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MG Midget and Sprite Technical - Midget front brakes and suspension mods

Hi there this is my first post on here

My car is a '74 RWA and fills in where my '72 RWA midget left off 20+ years ago. Yes old enough to know better!

I am currently planning / working on an engine transplant (180 bhp ish)

The car will be 95% road use, possible track day / hillclimb / sprint but mainly road use.

I have only done a few hundred miles but I am currently stripping the front suspension / steering due to a complete lack of self centreing, the steering wheel stays wherever I leave it - anyway this is not the reason for my post.

I am a tight @r5e but looking at the options for front suspension and brakes. I am aware of the FL kits for front brakes and top susp arm / coil over conversion. Which seems to add up to £800 ish.

Through fabricator friends of mine I think making a FL esque top arm and coilover conversion could be done reasonably economically but I am also considering adapting MX5 front stub axles which will give me "maintenance free" ball joints and 9 1/4" discs. The biggest problem is positioning the rack to give acceptable bump steer due to the low track rod end position on the outer joint with the MX5 stub axle. Also looks tight on 13" wheels for caliper clearance.

What are peoples opinions of the standard brakes (once recon'd, aeroquip / pads?) for fast road use. Would a pseudo FL front suspension mods and standard brakes be a reasonable option?

Cheers

Spencer

Spencer

On the brake side doing it cheaply would be Princes Calipers and Spitfire disks and braided hoses.

I opted for the KAD kit although expensive it slows you up very quickly for the Mintex pads.
K Harris

If you do go the MX5 route, use 14" rims with low-profile tyres.
David "Good luck getting front and back to match" Lieb
David Lieb

Hi Spencer
Probably stating the obvious here but have you greased the king pins and checked your tracking.
Have a look at the spridget racers they add an extra triangulating strut to the original front damper which is probably the least expensive upgrade option.
I have the 10” vented front discs with wilwood 4 pot calipers and frontline suspension---- worth every penny
As to 180bhp ish engine you will have to go the k series route to retain any from of street ability + you will also need gearbox and back axle upgrades…… seriously expensive!
Tim

t m dalton

Sorry I wasn't logged on I'm 'Spencer3'

Cheers K Harris,

Princess calipers as in the 70's Austin Princess (Wedge shape) car?

Does anyone know of a link to someone who's done this conversion. Does it use welded on bosses to mount the caliper to the stub axle or an 'adapter'. Does the spitfire disc have the same threaded holes as the Spridget discs or are they modified. Any pictures / links would be appreciated.

The 'plan' for the rear axle is either a narrowed Volvo / Ford Atlas / Mazda live axle or utilize a 3.62 Cossie rear diff and driveshafts that I am currently planning to use on another project with double wishbones and the MX5 rear uprights / brakes. I bought a written off MX5 MK1 which I have kept the suspension and steering from.

Cheers

Spencer
S Deakin

Hi Tim,

Because I have just bought the car I decided to strip the front suspension / brakes as a result of the lack of self centreing. I figured it was a reasonable precaution with an unknown car. The rubber bushes were all perished and the inner pivots were welded to the bushes (as usual!)

The right hand kingpin is tight in the stub axle (not looked at the LH side yet) so this is a starting point.

I am rebuilding the gearbox currently - its a Type 9 (2.8 version - longer first gear). As I mentioned above I have a 3.62 Cossie LSD rear diff and MX5 rear uprights / brakes which is intended for another project but could be used on the midget but staying with a stronger live axle would be easier?

The engine is a 2.0L 16V Vauxhall on throttle bodies with an aftermarket ECU. Which I am currently rebuilding to a pretty mild tune.
S Deakin

Hi Spencer
How heavy is the Vauxhall engine and will it fit?
I have to grease the front suspension every 1k miles other wise it stiffens/wears out….
Re rear axle mods IMHO (cost no object) narrowed ford axle on a four bar, coil over’s and a panhard rod
If you change the engine, gearbox and axles you may have to reregister the car and pass a SVA test (see the DVLA site)
Tim


t m dalton

Tim,

Not sure of the weight of the Vauxhall unit, I am sure its heavier than the 'K series' as it is an iron block but they are used in Caterham / Westfield type kit cars regularly so shouldn't be too bad.

