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MG MG Y Type - Clutch dilema

For more years than I care to remember(from early 1980s)I have put up with a mis matched clutch and bell housing assembly. The YA and cross shafts is 5/8 and YB 3/4 in). I have a YB with an 8in bell housing but the engine fitted is from a YA hence it has the 7 1/4 in clutch assembly. As mentioned on this BBS in 2013 this makes for an awkward clutch change (Info via R A Wilson etc).


file:///C:/Users/DMULL/Desktop/Bell%20Housing%20%20%20MG%20MG%20Y%20Type%20%20%20MG-Cars.info.html


My dilema is that if I want to go to 8in cliutch I have to change the flywheel to the larger 8 in one which means removing the engine as you have to remove the sump to get the flywheel out and thats not a job to do from underneath plus I currently have a leak free crankshaft oil seal (yes despite being a cork one!)!
Then I would need a new 8 in clutch assembly. The alternative is to just remove the gearbox and swop the YB 8 in bell housing for a 71/4 in one.

Am I best just fitting a YA bell housing?
The thing is that as both the car and I are from the 1950s I want to use the car quite a bit before I get too old to drive it and I would be interested in views on this - my gut reaction is its simpler and cheaper to fit the YA bell housing but that means getting a decent uncracked one?
D MULLEN

This might not help much but you could use a Morris 10 bell housing. They are the same as the YA housing. Trouble is that Morris 10 parts are not common either but it might improve your chances. The lever on the Morris 10 is slightly different but that could be managed by swapping with a YA lever or twisting it 90 degrees so the hole runs across the car instead of forward/aft. I have one in my shed but I am in Australia!

About 40 years ago I took the gearbox out of a Y tourer to repair it. I remember that after doing it I thought it would have been easier to remove engine and gearbox as a unit. Hopefully someone else on this thread might be able to comment on which way is easier to remove the gearbox.

Good luck
Bob Schapel
R L Schapel

David

It is and expensive solution ... but at least you get a decent bell house out of it ... and maybe some other spares too, but I just used the eBay search on the Classified Advertisements page and found this one for you.

https://www.ebay.co.uk/itm/MGYA-gearbox-with-gearleaver-/192492246060?

Any good?

The link you were referring to earlier Dave is

http://www2.mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&mode=archiveth&archiveyear=13_2013.dat&access=&subject=13&subjectar=13&source=T&thread=201306201824406429

Paul
Paul Barrow

Was it as long ago as 2013 - anyway, you imply you have a 7 1/4 in bellhousing which is cracked. Why don't you have it repaired by welding - I have a TD sump which was badly cracked on its underside, and it was repaired by welding (after preheating), and has never leaked. Perhaps you could you post some photos.
You mention a cork oil seal on the crankshaft - not sure where this is.
R WILSON

My YB bell housing is fine. I had the gearbox overhauled a few years back so that's fine too.

What I need to do (I think!)is swop the YB bellhousing for a YA one and that should be it. At present the YB bell housing is not really suitable for the 7 1/4 in clutch/flywheel currently fitted (my engine is a YA one fitted before I had the car)- see the previous thread link in Paul Barrows reply above.

To renew the flywheel to 8in (from 7 1/4 inch YA one currently fitted)the whole clutch assembly and flywheel would need replacing which involves the engine out and sump off and as the sump has a cork gasket for the crankshaft rear seal which is fine - no leaks - I would have to disturb it (when the sump came off.) You can't remove the flywheel without the sump off.

Looks like I should go to just taking the gearbox off and removing the YB bell housing (3/4 in cross shaft as opposed to 5/8 for YA)and put a YA one in its place. I think the 7 1/4 clutch should be OK for the sort of driving I do.

I hope this makes sense? If it does I need a YA bell housing. I did hear ages ago Tony Slattery had a spare one but it might be a bit expensive on postage from Aus! Given the number of Ford Sierra gearboxes now fitted a YA bell housing on its own should be available?
D MULLEN

I knew your car was fitted with a bellhousing for an 8" clutch - I thought you had a cracked 7 1/4" unit sitting in a shed. Finding a good 7 1/4" unit is probably your quickest solution - if you have to get one from Aus, then it can be sent quite cheaply by sea. Most Aus cities have shipping agents (much better than the UK), and it would take just under three months to get here, delivered to your door. To reduce the weight slightly, the cross shaft can be removed, as you would probably fit a new one, and bushes, over here - but you would need all the other parts.
R WILSON

I have attached a section drawing (approx half size) showing the 7 1/4" clutch, but with the release bearing and cross shaft moved back as for the 8" bellhousing. As can be seen, there is a large gap between the face of the carbon thrust bearing and the face of the release lever plate (part of the clutch).
During clutch disengagment, as the carbon bearing swings forward, it also swings down as it moves in an arc. Thus the carbon bearing will come off the bottom of the lever plate, and the inside of the carbon bearing will touch the top of the first motion shaft. These will make the clutch very difficult to operate, although the problem may ease as the clutch wears.


