Lotus Elan

Adjustable Rear Spring Seat

PostPost by: StressCraxx » Wed Feb 13, 2019 6:42 pm

Some great observations and recommendations.
Another concern I have is having an alloy tube (the threaded sleeve) over the steel strut tube. Add moisture between the two metals and galvanic corrosion will occur.

Any thought to replacing the original strut tube entirely with a threaded anodized alloy one?

Regards,
Dan
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PostPost by: JohnP » Wed Feb 13, 2019 6:54 pm

Is this what people are thinking of?

https://paulmattysportscars.co.uk/produ ... c-tube-lh/

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PostPost by: rgh0 » Thu Feb 14, 2019 11:40 am

Yes the two key issues have been raised

1. The seating of the floating sleeve on the top of the alloy housing
2. The fit of the loose threaded sleeve on the strut tube so it does not rattle around and does not corrode and lock up.


Issues such as how straight and round the strut tube and flatness of the top of the alloy hub casting becomes important

With any new installation you need to ensure the spring remains seated and loaded at full droop and with a floating support sleeve this becomes even more important.

I have an adjustable C spanner with a round pin end that fits multiple diameters as my front and rear adjustable seats are different that I use and this would be ideal for your sleeve with drilled holes. They are commercially available and you should be able to find at a tool shop or EBay.

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PostPost by: john.p.clegg » Thu Feb 14, 2019 1:32 pm

Rohan

Is your spring unloaded at full droop ?

John :wink:
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PostPost by: Craven » Thu Feb 14, 2019 2:10 pm

Further to my comment on roundness and size of the original damper tube, there will be a high friction area between the two tubes unless a good working clearance is designed in.
Possible idea may be arrange the bottom support ring be made as a two face collar so as to make a small area bush between the inner and outer tubes, do the same at the top with another collar so the outer tube is rotated on these top and bottom bushes.
This will help on friction and alignment if the original damper tube is not straight.
ps or lots of grease.
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PostPost by: rgh0 » Fri Feb 15, 2019 11:24 pm

john.p.clegg wrote:Rohan

Is your spring unloaded at full droop ?

John :wink:


To answer the question seriously :lol:
I have 150 lb rear springs and limited droop shocks and the springs have only a few pounds load at full droop so very close to coming off the seats

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PostPost by: john.p.clegg » Sat Feb 16, 2019 7:05 am

Rohan

Just being Pernickety....

John :wink:
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PostPost by: vincereynard » Sat Feb 16, 2019 8:23 pm

Craven wrote:Further to my comment on roundness and size of the original damper tube, there will be a high friction area between the two tubes unless a good working clearance is designed in.
Possible idea may be arrange the bottom support ring be made as a two face collar so as to make a small area bush between the inner and outer tubes, do the same at the top with another collar so the outer tube is rotated on these top and bottom bushes.


He has skimmed the tube for roundness (it was slightly distorted) and allowed a 10 thou clearance in the I/D of the sleeve.
I will possibly propose a stainless thrust washer twixt sleeve and the steel collar.

Other than that I think it is possible to over engineer something that is essentially simply. Once the height are set it may not be touched for years. Although the springs are new so they may settle a tadge.

Thanks for all the input and suggestions, they have been useful.

I'll let you know how I get on!

Vince
Last edited by vincereynard on Sat Feb 16, 2019 10:52 pm, edited 1 time in total.
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PostPost by: rgh0 » Sat Feb 16, 2019 10:29 pm

I would put nickel anti-seize between the strut tube and the rotating threaded collar on assembly to minimise the chance of it corroding in place.

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PostPost by: vincereynard » Sat Feb 16, 2019 11:10 pm

NICKEL anti seize is a new one for me Rohan.

What is the advantage over say copper antiseize or just Moly grease?

https://www.ebay.co.uk/itm/173777621173

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PostPost by: rgh0 » Sun Feb 17, 2019 12:43 am

I find it prevents corrosion and stops seizing better especially for aluminium at higher temperatures such as exhaust studs or bolts into the head or brake calipers bolts than the traditional copper based equivalents, so i use it as standard now.

https://www.henkel-adhesives.com/us/en/ ... b_771.html

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PostPost by: vincereynard » Mon Feb 18, 2019 4:06 pm

StressCraxx wrote:Another concern I have is having an alloy tube (the threaded sleeve) over the steel strut tube. Add moisture between the two metals and galvanic corrosion will occur.

Any thought to replacing the original strut tube entirely with a threaded anodized alloy one?
Dan


Dan,
Sorry I missed your comment.
Rohan has sorted your first concern.
As with many of my ideas this has grown from a simple job. In this case "can you get these "*******" hubs off for me? > Could you make a sleeve that fitted over the tube and mod the spring seat > How about a full length that is held by loctite? > How about using alloy for lightness > How about a "floating" sleeve that turned to adjust instead etc etc.

Replacing the whole sleeve had not occured yet. Although it does appeal as it could be slimmer and lighter. Would it be strong enough? Internal thread for the damper etc.

With it being held in place by interference I don't know enough to ensure that would be OK. Feel free to gave a go. Getting too techie for me!

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PostPost by: StressCraxx » Mon Feb 18, 2019 6:01 pm

vincereynard wrote:
StressCraxx wrote:Another concern I have is having an alloy tube (the threaded sleeve) over the steel strut tube. Add moisture between the two metals and galvanic corrosion will occur.

Any thought to replacing the original strut tube entirely with a threaded anodized alloy one?
Dan


Dan,
Sorry I missed your comment.
Rohan has sorted your first concern.
As with many of my ideas this has grown from a simple job. In this case "can you get these "*******" hubs off for me? > Could you make a sleeve that fitted over the tube and mod the spring seat > How about a full length that is held by loctite? > How about using alloy for lightness > How about a "floating" sleeve that turned to adjust instead etc etc.

Replacing the whole sleeve had not occured yet. Although it does appeal as it could be slimmer and lighter. Would it be strong enough? Internal thread for the damper etc.

With it being held in place by interference I don't know enough to ensure that would be OK. Feel free to gave a go. Getting too techie for me!

Vince


Hello Vince,

Ray at RD Enterprises offers a complete solution if you are interested. Go to http://www.rdent.com/ and look at the left side under Model Specific Parts, select Elan Parts and then select Suspension and Running Gear. About halfway down the list are choices for a complete replacement threaded tube that uses 2-1/4 springs, a slide on adjustable tube, plus the appropriate upper perches. Miles Wilkins or Sue Miller may have similar offerings. Best of luck to you.

Regards,
Dan Wise
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PostPost by: vincereynard » Thu Feb 21, 2019 10:41 pm

Too late Dan. The sleeves and modified bottom spring cups are made.

Just a matter of nagging him to finish a few other small bits and mod the A arms.

Anyway I have a NOS pair of full size springs so I wanted to try those first.
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PostPost by: StressCraxx » Fri Feb 22, 2019 1:24 am

Sounds great Vince,

Please let us know the result.

Regards,
Dan
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