Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Plus4 GDI and Spax dampers?

One more try using a different image hosting provider, they're coming out smaller than I'd like but they're definitely visible to me when I preview this post.



















Hope you can see then now, although what they show should not be unfamiliar to us all.

As our American frieds would say "you win a cookie" - well done that man.

Sir P

This is the correct way to fit telescopic dampers to a Morgan:





Spax are ok but I wouldnt use AVOs, despite this detail Rutherford definitely knew what they were doing, unlike the MMC!

Some nice looking (I believe they're Alfa 105 series) bump stops in this following post too

https://www.talkmorgan.com/ubbthrea...-rear-shock-conversion-on-4-4-fourseater

They were suggested by Peter Ballard of SSL, and knocked up by me. Seem to work well, been on a few years.

I've replaced Morgan's hard rubber block rebound bump stops.



With Triumph TR3 axle bump stops in polly.



They give 5mm more rebound travel.



And are easy to fit, simply remove Morgan's rubber blocks and wrap the new TR3 bump stops around the axle tube then secure with the supplied cable ties.



I'm now using 19mm compression bump stops on my Bilsteins.



Which leave me with 66mm of stroke.



With the car back on the ground and the weight on the axle/leaf springs I'm still only seeing 13mm of compression travel.



This is due to change very soon as part of my plan to turn my damper eyelets by 90 degrees, and at the same time extend the length of my Bilstiens by 35mm (eyelet to eyelet).



I will also turn my top mounts by 90 degrees.



How much addional ride height and damper compression travel I actually achieve will depend on sag, but I'm hoping to share out my meagre 66mm of ultimate damper travel giving two thirds (44mm) to compression, and with the remaining third of the stroke (22mm) going to rebound travel.

Montgue It will be interesting when you get that set up. Without the bushes, I wonder how “harsh” the ride will become.
However very interested in this mod.

Nice one Dave ! Nice to see it in the axle travel arc and bush rotation on the same plane!

Cheers Martin

However, to me it's really only logic and I'm confident others can see the same logic too. Forget all the other failures I've shared for a minute, anyone still in doubt that Morgan fitted the rear dampers 90 degrees out need only look at the deaful bush wear I've shown.

The following images don't lie, but serve as an inarguable witness to the dreadful and unnatural twisting forces at play.




Personally I really like the Rutherford kit, unlike the MMC's effort it seems clear the designer of this kit understood the movement of the axle and what was needed from a telescopic damper conversion, here's another look at the Rutherford conversion.




Perhaps the owners of modern trad chassis Morgans overlook the above as we already have telecopic dampers, however, it's such an improvement over what Morgan gave us I think we should also view the Rutherford kit as a telescopic damper upgrade rather than just a way to convert earlier cars from lever arm dampers.

At the end of the day whatever small changes we make such as simply turning the dampers by 90 degrees, we're still stuck with the beam axle and leaf springs, so we really can't expect miracles. However, letting the axle swing unimpeded and in doing so allowing the dampers to pivot freely, is surely the no-brainer starting point to improving Morgan's fundimentally flawed telescopic damper conversion?

I have to admire your continuing commitment and determination to make your car perform and operate better than when it was first built by the factory. Hats off to you.

I've always found that racing has been at the cutting edge of development and wonder what solutions (which can be transferred to the road) have they come up with for Morgans etc. with similar setups to deal with these twisting forces in the drive train and suspension?

Are there any advantages or disadvantages with your proposed system (other than cost) compared to eg considering replacing leaf springs with modern coil-over systems, like the popular SSL 5-Link,

Not really John, the reason I'm taking my own path is because I enjoy improving Monty, a considerable percentage of the pleasure I take from owning the car comes from developing it. Monty is largely used on the road, but must also perform well on the track and at hill climbs where I can properly test my cost effective changes, simple ideas that make engineering sense to me.

The SSL 5-Link is very expensive, I'm also not convinced the same or even better results can be achieved for a lot less outlay. As I see it, the two key challengs a suspention engineer is up against when designing solutions to improve the performance of the rear suspension on a Morgan are:

1. The lack of available suspension travel - Morgan's decission to place the axle over the chassis rather than the common practice of placing it under arched chassis rails will always limit available travel, and having such short stroke supension considerably limits the time available for the dampers to tame that big heavy axle

2. The far from ideal relationship between sprung and unsprung mass - A very light body suspended over a very heavy axle is always going to present challenges

An effective suspension tune that balances traction, handling performance and ride comfort requires a holistic approach that considers the total vehicle mass, its distribution across the front and rear axles, and most importantly the relationship between sprung and unsprung mass. On our cars the sprung mass is exceptionally low compared with the unsprung mass, in simple terms a super light body suspended over a big heavy cast iron solid rear axle will always present challenges when choosing spring and damper rates.

The two primary objectives for a suspension system are to isolate the passengers from road imperfections, and to keep the car's tyres in contact with the road at all times. The uncomfortable truth we must all accept is, with the percentage split between sprung and unsprung mass being far from ideal on our cars there will always be a limit to what can be achieved. The SSL five link is extremely expensive, especially for a setup that actually does nothing to address this fundimental design challenge.

Because the far from ideal relationship between sprung and unsprung mass remains, I'd be very suprised if a SSL five link would deliver any better results than the simple cost effective ideas I'm implementing on Monty, ideas that not only involve turning my Bilstens by 90 degrees, but will also include the installation of a pair of lightly sprung coil overs.