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MG Midget and Sprite Technical - Front Damper Top Link Kit

One of my front shockers has stopped damping and rather than buy a cheap reconditioned replacement, I noticed this idea from Peter May. Has anyone tried it instead of the Frontline equivalent? It'll be for road use.
The picture is courtesy of Peter May's site.

http://www.petermayengineering.co.uk/specialistProducts.htm#1.18.1

Thanks

Jeremy


Jeremy 3

Jeremy,
I would also be interested to know if anyone has made their own.
Neil
Neil (K series)

I wonder if one could construct a double arm version by using a longer spindle through the body of the shock, and have this carrying a second arm taken from a unit from the opposite side of the car.
Guy Oneandahalf Sprites

you corrcet that dosnt actually attach to the spindle in the shock, it attaches from that bracket bolted on top...interesting

From some reason I thought it attached thur the spindle
Prop

What Peter sells is the extra link - you'd still need to replace the damper. There are books with this stuff in ....


Daniel Thirteen-Twelve

That was a cheap excuse for a free plug Daniel.

PeterJMoore

This is a common mod on race cars running slicks and big brakes where you have to retain lever arms. It particularly assists stability under braking.

I'm not sure you'd notice any real benefit running road tyres and at road speeds though.

There are midget race cars which run the MGB lever arm which is effectively the mod Guy discusses - it changes the suspension geometry however and I haven't seen it used on a road car.

Pete - Daniel has no shame when it comes to book sales... :)
James B

James

We were running the MGB one on the Midget for a couple of years there. Handles beautifully and the camber was about 1 degree 30 mins to 2 degrees, it didnt tramline in the road and remained composed at all times.

PeterJMoore

Guy,

I'm sure it could be done but it would depend on the competence of the machinist doing the work. IIRC the shaft is stepped, the diameter near the lever being larger than the rear one so utilising the opposite standard arm would require a sleeve at least. IIRC the arm is fitted to a serration on the shaft and held on by a nut, although I have seen many with the arm welded to the shaft and no nut, I don't know if the welding is a factory thing or later recon thing. Also IIRC the crank that operates the 2 conrods and pistons is fitted to a serration in the centre of the shaft and staked in place. A bit of work for just a couple but doable given time, I've done similar serrations on occasions, the rest of the work being fairly straightforward turning and likely final grinding of the diameters.

Any rear link of this type or the Pater May item requires cutting the body work to make room for the link.
David Billington

David,
It would be beyond my abilities. The comment was just that - prompted by the simplicity of that overhead shot of the Peter May version. It would certainly be easier to just use an MGB one!

Guy
Guy Oneandahalf Sprites

I've made my own one.

uses the original damper (devalved) with the addittion of a second arm a la peter may. plate over the top which bends down past the edge of the damper. bolted to this plate is a track rod end with a bit of rack end still in it - this forms the extra bearing and the arm. the other end of the arm copies the outer end of the lever arm and the bolt to the trunnion is longer and goes through both. there's a telescopic damper behind as well, though that's joined on seperately.

it's good - got rid of flexy feeling under heavy braking, and massively lessened skitter when hitting lumps and bumps mid corner with the front.

http://www.flickr.com/photos/34910348@N08/3234431171/in/photostream/

the brake hose has to be repositioned, as theres a hole in the car for the extra arm where it was, and putting it in the 'early' position would result in it being squashed on droop. it's now lower down.
Rob Armstrong

I have this mod, and it does improve the stability, as Rob says however, you have to move the front brake hose to rigid pipe union, as this is where the second arm exits the body.
They don,t tell you this in the instructions.

Dave
Dave Barrow

"you have to move the front brake hose to rigid pipe union"
>> not on all models, the early ones routed the pipe differently, that's why it's not in the instructions.
David Smith

Thanks - this looks like a sensible mod but at £179 (+vat) is quite expensive although still a lot less than the Frontline (albeit you still need dampers).
One thing I don't understand is how the new second arm is joined to the damper? Is it obvious when you look closely at the damper?

Jeremy
Jeremy 3

I've seen MGB dampers on a road Midget and they work well. You need an adaptor plate to fit them.

