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MG Midget and Sprite Technical - More Type 9 GB in 1275 Midget Questions

Hi All, me again!!!!!!

I thought I had it solved but the Fickle Finger of Fate threw a spanner in the works.

Attached is an image of the Spigot Bearing installed in the clutch.


Rob aka MG Moneypit

The next image is of the Input Shaft.

The sharp eyed will have noticed this is a long input shaft shortened.

Now my problem is the splines on the input shaft foul on the shoulder of the Spigot Bearing Carrier preventing the Bellhousing from touching the backplate.

You may notice someone has had a go in this area and I dare say if I took it back a bit more (about 10mm) it may solve my problem.

I know it all worked before I installed the Spigot Bearing and stupidly, I didn't check after installing it.

Is there a way of installing a Spigot Bearing directly into the end of the crank shaft. Effectively, without using a carrier?

Rob



Rob aka MG Moneypit

Are you saying the input shaft is to short to enter the flywheel spridget bearing?

The input shaft looks like its got some wear around the splines at the front

Prop
Prop and the Blackhole Midget

No, the input shaft is a shortened long shaft. The long shaft was fitted to V6 engines, the short shaft was fitted to 4 cylinder engines, both with the Ford Type 9 Gearbox.

The long shaft has been shortened by cutting off the end and is now about the same length as the short shaft. The end of the shaft will enter the spigot bearing, but as I slide it forward the splines foul on the spigot bearing carrier preventing the bellhousing from touching the endplate.

Rob
Rob aka MG Moneypit

I did a quick diagram of the problem.

I'm pretty sure the problem is that the shortened long input shaft places the splined area too close to the end. If the splined area was ground back by about 10mm it would probably be ok.

Or if I could do without the spigot bearing carrier but mount a spigot bearing on it's own in the end of the crankshaft, it would be ok.

Rob


Rob aka MG Moneypit

Rob it is perfectly possible to buy phosphor bronze bushes that will fit into the crank and go over the spigot

Most bearing stockists have them in a variety of sizes

When I was investigating fitting the E30 Getrag box from a BMW I bought a spigot bearing for the job that fitted exactly

Sadly I cannot put my hands on it today

So measure the hole in the crankshaft (A)

And measure the centre spigot of the type 9 box (B)


Then decide how deeply you want it all sunk into the crank (C)

then ask for a phosphor bronze bush

A x B x C

Almost certain to get one the right size, if not the web is rife with 'methods' of opening the hole or machining the outers


I suppose you cannot grind off another 1/8" from the spliney bit?
bill l

Rob is this a previously used kit? Has that gearbox mated to that spigot bush before?

The spigot looks a bit bruised is it possible that it has goten distorted in some way? Although it's quite hard so maybe not all that plausible.

Alex
Alexander Sorby Wigstrom

As Bill says, it ought to be easy enough to do away with the carrier and find a bush to suit.
Dave O'Neill 2

Looking at it again, the end of your input shaft that doesn't have spines seems a bit short compared to an original short input shaft gbox.

If the kit your using was not modified to fit a spridget to begin with or an a-series engine with a different flywheel than yours then you might be right in the first place that you need to grind of that extra bit of spines.. IF you dare.

I'd say mine is a bit longer than yours, if i hadn't put the engine in i could have measured it for you. Maybe someone else can.




Alexander Sorby Wigstrom

I doubt you will get an off the shell bearing for this that will fit in the end of the crank as the A series input shaft was 1/2" OD spigot and the type 9 15mm IIRC, more likely an adapter sleeve will be required. Bronze bushes are available in metric and inch sizes but this application is going to need an inch sized OD if a standard midget crank and metric ID, that's not going to be a standard part.
David Billington

Bill, thanks for the info. I will investigate this but as David mentions it may be difficult if dimensions are a mix of metric and imperial.

Alexander. It's a mixture of bits collected over the last 2 or 3 years and was never a "kit" of parts.

David. Yes may be a problem. The hole in the end of the crank is 2 diameters. The standard 1275 spigot bearing is fitted in the inner (smaller) diameter hole. The type 9 spigot carrier has a tail that fits into the outer (larger) diameter hole. Maybe I can cut this tail off the carrier and fit it on it's own. Maybe with some thread seal, although when I got it it didn't fit in the end of the crank. I had to reduce it's diameter by a few thou. before it would fit and is a snug fit so maybe I don't need any thread seal?

I will investigate the possibility of getting a phosphor bronze bush, if that is a cheaper solution than butchering the present spigot bearing carrier.

