPost by: gjz30075 » Sat Mar 05, 2011 12:30 am

John, try to find a gearbox rebuilder near you who perhaps would have an empty case to borrow so you can mock it up.

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PostPost by: mikealdren » Sat Mar 05, 2011 9:17 am

John,
There are at least two versions of the M75 box that Spyder use. The Sierra box uses a cable clutch and the Scorpio uses a hydraulic unit. The starter motors are on different sides for the options. The Scorpio box is generally favourite for Zetec conversions but the chassis needs some 'relieving' to get it in. Of course it will different for a twin cam.

Call Spyder (or visit if you're near) for advice. They know all the options.

Don't forget to let us know the conclusions.

Mike
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PostPost by: AussieJohn » Sat Mar 05, 2011 10:20 am

The mt75 boxes have different ratios available; I think all the scorpios are the same but the 98 model has a taller 5th.
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PostPost by: Mark B » Sat Mar 05, 2011 12:44 pm

Spyder only really use the scorpio box for the zetec conversions which has the hydraulic clutch and starter motor on the offside (inlet side), there are still a fair few available (I know of a few round here) and are fairly cheap to have rebuilt. They do however have a sierra cable type mt75 box in their demo chassis.

I don't see any advantage of using the mitchell cotts mc75 box with the detachable bellhousing, as the bolt pattern for any 4 cylinder ford engine (apart from the duratec) is the same as the standard ford mt75 box.
The only reason mitchell cotts make it with the detachable bellhousing is because they supply westfield and others to use with a different bellhousing to match the duratec engine.

The mt75 box from the diesel version has the higher ratio 5th gear (0.76)than most of the petrol versions (0.83 apart from the 2.3), 2 years ago I was still able to buy the 5th gear cog from ford and had it fitted to my elan box when rebuilt, although you do need the layshaft too which I bought secondhand for £20 for the rebuilders.

Have a look at http://www.fordscorpio.co.uk/mt75.htm there's lots of great info about it on there, and http://www.maddoldbugger.supanet.com/gearbox.html regarding the taller 5th gear conversion.

I'd buy a diesel or 2.3 petrol scorpio mt75 box with higher 5th gear,integral bellhousing and starter on the offside, have it rebuilt, fit a new concentric cylinder (available for about £75 -£80 on ebay) and fit the transit drive flange to mate to your prop.
If you buy spyders gearlinkage kit (pricey but does the trick) you'll get the gearstick as far forward as you can (approx 2 inches back from standard) and it'll bolt straight upto your engine.
The other things are new starter motor and altering the hydraulic hose for the clutch.
You should have it done for about £850ish...

hth

Mark.

Edited to add- this would really be best in the mods section?
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PostPost by: AussieJohn » Sat Mar 05, 2011 1:25 pm

My mate gets the lever further forward than spyder[ exacttly in original 4 speed position] and also reduces the throw so its closer to original.
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PostPost by: worzel » Sat Mar 05, 2011 1:47 pm

Hi

The reason I'm thinking of using the Mitchell Cotts derived box is simplicity- if I get the RS2000 bellhousing altered to take an external clutch cylinder (which I have to admit I prefer) I can retain the use of the original starter and don't need to consider the flywheel or ring gear. Or I could get hold of a Rocket to BDA bellhousing which doesn't need any alterations to it and this bolts straight to the elan block and to the MCT box and again retains the original starter and external clutch cylinder so although pricier to do it actually requires far less work/alterations.

As I already have a modded T9 in my car I know how everything fits/actually does fit in practice- so no unforeseen problems (hopefully).

Regards

John
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PostPost by: gerrym » Sat Mar 05, 2011 1:59 pm

John, your idea has a lot of merit. The integral bell housing of the MT75 is not ideal and reduces ground clearance and even for the Scorpio derived boxes, the starter motor positioning is a little too close to the chassis rails (Spyder) to be perfect.

I have spare MT75 you could borrow, problem is distance with me being in Aberdeen. Then you could at least check clearances of the box part of the MCT75 solution.

Suggest otherwise just get a scrap box from a transmission overhaul shop (or wrecker).

Regards
Gerry
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PostPost by: Mark B » Sat Mar 05, 2011 2:17 pm

Hi worzel,

Ah I see where you're coming from now, I didn't realise that you had any of the parts already. I'll ask around to see if anyone has an mc75 box if you like?
It's true that the mt75 bellhousing hangs down, which is a problem in a westfield, but in the elan it's still well above the exhaust, at least it is on mine anyway, so not really an issue. I cut about an inch off the bottom edge of the housing on my westfield, as many others have done.

Aussiejohn, do you have any pics of your mates modification? I'd be interested to see how he's done it as there's precious little room. The spyder one works nicely and feels just like the original lotus box in terms of shifting, but is very expensive for what it is imo....

Cheers,
Mark.
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PostPost by: AussieJohn » Sat Mar 05, 2011 4:55 pm

I will try for more info. and pics. or a diagram but will be maybe a week to wait. John, if you have a type 9 in why go to an mt75? cheers John.
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