Will it fit? - I hope so! I have many measurements for the Vauxhall unit and the gearbox. I will most likely need to move the gear lever forward and sump is already hacked up to give more ground clearance but retain capacity. Its not as tall as a Honda F20 engine and I have seen pictures of one of these in a Frogeye without any bonnet bulges. Exhaust routing will be a challenge but at least its on the passenger side which will give me a little more leeway for making clearance.

Yes I am aware of the "8 point DVLA situation"

For a narrowed Atlas axle, LSD, discs with 4/5 links I was quoted £2000 as you say (cost no object) but out of my league price wise. But if I stick with a live axle I have a little more chance of not falling fowl of the DVLA!



S Deakin

Tim,

Wow, the front kingpins need to be attended to that regularly! Every 1000 miles! Definitely makes the MX5 stub axle option more appealing as a "fit and forget" solution.
S Deakin

Spencer -- If you do just the engine, then put the vehicle 'on the road' -- and see what happens with the dvla -- change the axles later!
Mick - She's off the rotisserie

Spencer.

Why...? If it ain't broke, don't fix it.

We have an Midget Atlantis (1970's built replica). 148bhp Caterham spec Ford X/Flow, Ford 2000E 4 speed gearbox through an Anglia back axle with 4.1:1 LSD. Rear suspension fitted with top links and a Panhard Rod, Fronts, 400lb springs +1" (it's built as a Road Rally car). Brakes: Front Std Midget with Mintex 1144 pads, rear std Ford Anglia.

I can assure you this car not only goes well but handles and stops well too. Ask anyone who has seen it on Track Days. Oh, I also run on Historic Cross Plies.....

All this Frontline, Big Brakes, Independent rear end five speed stuff is just cock jousting....

Mark.


Mark T. Boldry

Hi Mark,

Thanks for your comments

That was the reason for my post - to see what was the consensus on the standard front brakes / suspension, especially from people with higher output engines.

Basically as I stated in the first post it is basically a road car. So it will remain on standardish spring rates (will need to change the rate to compensate for increased vehicle weight and experiment from there)

If, once rebuilt (It already has aeroquip, currently rebuilding the calipers and researching old posts for pad matl's) the front brakes can adequately deal with some fast road use such as a couple of motorway 100 mph to 40 mph maximum decel stops and a bit of 'B' road less aggressive but more frequent use without fading horribly then the standard setup could be fine. Similarly if I am on the motorway and haven't used the brakes for 10 minutes I don't to have no retardation because the brakes aren't hot if I need them in a hurry.

I feel less comfortable with the top lever arm single shear arrangement so as a minimum I will probably come up with a triangulated / top wishbone arrangement which will probably necessitate a telescopic conversion at the same time.

Again as a road car having a 5th gear (ratio is about 0.82) I feel will be a welcome addition.

This just leaves reliability / maintenance as far as the front kingpin arrangement goes.

So I guess that will make me just a bit of a 'jouster...' ;-)

Thanks again for your comments and taking the time to respond

Spencer

P.S. Which track is that in the photo, I have been to most but don't immediately recognize it. Lots of trees - Oulton (If it is I don't recognize which corner?) I haven't been to Mallory / Cadwell or any of the 'smaller' circuits so I am guessing it's one of those.
S Deakin

That looks like Quary at Castle Combe?
K Harris

Cock jousting!

Excellent expression - and image - Mark!
Steve Clark

Well spotted, it is Quarry at Castle Combe.... What a great day we had there!!!!

Spencer.

Peter May's top triangulation link is, I believe to be a very worthwhile addition, I have yet to try it, however, the addition of telescopic front shock absorbers are, in my opinion, not necessarily worthwhile. The standard lever arm if fitted with good valves and kept topped up with suitable oil will not let you down. The problem is that people tend to want to 'fit and forget' these days. ALL cars that are driven 'spiritedly' need regular maintenance.

The Spridget King Pins do need greasing, but certainly not every 1000 miles. A good liquid grease or heavy oil is preferred as opposed to the regular grease gun type grease.

As for Pad material, I find the Mintex 1144 perfect for fast road use and track days. They work well from cold and only tend to show signs of fading when pushed hard on the track. We even use them in Anita's road cars. I would not advocate the use of the EBC 'green stuff' pads which are marketed well but don't perform as one would hope. There is another choice which I have yet to test and that is Pagid but at a much higher cost, it is debatable whether or not these would offer a better option to the 1144s.

