Lotus Elan

Anyone ever fitted a scorpio MT75 in an Elan before ?

PostPost by: Matt » Fri Jan 05, 2007 9:23 am

Anyone ever fitted a scorpio MT75 5 speed gearbox in an Elan before ?

I'm about to have a try at fitting a 2 Lt scorpio MT75 in my +2 if anyone could please let me know how they did it, it would be much appreciated

Any info on this subject would be very helpful

Thanks chaps

Matt
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PostPost by: niallf » Fri Jan 05, 2007 12:02 pm

Spyder Conversion based around MT75 mated to a 2L Zetec engine. Well proven route
http://www.spydercars.co.uk/

If you're talking about mating it to an original Lotus Twin Cam, I think there are several issues to do with the integral bell housing not easily mating to the engine. Andy at Spyder would probably give you chapter & verse on what needs to be done.

The Alan Voight style Sierra 5 Speed conversion may be an easier route.

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PostPost by: GrUmPyBoDgEr » Fri Jan 05, 2007 2:00 pm

Most of the bell housing bolt holes will match, maybe one bolt will be left hanging in mid air but not a problem.
Main problem is clutch actuation unless you have the type with a concentric hydraulic cylinder. You will also need a g/box out of a LHD car so that the starter stays on the side under the carbs. RHD variants will put the starter where your exhaust system wants to be. You will also probably need a suitable starter motor. Spyder can supply a gear change linkage that will put the lever up through the existing gear lever hole in your car. you will also need a new g/box mounting bracket and a new propshaft. Another problem is a suitable drive for your speedo.
For all of those reasons I left my Elan g/box in place when I fitted a Zetec engine.
There are quite a few threads on the Forum regarding g/box changes; do a search.
Hope I've been of some help?

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PostPost by: Matt » Fri Jan 05, 2007 3:18 pm

The gear box has the starter on the inlet side and has an inbuilt concentric hydraulic slave cylinder, which is a bit of luck !
A suitable starter looks kinda tricky will try the scorpio one.

Anyone know if the ratios with be suitable?

Anyone know more about a suitable drive for my speedo ?

Has no one here ever put this box with our engines ?

Matt
1967 Elan S3
1970 Elan S4 Sprint
1972 Europa TC
1973 Elan +2 s130/5
1978 Esprit S1
1981 Esprit S2.2
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PostPost by: msd1107 » Fri Jan 05, 2007 7:42 pm

Matt,

There are at least two sets of ratios for the MT75 gearbox.

3.89, 2.08, 1.34, 1.00, .82

3.61, 2.08, 1.44, 1.00, .83

3.61, 2.08, 1.36, 1.00 .76

There are five sets of speedo gears available to suit different differential ratios and tire sizes. They are for 15 inch wheels, so it is hard to say how well they match to 13 inch wheels. I haven't done any calculations to see if they would convert to our speedometer. However, there are places that will make you up a conversion box to convert any gearbox turns per mile to any speedometer turns per mile.

These MT75 ratios are sedan ratios, and are not suited to our light weight Elans.

As an example, with stock tires and differential, first gear is good for barely 30mph, and shifting from 1st to 2nd at 6500 brings the revs back to 3500.

I'm not sure what the aftermarket situation for alternative ratios is for the box.

The T9 gearbox has sources for different gearbox ratios. BGH (bghgeartech.co.uk) has several alternative ratio sets available. I recently got to drive one of these recently (in an early Elite yet! - courtesy of Mike Ostrow) and the two closest sets (2.66 or 2.75 1st gear) would be quite suitable.

Hope this helps. This 5-speed thread has been active for years, and I see no compelling drop-in solution available. Be prepared to do a lot of engineering and experimentation.

David
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PostPost by: mikealdren » Sat Jan 06, 2007 9:16 am

David,
Thanks for highlighting this.
Spyder's Zetec solution uses the first set of ratios. I've been looking at the gearing in top (with the Zetec torque I would like quite tall gearing).
I'll now give the first gear some thought!
The 3.64:1 final drive helps a little compared with the standard +2's 3.78:1.
Do I care about going faster than 30mph in 1st or am I just using it to get going? I suppose I'm not really into sprint starts in a +2 road car.
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PostPost by: gerrym » Thu Jan 18, 2007 7:35 pm

Mike, are you still looking for information on this?

I can offer the following having gone down this route:

The starter motor mounting is further down and further out compared to the bellhousing for the 4 speed Ford "rocket" box. You need the closing plate from the Scorpio to provide the correct engagement with the starter motor spigot. The choices for starter are to use a special starter motor from Brise or similar or go down the following route.
Standard MT75 (Scorpio starter). Custom flywheel machined to fit a modern standard ford starter motor ring gear (135 tooth Burton FT257B) and locate axially correct distance from the engine block face. I have a sketch with these dimensions. For the clutch if you are using the concentric release bearing (CSC005) then be aware that this has a flat face so needs a curly finger clutch pressure plate to work against. You could get a Lotus Sunbeam Talbot 8.5" clutch from AP but the RS2000 clutch is so similar and much more readily available and much cheaper LUK clutches are available that it makes sense to use this instead. The only change is to the PCD for the clutch mounting holes to suit. Refer AP website for approriate dimensions. Next thing to address is the setup height of the clutch. I found I needed to machine about 3mm off the mounting plate for the CSC005 to get some axial clearance.

