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MG Midget and Sprite Technical - Finally going 5speed!

Well, i've bitten the bullet and bought a type 9 5 speed kit! Apparently everything is there as per frontline. It will be this autumns project.

Theres actually an unbelievable amount of stuff in the archives on this, but yet I still have extra questions!:

I'm currently running a Peter May 7.5" clutch, which seems handy becasue a sierra plate is 190mm (7.48"). Does anyone know if I can simply use one with my exisiting cover?

I also have a special roller throw out bearing to go in, which is an exact replica of the original carbon unit but with a bearing, its not as per the peter may one as you dont have to cut the clutch pad away and run on the fingers. Will I be able to use this with the tytpe 9 set up? i.e. does the clutch release fork come out in the same place as the spridget one?

Wheres the cheapest place to get an angled speedo drive and which cable to I use thereafter?

Nick

Why don't you go the whole hog and fit a concentric slave?
Guy Weller

Might that be because not six months ago (or so) he bought at especially extortionate rates a sooper dooper device from the Yewnited Estates Of Amurricky said to be designed to work on pivotty bits? With the pad retainedededed!

Was you wasn't it Nick?

But as any dutiful echo ought to I'll say wot Guy said

"Why don't you go the whole hog and fit a concentric slave? "

And flog the posh doodah for big moolah...
Bill

Or flog all that inferior Ford stuff and go Datsun like all the best people.
Jeremy Cogman

Autumn project? IIRC BRB's 5-spd conversion took 2 days, using orig hydraulics. I used std FL kit.

Was absolutely delighted by the result; totally transforms the car for a longer journey. And if you seek the true midget experience on some occasions, you can always keep it to the first 4 gears.

A
Anthony

Because I don't know which concentric bits fit and work, Guy, you've helped me a lot with those pictures but even then you need special machining and some trial and error. My clutch with the ribcase is perfect... no really, perfect. No over or under throw, it all works fab. So my thinking is, if the frontline kit has the fork placed exactly as per ribcase then i'll just be able to swap the bits over, and yes, use my new-fangled throwout in the process.

Nick

But Anthony, it is too much trouble to break the 1st gear synchro for the "true Midget experience" ;-)
David "the troublemaker" Lieb
David Lieb

DAvid,
Do you have 1st hand experiance with breaking 1st gear syncro????

Curious as to what happened with the datsun 210 you where wanting to re-build.

prop
Prop

If you already have a flywheel with the 7.5" cover you only have to swap the plate for a Ford plate - there are books with this kind of info in...

Caterham or the MMC for the angle drive speedo conversion and you still need a special cable - I decided not to bother.

A complete Burton co-axial slave is cheaper than a new clutch cover that then has to be balanced. At the present time it is still a mystery why my new roller release bearing ate the fingers on my new clutch cover (600+ miles).

There is also a decent weight saving to be had and a clutch that can be bled in about 2 minutes.

And for completeness the Ford gearbox can be upgraded to a diverse range of close ratios at a future point in time whereas with the Datsun you're stuck with what youv'e got.

Daniel Thirteen-Twelve

Jeremy:-)

Bas Timmermans

So Bas, are you going to be the first to have performed a Datsun (Rivergate) and a Ford (Frontline) conversion, all be it that the Ford will be on my 1500. Looking forward to it on the 19th.

Rolf
Rolf 1977 1500

Wow does that make me an expert, please...

Hmm first we have to fit that Frontline thingy to your 1500 first before I can start to brag.

Bas

CU the 19th
Bas Timmermans

uuhhh, oohhhh!!!

Is this going to be one of those bugs bunny youtube moments....cant wait.

prop
Prop

"There is also a decent weight saving to be had and a clutch that can be bled in about 2 minutes. "

Aw Daniel, youre gonna spoil this BBS when they all stop telling us about bad bleeders!

Nick

my clutch was fine with the ribcase

it was when I changed to the type9 that it all began to go to the dogs

Still I hope it works out for you and if it doesnt there are enough of us "Concentricals" around to help talk you through any future changes
Bill

Do any of the concentrics run on the clutch pad, or are they designed to run on the clutch fingers? I'd rather avoid the latter as I means i'd have to butcher my cover to try.

So, if anyone here has run a concentric slave on the thrust pad of a 7.5" peter may clutch then, i'd love to know the details! Bill, yours is a saab unit right? how do you mount it?
Nick

Nick,

I haven't run a concentric against the thrust pad but have run a normal Ford release arrangement against the thrust pad of a 6.5" clutch for about 8 years without problems. I used a flat faced release bearing in that case but don't see any reason why a curved face release would have an issue.
David Billington

"Bill, yours is a saab unit right? how do you mount it? "

The Ford, and hence the Burton mounting device have symmetrical tapped holes on the concentric. The SAYAB device is assymetric with regards to its drillings so I had my ebay purchased mounting welded up locally with extra metal where I needed it then redrilled to suit the SAAB slave.

See picture

And at this point I would mention that had I thought longer and harder I might have gone the same way that Guy did later and "buy Ford" off ebay.

However the SAAB unit does make fitting the pipes inside the bellhousing rather easy and Guy had a hell of a hard time with his pipes. And using Parts For SAAB I have always had bargain replacement parts usually delivered the next day, I phoned at 4.00pm one day and the new master cylinder was in my sweaty little hand the next morning at quarter to ten...

