Lotus Elan

MCT/MT75 boxes fitted to a standard frame.

PostPost by: worzel » Sun Jul 31, 2011 10:34 am

Hi

OK- not really a new topic. At last I'm near to pulling out the oily bits and attempting to fit the MCT box but before I do can anybody who's fitted the std MT75 unit to either a std Lotus frame (or an early Spyder Stressed Skin version) tell me if they encountered a problem with the gearbox mounting rubbers. The alloy casing thru with the mounts fit (I assume they are the round type with threaded sections poking out of opposite ends) look like they'll be pretty close to the beginning of the enclosed tunnel in the chassis spine.

Regards and thanks

John
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PostPost by: tower of strength » Mon Aug 01, 2011 9:41 pm

You need the later MT75 from the ugly scorpio as oposed to the sierra/granada scorpio petrol 4 cylinder cars. You'll find the chassis will need relieving forward of the gearstick cut out to allow the wide top of the gearbox to clear, the gearbox mount can be made using a capri/cortina mount (I cant remember if the standard 4 speed one is the same) and a modified x member, the alloy mount on the MT unbolts. using the later box, its designed for a concentric slave cylinder, this i never sorted properly before selling my car, but the standard scorpio one would need spacing away from the gearbox to achieve sufficient throw for the clutch. the bottom of the belhousing needs loping off to allow room for the exhaust, a modified short remote needs to be made, i posted pics of this on my restoration posts,. the std output 3 prong flange needs changing for a transit one, use a maxi/europa 2 bolt pre engaged starter motor and get a prop made up.for the speedo drive, just knock out the plug and remove the electric sender, get a new oil seal and bung and the speedo gear for a sierra, the blue one i think.

thats about it!

good luck

Mark
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PostPost by: GrUmPyBoDgEr » Tue Aug 02, 2011 6:16 am

I'm afraid that I can't offer any help here because my Zetec Elan uses the original Elan G/Box in a Spyder tubular frame.

Sorry, but good luck.
John
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Editor: On Sunday morning, February 8th 2015, Derek "John" Pelly AKA GrumpyBodger passed away genuinely peacefully at Weston Hospicecare, Weston Super Mare. He will be missed.
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PostPost by: worzel » Tue Aug 02, 2011 8:35 am

Hi

Thanks for the info posted. I'm actually using a MCT box which is essentially the MT75 but without the integral bellhousing so I've a lot more choice than if using the stock MT75 unit. Because the fixing pattern on the MCT box is the same as the Type 9 I'm using the Rocket to BDA bellhousing which bolts straight to the MCT box and straight to the elan block without the need for any sandwich plates. Because of this I can still use the std elan flywheel, starter and ring gear so less to do there. As for the clutch operation because of the retention of the Rocket to BDA bellhousing I can still use the external std clutch slave cylinder. In effect the only major items that differ from the 4 speed set up is the box and the bellhousing so it's a relatively simple conversion in that sense. I can even retain the std clutch release bearing and arm by having a new release bearing guide sleeve made with a turned down section to match the internal diameter of the std release bearing. Since I'm using a Stressed Skin chassis the physical dimensions of the box shouldn't be a concern- the width of the box is only slighlty more than the Type 9 and the Stressed skin frame leaves about one and half inches clear each side. On a spaceframe this would clearly be a problem.

My only concern was the proximity of the MCT mounting lugs for the support rubbers- careful measuring indicates they'll be pretty close to the start of the chassis centre spine but I wanted to get others' opinions on this point.

Regards

John
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PostPost by: worzel » Tue Aug 02, 2011 8:47 am

Hi- again

Just some additional info- might help others who are contemplating something similar. The MCT box uses a cable drive for the speedo so in fact the std Sierra cable can be easily modified. Also, because the alloy cae of the MCT box doesn't have the projecting bits underneath it there is more room for the exhaust so nothing needs to be cut off the box or bellhousing- the only thing I'll have to do is have the exhaust run between the "Y" pipe and 15 inches back altered to re-route the pipe around and upwards by the side of the box as the MCT unit is about half inch deeper at this point bthan a Type 9. There are some downsides though (nothing's free is it). Although using a MCT box is simpler from a technical point of view it does require 2 expensive items- namely the special bellhousing (now costing around £400 new or about £200 seconhand if you can locate one plus a pretty expensive MCT box. These boxes do come up occasionally but because they were designed by MCT for use in some Morgans and Caterhams aren't exactly thick on the ground. Good used ones still fetch around £500 and new they cost anything between £1300 and £1800. I was pretty lucky in getting hold of a brand new one at a very good price. So it's swings and roundabouts- MT75 boxes are relatively common and cheaper but you have to spend more on altering some major items. MCT boxes require far fewer mods but cost a lot more to buy. Anyway- when I actually do the swap (quite soon now I hope) I'll definmitely post pictures/dimensions of the parts required/altered- might be of use to others.

John
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PostPost by: gerrym » Tue Aug 02, 2011 2:08 pm

Mark, your comment "looping off the bottom of the bellhousing" to provide decent exhaust pipe clearance around the MT75 gearbox. Any chance of a photo or sketch or what this looks like, where to remove metal, what metal to weld back in etc.

I think others have the same problem with lack of exhaust clearance around the box.

Regards
G
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PostPost by: tower of strength » Tue Aug 02, 2011 5:44 pm

sorry Gerry, I just got agressive with the angle grinder to get some clearance, the plan was to make up a cover plate later. The Scorpio type gearbox has a deep square base to the bellhousing so it bolts to the engine at the bottom of the sump, I didnt make a particularly pretty job of it to be honest and I sold the car on before finishing it. The gearbox was advertised for sale on here by the cars new owner as he has decided to re fit a four speed for originality as it was such an early car. Chris Hewitt, he may be worth calling.

regards

Mark
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PostPost by: tower of strength » Tue Aug 02, 2011 5:55 pm

Spyders solution to using the earlier gearbox is to route the exhaust manifold forward of the engine mount, then run it below the starter motor, hence the high ground clearance of the Spyder Zetec, if they used the later box, then the exhaust could follow the original route, i.e. behind the engine mount. Worzels Idea of the MCT box kind of makes sense, however its a fearsome amount of money from memory. If you know some one who is very handy at alloy welding, a neat solution would be to strip the fron case off the box and lop off the bellhousing, then weld a 10-15mm thick plate to the front of the gearbox,(in essence, this is the MCT box, although they use a new front casting, i think) drilled to fit the Elan bellhousing or the RS2000 jobbie, that would make life a lot easier. sounds simple doesnt it? :D I investigated this route but couldn't find a tame alloy welder at the time, then came across the Scorpio box, so persued this route. I understand that one of the very respected Lotus specialists (cant remember his name off hand) was experimenting with fitting a Mazda MX5, 6 speeder into a baby Elan, apparently his solution was neat and worked. I have no further info regarding this though.
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