Lotus Elan

'Safety' drive shafts

PostPost by: Matt Elan » Wed Mar 25, 2020 3:47 pm

Elan and Plus 2 Source book progressing well and I'm sorting out little niggles and tying up loose ends as best I can now. It was late in Plus 2 production when the 'Safety' drive shafts, diff output shafts and hub drives with the tube and spigot system was introduced to prevent the shafts failing about if a rotoflex broke up. I remember Mike Kimberly told me ha had worked on them after joining Lotus in 1969 but couldn't remember the exact date, and they are not listed in my 1971 Plus 2 Parts manual. So three questions:
Does anyone have the date or chassis number these were introduced?
I believe they were only fitted to the Plus 2 - can anyone confirm this was the case?
Was the tube bit on the central drive shaft or the dif and hub shafts?
Many thanks to the collective.....
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PostPost by: rgh0 » Thu Mar 26, 2020 12:01 am

My 73 Plus 2 had them before i fitted Cv's. The tube bit was on the drive shaft and the pins on the diff and hub shafts. I had a donut failure when they were fitted many years ago and they did not work :roll: The pin just shear off and the shaft flailed around as it normally does in this event , luckily it did not do to much damage. This is what started me going to Cv's on the Plus 2 and the Elan about 30+ years ago.

I dont know if they were ever fitted to Elans made in the 72 /73 period

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PostPost by: HCA » Thu Mar 26, 2020 4:23 am

Rohan - was your failure under race or harsh conditions? I have one in the first stage of failure that needs attention and wonder if it is OK to continue with the doughnuts or go to the expence of CVs. On the basis that the car will only be for road use, I am of mind to continue, but seek advice from the experienced!
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PostPost by: rgh0 » Thu Mar 26, 2020 6:45 am

The failure in the plus 2 was taking off in first gear on the road ( but i was taking off from the lights enthusiastically !! :D ) so it occured at low speed but this is when the rear shafts see the most torque so thats when they normally fail. If you have any significant cracking of more than around 3 to 4 mm deep in the donut rubber where it is bonded to the bolt plates or intermediate leaves I would replace it or get CV's as it can go from OK to failure very quickly and it does make a mess of the parts around it normally when it does even at low speed

I have run Cv's on my Elan and Plus 2 for over 30 years now with zero maintenance cost so if you intend keeping the car and using it and are not about showroom museum quality originality then I would change to Cv's rather than spend lots of money regularly replacing donuts

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PostPost by: JonB » Thu Mar 26, 2020 6:52 am

..and you can always put them back on if you ever change your mind.

But you won't. :D

[edited to add: I've PM-ed you]
Early 1973 Elan Plus 2S 130/5 - UK - Unit 50/1115L
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PostPost by: Greg Foster » Thu Mar 26, 2020 11:30 am

They were also on a std. elan, 1970 had them. Not sure about earlier.....or maybe someone added them.
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PostPost by: alan.barker » Fri Mar 27, 2020 6:22 am

JonB wrote:..and you can always put them back on if you ever change your mind.

But you won't. :D

[edited to add: I've PM-ed you]

Not as easy as that, you will need to weld new Pins on Diff Shafts + Hub Shafts.
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PostPost by: HCA » Fri Mar 27, 2020 8:13 am

Yep, I hear everyone, the upgrade is a must - especially if I my aim on this car is to make what is there a little easier to cope with. Having had many years of living with the horrors of the Mk1 Mini joints - anything rubber in the drive train must go :D

I would have hoped to make this upgrade as part of the body - chassis separation, but as I have one doughnut completely severed at one bolt and the other with age cracks, their replacement is now a safety issue. As the Rotalfex rubbers are not cheap, it is maybe false economy to simply replace them only to rip them out in a year (during which time driving will be limited if things continus as is :x )

I am fortunate in that I have a two post lift so can make the change in comfort, but what is required for this job in parts and procedure - I see the drive shaft pic in Paul Matty's website, but there must be flanges on top, and what are the pins you mention? And a change in shock absorbers is also part of it..?
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PostPost by: JonB » Fri Mar 27, 2020 8:26 am

alan.barker wrote:
JonB wrote:..and you can always put them back on if you ever change your mind.

