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MG Midget and Sprite Technical - 5 speed conversion?

Dear all,

I have recently succeeded in bleeding my slave cylinder after replacing with poor quality new unit and swapped back for repaired original and learning my hands are too sausage like to do this job on my own!

Anyway, a cheeky piece of carbon magically appeared on the floor and assume I have an issue with the release bearing. So I am left considering my options and would like advice.

I think I will simply replace bearing and clutch plate in the mean time and keep me driving now the weather is so good, but they've barely done a 1000miles before failing and wonder about the longevity of this fix. I think I should (eventually) change to 7.5" clutch, comments?

I found MED 7.5" clutch assembly with balanced lightened flywheel, would this work with a 5 speed box? If i go down this route at a later date?

I am keen to change to a 5speed box to make cruising a little more bareable. This I see as a bigger job,and need to research more before I commit to anything.

I'd love to be able to afford fronting to supply everything, but the missus would kill me if that was spent in one hit...it's easier to hide parts if they trickle in!

The obvious choice seems to be a type 9 box, there are a number of these available but am I right in thinking I should be looking for one from a 1.6Sierra or capri? Dows anyone know where I can source am appropriate unit? There are some recon on eBay bit still quite pricey.

Is it best to source bellhousing and prop shaft, gear leaver... from mmc or fronting etc?


Then I worry about cutting the crossmember etc, even with a shortened type 9 do I still have to perform surgery? I would prefer not to cut anything, but does it make much difference?

I have read about Datsun boxes but have found none, it seems like these are almost a straight swap, is it worth considering this option?

Um, lots of questions to start, I know there are loads of posts but still not convinced on what to do.

Any pictures of jobs to do like what to grind on bellhousing to fit new clutch would be a great benefit. Any advice, or help sourcing parts needed would be much appreciated, I imaging this will be a winter project and have plenty of time to prepare.

Any way thanks for any input

Pete
P J Gingell

Datsun option is worth considering, it is a better fit and Rivergate in the US do a good kit for them.
We get the odd box pop up here, I get notifications of when the come available which I could fwd if you like ... but then there is the freight issue.
Paul Walbran

Another option for the Datsun conversion is Gerrard's Garage.

http://gerardsgarage.com

They use the Datsun clutch which means that you would have to get the flywheel drilled to accept it. The advantage is that if/when the clutch goes out you don't have to try to source the clutch combination that Rivergate use, just get a standard Datsun 210 clutch.

Either one is a simple swap over. The hard part is getting the gear box. 1979 to 1982 Datsun 210 here in the states. I believe it has a different name in other parts of the world.
Martin Washington

Well lets just complete the jouney around the world

there is the toyota (T 2/3 ???) In oz land down under with the 5 spped kite made by delwood or dowood or duewood which is very plug and play


prop
Prop the cow killer

Okay update

DELLOW in oz and its a toyota T2 /T3 out of the ceilca..
You will have to look up the dellow website in austrilia for the specs the toyoata T50 is whats used on the 1500

prop
Prop the cow killer

Continental cousins.
I have fitted three Rivergate conversions in the past using the Datsun gearbox but here in the U.K. The gearboxes are difficult to source, apparently now years on from Rivergate, as are spare parts.
The Toyota gearbox is the same.

I have done quite a few T9 conversions but it seems that the day when you could pick up a Sierra gearbox for 20-50 are past.
BGH Geartech of Cranbrook, Kent are well known for their T9 and, due to demand, were considering re-casting the housings because of that continued demand. They might sell a s/h gearbox from their stockpile.
G.S.Escorts were advertising T9 gearboxes at 250. They are Widnes near Liverpool.

I am aware of someone fitting a BMW gearbox but not the detail.

Pete.
If you are a Masc member you will find several articles on fitting the T9 archived in the members only section of the Club website with pictures of how to do it.

Alan
Alan Anstead

Toyota Starlet box will fit without modifying the crossmember, just. The crank pullet needs to be removed when fitting/removing the engine/box assembly.

I think the T50 requires crossmember removal.

BMW box was fitted by someone here recently.

We have Starlet, Datsun and Toyota Supra boxes in 3 of our midgets, and I saw the BMW one as it went through the process. Of all, I think the Datsun one is simplest.
Clutch is quite simple with Rivergate, we have identified a plate that is a direct fit.

All these old in-line boxes are getting hard to source, as are parts for them. That's a potential advantage of the BMW unit as they are one of the few that have continued RWD.
Paul Walbran

PJ,
Unless you are prepared to source overseas and import a gearbox to the UK forget about anything other than a ford type 9. All of the others are for all practical purposes simply no longer available in the UK.

If your car is a 1500, then a viable alternative is to fit a Triumph overdrive gearbox rather than a 5 speed. It makes for a nice "period" conversion and is in many ways nicer with the 1500 engine than a type9 5 speed.

Both the 1500 overdrive and any variant of the T9 require the cross member to be cut out. Using a shortened gear shift extension doesn't avoid this either.

The other thing you may want to research is the use of a concentric clutch slave system as part of the upgrade. It's not essential and can be done later, but it has significant advantages.
Guyw

ok, thanks for all the quick responses.

