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MG Midget and Sprite Technical - frontline front suspension

Finally got round to starting an overhaul on my Frontline front suspension.
I have discovered that the AVO adjustable telescopic shocks have code number D3 500 and the man at AVO sales has confirmed that the number is indeed correct for a Frontline kit.
I have measured the fully open and fully closed distances, which are 405mm and 295mm, measured from centre of bush to centre of bush, but the AVO man tells me that isn't correct. I'm waiting for his response (and a quote, hopefully!) after Easter.
My car is an IOW frog and when I measure the shocks with the car stationary, it is 365mm centre bush to centre bush, which seems kind of logical to me. I will be interested to hear what he says, but if anyone could measure the distance with their car stationary, I would be grateful.
I am half expecting him to tell me that I have to go to Frontline direct, but I'm thinking of changing to Protech who custom build adjustable telescopic shocks for a reasonable price I reckon. So I'm thinking, as long as the fully open length matches and the stroke is similar ish, then that should work, or am I missing something?
All advice welcome!
aj robinson

I have a Front Line kit on my Mk4 Sprite. Do you need a measurement with the car resting on its wheels? If so access could be difficult. I suspect this would not be a problem with a frogeye opening front end.


Jan T
J Targosz

Hi Jan, yes, with the car at rest on its wheels. My frog has the bonnet tilting the other way so really easy. Doesn't have to be a frog, a midget would do to give me some idea of the measurement
aj robinson

Hope Nigel is OK as normally mention of a certain supplier of upgrades gets him posting.

M Wood

I realise that Frontline are the devil's spawn to some people but I hope somebody can just answer my question! Please!!
aj robinson

MK 4 Spridget with a 1275 engine, distance from centre top shocker bolt to bottom 14" with car standing on its wheels.

Jan T
J Targosz

Many thanks Jan, almost the same as mine then. That's very useful. And I'm tending to think I might be right about replacing the AVO's with Protech adjustables, once I have checked the stroke length. Unless I'm missing something obvious!? All advice welcome
aj robinson

Can AVO rebuild your shocks? Or someone else e.g. https://www.suspensionsupplies.co.uk/dampers who also do sales and probably good for advice.

I seem to remember Spax used to offer a rebuild service as well as J W Banks Limited for Koni (they were the UK agent for many years and IIRC the first company to import them), now: https://www.koniuk.co.uk/about/service-repair I do realise you do not have Konis.

Cheers
Mike
M Wood

Hi Mike,
The shocks are well shot and AVO told me they were too far gone.....
To be fair, they have been on the car for a loooong time and the adjusters are seized too.
aj robinson

I'm no expert but I would have thought that as well as lengths you need to consider damper rates. A Spridget and a Jaguar (for example) might have dampers of the same length, but the cars weigh different amounts and you will want different behavioural characteristics to give the handling you want.

I guess you can talk to Protech about what you want and they will be able to spec what you need.

No doubt others who actually know what hey are talking about will be along soon!

Jon
Jonathan Severn

thanks Jon, I had thought of doing that. Apparently the people at Protech are very good.
aj robinson

Do you have a problem with bump steer when a Frontline kit is fitted? There is certainly a twitch on my Sprite if I hit a pothole on a bend. (a certantity on the roads in Scotland)

When I fitted a new chassis to my Lotus Elan I had to experiment with shims under the rack mountings until I could raise and lower the wishbones without any steering deflection. I would try this on the Sprite but it requires the spring to be removed.


Jan T
J Targosz

Jan, no problem at all, even though the shocks are well past their prime.
Had an interesting chat with AVO this morning. My shocks are "exclusive to Frontline" so I have to buy from them. Also, the AVO guy tells me the fully open and closed dimensions are quite a bit different, being 377mm open, 270mm closed, although the stroke difference is almost the same.
Given my car sits on its wheels with an open length of 365mm then I'm a bit perplexed...
Thoughts anyone?
aj robinson

This rings a vague and long ago bell about the Frontline shocks only being available from them even though manufactured by Avo (there may have been chat about this on this BBS, worth trying a search of the archive). E.g from 2016: http://www.mg-cars.info/mg-midget-sprite-technical-bbs/frontline-suspension-shocks-2016081806594120921.htm (https://mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&mode=archiveth&archiveyear=97_2016.dat&access=&subject=97&subjectar=97&source=T&thread=2016081806594120921 ) The link in this thread to an AVO damper still works: https://www.merlinmotorsport.co.uk/p/rover-mini-coil-over-std-length-competition-only-adjustable-front-shock-absorbers-pa238-pa238

One thought - was what what fitted for the IoW Frogeye the same as the telescopic conversion for BMC/BLMC/BL manufactured cars? Is the weight of the car, suspension set-up, geometry and springs the same?