Finally, the 5 speed gearbox. Many will extol the virtues of the Ford, Toyota or Datsun box but before you make your decision, take into account availability of both the box and spares, the extra weight and the amount of cutting you may have to do to get it in the chassis. The Ford Type 9 being the most common over here in the UK, offered with many ratio options, so choose one with a tall first and closer ratios.

I hope this gives you food for thought, the choices are, of course, yours...

These are my opinions only based upon 30+ years of Spridge ownership.

Mark.
Mark T. Boldry

Mark,

Thanks again for your valued comments

Yes I totally agree about the gearbox comments, most of the Type 9's have a very short first gear, I have a '2.8 V6' version which has a longer first 3.36 compared to 3.6 for the normal Type 9 - but not as useful as the 1st gear in your 4 spd (2.9?).

I'm lucky that I know a few guys who spent many years rebuilding Type 9's so I have pretty good access to spares - but yes there are plenty of bits which are becoming difficult to get hold of.

I will be using a 2.0L 16V Vaux engine (C20XE) so to the best of my knowledge there are only bellhousings available for Type 9, T5 (Very heavy and big but good 1st gear ratio - 2.9ish) and the Omega box which again is pretty big. So I took the Type 9 as the smaller / lighter option.

Have you tried a front telescopic conversion? Just wondered how they feel. One problem I find with after market damper kits in general is they tend to be too stiff, I think they do this as people expect to feel a significant difference when they buy a kit (I'm not talking about Spridget kits - I have no experience of these) Dampers which are too hard are a perfect way to destroy ride without any gains.

I will give the 1144's a go, a quick Google seems to show they are about £35 - which seems more than reasonable.

What make / type of grease do you use, I am about to re-assemble the kingpins.

Cheers again

Spencer


S Deakin

Spencer,

I can't speak for the FL kit but having fitted a top link and telescopic dampers to the front of my frogeye it transformed the front end compared to the new recon lever arm dampers previously fitted. It also completed the set and gave me telescopics all round. Not difficult to build but make sure you trust the welding of whoever does it, particularly the outer end of the top link.

What would be good is to see a blind test comparison with a car fitted with the likes of new LA dampers, new recon LA dampers, Peter Caldwell LA dampers, and FL telescopic kit.
David Billington

David,

Thanks for your comments, it caused me to do a search of the forum for "Peter Caldwell" and threw up a few interesting points.

I guess I have no real idea of the vintage of my front LA dampers, whether they have ever been properly recon'd or if they were 'new' replacements.

It seems the UK is a minefield as far as recon'd LA's go - they are either repainted or last a short space of time? Maybe not true but most of the posts I read seem to point in this direction.

Also posts on here suggest that Peter May is 'anti-telescopic' - Again I just quoting from past posts so please take this into account.

Fundamentally a 'telescopic' damper (in its numerous forms - oil / gas / monotube tc...) is as used in most (all?) modern cars so I can only assume that Peter Mays dislike is based on the fact that most if not all commercially available 'telescopics' are mounted in single shear off the side of the lower wishbone and the top mount is connected to the inner wing of a Midget (In the case of some DIY installs I have seen - usually locally stiffened) or again a single shear mount with a reasonable bending moment due to the offset nature of the FL top mounting?

Again I am trying to second guess here so please take my comments in that context.

I think I might email Peter Caldwell as regards costs and availabilty of his recon'd units.

In light of your 'blind test' comparison I guess when I asked about peoples experiences of LA vs telescopics I would need to ask what type of LA's? As I guess poorly recon'd LA's vs a correctly valved telescopic will give a potentially different result to a set of Peter Caldwell LA's against overly stiff / incorrectly specified telescopics?

It's never easy is it?

Cheers

Spencer

S Deakin

Spencer,

My experience with telescopic compared to LA is with recon LA so the comparison is not fair to new LA, or Peter Caldwell LA which are supposed to be better than new and are available in adjustable versions.

My designing and fitting the upper link and telescopics was driven by the poor quality of recon LA in the UK in the late 1980s, and judging from what appears on the board it hasn't changed much. Apart from leakage the poor recon LA I had suffered from what I felt was significant play in the damper spindle which led to wheel movement without damping which I have referred to as lost motion, telescopic don't suffer from this issue.

