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Joined: Feb 2016
Posts: 7,941 Likes: 218
Talk Morgan Guru
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Talk Morgan Guru
Joined: Feb 2016
Posts: 7,941 Likes: 218 |
Shortening rebound springs as a means of removing any undesirable static pre-load will increase their rate! Added to which unless shims are used, you will likely end up with asymmetric rates as well as ride heights, although not sure what handling effects would ensue.
I understand latest factory kingpins are chromed but not hard chrome, please correct if I've got this wrong. FWIW after over 8000 miles absolutely no wear detected on mine.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
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Joined: Dec 2014
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L - Learner Plates On
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L - Learner Plates On
Joined: Dec 2014
Posts: 216 Likes: 2 |
I have heard differing opinions about SSL. Seems to relate to the driving style; hard driving sporty cruising etc. Personally I would go for the Tim Ayres Rutherford modified suspension solution. More info please - I have read about the Rutherford AVO shocks but nothing else Also if I do the Chrome king pins I assume I'll also need to fit new bushes and ream them out. I don't have reamers so I'd need to buy/borrow one presumably https://www.newelms.com/rutherford-parts/
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Joined: Dec 2011
Posts: 374
Learner Plates Off!
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Learner Plates Off!
Joined: Dec 2011
Posts: 374 |
Grumpy2, First, you have to check if your rebound springs are free at ride height. If they are free you have the right configuration. If not, the SSL front kit could be considered. But you have also to consider that the SSL kit allows to adjust and keep the clearance in the time and provides a third progressive spring which replaces the small upper rubber sleeve when the suspension comes at the full compression. The dampers provides a force related to the displacement speed of the hub, slowing the spring effect in order to avoid a "racket effect", but don't change the stiffness of the system. I have a 2005 Plus 4 and 2 years ago I installed The SSL kit which was provided with 2 adjustable SPAX dampers. A huge improvement. In a second time I changed the rear dampers by adjustable Spax dampers improving the whole. Former rear dampers were completly inefficient (like bicycle pump), former front dampers are right, surely due to the very hard former configuration where they work only a few. I made the work myself. You can find 2 type of reamer: expensible reamer or "normal" providing directly the final dimension . I use this second one (Librand) allowing machining the both bushes in one pass (you don't have to return the hub and use a guide): https://www.librands.co.uk/products-view-178.htmlYou have to find a large tap wrench, the square of the reamer is large. King pin replacement procedure: http://www.gomog.com/allmorgan10.htmlNB: SSL kit is provided with a detailed replacement guide. In terms of comfort, what you feel is acceleration. I don't have an accelerometer, but I made mathematics simulation models of both configurations with Scilab (freeware equivalent of Matlab). The acceleration with the SSL model are 2.5 to 3 less than with the standard configuration which could confirm the driving feeling... but it is calculation.
Regards 2005 PLUS 4
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no I understand the theory well enough but I can't see the optimum solution is chopping a bit off the free length of the lower (rebound) spring. Either way I assume the optimum solution would have the rebound springs in light contact with the stub axle assembly when the car is on the ground. Also, checked this morning and my top springs are light blue in colour does this signify anything? Gary
2012 Plus 4 in Sport Green. Much comfier than the Plus 8!
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Joined: Dec 2011
Posts: 374
Learner Plates Off!
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Learner Plates Off!
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As said above when you cut a spring you increase the stiffness.
In terms of mechanics there is 2 other concerns:
. On the cutted end of the spring you don't have a closed end which is not good in terms of contact. . The number of active coils must be an odd number of 0.5 in order to balance the upper and lower reaction forces and avoid the bending of the spring. In cutting a rebound coil to get just a kissing contact you may need several iterations and you are not sure to get this condition unless you cut an entire number of coil... but with what gap at the end?
After several miles the gap may increase due to the materials fatigue. The SSL design allows to adjust the gap easily in the time by adjusting the pre-compression of the upper spring.
Regards 2005 PLUS 4
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Joined: Sep 2016
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Yes I agree, I don't think I'd be too comfortable with a cut end pf spring in contact with a flat surface - it would eventually dig its way in.
Also I understand the theory too, thanks.
I'm interested to hear from some one who has cut the front rebound spring, how did that go?
2012 Plus 4 in Sport Green. Much comfier than the Plus 8!
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Joined: May 2015
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Talk Morgan Regular
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Talk Morgan Regular
Joined: May 2015
Posts: 611 Likes: 20 |
no I understand the theory well enough but I can't see the optimum solution is chopping a bit off the free length of the lower (rebound) spring.
Gary
Gary, I rebuilt the suspension without the rebound springs, set car on level surface and measured the gap they had to fit into. Cut them to length then it's not too difficult to fit them. One of mine was a bit tight but I left it. With the car is set up without the rebound springs you can see how much it's going to raise the ride height by before you chop them. If you have a press you can check the rate of the springs using an old set of bathroom scales. The parts books I've seen just have the part no of the springs, no info of rate. Cheers John Edit, I just use one of those thin cut off discs in an angle grinder. I made the cut at 90 deg to the spring's axis.
Last edited by John07; 01/10/19 03:19 PM.
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Joined: Sep 2016
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Has a lot to Say!
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OP
Has a lot to Say!
Joined: Sep 2016
Posts: 1,384 Likes: 56 |
no I understand the theory well enough but I can't see the optimum solution is chopping a bit off the free length of the lower (rebound) spring.
Gary
Gary, I rebuilt the suspension without the rebound springs, set car on level surface and measured the gap they had to fit into. Cut them to length then it's not too difficult to fit them. One of mine was a bit tight but I left it. With the car is set up without the rebound springs you can see how much it's going to raise the ride height by before you chop them. If you have a press you can check the rate of the springs using an old set of bathroom scales. The parts books I've seen just have the part no of the springs, no info of rate. Cheers John Edit, I just use one of those thin cut off discs in an angle grinder. I made the cut at 90 deg to the spring's axis. wow that seems very agricultural - does it work and is the ride better as a consequence?
2012 Plus 4 in Sport Green. Much comfier than the Plus 8!
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Joined: Oct 2013
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Talk Morgan Sage
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Talk Morgan Sage
Joined: Oct 2013
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Also, checked this morning and my top springs are light blue in colour does this signify anything? Gary
Good taste if they match the interior..
Steve
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