I still believe that original shocks are the best option, uprated and fitting the Peter May bits will give you a lovely feel on the road.

Mark.
M T Boldry

Anything involving rotating assemblies for damping should be swapped out for telescopic units.

Unless of course the rules and regulations for a class of motorsport insist upon using the original lever arm stuff.

Telescopics are a solid 50 years of development ahead of lever arms, and as such are much much more ideal in 99.9% of situations. Adjustable damping and rebound bring you into another world of handling characteristics and can easily be altered to suit your driving style/preferences.

Telescopics are the ONLY true upgrade that is worthwhile when it comes to dampening a Midget.

MGB lever arms are a close second place though. However we have just swapped out all the front end for Frontline and the difference was small, but enough to give that extra boost in confidence when it is required.
PeterJMoore

^^^ totally agree :) and my front shocks were for a mini and were only 30 quid each - 24 point adjustable
Rob Armstrong

What does the adaptor plate for fitting MGB dampers consist of / look like? Anyone got a photo or drawing?

Guy
Guy Oneandahalf Sprites

It is a flat steel plate

3 countersunk screws to mount into the original shock mount captive nuts

then 4 holes drilled and tapped in the plate to accept the MGB mounting points

When making them I would be inclined to measure what you are currently getting camber wise and adjust the making of the plate to suit, making the camber on both sides equal.

Hope that helps, I have no photos, but it is about 8mm thick maybe 10 at a push.
PeterJMoore

Jeremy3 -"One thing I don't understand is how the new second arm is joined to the damper?"
it isn't! it's mounted to the new right-angled plate that fits over the damper.
David Smith

Peter,
Thanks for that info on the MGB plate. Much as I thought. And I take the point about drilling it to set the camber angles. This was the bit that I was wondering about because no doubt the MGB levers are not the same length as the Spridge ones.

I had also thought that one should be able to devise a sliding plate arrangement whereby the adaptor plate has a threaded lug that is tapped to take an adjusting screw that bears against the edge of the chassis tower. Then with it assembled one could ease off the fixing bolts and turn the adjusting screw to alter the camber angle before locking down the fixing bolts. It could give very precise camber angle adjustment.

There, now, how do I claim intellectual property rights on that!

Guy
Guy Oneandahalf Sprites

Aah thanks David - all becomes clear once it's explained! Should have realised it was there for a reason.
Apart from Frontline does anyone else do a telescopic conversion?

Jeremy
Jeremy 3

Guy - already have the doodle in my notebook for the adjustable camber version.

Same idea as a Mini rear radius arm/camber adjustment.

However, the adjustment would need to be in the adapter plate to chassis part, as I would not like to introduce more weakness into the adapter plate mounting of the shock itself.

PeterJMoore

Peter,
All I was thinking was that the adapter plate itself would slide up and down the face of the fixed chassis shock mount plate. The holes that attach the adapter plate to the car would need to be slotted a little - not looking for much though. To make the thing accurately adjustable the adapter plate could have a turned down flange at the upper end, drilled and tapped to take an adjusting set-screw that would bear against the edge of the fixed turret.

A stronger way might be to slot the 3 holes in the fixed chassis plate and use longer bolts through a plate or large large washers/ lock nuts on the underside, but they would be difficult to get access to for tightening once the plate position had been adjusted. In fact if using the MGB shocks then the same 4 bolt holes could be drilled right through, slotted and fastened through to the underside. The sliding plate would still be needed to provide the accurate adjustment.

Guy
Guy Oneandahalf Sprites

I considered the Peter May conversion, but decided that Rose joints are too wear-prone for long-term use on a street machine. Peter May doesn't warranty his design for street use, either. Instead I went with the Frontline design and haven't looked back. Trouble-free and handles beautifully after three years of pounding around roads in the Blue Ridge Mountains.
Stephen Strange

dust and muck is why i went for TRE rather than rose joint. and the fact I had them lying about. whole thing cost £0.
Rob Armstrong

So it seems there's 3 options:
Peter May - but rose joints don't seem too well suited for road use
Frontline - only drawback sems to be cost
MGB shockers - but need to fabricate a mounting plate
or
have the original revalved which I see Peter May does for £37.
Rob (Armstrong - great name for a damper thread!) what's TRE?