Regarding single shear mounting, many cars have their dampers mounted this way but I see your concerns regarding the lower wishbone and cantilevered upper mount. The lower wishbone mounting should be arranged to prevent twisting of the side of the wishbone, one US offering cantilevers the mount off the side of the wishbone and is prominently featured in the failed wishbone picture I have seen a few times floating around on the net. Not sure if that was an early unreinforced wishbone though.

I've done about 70k miles on my bits and not had any issues with the lower wishbone mounting or upper cantilevered mount.
David Billington

>Also posts on here suggest that Peter May is 'anti-telescopic'

PM is a supplier to midget racers, converting the shocks to tube violates the rules in a way that adding extra triangularization with an additional top link does not.
Will Munns

David,

I have emailed Peter Caldwell so I guess I will see costs and availability from the US. If they are too expensive with shipping and a surcharge this may too push me in the telescopic direction.

Yes, from the posts I have read I am quickly coming to the same conclusion about reconditioned / new LA's in the UK.

I guess I should contact Peter May as well regarding who / how his LA's are reconditioned. Also I can ask about the 'anti-telescopic" quotes I have read on here.

Will,

The posts I read on here suggested that the Peter May comments were made in general and not as a result of specific race regulations. But as I stated previously I am uncomfortable quoting past threads so I apologize if this is not PM's general opinion of telescopics. I will ask when I phone him - there not far from me so I might pop down there.

Cheers

Spencer
S Deakin

Will,

This is the thread which I got the "anti-telescopic" comments from

http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgbbs&access=&mode=archiveth&subject=97&subjectar=97&thread=200707141323035380
S Deakin

Spencer,

IIRC 2 people who use the BB have gotten the Peter Caldwell dampers, the last person got the adjustables and IIRC it was in the last couple of months so hopefully they will respond with their opinions or you might find the info in the archive.
David Billington

Mark,

cock jousting......i've went through 6 standard chocolate gearboxes before i fitted the T9, never had a problem since, Theres nothing wrong with changing something which was rubbuish in the first place unless your one of the anorak pragrade.
Brad
B Richards

Spencer

David's upper arm and telescopic design is that sold as "Frontline"
It is a vast improvement in use over the lever arms IMO

I bought my FL setup at the NEC some years ago during the Classic Car show and as a show special deal it came VAT free. As a blag I managed to get them to supply them post free too.

Fitting required a little basic engineering activity but no more than drilling four holes, two new ones for the uper arm bearing plate and two for the brake pipes in the front inner wings

It totally transformed my car's steering on the road

I lost the vague wandering out of corners dictated by ripples in the surface and potholes on roundabouts that used to shoot the car towards Mongolia lost their powers. The dampers have not even been adjusted since fitting, simply doing the job nicely.

The type 9 gearbox simply does what is implied too, but as you know they are becoming rarer these days.

I do occasional track days in my car and with the type9 I can reach 110 (ish) on the longest straight

The standard brakes are more than adequate for a few sessions per day using Mintex pads, they would certainly be fine for motorway uses but if you are going to bung a big GM engine in maybe larger discs and four pot callipers could be worthwhile as an upgrade.

I certainly think the standard kingpin setup is easily up to the job, but grease every 500/1000 mls is not an unreasonable call, it will only take you ten minutes during a service

reminds me

must do mine this week

HTH you make up your mind



Bill

Spencer. As conventional grease will absorb moisture and it is corrosion rather than wear that brings an early demise to Spridget King Pins, I use an agricultural product called 'Sellarc'. It is applied using a pressure vessle through a needle point as opposed to a standard grease gun end. I apply this as often as I can, one or two squirts on a regular basis keeps it all in good working order.




Mark T. Boldry

The nozzle....


Mark T. Boldry

and the grease itself....

Mark.


Mark T. Boldry

Brad.

I quite agree... 'horses for courses'. I just prefer the Spridget gearbox. If however you have an engine producing more power than that unit will stand, then the options are open to you.

As for Chocolate gearboxes, I have rebuilt many Smooth and Ribcase type Spridget boxes and when using good quality parts, have no problems at all. Yes, in competition use, they need checking and rebuilding more often that a road car, but I have clients that use their Spridgets for Marathon events and they give good service.

Remember the good old saying.... 'Buy cheap... buy twice'.

In Spencer's case, he will have to choose a stronger gearbox, but we have already established this.

