Spyder driveshaft conversion

PostPost by: cadwell » Wed Aug 07, 2024 2:02 pm

I should be grateful if anyone who has installed Spyder, CV/Rotaflex drive shafts could let me know if their rotaflexes are distorted?
Photo shows my shaft without the safety cup fitted, and you can see that the rotaflex is pretty well unstressed and not distorted. The safety cup has 10mm flanges so when it is fitted to the diff output shaft it distorts the rotaflexes by 10mm which does not seem acceptable.
The only variable in the diff to hub measurement is the wishbone. I have Spyder adjustables fitted, which seem to be in spec.
The only way can minimise the distortion is by mounting the spiders onto the lower bosses of the rotaflex, which should bring the distortion down to around 3-4mm.
However, this should not be necessary as Spyder advise bolting the spiders to the high bosses,as per the standard Elan
Anyone got any ideas where the problem lies? The only conclusion I can come to is the shafts are 10mm too long, but as Spyder have sold 100s of these this seems unlikely.
Thanks
Peter
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PostPost by: alanr » Fri Aug 09, 2024 9:30 am

I can't quite work out from your pics what is causing your distortion.
However your bolt orientation is not correct as per the manual.
See here:-
'The Rotoflex metal bosses are offset in the rubber, three each way, and it is the HIGH bosses on each face that contact the drive shaft flanges.
When fitting bolts, their heads must be contact with the LOW bosses in the couplings. The exception to this is the bolts which secure the brake disc and coupling to both the outboard and intermediate drive shafts, when all bolt heads are towards the wheel'.

Alan
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PostPost by: rgh0 » Fri Aug 09, 2024 10:45 am

The bolts are also a little long and you can see they are probably hitting the diff output shaft bearing support area. The diff output shaft is also non standard and it looks a little thicker than the standard one

cheers
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PostPost by: elans3 » Fri Aug 09, 2024 7:49 pm

I fitted a pair to my last S3, and saw no distortion of the Rotaflex at all. Unfortunately I don't have a pic as it all went so well, but something isn't right there. IMO the best conversion to have, the Rotaflex on the inner being much kinder to the diff, but with virtually no wind-up. I loved them, and would fit another set tomorrow if I ever buy another Elan.
Current :- Elan S3 DHC SE S/S 1968,
1963 Alfa Giulia Ti Super Rep.
Previous :-
Elan S3 DHC SE SS 1968,
Elan S3 DHC S/E 1966
Elan S3 FHC Pre-Airflow 1966
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PostPost by: cadwell » Sat Aug 10, 2024 3:15 pm

Many thanks for your replies gentlemen.
I don't think that I explained myself very well, so I have done more investigations which show that the shafts are really 10mm too long.
Rohan, I am guilty of using bolts that are too long, but my excuse is that this was a trial assembly and I knew it had to come apart again to fit the safety cups. The marks on the diff bearing housing were done by a PO.
I have attached another photo showing the Spyder shaft and the safety cup temporarily propped up in position.
The gap between the face of the Spyder coupling and the diff flanges is 35mm. As the rotoflex is around 45.5mm it obviously will not fit.
The original Lotus shafts are 224mm long plus 2 x rotoflex at 45.5 = 315mm
The distance between the hub flange and the diff flange is 310mm so this is manageable given the variations on bump and droop.
I need to have a serious chat with Spyder on Monday morning! I will post the result.
Meanwhile here is a photo of my S4 99.9% complete, in Medici blue. BIt low I know, it was before I set the ride heights.
I had a 4 year old S2 back in 68, which was fabulous, but the front chassis uprights rotted. Whilst I was repairing it, I need a car to go for a weeks hoiday with a young lady in Edinburgh, so a very good friend lent me his one year old S3 SE FHC, which he had just bought for £1000. This was in Medici blus as well, and we had the most fabulous week, so you can say that i am reliving my youth which seems a long way away now that I am 82!

Peter
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PostPost by: cadwell » Sat Aug 10, 2024 3:18 pm

Sorry driveshaft photo file too large so cannot send unless some of you tech experts can tell me what to do?

Thanks Peter
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PostPost by: Spyder fan » Sun Aug 11, 2024 7:02 pm

Looking at the pictures you posted earlier I can see that your diff output shafts are non standard, the ears apoear to be at least 5 maybe 8mm thicker than normal. This is the problem and nothing to do with the Spyder items.
Kindest regards

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PostPost by: cadwell » Sun Aug 11, 2024 8:39 pm

Well spotted Alan, also Rohan had similar thoughts. Have measured everything and this is the problem, so Spyder shafts do not have a problem.

Thanks
Peter
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