Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rear Spring Shackle Access?

The 4 Seater 4 leaf springs I bought on my 2014 4/4 were sagged even after three years. The car was visually too low on the rear axle, it did not look nice and propper. Since leaf springs, even if they sag, still retain their spring rate I did not change my leaf springs but had the lowering blocks removed (red circle). This has drastically improved the driving and control feel of the rear axle. Because now the axle is "in" the leaf spring and no longer under it. This eliminates the negative leverage effects caused by the lowering blocks when cornering. At the same time, the spring travel has increased significantly, I have since then never had the spring at the stop. At the same time I have removed one of the two sandwiched rubber layers (blue circle) so that the car can still deflect well and freely. I have not noticed any further increase in the sagging of the spring/car height for three years now. Perhaps the sagging is reaching a point where it stops progressing. All in all, it was an inexpensive measure that had a very positive effect on the overall handling. However, I had to buy longer adjustable Rutherford AVO dampers because the old ones had become too short by this measure. My Avatar shows the ridehight after the measure.

I was aware of your website, Lorne. That gave me the trigger to try it out.

The problem is that some people service the rear brakes and re-use the same old flattened star washers, they should always be renewed, but a blob of blue Loctite does no harm

With respect, none of the following has been my experience with Monty, a Duratec Plus 4 that for the record must be pushing over 200hp now.

"Placing blocks under or over rear leaf springs is a cheap, quick, down and dirty way to raise or lower a vehicle, but they are far from the best way and exact a price to be paid in comfort and handling. They are understandable in amateur racing, where track surfaces permit, but most often at a prejudice to the pleasant use of the same car for any other activity. Facts and physics show that the use of such blocks causes axle wind-up and the need for panhard rods to stop the springs from moving sideways as the blocks also create a smaller flat surface and encourage twisting from side to side"

I suspect this is because I chose quality BCC anti-tramp springs that are properly tempered in Sheffield, and then paired them with equally high quality Bilstein dampers from Dan White of SSL. Trust me when I say Monty is absolutely pinned to the road, this was born out when my very first outing to Prescott Hill climb where with zero experience I was able to conquer the hill in well under 60 seconds, and this hauling two big 108kg guys and the spare wheel.

According to the regular experienced Morganeers I've engaged with at Prescott, I should expect my best time to fall to 57 seconds simply by losing the heavy passenger and spare wheel, this would place me alongside some of the fastest Plus 8s and 3.7 Roadsters. Not once have I suffered any 'so called' axle wind-up, and I would argue fitting a Panhard rod is actually a no-brainer as it only offers benefits, I suspect this is why it's such a popular enhancement, and not just on Morgans but literally any vehicle you care to mention that is burdened with a solid/live axle.

I have the impression that two topics are mixed up here. My post is not about the twisting of the spring in the longitudinal direction, e.g. when accelerating hard. There can help a special spring like you use Montegue, and / or the anti tramp bars. My point is that when the springs are brought to a greater distance from the axle by lowering blocks, the spring becomes more susceptible to twisting sideways to the vehicle, no matter how good the quality of the spring.
However, I must also say that the lowering blocks in your photo are not as dramatically high as the ones in my 4/4 were. Mine were exactly as high as the ones in Lorne's photo in his web article. So of course I had a higher negative impact before removing them.

I see the light now! You are a racer! I know a lot of racers. I have enjoyed pit-crewing in the UK and many venues in NA. I lived near a world famous Circuit (we pronounce it Sir'Kwee) for 40 years. I even have an international racer's license, though I leave the driving to stalwarts like yourself. I am at my happiest dealing with the cars, not the steering wheel.

But it is an axiom, that the very different environment for racer have makes their cars unsuitable templates for road going folk. Track surfaces are impossible smooth, (though racers always complain about them) they have many safety features, the support network is only as far as the paddock. They are not beset with bumper to bumper traffic and their speed keeps up a constant high airflow. I could go on. A road going Morgan has to meet many more complex challenges. To nullify the effect of leaf springs by stiffening them to the point they act as anti-tramp is a no-no. At one point, 25 years ago, Rob Wells, still owner of Libra Motive, had Peter M. make clamps for Morgan leaf springs that achieved the same effect as your anti-tramp spings. Wives stopped riding with the husbands that had them installed.


Yes. I had a long exchange with the owner. Proper leaf springs have become a crisis in the Morgan world and I am constantly searching. I was most impressed with his enthusiasm and he was the only mog bloke able to tell, with justified pride, of the specific quality rating of the metal used, which has been the heart of the problems for the last 18 MMC years. But "anti-tramp" leaf springs are a elementary no-no for a road going Morgan. I have over 300 bhp and a lighter Morgan than your own and I use anti-tramp bars made and designed by the dear Peter Mulberry. They allow the leaf springs to function as Leaf Springs are supposed to. Our cars, having a 50-50 weight distribution, should have the same spring rate at the front coils springs and the rear leaf springs. But racers try all sorts of things, bless'em. I find that if a mod makes a racer feel more confident..they race better.


Yes I know of Dan White for many years. My dampers are from David Rutherford, made for my Morgan and its leaf springs, which anyone can manage by describing their Morgan specifications to a knowledgeable Rutherford AVO person. BTW, AVO makes to Rutherford's specifications, not there own. He could have them made by anyone. The dampers sold by AVO to Morgan owners are not the same.


That is a mixed blessing. Losing a passenger and the spare wheel dramatically changes the balance dynamics of a Morganr, though you can learn to compensate. Losing the spare wheel also loses you all-important rear traction.


