Suspension refresh

[Smithy111]

I was worried they might be too harsh for road use or wear out quickly. Does anyone have any experience with the SJ ones?

[Andyww]

The poly bushes I had on mine (not sure the source) made the suspension really stiff, especially the one on pre-85 cars which connect the ARB to the lower link. If you wind the nut up to the shoulder on the ARB the bushes are compressed to rock solid. If you dont wind it up to the shoulder but nip the bushes up, it comes undone as has happened to people on this forum.

Also the lower link twists when it moves up/down and the large lower link to chassis bush needs to be compliant enough to allow this.

If SJ can confirm the shore rating of their poly bushes is exactly the same as the Lotus ones which were designed by world leaders in suspension then they would be OK to use IMHO otherwise not. Ditto shocks should be valved for bump and rebound dyno curves as per Lotus design not some random single adjustment knob.

 

[silverfrost]

I think you hit the nail on the head Andy, a lot of folks are saying they are way to hard for the suspension.

[Smithy111]

I’ve gone with all pu bushes and have a question which I can’t seem to find a definate answer to - I’ve greased up the steel collet and inserted it into the bushe with the supplied grease and I assume you grease the inside of the collect where it will pivot on the bolt shank? If so do I use the same silicone grease supplied or copper slip?

[Andyww]

None of the bushes should pivot on the bolts at all, otherwise there will be a huge wear problem. So no grease there. I suppose a bit of copper grease would be OK to prevent all rusting up but there should not be any movement there.

Edit: Just re-read. Are the bushes the type where a collet rotates inside the Pu bush (hope not) or just PU versions of the original bonded bushes?

[Smithy111]

There the super flex ones that SJ supply, seem nice a soft really, thought they would be harder. So the collet twists inside the bush due to the washers tightening up on the collet? I’ve applied pleanty of grease to the outside of the collect

[Andyww]

the original metalastik bushes are bonded rubber so that the outer and inner metal sleeves are permanently bonded to the rubber between them, and when the wishbones move only the rubber flexes and nothing else.

The whole point of that design is so there are no parts moving against each other and also the rubber acts like a rising-rate spring because as it deforms more, it resists more. This is part of the suspension characteristics designed in.

The pictured look completely different and, wrong.

There is some good info on the suspension and bushes here:

https://www.thelotusforums.com/forums/topic/64078-spring-and-damper-recommendations-for-86-turbo/?tab=comments#comment-506289

 

[Smithy111]

Ah I understand now. So why are most poly bushes this sort?  Power flex have been around years and must know what they are doing? Also why would SJ be selling them if their wrong? I saw the bonded Lotus poly bushes but they are very expensive by comparison. What problems are you saying I may have? Wear quickly?

[Andyww]

Seen these over on Ferrarichat as well, people fit them to 3x8s which also use bonded rubber originally. 

They fundamentally change the suspension characteristics just to save a bit of cash. Admittedly there is a big time saving on the Ferrari as well because the OEM bushes are spot-welded into the wishbones and take absolutely hours to change. So on the F you can burn out the rubber and leave the outer part in the wishbone.

Its a kludge though, the cars dont ride as well and people have reported squeaks and other noises as the rubbing parts wear, which necessitates regular dismantling and re-lubrication.

The original bonded rubber are expensive but Lotus used them for good reason.

[Smithy111]

Well I’ve bought them now so I’ll try them and if they give me problems I’ll replace with bonded rubber

[Smithy111]

Thought I’d give a little update, (we all love oily bits pics!) just waiting for the front springs from SJ which should arrive tomorrow:

[Smithy111]

Oh and if like me, you have an early pre 85 front suspension and you don’t like any of the aftermarket damper options as originals are obsolete, make your own out of a pair of post 85 dampers very carefully using a 1mm angle grinder disc 👍

 

Edited July 17, 2018 by Smithy111

[Steve4012]

Have you compared them to the originals and found them to now be identical?

[Smithy111]

Yes they are identical only the spring platform is different, I can't understand why they cant be produced without the platform from the factory? I guess lower numbers of trunnion cars

[skiing]

Very interested you did this Smithy - I am replacing my fronts with Avos but tempted to do this at some point as well...

[Smithy111]

I did phone a few places but none were interested in doing it one wanted £50! It was so easy took about 5 mins per shock, clamped the angle grinder in a bench vice and turned the shock by hand against the blade with the usual safety precautions of course, then painted to stop corrosion.

Car should be back on the road tomorrow!

 

Edited July 18, 2018 by Smithy111

[Gis]

Looks great Chris. Nice clean setup.

[Andyww]

On 17/07/2018 at 23:20, Smithy111 said:

Yes they are identical only the spring platform is different, I can't understand why they cant be produced without the platform from the factory? I guess lower numbers of trunnion cars

Its possible that the factory is running on old stocks, maybe neither version are produced.

[C43]

agreed looks really nice, be interesting to see how much difference there is in the driving.

When you fitted the front upright did you have to force it much to line up with the top ball joint? On mine I fitted the front upright to trunnion at the bottom and I then had to push the upright quite a lot forwards to line up with the top ball joint. I took everything to pieces and swapped parts around in case something was bent but could not find a problem. It was the same on both sides.

enjoy the drive

C43

ps nice job on the new brake pipe, they are a pain to get right with the tight bend radius

pps agree regarding damping, the new after market ones are too stiff. 

[Smithy111]

Well all finished today and took it for an hours drive and all seems well, brake pedal seems to travel a bit further than i remember but stop just fine so will bleed the system again in case theres still some air in the system although i did use an ez bleed?

Its noticeably lower than before with the non air con springs which for reference are the same wire gauge as the air con springs but about half inch shorter. Have about 6 inch under front cross member but only about 3.5 under, undertray! Seemed ok over most speed bumps and has a dry sump/Essex look about it!

Christian - Fitted mine the same way, one side lined up spot on the other was slightly out and could easily push it up and into the ball joint. I did assemble everything loose before torque up with the axles at ride height. And yes those s bend brake pipes were a pain to get right without over bending them and collapsing the pipe. Poor really from SJ considering they are £7 each, it should really fit without modification.

[Andyww]

Good job!

I had a lot of trouble bleeding mine using a Sealey pressure bleeder, it seemed to make them worse. I went back to the old fashioned method and was fine.

[Smithy111]

I might try that as i noticed to start with the back wouldn't bleed until it was pumped once? (i have replaced all four hoses with braided ones).

Andy, what is your ride height as you have a similar setup?

[C43]

cheers mate, car looks really great.

[Andyww]

On 20/07/2018 at 00:25, Smithy111 said:

 

Andy, what is your ride height as you have a similar setup?

I have 170mm under crossmember which is the exact factory figure.

[markt]

Very nicely done Chris   Like your thinking with the shock absorbers too. Any idea why it's sitting lower (and better in my opinion)?