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MG Midget and Sprite Technical - Five-link axle?

Has anyone converted a semi-elliptic car to a five-link setup at the rear?. I'm thinking of converting my Sprite while I'm fitting the Sebring bodywork, and any positive advice would be welcome. I have a Mk 1 axle case, which already has the pickup points for top and bottom radius arms, and the car already has a Panhard rod (although I was thinking of using an 'A' frame, like the Seven, with coil-overs straight up to a point above the casing). I'd be interested to know if anyone here has done similar, and, for instance, what dampers were used.
David le V.
D le Versha

There are several cars sometimes 'on here' which have been converted trailing arms (2 per side, stacked vertically), Panhard, and coil-overs mounted to brackets fabricated between boot floor / rear shelf.

There's are question that might be asked first: what do you use you car for, and what are you trying to achieve?

A
Anthony Cutler

There's are question that might be asked first: what do you use you car for, and what are you trying to achieve?


Anthony is dead on...id pay attention to that question, rearend conversions can get expensive FAST

The "few" Ive seen, used a tube cage that everything attached to ...My guess not only doess it make it easier to build from ... if your doing that kind of driving then the sheet metal may not be up to par

but Ive only seen this set up in extreme racers...nothing road worthy
Prop

For ease, why not just retro-fit the Mk1 midget/Sprite brackets for the upper arms aswell.

As for the coilovers, as mentioned above, brackets fabricated to the strengthen the chassis leg/axle strap mount seems the easiest method along the same lines as the frontline rear shock conversion.

You could of course go all-out, but you really need to consider what the car is to be used for before going any further. 90% of the time, the leaf springs and a good shock setup will be good enough for what you need, even in competition

PeterJMoore

As has been said, the cost of a proper rear end for a Midget will be very expensive.

You can get a good condition, Mk1 MX5 for around £1k with a years MOT.

So why try to reinvent the wheel when at the end of the day you will never approach the refinement of the MX5.

It is a Midget with a leaf spring rear end, accept it or buy an MX5.

eddie
Eddie Cairns

Eddie

Some of us enjoy our classics for the likes of competition

The likes of the midget gearbox would be changed for the toyota or ford 5-speeds to gain greater reliability whilst remaining in a classic, also allowing for better syncros (ie 1st gear) and in general a much stronger gearbox which proves very difficult to damage with the power an a-series can produce.

In the same way, the back end can be modified to be more appropriate for the use of the car. Say for example rallying or circuit racing - the adjustability and ease of servicing of a good 5-link rear is apparant when it comes to the Mk2 escorts (originally leaf sprung) and midget race cars (again originally leaf sprung)

Again with engines, K-series is faster, easier to fuel, less prone to leaks and starts first time every time due to its age and the 50+ years of development over the a-series. As such it is a good way to bring classic car owners out on the daily tramp to work whilst also being able to worry a lot bigger and more powerful cars when on track.

Modifications are done to make a car individual, but most of all to improve upon what is commonly seen as out-of-date technology.

I can understand your reply if the intentions were to be entered in concourse d'elegance or maintain originality, but even asking about the upgrade would hint that neither of those aspects of the "enthusiast" are going to be of interest to David.

PeterJMoore

MX5?????? I've had Elans, Europas, Sevens, an Eleven, and a single seater Formula Ford............... but never a bloody MX5. Good grief!
Peter understands, at least......
D le Versha

"I've had Elans, Europas, Sevens, an Eleven"

Sorry, I did not realise you had had it that bad, not convinced there is a cure for that!!!!!!!!!

I remember in the early seventies, one of the guys in the office bought a new John Player Special Europa. He could not take it out in the wet because it would cut out.

The foreman in the Lotus Dealer took it home each night for a week to try and find the problem. They never cured the cutting out problem and the dealer bought it back off him after three months as it was so unreliable.

eddie
Eddie Cairns

"Modifications are done to make a car individual, but most of all to improve upon what is commonly seen as out-of-date technology."

Peter

I have got a kind of block here.

I have no problem with the gearbox mod.
Same with the Frontline suspension and brake kits together with electronic ignition.

I accept the Qcar idea that you come up behind a £60k car and show it a clean pair of wheels.

At some point and by now with the mods I have mentioned it is getting a bit daft but the cost is getting towards the point of being just a bit silly.

I have the feeling that if you want all the modern features you bite the bullet and buy the modern machine that has it already done.

OTOH I'm sure if you buy a new modern £30k car and sell it four years later you can easily be hit by £15k in depreciation, so who is right!!!

eddie
Eddie Cairns

the answer's no then..............
D le Versha

David,

I wouldn't be so put off as 5 link axles and more have been done many times before on spridgets, they have been around for 50 years+. They have been done for road use, no reason not to as they can provide a better solution but at increased cost over he basic 1/2 elliptic the OEM chose. IIRC some regulars here have 5 link axles but haven't responded yet. A good trawl of the archives should turn up useful information.
David Billington

what Im doing is a mazda 2nd gen. RX7 solid rear axle from 1984-85 GSL-SE ... with LSD and disk brakes...rated to 250 HP then ill do some custom linkage

but Mark T was working on a ford cornthia rear end before he left to OZ for the midget that looked vary promising and was an almost duplicate to the midget just alot stronger..might check with him in OZ on the details...that would certianly be a good set up and inexpensive (if such a oncept exist for rearends)

Rearend conversions sounds cheap at 1st on the surface, then you start adding up the detais, and wow you can spend the kidds collage fund real fast.

On the MX5 I didnt realize they had a soild rear axle in the eary stages...what year... to late for me but id like to have that info on file...or was that just in the UK... here its a indepedent set up ...least the later ones that I looked into

Thanks

Prop
Prop

Providing you have basic engineering skills - ie the ability to measure, cut and weld steel, then without having to pay someone to do the work, a 5-link rear end really isn;t overly expensive.