Jeremy
Jeremy 3

Ermm, its urban myth that rose joints wear out quickly.

As a matter of course we changed them annually on the WRC cars whether they were worn or not.

Well they do wear quickly, but only when uncared for.

Well greased with rubber boots and not only will you have less road noise than bushes (although about the same as poly) but there isnt any room for play, and as such would tighten the whole thing up for the driving experience.

Jeremy - TRE is Track Rod End
PeterJMoore

Thanks for the TRE explanation Peter.

Jeremy
Jeremy 3

Had alook at the damper today. The oil (what little there was in there) was a horrible and very mucky grey sludge.
Withdrew it with a syringe and replaced with what was available (3 in 1) and a notable improvement, damping again!
Question is will the 3in1 work in the longer term or do I need to get hold of soem fork oil?

Jeremy
Jeremy 3

no

I expect the 3-in-1 oil to eat the seals inside the shocker

But this will give you time to organise a replacement pair 'cos you would change both at once wouldn't you?
Bill 1

Thanks Bill,

of course or I may just get some proper fork oil...
The other three are perfect and I'm loathe to bin the other front one and replace it with one of the 'reconditioned' ones out there.

Jeremy
Jeremy 3

The first rule of fight club is, "you never replace one damper at a time". Change them in "axle sets".

Same as tires.

yes, it can be done, just like re-using an old throw out bearing when you change a clutch, or drinking milk past its "sell by" date, but it is not wise.



Norm
(the milk part was a joke)
Norm Kerr

At Mallory Park, I ran in Class A of the MGCC Midget Challenge, this allowed me to try a new front suspension top arm, see photo. The weight of the two lever arms, including Peter May extra link, minus the weight of my new arms, gave a saving of 6.49 kgs. This new top arm is based on the same geometry as the MGB lever arm, I used to run these on my class A car in the nineties, see Daniels book page 72, the advantage of using this geometry is the length of the arm, it is longer than the Midget so you have less camber change in roll. fitting on my new class B/A car is not ideal, because the support for the top of the telescopic shock, is too close to the rear set screw for the rose bearing, I used the standard midget trunion with a supaflex blue nylon bush, I think this will now change to a Nylatron bush. As built the prototype pair ran out of adjustment thread so that the max negative camber obtainable was 1.5 degrees, this will be changed by altering the amount of available thread. I am thinking of producing a small run of these top arms if anyone is interested.


G.M. Adams

is there a jounce bumper, or does the new A arm hit the frame at full stroke?

Maybe the angle of the photo. It could be that the forward arm, or the cross piece, is right above that hole that the jounce rubber goes in and you just haven't installed it yet, when you took the photo?



Norm
Norm Kerr

Would you include mountings, or diagrams to make them, for a telescopic conversion with the top arm (effectively making this an alternative to the conversion sold by Frontline)?
AndrewF

oops, I said "jounce", but I should have said, "rebound" (then the arm is rotated all of the way down).

Norm


Norm Kerr

Norm, the telescopic shock is the stop which prevents the arm touching the chassis, when the suspension goes to full droop. The photo shows that I pick up the inside wheel in roll, i prefer to do this as this tyre is not loaded. A rubber stop can be offered with the kit of parts, depending on how you want to use the car, roed/track.



G.M. Adams

Andrew, if you are keeping the inner wheel arch, then a double shear bracket could be used, road cars require longer suspension travel so the telescopic shock length would need to be considered when positioning this type of bracket. If you contact me at the above email address I can discuss your requirements. I no longer live in the Netherlands, I have returned to the U.K.
G.M. Adams

G.M.

like Andrew I'd be interested as it looks a well sorted solution but would be for a road car, with inner wings intact.

Jeremy
Jeremy 3

Jeremy
Please contact me on the email address above, to discuss.