Spencer, Yes I have driven a car with a 'Frontline' front suspension and I can concur with the above findings, it does drive well. But... I will still stand by my comments above, a car running good lever arm shock absorbers will drive and handle just as well.

At the end of the day, I would say a well driven standard Spridget is proably better than a badly driven modified one....


Mark.
Mark T. Boldry

Thanks again for the comments guys,

Based on the feedback I have received I have decided to start off standard (Shock horror!)

I am rebuilding with standard rubber bushes (Already bought these) then assessing the kingpin / stub axle for its apparent rotational stiffness?

Then the LA dampers need to be assessed? Initially looking at free play, seeing if there is a reasonable level of resistance (damping) and if the two units are similar in the level of resistance. Maybe acquaint myself with its internals.

Then depending on my confidence in the units I have versus the cost and availability of Peter Caldwell / Peter May units I will decide whether to remain with LA's and look to doing the triangulation mod.

If my units seem duff / asymmetric and getting replacements looks too expensive or I don't have confidence in the units I can buy then telescopics will be pursued using a DIY FL type installation

Check the rate of the front springa nd the free lengths to see if they are similar.

In parallel I will rebuild the calipers with new seals and pistons if necessary, aeroquip is already fitted and I will probably replace the brake fluid - if comes out looking grim then I will have to look at master cylinder seals and rear cylinders I guess.

Get the car setup - tracking / tyre pressure

Then I will try:

Mintex 1144 pads

Lowering the front ride height (Lowered front spring pans)

11/16 Farb

Stiffer front springs - not sure about this mod?

This way I can assess each change over a few weeks of driving and in the mean time get a better feel for the braking performance.

And I can research a little more as far as bigger disc (Spitfire discs?) and suitable calipers go.

Its a plan - All I have to do now is stick to it and try and 'KISS'

Thanks again for your helpful responses to my first post. I can report back with my rebuild / driving experiences if it is of interest.

Please feel free to make any more comments on my 'plan' and anything else relevant.

Cheers

Spencer


S Deakin

The 400lb std ride height along with 11/16" ARB and std lever arms (perhaps using uprated valves, but play with that...) will work well.
A note of interest; I have used on more than one occasion the 'New' lever arm shocks, and on two occasions I have had to return these to the supplier as the internal rocker had come adrift from the main shaft. I'm sure there were a bad batch as I have not had this occur in the last 12 months.

Spencer, your feedback and ongoing reports of development will be followed with interest, not only by myself but many others too I'm sure.

Good luck.

Mark.
Mark T. Boldry

nice logical and progressive approach, yes please keep us updated with your findings.
David Smith

Spencer, as you are starting with a fresh rebuild, I would suggest dumping the rubber bushes and install polybushes instead. They are far superior and last longer. IF you start with rubber bushes, then decide to go polybush at a later date, you have to remove the wishpans and it's probably not a job you want to do twice.

Matt
Tarquin

Spencer

I run a midget and a sprite and can tell you what it is like driving a std car (Sprite) and one with the F/L kit, poly bushed, 400lb -1" springs, 11/16" FARB and new drop links (Midget).

The Midget is so well planted on corners and gives lots of confidence but do get the tracking sorted asap.

I left mine a month as I was after new tyres as well and all though it cornered well it did not handle low speed bumps at all and still "skittered" so mich I was contemplating changing it back but now sorted it blows your socks off.

The Sprite scares me as it roll's around corners where the other is planted and I fitted refurbished front LA dampers last year now considering replacing the springs to see if that helps but that will be for std ones and perhaps fitting a thicker FARB to help with some of the cornering woes

Shaun
Shaun

Matt,

I have tried "poly bushes" on another car a few years ago and my experience with them was pretty bad? After a few hundred 'track' miles the lower inner wishbone poly bushes had so much play I could hold the wheel and tyre at 9 and 3 o'clock and it would move 1 - 2mm.

When I removed them and examined them inner wishbone pivot bolts had about 1mm of freeplay to the inner bore of the poly bush. When they were new the pivots were a tight fit in the bushes.

I spoke to the manufacturer and fitted another set (different shore hardness / modulus / colour) but exactly the same happened again?

I guess its dangerous to generalize from this but it did put me off using them again. What 'make' are the bushes that you use?