R WILSON

Many thanks for the details Richard W.(I think its Richard?) and the diagram..yes the YA bell housing seems the best way go go. Sometimes it helps to get other Y ownerd views on something like this so thanks everyone.
D MULLEN

I should have said 'moved back 7mm as for the 8" clutch bellhousing'. The large gap I mention becomes about 8.5mm.
R WILSON

R Wilson has made a good point. Probably, all you need to do is change the carbon thrust for one with more offset. There should be no issue with the YB bellhousing if it is fitted with a carbon thrust which has sufficient offset. They come in several offsets for different cars and hopefully there is one which suits your situation. As an alternative, a clutch specialist might be able to adjust the release plate height a bit if you can't get a carbon release bearing to suit.
I am not sure about this but sticking with the original YB bellhousing might also prevent having to change the length of rod or cable set-up to match the different shaft position of a YA bellhousing?

Bob Schapel
R L Schapel

Having been looking for a couple of years I eventually found found a good replacement YA bell housing at Stoneliegh this year for £75 only to then find an even better one for sale at £45 ten minutes later!! YB housings are much easier to find. You do get a much stronger improved casting with the YB.
Peter
Peter Vielvoye

Perhaps I should say that with such a combination, you wouldn't actually drive around with the 8.5mm gap. The operating rods etc would be adjusted to reduce the gap so that the play at the pedal was correct. However, the 'arms' of the clutch fork (that hold the thrust bearing) would start off leaning well forward and down in the arc of travel, and then get worse as the clutch was operated. I like the idea of a thicker thrust bearing - I wonder if only the carbon ring could be made 7mm thicker.
R WILSON

Another point to note is that the clutch centre is 1 in on the YB and 7/8 on the YA due to the first motion shaft difference on the YB gearbox.(1 in as opposed to 7/8 in diameter) so if you do fit a YA bell housing you have to use a 7 1/4 clutch plate with a 1 in centre eg from an early Hillman Minx
I wonder if the T type lot ever sorted this issue of later bell housing and the 7 1/4 clutch arrangement?? It would be ideal IF you can fit a wider clutch release bearing.
D MULLEN

I have to admit I did not know about the increase in spline diameter for the later 8" clutch. I wonder if the diameter of the 1st motion shaft behind the splines and through the thrust bearing was also increased - this would make your combination even more likely to foul as the thrust bearing swings through its arc. Anyway, you either need a 7.25" bellhousing, or make and fit a thicker carbon ring. As the latter is unproven and still needs the gearbox and bellhousing to be removed, a 7.25" bellhousing looks to be your best bet. However, I wouldn't turn down an 8" flywheel and clutch - just a bit more work.
I hadn't previously heard of anyone with your combination, but some years ago there was an article in a T type magazine (cannot remember which) about fitting an 8" flywheel and clutch into a 7.25" system. Apparently it is possible, and I have since met a couple of people who have that combination in their cars. However, no-one has mentioned that the clutch centreplate splines were 1", but the 1st motion shaft splines were 7/8". I can only assume that the number of splines are the same and the shaft fits inside the centreplate - and the people doing the work were not aware of and did not notice any difference. If there is or was a different solution, I would be interested to read about it.
R WILSON

I'll report back when I get it sorted. I think Neil Cairns knows a bit about all this but the upshot wouls seem that an odd combination of parts will work but not work well and a proper solution is as to go with the one fitted originally (which i guess is in my case an 8in flywhel and clutch). Will report back when i decide what to do... and do it - hopefully in summer.
D MULLEN

If you go for the 8" flywheel and clutch, the ring gear had 120 teeth, and went with a starter motor with 9 teeth. The YA engine had both the 93/10 and the 120/9 combinations.
R WILSON

This thread was discussed between 25/03/2018 and 29/03/2018

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