QED Concentric Clutch Slave Cylinder

[alaric]

The slave cylinder is like a set of bellows that's lightly spring loaded towards the clutch cover. The clutch cover / diaphram spring has a plate on it, so the springs are not ever in contact with the bearing. The input shaft to the gearbox has a bit of lateral movement in it. The flywheel has a needle roller bearing in it which is there to align the input shaft of the gearbox with the clutch assembly. So there really shouldn't be lots of sideways movement when the thrust bearing is in contact. Also, the end cover of the thrust bearing has, I think, a little play in it, in other words the bearings are designed to allow a little lateral movement, and being bearings they are frictionless - imagine the plate sandwiched between the clutch cover and the bearings...

Hope that's correct as I've just reasoned it out. Also, a lot of older cars used a granite friction surface on the clutch cover, as that material 'flows' and helps take up play. Don't think that's needed here though, since the good old spigot bearing is there to save the day.

My slave cyl is not leaking. The copper pipe that feeds it isn't tight enough, and dear old Allan's pipes are a harder copper than you can use so the seals aren't easy to form - I may remake them.

Have to rush out to dinner now. I don't think the slave cylinder is normally a problem - I know of 4 others with the conversion that have not reported a problem. Allan is not really terribly useful at after sales support though is he.. bless him.

Hope that helps and that I'm not completely barking.

Sean.

[gwiz22]

Thanks to everyone for sharing your various experiences and suggestions.

Sean,
Thanks for taking the trouble to load up the photos of your set-up. From then I can truly understand how this mod is effected. I guess my issue will be, whether I can find an adapter that fits into the Plus 2 five speed box to take the concentric slave cylinder.
Although the Lotus/Maxi 5 speed doesn't have the slickest of changes, it is 5 speed and I would be happy with it if I could just improve the fierceness of the clutch when taking off and crawling in traffic. I've read the posts regarding energy build up in the rotoflexes etc. and the err eer eer action is ever present when changing gear and at low speeds, so today I bit the bullet or should I say credit card and ordered a pair of CV driveshafts from Susan Miller. So a little job at the weekend. I hope they help, if not I guess I'll be looking to see if I can find or have made the aforesaid adapter. I don't really want to go to the expense of Alan's T9 conversion, elegant though it looks as I already have five speeds but this damned snatchy clutch does not make for a pleasant driving experience in an otherwise fantastic car.
Regards
Graham

[GrUmPyBoDgEr]

It's just occurred to me; take a look at "Demon Tweeks", I recall that they have a couple of hydraulic concentric clutch set ups & various adaptors for them.
Good luck.
John

[rgh0]

Graham
A fierce clutch snatch does not normally relate to the throw out arrangement and I would not expect changing from the standard arrangement to a concentric cylinder to change it if its a porblem. My 5 speed plus 2 has never had problems in this area either when on donuts or with the CV's now

Having said that the donuts on the back of a plus 2 dont help and replacing with CV's may make the clutch take up easier to control.

The problem normally relates to damage to the friction plate linings or pressure plate and flywheel faces such as wear, overheating or oil contamination giving an undesirable coefficient of friction versus slip speed characteristic.

It can also be due to broken or loose springs in the friction plant centre.

There is also insufficient clearance between the gear box end of the input shaft spline and the end of the friction disk hub which can lead to the hub binding between the spline end and the flywheel when assembled which may aggravate the problem you have. The fix is to shorten the hub on the friction disk by a small amount.

Friction plates also come in 2 type - solid or flexible. The solid type has the lining rigidly riveted and bonded to a solid central disk, stronger but has a more rapid take up. The flexible type has the friction linings carried on a flexible metal spring arrangement so the frintion disc compresses slightly when clamped between pressure plate and flywheel giving a smoother take up.

If your CV's dont cure the problem I would pull the clutch and flywheel and take the lot to a clutch specialist for them to check out and overhaul. My clutch specialist will not guarrantee the peformance of a new pressure plate and friction disk unless he also grinds the flywheel surface flat and to the needed surface finish

cheers
Rohan

[gwiz22]

Rohan,
Thanks for a detailed response. You more or less confirmed my thoughts on the slave cylinder, that's why I was hoping that there may have been someone on the forum who has gone down this route and had some experience in order to make a comparison. My new CV driveshafts have arrived today so hope to find some time over the weekend to fit them. If they improve the situation then Hooray!!! If not, I guess it's engine and box out. There's a fair amount of oil leaking from both and it's difficult to see if it's coming from the rear crankshaft seal, which I guess is how oil would get on to the friction plate.

The car was completely restored by Kelvedon Motors for the previous owner and has only done circa 4000 miles since, albeit over a long period 18 years. I'm pretty sure new clutch components would have been installed judging by the quality of the rest of the car so not sure how anything untoward could have happened to the clutch during that time.

Any of your diagnoses could apply so thanks for taking the time to explain them all. Accordingly, I think you're right, the problem must be with the clutch somehow and I won't know what till I get it out. That will have to wait for a few weeks.

Regards
Graham

[worzel]

Hi

Couldn't help but notice the message from "KStrutt" and his use of the std Sierra friction disc in his Type 9 conversion.

I converted mine some 11 years ago and after many conversations with the guy who first designed the altered box back in 1982 (yes really) he told me that the std Sierra friction plate will work but is not really the correct one. Instead the correct one is obtainable from DemonTweeks and, if my memory is still ok, is a racing item for a MGB. Pricey though- mine cost around ?75 in 1999.

This disc is thinner than the Sierra one which I thought at first might actually cause it to slip but apparently the reverse is true ie the thicker one is more inclined to slip.

I never really liked the idea of the enclosed hydraulics of the concentric clutch system so I stuck with the std setup- a leak (admittedly not likely to happen) would involve an awful lot of work!

Regards

John

[alaric]

Re the Sierrra clutch plate, I put the standard one into my T9 conversion, but used a competition diaphram spring from QED. I've yet to get the chance to test it other than in the garage of course - one day I'll get the car on the road... although wth fuel prices the way they are in the UK it'll be costing about 23p a mile to run. Wonder when the gov will relent and decide they've grabbed enough tax?

All the best.

Sean.

[gwiz22]

Well I've installed the CV driveshafts and the car appears much better. I've only had a chance to take it for a short spin round the block, but certainly the windup and err err err feature has gone andthe take off is smoother. I'm looking forward to taking her for a long run now the nice weather is here to experiance all driving conditions. If anyone is planning on doing the conversion, allow plenty of time, It took me an afternoon a side. I guess I encountered most of the difficulties detailed in other posts but was lucky in the fact that the car had undergone a complete restoration with only a few thousand miles since so the bolts were not seized as the restorer had used liberal amounts of copperslip. If anyone is planning afit CV driveshaft, I took some pictures throughout the process and would be happy to post them with few explanatory words.
Thanks again to everyone who chipped in with their thoughts and experiences.
Regards
Graham