Lotus Elan and Lotus Elan Plus 2 Forums

Hello everyone, armed with all the advice and tips in the archives I
am attempting to replace the rotoflex couplings on my 1969 +2 next
week. When I was underneath the car today however looking at what was
involved I noticed that one of the intermediate driveshafts is
the 'failsafe' type but I can find no mention of these in my manual.
How will this affect the job, for example will I have to remove the
suspension strut on that side. I'll ponder the problem over a couple
of pints in the Joiners Arms tonight but just in case this doesn't
provide the necessary inspiration I would be very grateful for any
advice.


Regards

Ken
Morpeth
Northumberland

What the heck is a "failsafe" intermediate driveshaft?



Tony V



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From: ***@***.***lto:***@***.*** Behalf
Of kandmpc
Sent: Saturday, June 18, 2005 2:37 PM
To: ***@***.***
Subject: [LotusElan.net] rotoflex/failsafe driveshaft



Hello everyone, armed with all the advice and tips in the archives I
am attempting to replace the rotoflex couplings on my 1969 +2 next
week. When I was underneath the car today however looking at what was
involved I noticed that one of the intermediate driveshafts is
the 'failsafe' type but I can find no mention of these in my manual.
How will this affect the job, for example will I have to remove the
suspension strut on that side. I'll ponder the problem over a couple
of pints in the Joiners Arms tonight but just in case this doesn't
provide the necessary inspiration I would be very grateful for any
advice.


Regards

Ken
Morpeth
Northumberland











CopyrightC LotusElan.net and the author:





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There is a "centralizing pin" that protrudes from the end of the shaft,
passes through the open center of the rotoflex coupling, that engages a
matching socket in the output shaft.

In the event of a coupling failure, you lose drive transmission, but the
shaft cannot flail around damaging suspension and bodywork. Instead it
remains in place, captured by the pin and socket, spinning furiously with no
rotoflex to transmit the drive.

I believe these came fitted to later driveshafts. There is also an
aftermarket retrofit kit available.
The picture of it here: www.davebean.com/specials3.htm#MCCenter may explain
it a lot better than I did above...

Regards,
-John
'69 Lotus Elan S4 DHC 45/8290
'74 1/2 Jensen Healey #18918

I built my own ?failsafe? a bit different way. I drilled and taped each
end of the half shaft and installed a step bolt (normal bolt would work OK
too. Then I made triangular plates and welded about 1 ?? tubing in the
center. The triangular plate bolts to the opposite shaft (diff or upright)
along with the donut. This adds slightly to the length of the half shaft
but I shaved a bit off the half shaft flanges to compensate.



The triangles actually have to be cut down to kind of pinwheel shape to
clear the other 3 bolts and prevent binding.



Result: I once snapped one of the outboard bolts and was able to drive 20+
miles home.



Ken

'69 Lotus Elan +2 with BDR

_____

From: ***@***.***lto:***@***.*** Behalf
Of John Palmer
Sent: Saturday, June 18, 2005 8:54 PM
To: ***@***.***
Subject: Re: [LotusElan.net] rotoflex/failsafe driveshaft




There is a "centralizing pin" that protrudes from the end of the shaft,
passes through the open center of the rotoflex coupling, that engages a
matching socket in the output shaft.

In the event of a coupling failure, you lose drive transmission, but the
shaft cannot flail around damaging suspension and bodywork. Instead it
remains in place, captured by the pin and socket, spinning furiously with no

rotoflex to transmit the drive.

I believe these came fitted to later driveshafts. There is also an
aftermarket retrofit kit available.
The picture of it here: www.davebean.com/specials3.htm#MCCenter may explain

it a lot better than I did above...

Regards,
-John
'69 Lotus Elan S4 DHC 45/8290
'74 1/2 Jensen Healey #18918















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