Shaun,

You talk about the 'skittering' - I assume this was with the Midget? Did you make all the changes you mention at once? You say you nearly changed back but got it sorted - what did you do that changed your opinion / stopped the 'skittering' and improved the low speed bumps?

Again thanks for the information

Spencer

S Deakin

I have the early FL kit (1993/4) and Toyota box plus a LSD and KAD brakes, wouldnt dream of going to Armstrongs or a standard 4speed box and Diff.

After all if your going to "cock joust" you want to win:)


K Harris

if you're going to cock joust you need to quote some lap times....
David Smith

Spencer

Yes I made all the changes in one hit......

It was one of those while i'm changing this I might as well do.....

The poly bushes I have used are from the MGOC I have used yellow at the bottom and red at the top.

I found the cause of the skittering was down to the tracking of the front end and once done the front end is so much more compliant.

The front end still feels very stiff and I would like it a little bit softer and don't know if I should change the ARB for a slighter thinner one to allow a bit of softness or it's the springs are too stiff.

Having said that you can take corners so fast but I still have got to weld up the ARB hangers which is a job for the winter.

Shaun

Shaun

The lower/inner bushes aren't under anywhere near as much stress as the top/outer: this is the only one on mine I replaced with poly (2 if you count both sides, then); plus the rear spring hanger bushes (also v easy).

I keep a sheet on BRB's mods, that's been an XLS since '93. After '02 I combined it with the services XLS... these are the suspension changes... A

July 1978 Rebuild suspension; new KP, FP, bushes
01-Aug-93 11/16th anti-roll bar
01-Oct-95 New disks and pads
01-Apr-96 Frontline suspension conversion
01-Mar-99 Frontline big disk (vented) and calliper conversion; aeroquip hoses
01-Jul-99 Chopped down front springs
01-Aug-99 Rear telescopic damper conversion (5199)
01-Aug-99 Stiffer front springs and polyurethene bushes on anti-roll-bar (5199)
Oct '00 Lowered front suspension (nuts under pans)
11-Mar-01 Polyurethene bushes on rear spring hangers and top wishbone trunions
11-Mar-01 Ant-tramp bar on rear o/s
27-Jul-01 Strut across suspension tops
30-Aug-02 Rear Panhard rod, designed and fitted with Paul in Castleton (119849)
28-Jul-04 Installed RTL
21-Oct-06 Fitted ally tubes to lower front susp approx 1/2 inch
1-Mar-08 Raised front susp 1/4" by shortening springpan spacers (to allow for passengers)



Anthony

1/4 mile at Santa Pod 18.35 @ 71.57 mph

I understand with my mods, I wouldn't be eligible for racing, so its the 1/4 mile for me with no restriction on mods or noise..
K Harris

Anthony,

I take it from your email address you have a k series engined midget?

Did the increased weight of the conversion have a significant effect on the handling / braking requirements of the car?

Which of the suspension / brake mods were the greatest improvements over std?

Did you specifically avoid poly bushes for the wishbones or just never ended up doing it?

Anthony / Mark T,

Do yo use the std Midget rear axle (either with or without LSD) if so how well has it faired with your respective power / torque levels? I'm just trying to gauge whether it is a complete "no-no" which is what I had thus far assumed? Or does it become a 'consumable' needing planned / unplanned rebuilds.

The XE I am rebuilding has 150hp as std and seem to vary between 165 - 185 hp with throttle bodies and a tubular manifold so power will be in this range.

Sorry for the list of questions!

Cheers

Spencer






S Deakin

the k is significantly lighter because it's all ally.

Russ eats diffs, the rest of us manage to mangle halfshafts (but I only did this when I was in 1st with one wheel on a slippery drain cover).

There are uprated halfshafts available, and for 160bhp I would consider these a eventual requirement - you may as well do them upfront.
Will Munns

Hi Spencer

As Will says, the K is significantly lighter. Hence, I had to lower the suspension (finally in 04 having converted in 02) by 1/2", and then raised it again later to better accommodate by 1/4" to give a bit more leeway on tight corners when taking heavy passengers.

With the front being lighter, it doesn't dial-in quite as high a brake-force on the MoT dyno as it used to do (the front wheels lock up earlier); of course on the brake test m/c there's no weight transfer that would happen in 'real life').

