Lotus Elan

5 speed to 4 speed conversion

PostPost by: Dieschelan » Thu Oct 15, 2015 4:28 pm

I'm thinking in change my 5 speed gearbox for a 4 speed. What's different from 5 to 4?Can I use the same bell housing and clutch?
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PostPost by: Mazzini » Thu Oct 15, 2015 4:46 pm

What sort of five speed are you thinking of? That's the starting point I suppose, then search this forum, it's all here.
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PostPost by: Dieschelan » Thu Oct 15, 2015 4:56 pm

I have the original 5 speed gearbox in my elan plus 2. This gearbox is very bad and I have decided to put a 4 speed gearbox. My question is What parts are neccesary for the conversion? :roll: :roll:

regards
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PostPost by: Mazzini » Thu Oct 15, 2015 5:38 pm

Oh sorry I misread you! I'm so used to people going from 4 to 5 not the other way round.

I have a 2000E box and all the bits bobs and brackets if you need anything.

The Lotus bellhousing for the four speed was from a 105E Anglia as was the release mechanism. I've gone over to the hydraulic circular release mechanisms, lighter to use and I think more reliable. The clutches are different too.

Oh and a completely different propshaft too...
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PostPost by: rgh0 » Sat Oct 17, 2015 1:25 am

You will need a new prop shaft, a new gearbox mounting bracket to the chassis and the spacers for the gearbox mount. You will need the complete 2000E gearbox including bell housing and gear lever. You will need a new clutch plate with the correct spline for the 4 speed and a new throw out bearing and carrier. You will also need to remove the input shaft spigot bearing carrier in the flywheel and mount a new spigot bearing in the end of the crank.

If you sell the 5 speed unit along with all the bits you take off so some one else can do the reverse conversion you should make a nice profit on the change over even if the 5 speed needs a major rebuild.

cheers
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PostPost by: Dieschelan » Sat Oct 17, 2015 7:37 am

rgh0 wrote:You will need a new prop shaft, a new gearbox mounting bracket to the chassis and the spacers for the gearbox mount. You will need the complete 2000E gearbox including bell housing and gear lever. You will need a new clutch plate with the correct spline for the 4 speed and a new throw out bearing and carrier. You will also need to remove the input shaft spigot bearing carrier in the flywheel and mount a new spigot bearing in the end of the crank.

If you sell the 5 speed unit along with all the bits you take off so some one else can do the reverse conversion you should make a nice profit on the change over even if the 5 speed needs a major rebuild.

cheers
Rohan


Thank you Rohan for your reply. I will go for a close ratio gearbox for my plus 2. 5 speed gearbox is a bad gearbox with a lot of problems. And 4 speed gearbox is more precise in gearchanging. I think a close ratio gearbox with a 3,77 differential and a tuned engine (around 145 hp) is a good combination.
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PostPost by: c.garde » Sat Oct 17, 2015 8:50 am

Gentlemen ,
After the thinn input bearing failed I rebuild the box ca 1980 . I Upgraded and , modified it in several areas, this resulting in a very nice and easy gearchange . No more jumping out of -5th , no more lane changing when shifting up . ( ofcourse not quite up to the standard of the Ford item , but nice , thank-you . Far better than when new )

This box worked without a single hikcup for more than 100.000 miles.
When eventualy I did rebuild it during a complete very last bolt restoration it was still in good condition .
This time I incorporated futher modifications re. my good friend Victor Hollnagell, who on his part had continued HIS upgrades on the basis of my notes from way back.
By the way I must inform that my own " finetuning" was based on information and help given freely by people at Lotus during a visit. ( i.e. the sync. block 3/4 was, then, a Lotus special modified item )

Careful and experienced rebuild will give you a nice box.
Mr. Boulton is to be warmly recommended ( He did sterling service with my diff. There was a knot I could not solve by my own )

Claus in Denmark
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PostPost by: Spyder fan » Sat Oct 17, 2015 5:47 pm

In the Uk we have a saying "Don't throw the baby out with the bath water "

I have never experienced a Lotus 5 speed gearbox as fitted to the +2 or a very few Elans, I have heard that they are not as precise a gear change as the 4 speed gearbox and prone to problems, but having experienced the 4 speed gearbox I can tell you that very few gearboxes compare to them in their precision of selection, in short they are a very nice gearbox to use. However on a long fast trip you will need ear plugs for the noise in running your twin cam at over 5500 rpm and deep pockets for all the fuel you will use. So I'm going to defend the 5 speed Lotus gearbox and tell you to investigate having it properly rebuilt and perhaps modified, speak to Claus who has replied to this topic, he appears to have experienced problems and has overcome them.