Guyw, I think I am inclined to agree with you about only considering type9 box, I have a 1275 so the triumph is not an option.

Alan, I am not a masc member but will look into that, it sounds useful. I will also look at those 2 sources thanks.

The whole conversion or me won't be immediate yet, but I do need to fix the bearing so the engine will come out this week. But I am unsure of what to replace it with: since the engine has been uprated I was thinking of replacing the whole clutch with 7.5" clutch, roller bearing and lightened balanced flywheel from MED (http://www.med-engineering.co.uk/products/clutch-assembly/inline/med-midget-st1-steel-flywheel-assembly) this seemed to me to be worthwhile outlay if it fits with type9 box.

but as I wasn't expecting to spend any money on the midget this summer this is still a lot to spend (especially when she is expecting a new bathroom)

I see three options for me:

1. just replace standard release bearing - nice and cheap and would hope to last until I set about gearbox conversion.

2. 1275 Roller Release Bearing Kit form Peter May. any better than standard part?

3. MED assembly- more robust than standard I assume and hopefully saves further outlay when conversion takes place.

or option 4/3. get impatient, take out a loan and get complete kit from frontline - think I would be killed and the car torched!

any other options worth considering or words of wisdom?

many thanks so far.

pete
P J Gingell

Hi Pete,
There has been a long-running problem with the standard replacement carbon clutch release bearings, with many reports of premature failures. As far as I can recall the critical pointer to the defective part was whether or not there was a small radial hole in the carbon part of the bearing, possibly to locate a split pin. This seems to generate a weakness and result in the carbon breaking up.

The best solution is to fit a ball bearing type release bearing such as the Peter May version. But see what Alan Anstead has to say about the available options!

The MED offering would certainly be a simple all-in-one solution, but to me looks an expensive approach! If you want a lightened and balanced flywheel I would think the best thing is to take your existing flywheel to an engineering business and get them to do it for you. Unless you are racing and looking for reliability at very high revs, it shouldn't be necessary to get the whole assembly balanced together with the clutch cover. Each of the components of the flywheel and clutch assembly should be supplied as individually balanced anyway, so that when assembled the whole remains balanced as well.

What I think is worthwhile, is to get the flywheel,crank and harmonic damper balanced as a unit, but that is something to do when having a full engine rebuild done, which I suspect just isn't anywhere near being on your agenda just now!

If your clutch is worn that is a reason for replacement, and maybe worth fitting a non-standard 7.5" clutch cover. But my T9 conversion uses a standard 1275 clutch cover which just accommodates the slightly oversized (>6.5")clutch driven plate that I use and this mates to the splines of the T9 input shaft. It can be done without the expense of a larger clutch which I think requires the flywheel to be refaced and drilled to take the modification. Again, if you are going racing or looking for a high level of performance then the larger clutch would be necessary, but in my experience (85,000+ miles of fairly enthusiastic road use) its not essential. You pays your money . . . .etc.

Guy
Guyw

See www.masckent.org.
Alan
Alan Anstead

P J

here is my take... go with the peter may roller bearing as the carbon bearing is to unreliable

another option would be the concentretic bearing but for my recommendation no

lbecause of the huge cost of a 5 speed box and conversion look around this summer and fall ..and look for an engine /5 speed combo prefable from a whole car and just sell the cars remains to the salvage yard

your looking a minume $2500 USA TO do just the 5 speed box but if you get a hole car with the datsun A 15 and its 5 speed box... thats a much better option as the datsun A15 engine is an almost sister twin to the bmc Aseries engine but it has twice the hp as stock 8 port head not 5 port simiease and its a 5 main bearing vs 3 for the bmc

there easy to rebuild lots of parts an everything will mate up .. just modify the engine mounts and the drive shaft ... and there you go.

the datsun is just an example and i certianly wouldnt use a car with efi or electronic ignition... basic and simple like the midget

sounds extreme but your gojng to have at least 3500 with extra parts and tool needed so might as well make it simple and get the most bang for the dollar
Prop the cow killer

Best option... sell your car and buy a midget with the 5 speed already installed

most of our midgets that get rebuilt almost al2ays sell at a loss for the work and money we put into them

we have a saying the most expensive migets are free .... at the other end a very cherry nice top end dream machine will never sell for what they should... wnd the savings can be huge

this way you might break even in the money or a little behind ... but you sqve a truck load of time and aggervation and its all just drive and have fun

let the other p o fool deal with all the tears and pain before he sold it to you at a loss
Prop the cow killer

thanks again guys.

I am just deciding between roller release bearing and the 7.5 clutch and flywheel assembly (I have heard you advice Guy)
P J Gingell

thanks again guys.

I am just deciding between roller release bearing and the 7.5 clutch and flywheel assembly (I have heard you advice about standard clutch cover Guy)

prop, probably good advice also. But i'm not worried about the resale value as it's more of an emotional bond! I rebuilt the engine only a year ago and don't want to change this, but do see a value in the donor parts you suggest.

started engine removal today, just have to clear space to store the engine. what would people do? I was just going to remove engine, but would it be easier/better to remove engine and box together?

cheers

pete
P J Gingell

Pete
Some prefer to pull the engine and gearbox as a unit. I just pull the engine.