No you wouldn't have tramp with the springs you chose. Neither di the people who bought the Libra Motive anti-tramp devices. In the days even further back, 2-seater racers used to fit 4 seater 7 leaf springs. After trying everything out, I installed a Mulberry Panhard system..everything but the rod itself. Considering how simple the Morgan trad rear suspension is, one can stop unwanted lateral movement merely by adding something that prevents the leaf springs from moving sideways. Easier and safer. https://www.gomog.com/allmorgan12.html#Alternative


That is EXACTLY right!


The picture I posted is from a Factory MMC 4/4 Runabout. (was that what it was called?) It was an attempt by the MMC to create an entry level Morgan and they left off the spare wheel. Sadly, the specification they used was from Richard Thorne, where Simon told me he had created it. He used the same leaf springs used on all other Morgans of the day, regardless of THEIR spare wheels and model. Probably, he was not given a choice. The rear end, of course, popped up high, so they brought it down with those lowering blocks. But that did not alter the fact that the leaf springs were for heavier cars. Back breaking. The only solution would have been to experiment with different springs rate to find a proper one or add a bag of sand at the very rear. (sigh) Some owners fit a spare wheel.

Forgive them.The company was going through hard times.

L

Thx Heinz. You made my day.

Ok, so here are the facts as I found them on my 10,000 mile 2012 Duratec Plus 4!

The truth is the rear springs Morgan fitted to Monty when they made the car were an absolute joke, they had gone soft in under 10,000 miles so clearly weren't tempered correctly, if at all!

I also strongly suspect the wrong steel used, a leaf spring should be made from 5160, then oil quenched at 829C and finally tempered at 430C – 700C, the properties of proper 5160 steel are:

* 0.70% - 0.90% Cr
* 0.15% - 0.30% Si
* 0.75% - 1.00% Mn
* 0.56% - 0.64% C

The properties of Morgan's leaf springs are as follows:



I wouldn't worry about the effects of lowering blocks until you've replaced Morgan's comedy leaf springs with a set of properly quenched and tempered springs made from quality 5160 steel. For the record, the anti-tramp properties of BCC's springs are simply by virtue of the pack being built heavier forward of the rear axle, there's an extra leaf in there.

A leaf spring is also a trailing arm, if you want to improve axle location and limit twist you simply need to make the spring heavier, the issue with this is the heavier you make the leaf the harsher the ride becomes. However, a good compromise can be found if create a hybrid leaf, to do this you build the front half of the spring heavier than the rear half, the lighter element behind the axle provides the compliance allowing the forward half to be built way heavier than you could if you went with a traditional pack that's the same across its entire length.

Such hybrid leaf springs are nothing new, they're certainly not an innovation from BCC or even Owen Springs in Sheffield who are the producer, they've been around for decades. However, they are reasonably new in the Morgan world, my understanding is William's Morgan commissioned the first set to circumvent the race regulations that precluded the use of anti-tramp bars.

When I supplied my anti-tramp springs to Techniques Morgan it was clearly the first set they'd fitted, because their comment on them was...

"They're actually softer than the springs we normally fit", but I think what they wanted to say was "The rear half is softer than the springs we normally fit".

I can confirm the BCC/Owen Springs anti-tramp springs perform brilliantly, as the name promises I'm experiencing zero tramp in 200hp + Monty with these springs and the ride quality is extremely good for a car with a live axle. However, springs are only half the story, the real secret to good rear suspension performance is to match the springs with quality well paired damping, and in my long experience nobody builds a better damper than Bilstein unless you want to start spending a king's ransom on Ohlins kit.

All this talk of the negative impacts of lowering blocks really needs to be put in perspective against the dreadful quality springs Morgan used and the super budget dampers they fitted too, before people start stressing over the small amount lowering blocks move the spring away from the axle they should start by fitting a set of quality springs and dampers as this will deliver by far the biggest benefit simply because Morgan used such poor quality components. I would then recommend the use of a Panhard rod as without one as Morgan supplied the car there's a lhuge amount of lateral axle movement, personally I'm not a fan of rigid anti-tramp bars as they have the potential to introduce harshness.

My hope was the BCC anti-tramp springs would mean I could get away without fitting rigid anti-tramp bars, and this strategy certainly paid off, I then paired them with a set of quality dampers that Dan White from SSL had co-developed with the suspension engineers at Bilstein. This recipe worked better than I ever could have hoped, the Bilstein dampers are fantastic and are extremely well matched to spring rates. The separation I recently experienced was down to damper rod rotation, personally I think I just got unlucky as there are quite a few threads for a full unwind incident and the rod will be rotating in both directions.

To wind all the way out was highly unlikely but it did happen, Bilstein really should have at least used a thread locking compound on assembly to stop the rod rotation, something I was able to correct when I simply screwed the top mount back in to reassemble the damper. Upon refitting the top bolt I was super pleased to note the significant resistance in the Bilstein damper, this in contrast to the AVO dampers that were on the car when I took ownership of Monty in the summer of last year. These AVOs were completely blown with literally zero resistance, they were damper by name only and pure decoration, in defense of AVO I doubt even a set of quality Bilsteins would have lived long trying to tame those awful original leaf springs.

The original leaf springs were so soft they would have been whipping over an excessive range of movement with waves resonating down their length, no damper can survive that, but AVO would still do well to move on from their dreadful bubblegum bushes. These Cheesium bushes are nowhere near as durable as the proper suspension grade rubber bushes used by Bilstein, the Bilsteins also came with infinitely superior bumpstops that are essential to save the damper internals and ensure a long operating life.

The secret to a good handling Morgan that retains decent ride quality isn't actually a secret at all, because it really isn't any different to giving any other car well performing suspension, start with quality springs then be sure to pair them with quality well matched damping, and if the car is burdened with a solid axle a correctly installed Panhard rod or better still a Watt's linkage will only deliver further benefits.

Thems the facts folks

I hope you didn't waste the cheese it's making me quite peckish