Lotus Elan

Adjustable Rear Spring Seat

PostPost by: mbell » Fri Feb 22, 2019 1:43 am

Yes photos would be very much appreciated...
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: vincereynard » Fri Feb 22, 2019 8:12 pm

mbell wrote:Yes photos would be very much appreciated...


I shall do soon as I have all the bits back.

What is the recommended loctite for bearing retention? The engineer mentioned 638?
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PostPost by: vstibbard » Fri Feb 22, 2019 10:28 pm

Hi All

Here's my solution to easily adjustable rear wishbones without having to remove them to adjust.

We solved this by using "barrel" nuts, essentially the bush or rose joint is screwed into the centre of the barrel nut and the outer thread of barrel nut screwed into the wishbone. To adjust you simply release the lock nuts (one on barrel nut to wishbone other on rose joint to barrel nut and adjust barrel nut.

Here is photo as fitted to my 26R:
p1000439.jpg and
Rear wishbone barrel nut and rose joint


Note, this photo does not have the barrel nut lock nut fitted which we did to be sure and to provide additional support for the barrel nut. Also when finished the thread was shortened to ensure it was inside the wishbone, greased and caps fitted to stop grit getting in.

I've done same on a road car with bushes which using an adjustable inner bush (like Spyders). In this case we've only use a lock nut on the bush to barrel nut. as the bush does rotate. The road car has steel barrel nuts as the maintenance.

Hope this simple solution is of use.

Cheers

V
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PostPost by: rgh0 » Fri Feb 22, 2019 10:31 pm

Suggest you read through this at the following link as many options depending on the exact circumstances of what your doing.

cheers
Rohan

http://www.ferret.com.au/odin/pdf/showcases/103728.pdf
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PostPost by: 661 » Sat Feb 23, 2019 12:18 pm

vstibbard wrote:Hi All

Here's my solution to easily adjustable rear wishbones without having to remove them to adjust.

We solved this by using "barrel" nuts, essentially the bush or rose joint is screwed into the centre of the barrel nut and the outer thread of barrel nut screwed into the wishbone. To adjust you simply release the lock nuts (one on barrel nut to wishbone other on rose joint to barrel nut and adjust barrel nut.

Here is photo as fitted to my 26R:
P1000439.JPG


Note, this photo does not have the barrel nut lock nut fitted which we did to be sure and to provide additional support for the barrel nut. Also when finished the thread was shortened to ensure it was inside the wishbone, greased and caps fitted to stop grit getting in.

I've done same on a road car with bushes which using an adjustable inner bush (like Spyders). In this case we've only use a lock nut on the bush to barrel nut. as the bush does rotate. The road car has steel barrel nuts as the maintenance.

Hope this simple solution is of use.

Cheers

V




Forgive me Vaughan, I'm trying to get to grips with that. As I have it in my mind, if you rotate the barrel 'nut', it not only rotates within the wishbone ( moving itself either forward or back) but it will also rotate itself at the same time about the threaded rod of the rose joint and merely leaves the head of the rose joint where it was before. I know I must be missing something here, but can you please expand?
Additionally, a quick search on the web doesn't show any sources of a barrel nut of adequate proportions, threaded inside and out. Do you have a contact?

Thanks
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PostPost by: 661 » Sat Feb 23, 2019 12:20 pm

Ahhhh!
The barrel nut isn't threaded within the wishbone, only at the end that accepts the nut.....
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PostPost by: vincereynard » Sat Feb 23, 2019 1:46 pm

661 wrote: As I have it in my mind, if you rotate the barrel 'nut', it not only rotates within the wishbone ( moving itself either forward or back) but it will also rotate itself at the same time about the threaded rod of the rose joint and merely leaves the head of the rose joint where it was before. I know I must be missing something here, but can you please expand?

Thats exactly what I thought unless the rose joint had a L/H thread? I know I must also be missing something.

661 wrote:Ahhhh!
The barrel nut isn't threaded within the wishbone, only at the end that accepts the nut.....


But
vstibbard wrote:Note, this photo does not have the barrel nut lock nut fitted which we did to be sure and to provide additional support for the barrel nut. Also when finished the thread was shortened to ensure it was inside the wishbone, greased and caps fitted to stop grit getting in.
V


Would that not indicate that it was threaded all the way? I've sent a PM for the cronically confused.
It certainly looks neat and strong.

rgh0 wrote:Suggest you read through this at the following link as many options depending on the exact circumstances of what your doing.
http://www.ferret.com.au/odin/pdf/showcases/103728.pdf
cheers
Rohan


Thanks Rohan. Quite a choice. I note it doesn't seem to mention 638 at all!
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PostPost by: vstibbard » Fri Mar 01, 2019 9:05 am

Sorry works crazy at the moment so I've not made it to the shed.... Its quite simple, the outer thread of barrel nut and wishbone is right handed and inner barrel nut is left handed thread, with a left handed thread rose joint is all it takes.

The wishbone has them on both inner ends, so to adjust either wind barrel nut in or out, one to adjust toe and both barrel nuts to adjust camber.

Cheers

V
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PostPost by: vincereynard » Fri Mar 01, 2019 11:07 am

vincereynard wrote:
661 wrote: As I have it in my mind, if you rotate the barrel 'nut', it not only rotates within the wishbone ( moving itself either forward or back) but it will also rotate itself at the same time about the threaded rod of the rose joint and merely leaves the head of the rose joint where it was before. I know I must be missing something here, but can you please expand?

Thats exactly what I thought unless the rose joint had a L/H thread?


Many thanks Vaughn, very neat.
I considered something similar a couple of years ago but did not get around to pondering the details.
I'll have a word with an engineering chap!

I suppose the adjustment is provided by the R/H and L/H threads being a different pitch?
Last edited by vincereynard on Sat Mar 02, 2019 11:09 am, edited 1 time in total.
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PostPost by: 661 » Fri Mar 01, 2019 12:49 pm

vstibbard wrote:Sorry works crazy at the moment so I've not made it to the shed.... Its quite simple, the outer thread of barrel nut and wishbone is right handed and inner barrel nut is left handed thread, with a left handed thread rose joint is all it takes.

The wishbone has them on both inner ends, so to adjust either wind barrel nut in or out, one to adjust toe and both barrel nuts to adjust camber.

Cheers

V

Very smart.
Presumably you had to have that engineered rather than it be an off the shelf item?
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PostPost by: vstibbard » Fri Mar 01, 2019 11:15 pm

Hi Graeme

I had them machined up, its a simple job, we made the steel ones in the photo, we then made aluminium (can't remember the alloy number) which were then hard coated which were sized to accommodate +/-1 deg from the initial set up which are track only and fitted to the 26R.

If there was interest I could get a price for set (4 off) of the barrel nuts. Remember that I've also made jigs for front and rear wishbones, with rears able to make std 26R i.e TTR style, or to suit the barrel nuts.

What gets more involving is the rear wishbones need to be modified, or new fabricated which is expensive as the guy I use is an absolute craftsman and perfectionist who uses only best materials, it involves the tubing and machining up all the ends and welding, and finished in electrolysis nickel to protect the steel.

Any one looking closely at the photo should also note the smaller diameter rose joints and bolts for the inner wishbone mounts, as the original rose joints which suit standard inner wishbone bolts are massively over engineered and heavy. We machined spacers (visible) which are required to position the OEM rose joints anyway to align front to rear track accurately which also reduced existing wishbone mount diameter to suit the smaller bolt diameter. The spacers are more intricate to machine but we had to make the others anyway.

Add lightness first ...

Cheers

V
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