Going back to Rotoflex

[greg40green]

For the last few days I've been lying on my back under my Elan Sprint fitting / swapping a 3.7 diff for a recon 3.5 ,changing wheel bearings , diff bushes , loto cones , A frame bushes etc etc.
I bought a new set of solid drive shafts which I've done a few hundred miles on and for some reason I cannot settle with them so I'm fitting a new set of rotoflex tomorrow to finish the job.

I have run TTR solid shafts , Performance unlimited solids ( remember them ) , Spyder solid with one rotoflex coupling and standard rotoflex couplings , never tried CV shafts though.
For smoothness 'I personally' prefer the rotoflex couplings ( I run a set of TTR on my S3 without issues) I have never had a rotoflex let go on me although over the years I have seen some pretty rotten ones.
I had a diff output shaft shear on me whilst running a set of solids totally my fault as I fitted a set of solids without checking any of the other bushes then set about testing the benefits of the direct drive with some spirited driving.
With the solid drive shafts now transferring more of the energy directly to the wheels the diff bushes demonstrated their age , the diff twisted under load via the worn bushes and bang!
Nothing wrong with the solid drive shafts just a lesson learned ie check all your bushes as they are serviceable items.
Any one want a nearly new set of solid drive shafts with fixings?

[Bud English]

... But now, as Gus mentions, we need to find someone who has used them in an Elan (or Plus 2).

From the Lotus Club link four posts up..."Others have had similar positive results with the conversion. We have about 20 cars running with them now, at least that we know about." The article, near the bottom of the link, also mentions cars with the conversion running without failure for over a year. Pretty good anecdotal evidence that they work well.

[Sea Ranch]

Yeah, Bud, but I guess I was reading "car" within the context of the article, where the writer John Mihalich talks about Lotus Formula Fords. The "20 cars" he references in the last paragraph could be any cars, but I am assuming they are Formula Fords. They have one donut per side, inboard, and presumably shorter suspension travel . . .

I think this was Gus' concern, as well. I will attempt to contact the author of the article, and also find the NA supplier(s) and query them.

Randy

[SJ Lambert]

My Dad had a fair but to do with the suspension geometry of these ANF 1.5 litre cars back in the day - they used 3.78" PCD DONUTS and the next size up with good reliability.

(He & I are giving one a freshen up now - see the Open Wheeler Gets A Birthday thread in the FREE PARKING section).

We've satisfied ourselves that the currently available 3.78" heavy duty original style ones will be worth a punt in our Elfin Mono. We may upgrade to a set up utilising the next size up "Metalastiks" as our next move.

[Sea Ranch]

Awesome picture, Mr. Lambert. I cannot imagine the lateral g forces in a vehicle like that!

Unfortunately, I'm not sure of your meaning regarding Elans and Plus 2s. I don't understand what the currently available 3.78" PCD donuts are? Are they the same as we are currently using in our Lotus Elans, or are these the Volvo/BMW pieces as seen in the article you linked?

Sorry . . . one inquiring mind wants to know whatever details you can share!!

Thanks,

Randy

[SJ Lambert]

G'day Randy

The donuts we use in our open wheeler are exactly the same as the original spec Lotus Elan ones - they are on the 3.78" PCD. These days there's a heavy duty one available as a replacement for the original Metalastik rotoflex # 21/892 - the heavy duty one is part number 21/967/1 and is of UK manufacture. I am sourcing them locally to me in Melbourne, in preference to the Febi-Bilstein couplings - but it looks like they would work as well if that article is anything to go by.


Dad reckons that at some stage we ought to re-engineer the rear end of our Mono to accept the larger rotoflex couplings that are on a 4 & 7/16" PCD as back in the day when driven long and hard (as Alf Costanzo is doing in that shot) the 3.78" original spec ones could get marginal - we are getting more power out of the motors these days, but have no where near enough driving ability to get the rear end hooked up light Alfie could (and still does in F5000s - he was Aussie Gold Star Champion 3 or 4 times in a row!!)

I see no reason why the original style ones wouldn't be fine in an Elan.

Cheers

James

[SJ Lambert]

This is the set up on our car

[Bud English]

Yeah, Bud, but I guess I was reading "car" within the context of the article, where the writer John Mihalich talks about Lotus Formula Fords.
Randy

Yeah, and I must have been reading what I'd hoped to read instead of what was actually written. Wishful reading works just like wishful thinking. Gus's caution is well founded.