Be sure to prepare the upper mounts to be strong enough to take the abuse that a suspension mount should take. The same applies for the coilover mounting.

2 link bars on each side, made from good quality steel tubing, with sleeves and helm/rose joints in the ends. Modify your spring plate to accept the rose joint without lateral movement and the lower axle bracketto do the same.

My advice is if you want to do it just get out to the garage and get stuck in, taking lots of measurements from common datum points and writing every detail down.

Go for it, worst case is you can sell the springs from the coilovers and use the shocks with a semi elliptic spring if it all goes wrong and still have a good setup.
PeterJMoore

>>>>>>>>>Providing you have basic engineering skills - ie the ability to measure, cut and weld steel, then without having to pay someone to do the work, a 5-link rear end really isn;t overly expensive.<<<<<<


I think its more then that peter, Yes your correct on the basic basis, but few people have the correct tools and even fewer have "Quality" tools, but the biggest sticking point is a general fear or apperhinsion to try to go beyound where they are at in there skill levels, I dont know if its a lack of confidence or the a general fear of just screwing up and failing that holds them back

Case in point, Look at the genral lack of threads dealing with DIY head porting...few and far, I did mine, not sure if it works yet, hopefully find out soon, But few people are willing to try...I wonder if people know something I dont...LOL

Prop...
Prop

Thanks guys - I knew somewhere out there would have some spirit. I am a metal smith, and have experience of rebuilds (inevitably) on Lotus cars, so I understand the stresses and strains imposed. I was going to use rose-jointed links on one side of the car, so there is room to tune it in when it's all done, and was thinking about going up through the floor onto specially made brackets with the dampers. I know Graham P. has that kind of setup on his Frogeye, and he says it's great.
I used adjustable platform AVO springs/dampers on my Banks Europa a few years ago, and that allowed for setting the level easily. My Sprite has a Ford 1300 crossflow motor, is low geared (for acceleration), and is reasonably quick now. When I fitted the engine, I moved it back about five inches, and although the engine is heavier, the car feels better balanced. Last time on the rollers, it showed 80bhp at the wheels, which, with the low gearing, makes the car pretty quick, but always looking for more... Changing the bodywork to Sebring fastback in September, which will lighten the whole car, and will try the five-link setup (using the Frogeye casing) then.
Here's a photo of the engine bay (Twin Weber 40s fitted since).

D le V.


D le Versha

Rob Griffiths uses a Sierra diff and I think it's a 5-link rear end, in his very quick K-engined Midget. His contact details are at
http://www.rgraceengineering.com/
The car is dark blue and is registered DAYnnnC - somebody must have pics somewhere!
David Smith

He uses a double wishbone setup with the Sierra diff
S Deakin

Prop,

I've done my head and I know a couple of other people that have done theirs. We all used the bible Vizard and it all went well. How well the heads work against a professionally done one we won't know. The heads were done in the late 1980s so the BB wasn't around. A point about getting them done professionally these days is that they should get it right. In the late 1980s you could pick up good heads easily from a local breaker for £10 - £15 so if you screwed up it wouldn't have been as much of a problem.
David Billington

http://www.spritespot.com/gallery/view_photo.php?set_albumName=toomanyspridgets&id=robsdisc2_025

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

These might help?
rob thomas

Have a recollection that Jack Wheeler ran a Spridget in International endurance racing in the 60's with Lotus Elan suspension...?

JB
James Bilsland

If you want any ideas on multilink rear suspesion for Spridgets take your camera along to the next Midget Challenge race (Cadwell Park 4/5 Sept) and take some piccies of the Class A cars...

Regards

JB
James Bilsland

Prop.

It really isnt more than that, providing you go slowly and methodically and have a firm plan sketched out then it really is just a case of getting stuck in.

Same as anything really, a car is just nuts and bolts, one nut and bolt is no different to another.

http://www.grp4fabrications.com/index.php?cPath=23

have a gander at that, then search Gp4 Mk2 Escort on Google, get the inspiration going, then shuffle out to the garage with your cigarette packet notes and drawings and enjoy the next few evenings playing on your car.
PeterJMoore

Robs car!

Not a five link but

One of my favourites!

Carl


C Bintcliffe

Its not as quick as Will Smallridges car though... and that still has an A series engine (a good one mind) :)
James Bilsland

... Rob/Ian's car is very solidly built... def not a lightweight... I must confess to having many pics of it!

A
Anthony Cutler

Maybe just build a tube frame chassis and bolt some spridget panels to it?
Trevor Jessie

Trevor
It is a lovely car that has undergone continual development over about 15 years, here are a couple of photos I took when it first appeared.


C Bintcliffe

and another.

Thats a one piece aluminium front that Rob made with matching rear wings! I think the car was fitted with 15" Healey wheels at the time.


C Bintcliffe

my frog eye (Loose discription) has a modified
rear axle with adjustable telescopic dampers
to turrets in the boot. but still has 1/4 elipitical
springs. but at some time in its life its had a
custom MK 2 rear end grafted to the frog eye centre
section. It sports 8 inch wide 13 inch wheels
with no arch extensions! i think it was built in
1986 for circuit racing. I hope to take it on the hills next year. after getting gear box re built
( straight cut) regards Pete
P C Knightley

Whilst hardly the pinnacle of high tech, my old hillclimb Midget used leaf springs and Spax telescopic dampers and just a panhard rod. I used to run slicks, and the handling was spot on, very progressive and very tight on the faster corners. I guess it depends on budget, but simple is often best. Used to do 61 secs at Loton as a guide.
Neil
Neil Williams

This thread was discussed between 02/08/2010 and 07/09/2010

MG Midget and Sprite Technical index

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