Lotus Elan

5 speed conversions

PostPost by: worzel » Sat Oct 09, 2010 12:54 pm

Hello all

At the risk of "re-hashing" an old topic something that might interest a few out there.

Basically I've been playing around with a few ideas (more out of interest really) on T9 boxes that might allow the hands on owner to do a 5 speed conversion at minimal cost.

I should get the last few items from my friendly presision engineer within the next couple of weeks- all of the intricate work has already been done- I'm just waiting on the last 2 parts..

In a nutshell- I'll have the parts for the following-

To convert the 5th selector fork to eliminate the separate 5th interlock washer and have the one in the main casing perform that function (as per the AV system but simpler). This is the basic operation that actually permits the lever to be relocated forward

The 2 components required to reinstate the spring loading mechanism against 5th. One fits inside the box (an easy job). The other requires a captive nut welding in the lid of the box. The overall height of the screw in spring plunger is about 1.25 inches so shouldn't be an issue with body fouling.

For owners wishing to retain the Ford lock out for reverse you can use and modify the std sierra gearlever (only the upper visible part is altered- purely for cosmetic reasons) or if preferred I can supply the separate mechanism that provides a cam resistance against reverse. This operates via the lid of the box and is easy to instal

The idea is that the "handy" owner could modify his /her own box at minimal cost.

You would need to have a small amount of welding done, cut/shorten a few items (nothing serious and supply your own box.

If not confident about stripping a box rest assured that of ALL of the box internals ONLY 5th selector fork is altered. Here, only the rear "arm/leg" is removed. There are NO radical box alterations apart from having the alloy tail cut at the appropriate point and having the gearlever platform welded in its new position- an easy task I assure you and the least complicated operation required.

Since it would be advisable to have any box overhauled the alterations could be carried out with ONLY the lid, tail housing and selector rod removed. One hole has to be drilled through the sandwich plate and the gearbox casing. This could even be done with the gears left in situ then when the box is stripped for overhaul the internal can be washed/cleaned (advisable anyway).

If a professional gearbox builder was used for the rebuild the box could be 95% reassembled leaving out only the selector rod, the forks and a few minor pieces. The owner could then finish the reassembly himself- basically just bolting things together.

Prices- For the parts I'd supply I want to cover the development costs I've incurred- these aren't a lot since I took a lot of time working out the idea so haven't had to "rethink" things and have alterations made.

For the spring loading mechanism for 5th- about £90
For the reverse lock out system- a bit less- about £45
For the parts required to enable the lever to be relocated- about £135

I reckon a competent owner could alter a box for about a further £200 or so. You'd have to factor in the cost of a gearbox rebuild as well.

If any owner is interested please get back to me on [email protected] or 0151 480 8400.

If no major interest is shown I'll have the parts anyway since most have already been made. I'd be prepared to sell these to cover my costs and give some help (ie explain how it's done) to a buyer.

I don't need the parts because I already have a converted box and I only did this as an interesting exercise.

regards

John
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PostPost by: colin55 » Mon Oct 11, 2010 5:21 pm

Hi John

I think we may have spoken about this subject before. I haven't had time to try the convsion myself yet but I was wondering if you have any photos to act as inspiration ?

Regards Colin
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PostPost by: bill308 » Mon Oct 11, 2010 11:19 pm

John,

A couple of years ago you offered me a spare T9 conversion that I came very close to buying. The problem for me was that it was not a complete kit and I'm not a gearbox guy. To source the bell housing and all the other bits was more than I wanted to do. I simply didn't want to take on another project with ongoing S2 Elan and Ferrari 308 projects. I wound up purchasing a Voights gearbox and had John Esposito, a local gearbox guy, do a BGH gearset change for me. I now have probably the first Voights conversion in the USA. Russ probably has the second.

It will be at least next summer before I get my S2 on the road and have a chance to evaluate the Voights/BGH conversion. The other thing is that if one goes this route, it is relatively expensive. It cost me about $1500 for the Voights conversion plus shipping plus the BGH gearset plus gearset installation.

Would you be interested in documenting your conversion so that John Esposito could produce it and make it available to the Lotus community as a bolt on conversion?

In order to be attractive, I think some basic criteria need to be met:

1. Alternate BGH gearsets would need to be accommodated as the stock ratios suck. Is there anything in your conversion that would preclude their use?

2. The gear shift must be positioned in the same location as the OEM 4-speed.

3. There must be a solution enabling use of the OEM speedometer.

4. An OEM flywheel or aftermarket low inertia flywheel must be doable.

5. A suitable clutch and pressure plate must be defined.

6. Drive shaft and output shaft changes must be defined.

7. Transmission mount changes must be defined.

I have no interest in making money on this endeavor. I simply wish to facilitate production of an affordable 5-speed for the community. I do not know if John Esposito would interested in pursuing this project but he does offer 5-speed conversions for a variety of British Marques. If he can produce a limited number of conversions at an affordable price, the Elan community will benefit.

Bill
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PostPost by: worzel » Fri Oct 15, 2010 9:41 am

Hi

I don't have a problem detailing what I've done- once it's seen in "bits" it's not hard to figure out anyway.

I've covered some of these points before but to draw them together-

The conversion doesn't affect swapping ratios in any way.

The std flywheel is retained- no mods to it

Ditto the clutch cover- the friction plate is a racing item available from DemonTweeks- about £80

The gearbox mount is retained- you just need to have a new, different metal support bracket made- quite easy

Speedo- not worth altering the std Ford item (in my opinion) just "hybridise" a Sierra cable with the std Lotus one- or get Speedy Cables to make up a special

Propshaft- just supply the overall dimensions, yolk size and spline pattern to GKN and they'll make one within about 2/3 weeks- about £150 nowadays.

The only "issue" is the bellhousing- availability is not a problem- new ones are still being made and quite a few are on ebay. Cost is problematic though- between £350 and 400. Secondhand - if you can locate one- probably now about £200.

Lever position- this seems to cause agonies- how far do you want to go with this?- there seem to be umpteen ways nowadays of shifting the lever- all varying in complexity. The most complex way seems to be the AV route. My only problem with this approach is what happens if things "break"- it's obviously quite possible that this won't happen (low usage etc) but their boxes certainly are radically altered from std.

It's possible to convert in a similar fashion to their system but with far less alteration. This might not suit everybody though- the alloy tail is "cut and shut" rather than being specifically cast new, the spring loading system against 5th also differs (but works equally as well), and reverse lockout is no longer push down and leftwards but operates via a sprung cam.

IN my car the lever is SLIGHTLY aft of the 4 speed item- not a problem for me since my centre console is a one-off I designed and the flat tray around the lever is a separate item so different lever positions are easily accommodated. Originally the lever was exactly as per the 4 speed one (achieved via short remote) but I preferred a vertical orientation of the lever rather than a backward sloping one so altered it to suit.

I'd only add that of all the conversions I've seen- I've seen 4 in person and know of at least two other different ways none is superior in the sense that the shift quality differs. All seem to work equally well- but the costs vary enormously- mine cost about £550/600 11 years ago (that was for everything) so pretty cheap. Despite being the simplest way to convert the box the only thing that has gone wrong is 3rd is becoming noisy- but that's due to the actual gears /bearings wearing- the change to the linkage doesn't affect the actual gears.

I'll put some pictures up in the next few days- the only problem is that of explaining how it all fits together.

Regards

John
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