G.M. Adams

It can't be much harder to bring that damper inside the top arm, can it? It might give a little more room to play with tyres.

http://www.spritespot.com/gallery/view_photo.php?set_albumName=toomanyspridgets&id=q3

Ignore the awful single-shear bottom links. :o)
rob thomas

Rob
No not really, however it is allways a compromise when building something that will sell, to provide something that covers a range of uses. Sometimes you aim for competitors and sometimes road car owners, this top arm is trying to do both.
To bring the coil over damper inside the arm, requires the turret to be cut and shut, this is obviously not a bolt on option and while some owners have welding and cutting equipment, the majority don't.
The rules of most championships that Midgets compete in, would not allow this change, The exception being class A of the Midget challenge, there are only a few of these cars and most have already made this modification.
So the real reason why the shock is to the side, is that I don't think enough owners would want the coil over damper inside the arm when you consider the extra work/cost and how you would then use the car. It can be done and if enough owners request this set up, then it could be made and sold.
G.M. Adams

Graeme

Lets ask Larry if we can run your mod in class B... I'd certainly run it if allowed... :)

Nicely engineered (as always)

Regards

James

James Bilsland

Thanks James,
I think it might not go down to well if I suggested moving away from the Midget lever arm, however If you were kind enough to suggest a change, I would be most grateful and I might make a small contribution to your racing fund. Are you going to the drivers meeting on Sunday? Free lunch you know, free debate also, a good debate is like a good argument, only without the insults, shame.
G.M. Adams

Graeme

I think Rob meant bringing the shock in and not changing shock and spring for a coilover.

I like the look of the set up but as Rob miss the bolt on possibility for a shock.
And i am in doubt about the rose joints.
-are they durable enough for a road car?
-you have the abillity to change the King Pin angle, fun to experiment with castor but also a big torsional load on the botom wishbone and mount.

Both no problem for a race car but on a road car where a bit of a ham fisted mechanic sets it up it might be a problem.

Not trying to flame your effort just trying to help the development!

As said i like the look and the fact that you do not need to drill holes (as with FL)
Onno Könemann

Onno,
Do you know the village of Oud zuillen, on the edge of the river Vecht, near the town of Maarssen, at the edge of Utrecht. My wife and I had four and a half years living in a rented house, in the grounds of Slot Zuilen, a happy time.
Between the back of the steering arm, where it bolts to the stub axle housing and the turret, is just enough room for a telescopic damper. This would mean changing the shape of the arm in plan, the strong v shape would become more of a u shape. The open/closed length of the damper would also make the top mounting difficult.
For a purely road car, where the condition of the road surface is not good, something you don't have to worry about in the Netherlands, apart from hitting the drempels (sleeping policemen) at 80kph instead of 50kph, a version of the top arm where the inner end of the arm is bushed with nylatron, would be made. This would have a preset length so the camber angle can be fixed, at 1 degree.
Rose joints can be used on the road, you just have to maintain them and change them more often. I wonder how many Midget owners that have Peter May's panhard rod have changed the rose joints recently.
Putting the telescopic damper to the side is one of those compromises that you have to put up with sometimes. If you visit the guys at Angloparts say high from me, they were kind to me when I restored my MGA.
Graeme Adams

Onno,
Sorry, that should read 1 degree negative for camber.
Tot ziens.
Graeme Adams

Graeme,

Yes i know Oud Zuilen i have driven through it ;).
The Slot is verry nice.

A bushed version would be a good solution and a redesign of the botom spring pan might make it easyer to fit a shock or coil over but now i am pushing it ;)

You have seen through my driving style quickly (going fast over "drempels")

I never go directly to Anglo parts.
At the mgworkshop ( www.mgworkshop.nl ) i can usualy get a spot to work and they are family so easy shopping ;)
Onno Könemann

Just digging through the archives

Does anyone know the length of the MGB lever arm top link compared to the std midget top link?

Do you keep the inboard upper point at the same height as a std Midget? Or is it higher to allow full droop travel still?

I am currently balancing the pros and cons of:

Std geometry but improved top link stiffness

Revised geometry (MGB like) with improved top link stiffness

MX5 upright - but it requires that the lever arm mount area is pretty well demolished and start again to get correct roll centre behaviour / camber compensation / bumpsteer etc...

Cheers

Spencer
S Deakin

This thread was discussed between 17/10/2010 and 11/12/2010

MG Midget and Sprite Technical index

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