Other things to note is that the Scorpio standard stater motor (solenoid) will have a very slight clash with the spyder chassis diagonal brace. Solution is to dimple this away from the starter. The standard Lotus handbrake cable was a fairly heavy rub against the bellhousing where the starter motor mounted so the threaded chassis mount was relocated lower down.

Completely different option for the MT75 gearbox conversion might be to use a MCT75 gearbox which has no integral bellhousing.

Gerry M
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PostPost by: Greg Foster » Fri Jan 19, 2007 11:37 pm

I am considering installing a modified 5 speed box remanufactured by a company called Quantum mechanics. They supply everything for about $2,400 US +tax and shipping. I haven't asked for any references of those who have done the change over.
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PostPost by: mikealdren » Sat Jan 20, 2007 8:24 am

Gerry,
I'm going the Spyder Zetec route. I've bought a Focus Zetec engine (a great Ebay bargain) and Andy at Spyder is prototyping a Focus engine.
I expect that I will have a few challenges - the water pump for one, but I'm currently working on the bodyshell and that is taking me quite a while.
I'm amazed at how many holes there are in the bodyshell, the passenger compartment was like a colander.
Mike
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PostPost by: Greg Foster » Sat Jan 20, 2007 12:12 pm

I found the info on the transmission swap fyi

Quantum Mechanics
505 Wheeler Rd.
Monroe, Ct 06468 USA

Owner John Esposito
Phone 203-459-9612
FAX # 203-261-8497
I am not sure what they are out of or gear ratios but talk with him. He rebuilds trans, overdrives, diffs.
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PostPost by: garyeanderson » Sat Jan 20, 2007 12:52 pm

Hi Greg

I was unaware that John Esposito did conversions for the Elan/Plus2. I know he had them for MG's and Triumph's but the shifter on the stock Ford Type 9 gearbox (which is what these are based on) is 8 or 9 inches further back that on either of the Elan types. Is this something new?

John's web page - Quantum Mechanics
http://www.quantumechanics.com/categori ... x&catid=17
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PostPost by: mac5777 » Sat Jan 20, 2007 7:06 pm

Greg, I had a John Esposito 5 speed installed in my 1970 triumph spitfire. Five years ago it cost about 1,800.00. And much more to have someone else install it. 2nd gear was a little sticky on the ford type 9. The shop that installed it had some adapting problems to do to get it to fit.
I also did not know that he has a conversion for the Elan.
On the spitfire the original gear shift was set very close to the dash and radio. The ford type 9 was set back about 6+ inches. It was a much more comfortable shifting position. It was close to the brake lever but out of the way while driving.
I did like the 5th gear on the hwys.
I thought about a 5 speed, on my elan, for a long time but they all seem to have some problems. if a type 9 ford will really work, it may spark a new interest. I did have Rich Kamp install a new 3:55 ring and pinion gear and I use the standard tall tires and at 60 MPH, RPMs of 3500. I don't know how much more a 5th gear would add to lower the rpms ??
If anyone has tried John's conversiion on an Elan, let us know how easy it was and how easy the gears changed.

Interested Sarto
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PostPost by: mikealdren » Sun Jan 21, 2007 9:07 am

Gerry,
Sorry my earlier reply seems rather curt and many thanks for your detailed reply. I have already bought an MT75 box and it should be easy to fit because I am using a Zetec engine.
My concern is about ratios. David's email above suggests that first gear will be rather low because the Ford gearing is designed for getting a heavy car off the line and not for optimum acceleration. I don't intend to race so I'm not too bothered but I wonder how do you find it in practice?
Mike
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PostPost by: msd1107 » Fri Jan 26, 2007 1:50 am

RE: MT75 conversion.

Installing a MT75 into an Elan with 155-13 tires, 3.77 diff, and using 6500 would give speeds of 29, 55, 85, 113, and 138.

A well tuned TC (FHC anyway) should be able to pull 6500 in 5th.

However, one problem is with 1st and the 1st to 2nd change.

The drop from 1st to 2nd is 87%, far greater than the desirable 50% of a sporting gearbox. This means that if you shift at 6500, the revs come back to less than 3500! In normal driving, shifting at 3000 brings the revs back to 1600, barely off idle. You will always notice the engine bogs on the upshift to 2nd.

However, the top 4 ratios are very like our TC CR gearbox. If the top 4 ratios are converted so that top is 1:1, they become 2.53, 1.639, 1.219, and 1.00. This is quite close to to the 4 speeds ratios. So you could consider the gearbox as a high geared 4 speed with a startup gear that is hardly used.

It is unfortunate that alternative gearsets have not been developed for the MT75 as they have been for the T9.

I guess that each owner does to his car as he sees fit, and lives with the result.

David
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Last edited by msd1107 on Fri Jan 26, 2007 3:32 pm, edited 1 time in total.
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PostPost by: mikealdren » Fri Jan 26, 2007 10:51 am

David,
Interesting comments. My Zetec should have a lot more torque than a twincam and that will go some way to offsetting the drop in revs.
As you say, it'll still be quite low geared and I may even end up starting in 2nd and rarely using 1st. I guess I'll have to wait and see.
regards
Mike
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