IMO the 11/16 ARB is the best single mod on a Spridget; good value and easy to fit. Uprating the pads to 1144 is very beneficial, assuming your disks are in good condition.

On the poly bush side, a bit of both. If I had the wishbone off, I might have considered fitting them on the lower/inner; but as I said, these are no-where near as stressed as the top/outer.

I use standard axle. I overheated one diff at Martini (Wiscombe Park Hillclimb) by not feathering the throttle enough on a tight LH/uphill. The spinning n/s/r caused the diff to work too hard, heating the bushes under the diff gears so that they grabbed the shaft and broke the retaining pin. This allows the pin to tap the pinion gear on each rotation. Bought a s/h diff. (You will learn to feather the throttle rather than on/off with the Aseries.)

Russ has annihilated several pinion gears when setting off WOT with sticky tyres (210 bhp and ~160 lb-ft torque) from his K.

Many people fit LSD and uprated shafts as a precaution; but I have std setup and avoid wheelspins, doughnuts and WOT in 1st. My 1/2 shafts are also original, and have never been swapped side-side, which helps. They showed no signs of distress when last out a couple of years back. The car has done 4 years of hillclimbs and sprints (12-15 events/year), the last 2 with the K installed.

Your 2ltr(?) Vaux engine will be very torquey, so you'll be more at risk than the average K conversion - but frankly, I'd swap the engine and then beef up the rest as a rolling project.

A
Anthony

Will / Anthony,

I can see why the K series is a popular conversion then, I just assumed that with the 5 spd as well it would be heavier!

I think I have a reasonable amount of mechanical sympathy so maybe I can start with the std rear diff and see how everything else goes. I guess it will just be the cost of a new prop if I decide or need to change later on to another type of diff (i.e. non spridget)

I have a Cosworth 7" 3.62 LSD and driveshafts waiting in the wings if it all turns to 'chocolate' :-)

The main reason I want to go for an engine / 5 spd conversion is reliability and performance. I did the 1330 / 286 / 45 DCOE in the 80's with my first Midget (XUX 982K - Midgets Reunited anyone?)

Ideally I want to be able to do a few hundred miles a week in it without being stranded on the hard shoulder of the M5 too often.

But it will be standard 1275 A series (Lumenition) until next year though while I experiment with the rest of it.

Cheers

Spencer

S Deakin

All shiny and ready for action (If required!)





S Deakin

Mark,

i agree with buy cheap buy twice, the best gearbox i ever had was one i did myself, the worse from a major MG parts supplier, it lasted a month, then again i'm 'ard' on them, which was why i went for a T9 & Ford clutch in the end.
I did however end up using a TVY gearlver as the FL version wasn't very ergonomic, but thats another thread.

Shaun,
Be sure to weld up your ARB mounts soon, mine ripped out during a fast up hill corner near Stonehaven where the car was fully loaded up & balanced perfectly at quite a high speed, things went quite wobbly & quite horrible when i lost the ARB.

My best advice however is to fit all your best bits to the Sprite & the worst to the MG :-)
Dare to be different.

S. Deakin,
if your interested in a brake conversion, email me, i've done all the trial fits now & am away to order the final ali stock for the spacers. I may issue the CAD diagrams out, but as Shaun has an engine rebuild & a new kid on the way i could set up a Shaun's slow motor rebuild charity :-)) instead

cheers
Brad
B Richards

Hi Brad,

Very interested in the brake conversion

My email is spencerNOSPAM@NOSPAMgandalf.demon.co.uk

Deleting the "NOSPAM" bits :-)

Sorry if I can't see / find your email address

Cheers

Spencer
S Deakin

Spencer.

The axle is NOT a strong point if high power and torque is to be put through it. Anita's Atlantis uses a Ford Anglia 'English' axle and I am currently making a Jig in the hope that I can manufacture and sell a conversion kit based on the Anglia axle. The width is correct and it is a lot stronger even with std shafts. Diff ratios are available and strong!

Call me if you like on 07889 799033 (keep trying).


Mark.
Mark T. Boldry

That diff could look like this...
Excuse the missing coilover, Nitron double adjustables on the way! £740 for two shocks!!!!!!!!


R Griffiths

very tidy

what spring rates will you be using

or is it a "gotta shoot you if I tell you" type secret?