But you won't. :D

[edited to add: I've PM-ed you]

Not as easy as that, you will need to weld new Pins on Diff Shafts + Hub Shafts.
Alan


Only if you want the dubious reassurance that they will actually work in a doughnut failure. Which from the sounds of it they don’t!
Early 1973 Elan Plus 2S 130/5 - UK - Unit 50/1115L
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PostPost by: alan.barker » Fri Mar 27, 2020 8:55 am

Hi Jon,
for sure a personal choice and it depends what you want to do with your car.
From 1976 to 1991 my everyday transport was a 1968 +2 for 2 years then a 1970+2S until 1991. Average mileage 25,000 per year. Always Rotoflex Couplings no problem if checked on a regular basis.
Here in France since 1992 driving 1973 +2S130/4 and 1972 Elan sprint fhc both with Rotoflex Couplings no problem. But in France only Sunday and Car Club driving maybe 1,000 miles per Year maxi.
It just depends on use and personal tastes. The same for other things such as Chassis where i would only fit Lotus Galvanised (sorry if i've opened a can of Worms).
For sure a Classic Lotus is not like a modern car where you just turn the Key and drive. But surely you buy a Lotus so you can tinker and amuse yourself :wink: :wink: (when you're in the Dog House)
If not just buy a modern car.
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PostPost by: 512BB » Fri Mar 27, 2020 9:06 am

' The same for other things such as Chassis where i would only fit Lotus Galvanised'

Nobody will be fitting a galvanised chassis any more as they are no longer available, from anyone.

Leslie
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PostPost by: HCA » Fri Mar 27, 2020 9:12 am

Did a bit of research, made easier by there being something on youtube as well. So the upgrade is not complicated, it is a straight swap - but still leaves me with a question regarding the shock absorber 'droop' and pins mentioned elsewhere..?

There are a few offerings of cv drivehsafts - are they all the same at the end of the day?
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PostPost by: alan.barker » Fri Mar 27, 2020 9:29 am

Depends how much you want to spend. Have a look at past forum posts.
Limited shocks are only needed on a baby Elan and it depends what CVs you buy.
Alan
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PostPost by: Foxie » Fri Mar 27, 2020 12:48 pm

rgh0 wrote:The failure in the plus 2 was taking off in first gear on the road ( but i was taking off from the lights enthusiastically !! :D ) so it occured at low speed but this is when the rear shafts see the most torque so thats when they normally fail.
Rohan


Many years ago I was driving to an important meeting in to the centre of Dublin in the morning rush hour.

At the lights at the Silver Tassie pub there was a long queue in both lanes.

However, the right turning lane was empty.

I took the right turning lane and drove up to the lights. I reckoned with the great acceleration of my Plus 2S, combined with my lightening fast reactions, I would get away first, and cut back across all the tortoises.

The instant the lights changed I floored the throttle and dropped the clutch. There was a tremendous bang from the back of the car, and I was going nowhere, as the rest of the traffic drove by, with much jubilation and blowing of horns. :oops:

I had no drive, but I had no brakes either.

When I was eventually able to roll the car to the hard shoulder and investigate, I found that not only had the rotoflex completely disintegrated, but the flailing shaft had snapped the brake caliper clean off its mounting lugs. :shock:

Needless to say, I did not make my meeting.

Soon after I fitted CVJs. :)
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PostPost by: mbell » Fri Mar 27, 2020 6:11 pm

[quote="Foxie" but the flailing shaft had snapped the brake caliper clean off its mounting lugs. :shock: [/quote]

My car has repairs that showed it suffered a similiar fate at some point! I was very happy that it came with CV shafts already fitted :)
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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