I'll do another couple of pictures of the fitted doodah in a minute


Bill

My SAAB release bearing is flat fronted which may add to my "on or off" clutch pedal, so I'd have no compunction in using it against the clutch diaphragm pad

another piccy
Bill

bugger!


Bill

wrong blooming button AGAIN!

As you can see I set the cylinder so that the bleed outlet is slightly canted higher than the inlet pipe so fewer issues when bleeding it all.


Bill

with this you can see how the pipes in and out are run and now the slave has its release bearing fitted showing its basically flat front

By reducing the thickness of the backing piece there is plenty of scope for running the clutch with the pressure pad on its diaphragm fingers [pay your money and make the choice to suit yourself here]

Now I have left out the heavy duty assister spring that normally lives inside the concertina gaiter behind the thrust, but when (IF) the engine comes out next time I will be fitting it to assist the pedal action a bit.


Bill

Thanks for the info bill, it looks a good conversion, but alas too much work for me I think. I dont have access to too many machines. Just a drill thats about it! Also, if your bearing is flat faced and your running it on the clutch pad then you shouldn't have an on/off feeling. It 'should' be progressve.

Nick

And as a final word

how to bleed my clutch

tucked tidily away behind the cylinder head within easy reach for a bloke standing up.

I attach Eezibleed one end, pressurise and open other end (often with a length of pipe attached, easy)

EASY!


true confessions time

I've only done it one time
it worked like a dream and I hadn't put a pipe on the end
just a stream of fluid rising a few inches with optional extra air bubbles in the stream that soon dissipated

Just DONT crack it too wide or you may have a slightly nasty localised rain (type) storm


Bill

Mine is running against the fingers rather than the pad

Other times other choices!
Bill

Bill,

Straight diaphragm fingers or curved at the inner end?.
David Billington

Hmm, cant quite remember I'll have to look it up but I think basically flattish, hence the on-offnessness I think David

I'll go and prowl my pictures folder, hang on

ah

this I think, is the one that broke its diaphragm and I don't remember the next one being any/very different

the replacement for this one however came from the Moggy Minor Centre, so could have been different on its tips

Doesn't seem to be a large number of pictures of healthy plates in my archive, dammit!


Bill

a flat throwout bearing is not designed to run on curved fingers and visa versa. Mismatched eitherway would almost certainly lead to premature as you'd be point loading one or the other.

now you can tell me that you'rs has run for 50,000miles!! and that i'm talking BS!
Nick

Nick,

In my experience the flat faced release bearings run against clutch diaphragms with curved tips and curved face release bearing against flat diaphragm fingers. Different ways to achieve the same end where the contact point on the fingers moves as the diaphragm moves. Attached is an image of the flat faced one that I used against the 6.5" release face for about 50k miles, but not recently as you can see from the rust on the face. A somewhat wider face than Bills concentric by the look of it. The release shown is from the smaller Ford 4 speed boxes but I believe similar are used in some type 9 installations.


David Billington

not me

mine has done about twelve or fifteen thou since I did its replacement (No trip on the speedo, no mileage record, in fact)

I suspect the greatest part of my on-offness is down to not fitting the inner strong spring and not allowing a little more space between bearing and fingers

however it works even in heavy traffic and with my arthritic knees, so it stays "as is" until a possible later date...
Bill

I had to remove the flat faced pad from the clutch cover because the hole in it wasn't big enough to allow for the ford central "guide". From my calculations this has to protrude inside the clutch cover just a bit. Removing the pad allows the guide to fit neatly between the fingers, without any danger of contact.

The Ford unit has a flat face, but with a slight radius on the outer edges. In operation, it works very smoothly and progressively with no uncomfortable stepped "lift" when working against the fingers. When I last looked, after about 3,000 miles of use, there were no wear marks showing.

The ford unit also has a spring hidden within the bellows. But it is quite light, certainly not an "assistor spring" as Bill describes the Saab one. It is there simply to keep the thrust bearing in firm constant contact with the clutch, with sufficient pressure that they rotate together in happy unison.

I said on an earlier message that the Ford unit has a stroke of 12 mm. That is the maximum travel available. With the Spridget mastercylinder (1971 style) the actual stroke achieved is about 8 mm which fits rather neatly with information that Daniel gave.
And yes, bleeding is a dream. You can even bleed by simply cracking open the bleed nipple for a second or two as it gravity feeds through without any help from an easibleed or an attractive assistant.
Guy Weller

I wonder if i can open up the inside of my thrust pad to accomodate the tube in the type 9, or failing that trim the tube back so that it doesnt get into the clutch cover. I've heard people having to cut that tube but i can't remember why.

All of your suggestions will probably make so mucb more sense to me when i have the kit and engine in front of me! thats probably a good few weeks off though!
Nick

Nick

I was trying to open up the centre hole in my thrust pad when it simply got so small in x-section around the gripping edge where the fingers mount that it just popped off onto the lathe tool

So I was forced to adapt to suit

I do feel that this enforced mod was absolutely vital

best job on the car
Bill

Nick,
The guide tube that I was referring to is not the one that forms part of the Type 9 box front plate. It is part of the concentric slave arrangement.

Guy Weller

This thread was discussed between 08/07/2008 and 09/07/2008

MG Midget and Sprite Technical index

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