(does look the business though)
Bill

Should be 200lbs ish, testing next week at Mallory if the shocks come! We have 175s all the way up to 350s will be trying various.
Then its out defending the 4 hour MGCC Snetterton win on the 5th.
R Griffiths

Thanks for that

the set up is similar to my mental picture for Lara's tail end

so good luck with the testing at Mallory

And defending too
Bill

Mark,

Thanks for the offer I will take you up on the offer and give you a bell to pick your brain.

R Griffiths,

Thanks for the photo

Do you have any photos of how you integrated the rear structure into the rear bulkhead. Did you use a jig to make sure everything was in line or lots of measurements :-)

David Billington,

I think I have found what you meant about 'lost motion' in the LA dampers.

There is no free play along the axis of the LA with the damper unit but when I rotate the LA I have two distinct types of behaviour:

1.) If I move the arm very slowly then there is a reasonable amount of resistance (damping) and no perceivable lost motion.

2.) If I move the arm a little more quickly and repeatedly then all of a sudden there is a large area of no resistance (say 10 - 15 degrees) and then some resistance. As I move it back and forth the lost motion increases if I increase the sweep of the motion.

If I leave the damper a short while the lost motion disappears but will re-appear if point 2.) is repeated.

So the reconditioning hunt begins, no response from Peter Caldwell yet

Spencer


S Deakin

How's this? No jig just a digital level gauge and a lot of skill!

Rob


R Griffiths

Hi Spencer fully adjustable front $169 core charge $40.00,rear $149 core change $30.00 hope this is some use.
Gary
gary knowles

Mark - what are the x plies you run?
Shawn

Opps that should have said TVR gearlever, dyslexic fingers again.
Brad
B Richards

Shawn. Dunlop CR 65 4.50M section in 204 compound.

Mark.
Mark T. Boldry

Lovely job Rob

now to work out whether its sister could live under a mostly standard Midget back end...

:-)
Bill

R Griffiths,

Thanks for the photo, looks very good. How did you decide on the roll centre position and camber change etc... Again sorry for the questions just interested in how you arrived at the wishbone lengths and pick up points that you have.

Did you use a 'live' axle in the same car? Any comments on the difference in handling / behaviour?

I notice you have a walk in pit - every garage should have one!

Gary K,

Thanks for the info, I assume the $40 and $30 respectively is the 'surcharge' for outright purchase and that there will be postage / import costs / duty on top of those prices? I am still waiting for a reply from Peter Caldwell which will hopefully clear this up.

Cheers

Spencer


S Deakin

Spencer whats your e mail i could forward on the answer i got from Peter can't log in when in work.
Gary
gary knowles

I took a lot of the design from a Fisher Fury, measured roll centre and camber change to get to where it ended up. Difficult when its all got to be so narrow!

Yes ran the car with the live axle, was very good as it had been developed and raced in the cockshoot cup for many years before the upgrade.

The independent is much better riding the curbs and can now be adjusted in all ways. Also now indestructable!
Fantastic leaving two huge black lines on the warm up lap!

As for the pit I hate it! Just moving premises and I will have flush mounted scissor lift!Joy!

R Griffiths

Gary,

Thanks for that, my email is: (Deleting the 'NOSPAM')

spencerNOSPAM@NOSPAMgandalf.demon.co.uk

R Giffiths,

Yes, the MX5 wishbones / suspension I have looked at would require being narrowed by 200 - 250mm! Putting the inboard pickup points very close to the diff body (If I left the wishbones the same length and just moved everything inboard) and pretty short driveshafts.

If (A big if) I decided to progress the Cossie diff / wishbone rear end I was planning to make the assembly off the car initially. So I would have a structure which holds the diff and has the inboard pick up points, I would then 'just' need to connect that structure to the rear bulkhead and cutout whatever sheet work for clearance necessary.

Spencer




S Deakin

A Little update,

I popped into Peter May Eng. (To buy my wishbones) and spoke to him regarding the telescopic conversions and it was clear he was not a 'fan' of those conversions available.

Regarding LA dampers he said he hadn't had much success with new units and recommends / uses reconditioned units. He also stated that the recon units have not been without problems themselves but if there is a problem it is usually immediately evident (i.e. fluid loss).

They also stated that they have not had any problems like those I described earlier in this thread with 'poly' bushes.

Spencer


S Deakin

This thread was discussed between 13/09/2008 and 23/09/2008

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.