If you really want to change to a 4 speed, then Rohan's reply is a perfect list of what you need.

Let us know what you decide, there is also the option of using a Ford MT75 5 speed gearbox or a type 9 gearbox, also 5 speed, but you are going down the route of non Lotus standard if you go there, there are lots of topics here regarding those conversions.

Regards

Alan
Kindest regards

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PostPost by: gjz30075 » Sun Oct 18, 2015 8:37 am

Dieschelan, PM sent
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PostPost by: Dieschelan » Mon Oct 19, 2015 5:47 pm

Has somebody experience with the close ratio gearbox in a plus 2? I have a 3.77 differential. Is it a good combination or better the semiclose ratio gearbox?
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PostPost by: CBUEB1771 » Tue Oct 20, 2015 2:55 am

Dieschelan wrote:Has somebody experience with the close ratio gearbox in a plus 2?


It will be interesting to see if there is a reply from someone who has installed a CR gearbox in a +2. I have a feeling that the 2.51 first gear ratio of the CR gearbox would be unpleasant in something as heavy as a +2 coupled with the 3.77:1 CWP. I suspect it would be a bit of a pig getting away from a standing start. Keep in mind that the CR gearbox was originally supplied as an option with the early Elans with 3.9:1 CWPs. That combination would produce brisk acceleration with the 2.51 first gear ratio.
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PostPost by: l10tus » Tue Oct 20, 2015 7:40 am

From my own experience driving my Sprint with 3.54 Diff and semi-close 4 speed box it is an absolute disaster! ( the gearing design, that is!)

I can't believe how low the gearing is!

From 1st., 2nd., 3rd.To 4th. and you may have reached 40 mph !

50MPH is 4000 RPM - no wonder we only get about about 15 Miles to the gallon!

Driving the Elan for anything more than 20 miles is painfull.

Far too low geared.

And you are thinking about a 3.7, or even worse, a 3.9 Diff ! - no chance!

I've just run in the engine, and am already preparing to change to a +2 Lotus speed box, but think this is probably not even going to suffice?

Modern cars have spoilt the classic car experience for me, their 130 - 200BHP easily pull much higher gearing, and literally run over an Elan type classic, in probably 3rd. Gear.

It's too easy to do in excess of UK motorway speeds, at less than 2000 RPM in modern diesel powered cars.

It feels like the motors' neck is being wrung in the Elan at 60MPH ! - I just can't do it!!!!!

I'm sure that's why all these barn find Elans have about 50,000 miles on the clock - the engines were all shot by then, due to the over reving they'd received !

Do not do the conversion you'll regret it! - (IMHO).

Just my two pence worth!

Regards,

Phil.
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Sometimes my Lotus makes me cry.
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PostPost by: gjz30075 » Tue Oct 20, 2015 9:25 am

l10tus wrote:From my own experience driving my Sprint with 3.54 Diff and semi-close 4 speed box it is an absolute disaster! ( the gearing design, that is!)

I can't believe how low the gearing is!

From 1st., 2nd., 3rd.To 4th. and you may have reached 40 mph !

50MPH is 4000 RPM - no wonder we only get about about 15 Miles to the gallon!



Phil, are you sure your gauges are accurate? My tach and speedo are dead on and I'm turning 4000 rpm
at 70 mph with my Sprint with a 3:77 diff and semi close 4 speed. I'm thinking a 3.54 diff would put me
at about 3500 rpm or so, at 70 mph.
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PostPost by: pharriso » Tue Oct 20, 2015 10:52 am

I'm the same! Still loud though! :roll:
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PostPost by: l10tus » Tue Oct 20, 2015 2:37 pm

Kev,

Sorry to hijack the thread - that's not the plan !

Just thought my experience would give you another view.

Phil.

Did you mean 'yes, it was very low geared', or your speed and revs matched Greg's, but it is hellish noisey to maintain all those revs at that speed ?

Greg, you may have a point !

I was thinking of checking the gearing by doing the 'count the wheel vs Propshafts revs' method, to confirm the Diff ratio.?

Certainly dosn't feel like 70 at 3500 revs. Though!

Perhaps the PO. Swapped the Diff ratio ??

I must admit I only carried out an external inspection of it, during the refurb.

I suppose worse things have happened at sea (as they say!)

I just hope I find out the Diff ratio is 4.1:1 or so, that's how bad it feels!

Regards,

Phil
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