I guess if exclusive to Frontline there may not be scope to find out what the spec of the damper is so you could get someone else to make you a set.

Best of luck
Mike
M Wood

Hi Mike, I've searched the archives and actually been part of a lot of the conversations!
As far as I know the IOW frog has the front end of a donor midget and the same front suspension setup. Weight is about 780kg I believe so not too far out. The Frontline kit on mine was added by a PO a long time ago, but the code number on the AVO dampers is the same as that used now, but the length appears to be shorter on the latest setup.
I'm waiting for a quote and info from Frontline but not expecting much....
If I don't hear from them, or they now use a shorter shock, then I will go to Protech who seem very informative and change like for like.
Andrew
aj robinson

Had a very good chat with Frontline today, which was very informative and enlightening.
They do indeed sell the AVO shocks: £342 delivered. This also includes some spacers which are necessary to adapt the "old" system, which I have. Frontline also confirmed the fully open distance as 380mm and fully closed as 275mm. Frontline reckoned that the fully open distance wouldn't be a problem on my car and I can kind of see why after discussing it with them.
I guess I have a choice to make, as Protech custom shocks, same size as my current ones, would be £221 delivered. I have just fitted their shocks to the rear of my car and they look/feel/seem bulletproof.
Again, any advice/opinions much appreciated!
(I'm a bit surprised more people haven't weighed in yet, but maybe it's because it is Frontline. Actually they have been very helpful)
Andrew
aj robinson

Hi Andrew,

You said, "This also includes some spacers which are necessary to adapt the "old" system, which I have. "

When you say you have the old system, do you mean the original with oilite bushes?





anamnesis

That is indeed correct, I have the oilitebushes with the grease nipple on top of the arm.
Apparently the "new spec" shocks have a narrower diameter and sit slightly differently as a result. I'm assuming the spacers move the new shock towards the rear of the car slightly, to be in the same vertical line as the old ones. If that makes sense.
Rather than faff about, with spacers and "trying to make it all work" I might go the Protech route. Not sure I want to fork out for a whole new system but it is an option.
aj robinson

The mk2, with nylon(igus?) bushes, also have a reduced -ve camber.

The mk1 which is what I have, had 3/4" long oilites. Mine is off the car.

For years now, I've been meaning to get around to boring the arms deeper, too accept 1 1/4" long oilites, available from bearingboys or simply bearings very cheaply. Longer internal surface area, more support, less wear on the pins, when I finally get/have made, new pins.

The side thrust is another matter. What it needs is sacrificial replacable washers, nylon or other. Maybe this year I'll do it.
anamnesis

I might just refurb mine too with delrin bushes. The ends of the arms on mine have almost zero gap and can't be bothered altering them to fit washers. I'll see how it all looks when its apart.
aj robinson

Ah yes, delrin. Is that what FL used in the later version Andrew?
anamnesis

they use a bush by a company called IGUS. I think its all pretty similar, although IGUS do myriad variations
aj robinson

My kit has blue plastic bushes but I don't what material they are.

Jan T
J Targosz

Hi Jan,
Not sure what colour Frontline use but IGUS have a blue "Iglidur A350" in blue. Others are white/black/grey/beige but not sure if the colour is definitely relevant. The IGUS website has all kinds of different bearing materials. I think the Frontline website shows white but again, don't know exactly which compound they use.
aj robinson

Had some info from Protech yesterday, their telescopic cover a large range of cars and they have confirmed they would be suitable for my particular needs. !6" damper (404mm) has a stroke of 133mm so a little more than my current AVO's. Much, much cheaper too, so might be worth a go.
aj robinson


Bit of a de-lurk, but hopefully following of some use...

I have what I assume is a REALLY early Frontline kit, as it came with red Koni dampers.

Improbably, I still have the box, it having been sat at the back of a shelf in the garage for 25 years at least.

Attached is a photo of the label on the box, although it is very faded.

Might that be of any use as an alternative source for dampers?

Interesting to hear that the camber was reduced in later versions of the kit. I fitted my kit at the same time as 400lb shorter springs, and a 3/4" antiroll bar, and yet the front end still ended up being incredibly 'pointy'. Much fun when young with quick reactions and no fear, not sure sure would be a good thing now.







K

I did have a look at Konis amongst others, but the protect stuff is top quality and rebuildable. Plus, the people there are really helpful.
I'm not sure why the camber was reduced but other, wiser heads on here can probably answer that question.
aj robinson

This thread was discussed between 07/04/2023 and 19/04/2023

MG Midget and Sprite Technical index

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