A type 9 conversion does not have to be mega expensive depends some times on how hands on you can be and what skills you possess.
You will need a bellhousing. Buy or make.
You will need a chassis kit. Buy or make.You will have to cut the chassis for the T9.
The propshaft is probably best bought.
You will need a hybrid clutch plate.
Clutch cover depends on what release bearing you use any thing other than concentrc or Peter May will require a QH cover.
Shortened remote or not is personal preference but again make or buy.
Cheap speedo cable is to use a Sierra one otherwise hybrid with right ange drive.
Your speedo will at some stage need re calibration.
If not home made I usually source, or I ask folks to source for me to fit to their car, parts from Morris Minor (Birmingham) ltd part of the David Manners Group.

Pic is of one of my bellhousings made from an A series gearbox in the making.

There is currently a thread running under MGA where someone has posted a diagram showing which T9 gearbox you need to source.

Alan

Alan Anstead

What to look for in a Sierra box for a Spridget

Hi-Gear don't supply parts for a Spridget conversion

Alan

Alan Anstead

Personally I'd go with just converting to a Peter May roller release and stick it back together.

Unless you are putting out huge amounts of HP the standard clutch should be fine. I think the MED one is probably a bit OTT, but then I suppose if you intend modding in that area in the future it might be worthwhile.

I've got a Type 9 in my Sprite and it uses the standard Frontline clutch cover and plate on the standard flywheel. It's coped well with at least 50% more power than standard and hundreds of full bore starts on sticky tyres.

I'd like to lighten my flywheel/clutch assy at some stage but I'm a bit unsure what to go for. The MED set up is an option but I don't know if I could get a plate for the Type 9 to suit. It's another of those jobs I never seem to get round to!
john payne

This website http://www.p9cyoplates.co.uk/ claim to do an A series to RX-8 5 speed box conversion plate but I have emailed them and at the moment they have not developed the one for the A series engine. They are looking for someone to lend them a suitable A series engine to develop the plate for it.

The RX-8 5 speed is a tough gearbox but is about the size of a type 9, it also has the same input shaft dimensions as the Type 9 so you can retain your 1" x 23 clutch plate. The gear lever position is a couple of cm back from the type 9 and there doesn't seem to be any way to shorten it.

The advantage of the RX-8 5 speed is price. 50 to 90 will get you a good one. 1st ratio is similar to Type 9 but 5th is .78 (I think).

Just one more option.

Rob

Rob aka MG Moneypit

John,

I would expect many of the off the shelf Ford 7.5" clutch plates used with the type 9 would drop straight into that MED set-up.
David Billington

Thanks again Alan, i think I have found a few pictures of your handiwork now. the bell housing you've made looks awesome.

I myself have no welding skills sadly, so am not sure if I can make one of these myself; how do you cut the bell housing down?

I think I am sure which box I am looking for now, thanks and can keep an eye out.
P J Gingell

I agree john I am going to go for peter may roller and see how that goes and plan the gearbox swap for sometime in the future.

thanks all for the advice, I will be back asking for more when I get started!

cheers
P J Gingell

Pete
Used an angle grinder to detach the bellhousing from the A-series gearbox. I had to enlist the help of a Tig welder to finally secure the end plate.
Alan

Alan Anstead

If planning on cutting up an A series gearbox to get the bellhousing for adaptation for a 5 speed, can I suggests sourcing another gearbox. Proper Spridget ribcase gearboxes are becoming increasingly hard to find even in need of reconditioning.

A quick search should locate a gearbox from a Morris minor or an Austin A30 / 35 that can be butchered rather than destroying the better version ribcase box. If you need to cover costs, you should be able to sell the Spridget ribcase for much more than the cheaper version Moggie/A30 one.
Guyw

Just to add to what Guy rightly says a couple of people I know have had their gearboxes refused by a reconditioner when they, unknowingly, presented non Spridget gearboxes that had been installed at some time in their car's history by previous owners.
Alan
Alan Anstead

Alan...i dont understand ... you mean if its a 5 speed conversion the shop wont work on it ?

That RX 8 possiable conversion sure looks like the bees knees...im looking forward to seeing that...

prop
Prop the cow killer

Guy commented on not using a valuable Spridget box to cut up in order to use the bellhousing for a five speed conversion as I have done. I used a knackered smooth case box for one conversion on my 948 Frogeye and was given an empty ribcase box for the other.
Guy is correct as good Spridget boxes as becoming hard to get hold of.
They are also in demand by people wanting to get a Spridget box reconditioned as reconditioning firms will only accept Spridget boxes as two of my members found out when they presented boxes from their cars to be told the boxes were non Spridget and unacceptable.
Alan
Alan Anstead

I'm really trying to avoid a 5 speed conversion, but since gaining a few horses it just runs out of gears!
Karl Bielby

This thread was discussed between 19/07/2016 and 25/07/2016

MG Midget and Sprite Technical index

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