Rotoflex couplings

[alanr]

Interesting...
Are you confident that the size of the GT6 Rotoflex coupling, PCD etc, is exactly the same size as the Elan ones? I may be wrong but I think the GT6 ones are a different size?


Alan

Further to this after doing a bit of Googling..
GT6 Rotoflex couplings have a different PCD to Elan/Imp etc. so will not fit!
GT6 have a PCD of 4.40.
Elan/Imp etc have a PCD of 3.78.

Alan.

[pimkeirle]

You are absolutely right, turns out I was mis-informed, not only is the PCD different, so is the hole diameter.
Thanks again to everybody who has written replies.
Mike

[Lotus 50]

I get that a real 'CV' is probably better in every way, but I'm sticking with the old rubber stuff so I get the original experience.

Otherwise, how far down the resto mod road would I go?

[Andy8421]

I get that a real 'CV' is probably better in every way, but I'm sticking with the old rubber stuff so I get the original experience.

Otherwise, how far down the resto mod road would I go?

A good question. My view is limited safety / reliability mods make sense, particularly if you keep the original parts should a new owner choose to refit. A better radiator, alternator, electronic ignition are all worthwhile.

The Rotoflex were a cost choice, and I am convinced Chapman would have used plunging CVs if they had been available at the same price point. Worth noting that the 26R came with Hooke (UJ) joints and sliding ball splines in place of the Rotoflex. I suspect that stories about the Rotoflex 'improving handling' are Lotus justifying their use.

Rotoflex will fail eventually, and they don't fail safe. They are not used in historic racing.

I personally don't like the 'surge', but there are many on here who prefer the feel. There are some suggestions that modern Rotoflex aren't as good as the originals, but its not clear they were much better in period. Tony Rudd mentions in his book 'It was fun' that Rotoflex were the biggest cause of warranty claims on the Elan during its production run.

If you do choose to stick with Rotoflex, I would recommend that you regularly inspect them for splits and delamination at the interleaving steel plates.

[rgh0]

..... There are some suggestions that modern Rotoflex aren't as good as the originals, but its not clear they were much better in period. ....

The modern replacement rotoflex with the pressed steel leaves joined together to form the bolt holes is clearly inferior. The orginals were bad enough and failed if used "enthusiastically" If replaced them on my PLus 2 and Elan 40 years ago due to failures. In my personal experience the handling is not affected in any signficant way

cheers
Rohan

[trw99]

It is my understanding that recently produced doughnuts are of better quality than was the case a few years ago and I have heard a few owners say they have been pleased with these more recent items.

I also feel that the doughnuts do not like to be at full droop and that being so could well shorten their useful life.

It would be helpful to know what others experience has been of the doughnuts available in the last couple of years. Mine on the Sprint are of the older, better recipe rubber. They are starting to show some signs of age, but no horrible looking splits or cuts. However, I shall be replacing them this winter, so I shall be interested to hear about those currently available.

Tim

[The Veg]

I've heard the point made that while the Rotoflexes may have been fine in the light little Elan, they're really a bit out-classed when used in the bigger, heavier Plus 2. I've only driven Plus 2s with CVs so I can't make any comparison but I like having a solid, accurate, responsive delivery of power through the system. There's no substitute for that.

[alan.barker]

i am surprised they didn't do the same as Triumphs of the same period
Alan

[Andy8421]

i am surprised they didn't do the same as Triumphs of the same period
Alan

Alan, we should be eternally grateful that Chapman only used the front suspension from Triumph for the Elan. The Triumph rear suspension at the time was a dreadful swing axle design that was the cause of many a Herald ending up in the hedgerow.

resized_tilt_herald.jpg (28.8 KiB) Viewed 1711 times

[alan.barker]

Sure but the thing to do was fit the SAH Kit which corrected that. I think there was a mod on the mk111 GT6.
I have 2 TVR M Series which use parts from the TR6 no problem. Although the wheel bearings are the weak spot. Jag Diff solid.
Good dtuff remembering the quirks of different classics.
Alan

[Andy8421]

Alan,

There were solutions around at the time, but they all cost money. The 26R solution was a case in point. UJs were cheap, but the ball splines expensive.

[alan.barker]

100%
But on the TVR no ball splines no locking up and with a 3000cc V6 lots of torque.
I think the 26R is a different situation under race/competition conditions.
I know someone with uj type driveshafts on his +2S and no problems. He drives many kms.
Alan
Ps. I would think the ball splines on a 26R were often replaced.

[MACCA.GLM]

If I were you I would ditch the rotoflex altogether like Rohan said as the rubber and bonding is not up to scratch now and if one of those decides to take a hike the damage can be awful.They are also a pain in the butt to change as well.

Cheers G

[alan.barker]

"Pain in the butt to change" mmmm that depends on your technique.
Alan