Rob
Rob aka MG Moneypit

I took the flywheel off (again) and extracted the Spigot Bearing and Carrier as supplied by MMC and measured it's outside diameter. It was 22mm (21.95mm to be precise) and inside diameter 15mm and the hole on the end of the crank is 15mm deep.

I have ordered a 22mm OD x 15mm ID x 16mm Long bush from
http://www.getyourbearings.co.uk for the princely sum of £6.97p including postage.

Due to arrive on Wednesday.

It's funny that the crank should have a 22mm hole in the end. 7/8" is 22.23mm but it is definately smaller than that, the Spigot Bearing Carrier from MMC definately has a 22mm OD, is an interference fit AND it originally didn't fit at all. I had to reduce it's OD by mounting it on the end of a drill mandrel and using a flat file while it rotated.

Hopefully, this will be the last obstacle.

Rob

Rob aka MG Moneypit

I hope that awesomely expensive bush does the trick

:)

Don't forget to load the phosphor bronze by soaking it in oil before you use it

A well documented short cut is the place the bush over the fleshy part of your thumb, other hole pointing uppards. Fill the hole with oil to the brim

(your thumb should hold it withoout spilling any/much)

Then place your other thumb on top of the oil-in-the-hole and squeeze, you will see oil ooze out of the surface of the bush

The pressure you impart forces the oil into the oil bearing interstices in the structure of the phosphor bronze

I still prefer overnighting submerged in a small oil pot
bill l

Bill,
I expect Nick could do a nice cartoon of you to illustrate that last sentence of yours !
Guy Weller

:)
bill l

Rob,

I suspect you were lucky in getting that feature at that size. IIRC the standard spigot bearing fits ahead of that feature and is 5/8" OD and 1/2" ID and will be tightly controlled, just look at the housing bore size for the bearing you bought in their information. That bore you have at 22mm doesn't provide any purpose other than clearance on the input shaft from what I can see and so I expect it would have a wide size tolerance so maybe due to tool wear and size not being important you have a nominal 7/8" (a guess) but conveniently undersized and suitable for a 22mm bush.
David Billington

Hi all, the bush arrived and it is slightly too big to fit in the crank end but only 0.1mm to 0.15mm out.

What is the best way to reduce the diameter considering it is Phosphor Bronze. Bear in mind I don't have a lathe but I can muster up a vice, a battery powered drill ( a half decent one), vaious sizes of sockets to act as mandrels, and a couple of files.

Rob
Rob aka MG Moneypit

Electric drill, big sod off bolt small enough to fit the drill and needing only a few thou packing to make the bush fit...



No Rob don't do it

Do you have a school locally with a metal working shop?

Local blacksmith?

Half decent jobbing garage?

Get the few thous you need turned off on a lathe

There is a well known advisory restriction on machining phosphor bronze bushes, because the turning motion 'fills in' the pores in the metal that holds the oil in normal use by skinning over the pores with turning fraise

SO I wouldn't advise getting it turned normally but you don't need to disturb the porous centre part of the bush, only the outer 'skin' which doesn't need to move in the crank

So I advise plan A

find a friendly lathe owner

(The big bolt inna drill scenario leaves you with the attendant risk of running off centre, buggering up the bush and looking at RERUNFROMSTART with another new bush. 'Taint worth it mate, for a few seconds of proper turning)



cue disagreeing voices...
bill l

Hi all, finally getting somewhere with much progress today.

Bill, I used the electric drill method. I just couldn't wait to find and arrange for someone to do it for me. As you pointed out it's only the outside that would have it's pores blocked, so I took a chance.

I got the spigot bearing installed and did a dry run without flywheel and clutch. Blow me, the gearbox wouldn't rotate because the lead-in to the splines was fouling the spigot bearing. So, I ground back the splines by about 5mm and made sure it ended up 15mm diameter right up to the splines.

After that, I assembled everything and placed the Engine/gearbox next to the car and ran a flexi pipe from master cylinder to slave cylinder. With an eezibleed it took less than a minute to get the whole thing bled. An almost instant firm peddle. SWMBO sat in the drivers seat and operated the clutch for me. Works wonderfully, nice smooth action and light too.

So a warning to those who buy a type 9 with long input shaft. There is more too it than cutting a bit off the end.

Thanks for all the advice. Next step is crossmember modification. No doubt it will all go smoothly .... NOT.

Rob





Rob aka MG Moneypit

good news at long last

Well done Rob
bill l

This thread was discussed between 25/09/2014 and 04/10/2014

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