Lotus Elan

To Rotoflex or not to Rotoflex

PostPost by: ed_vh » Thu Oct 25, 2012 9:44 pm

My Rotoflex couplings have died a death after a couple of years of little use of my Lotus+2S130 (her curse for my lack of use!). The question now is which way do I go;

1. Lotus Roto's at ?80 each
2. Ebay Roto's (a copy) at ?30 each
3. Chuck the Rotoflexes and change for a CV system like Mick Millers

The roto's only seam to last me about 3 years each set so it is quite an expense at ?320 a go. I like the idea of the CV joint stopping this and getting rid of the spongy pulling away in the Lotus. BUT will they damage the car? What do they cost? I see some of the comments that anything but Rotoflex is damaging but has anybody fitted CVs and experienced problems? My car is all original but I am not a purist, I would be happy to change.

Thoughts appreciated. (I know it has been discussed before on the forum but it would be good to get some opinions from those that have tried CV type replacements)

Thanks

Ed
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PostPost by: gjz30075 » Thu Oct 25, 2012 10:32 pm

Number 3 is your only option. Mine have been on for over 30 years.

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PostPost by: Kerryt333 » Fri Oct 26, 2012 12:00 am

I put CV driveshafts on my + 2S130 3years ago & although I haven't done many miles in that time,
they still look brand new & I haven't experienced any problems when I have been out in the car.
They are so quick & easy to remove & put on again compared to Rotoflex's,& the only rubber part that's
exposed to the elements is the small gaiters, which are not under constant stress like Rotoflex's.
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PostPost by: billwill » Fri Oct 26, 2012 1:27 am

The same issue is currently being discussed in the Elan section.

ClicK elan-f14/rotoflex-question-t26414.html
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PostPost by: vernon.taylor » Fri Oct 26, 2012 5:47 am

4. Spyder hybrid driveshafts

http://www.spydercars.co.uk/pg4_spy_driveshaft_conv.htm

The rotoflex life is supposed to be greatly increases whilst keeping the cushioning effect.

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PostPost by: RichC » Fri Oct 26, 2012 9:03 am

yeah go for option 3 ... fit and forget
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PostPost by: types26/36 » Fri Oct 26, 2012 10:22 am

Kerryt333 wrote:I put CV driveshafts on my + 2S130 3years ago & although I haven't done many miles in that time,
they still look brand new & I haven't experienced any problems when I have been out in the car.
John


I think the issues relate to the two seater Elan as I believe Sue still supplies the CV conversion for the Plus Two, this would indicate the short shaft length of the two seater is causing the problems.
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PostPost by: ed_vh » Fri Oct 26, 2012 11:33 am

Thanks for the replies. So;

spyder half conversion ?500 (+ 2 Rotoflexes = ?660)
or www.elantrikbits.com convertion ?1100
or a set of rotoflexes ?360

hmmmm. Do I have to take the differential out for the spyder conversion?

I like the elan trick bits conversion but ?1100 is probably quarter of the value of my car!

choices choices..... :?
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PostPost by: terryp » Fri Oct 26, 2012 12:45 pm

What about TTR UJs about ?575.00 - just installed them and look very blingey especially with the plated calipers!
P1010172.JPG and

You do have to fit drop restrictors or TTR Shocks

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PostPost by: bast0n » Fri Oct 26, 2012 12:54 pm

I have Sue Millers on mine and it transformed the driving experience, and have done countless thousands of miles without a problem.

Two UJs, a sliding spline and droop restrictors is not in my opinion a sensible way to go. Add lightness and simplify as some one once said................. :roll:
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PostPost by: kstrutt11 » Sat Oct 27, 2012 8:47 pm

I have the spyder ones on mine, the rotoflexes come with the shaft kit and do seem to last longer (the shafts have pin and socket which keeps the joint concentric), you don't need to remove the diff to fit them but if you have the safety shafts with the anti flail pins these will need to be cut off, I did mine in situ with a angle grinder.
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PostPost by: StressCraxx » Mon Jan 28, 2013 5:30 am

Has anyone considered these as alternatives? Its called a guibo in BMWville. It is sandwiched between the trans and driveshaft and supported by a steady bearing.

http://www.bmwpartsweb.com/Part-Number/Product-Detail__26117511454_O-prd-E_6BB4EABD.aspx

I am thinking about taking a donut to a bmw shop for comparison. I understand some spacers/washers may be needed....
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PostPost by: vernon.taylor » Mon Jan 28, 2013 8:23 am

Salut StressCraxx

Interesting but aren't they for propshaft use? Probably not designed to work at extreme angles. Also read they are directional + they split, too:

guibo.JPG and


Keep us informed.

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PostPost by: gearbox » Mon Jan 28, 2013 9:21 am

I don't think the BMW driveshaft donut was designed to operate at the angles required by the Elan, especially at full droop, so they will most likely also fail. I would think the key to any of these conversions whether it be CV's or U-joints, is to limit the droop of our cars. I just bought TTR's fast road Konis which has a 2" droop limiter installed. But anyone can retro fit a set of cartridge shocks by opening up the top and inserting a 2" nylon tube inside. All you need to do is fabricate a tool to screw open the top and a 2" nylon tube with an OD just smaller than the ID of the cartridge and ID just bigger than the shaft.

Back in the day, most Elan owners were fabricating their own CV conversion kits from VW Beetle drive shafts. After speaking with many of these guys and some manufacturers of the current CV kits, I decided to make my own. Toughest part was cutting down the VW OEM shafts as they were hardened steel. But a cut off wheel on my die grinder did the trick and was able to clean up the cut on a lathe. Most of the kits I have seen uses the Type 1 Beetle CV joint, but I understand the Type 4 has a wider range of operation, 12 degrees versus 22 degrees respectively. But again, from everyone I spoke with, the Type 1 was good enough as long as you had some kind of droop limiter. At the end of the day, the shafts costed me $350 to make, including 4 brand new Lobro GKN CV joint kits including boots. I could have saved $260 for the kits making my total cost closer to $90 USD, but didn't know the history of the used CV's and wanted to do it right anyway. I also bought a CV diff output shaft and outboard adapters because they were available, but you can just fabricate the adapters on both sides from 0.50" thick aluminum plate for a few dollars. You can see a step by step process that took me about two days to do at http://thelolaregistry.com/Projects/LOT ... ersion.htm


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PostPost by: CBUEB1771 » Mon Jan 28, 2013 5:03 pm

StressCraxx wrote:Has anyone considered these as alternatives? Its called a guibo in BMWville. It is sandwiched between the trans and driveshaft and supported by a steady bearing.


This was kicked around a few months ago. I would be very careful of the torque rating as the guibo joint is fitted upstream of that great torque multiplier called the final drive.
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