Has anyone with a Plus 2 fitted the QED concentric slave cylinder kit to a Lotus 5 speed gearbox? Or in fact any alternative clutch slave cylinder mechanism. I find the clutch on my 1973 Plus 2 very snatchy. As I plan to take the engine and gearbox out to fix oil leaks on both, I could instal it at the same time with the hope this mod might make the clutch lighter and more progressive, rather than the on/off operation it has at the moment. Best Regards.
…and if you ever have to work on the slave cylinder it’s an engine out job…
John 
All modern manual drive cars are built this way - so I guess reliability is a given.
I intend to go this route when I get around to fitting a T9 box.
I also use a McLeod unit on my T5 conversion with no failures so far.
We should have an emoticon for knocking on wood…
Tom
Tom,
I’ve found McCleod clutches on the net. I’m not sure their products are avaialble here in the UK. I assume from your post that a T5 is alnernative gearbox. If so, what car is it from? Did you fit it yourself?
Regards
Graham
the T5 is the Borg Warner 5 speed as used in the Sierra Cosworth this side of the atlantic, I believe it was a common fit to Mustangs in the States?
Mark
Hi Graham
Please have a look at the following couple of posts, it took all winter to burn the subject out and summer is here and its time to drive a bit while the weather lasts.
TomR 's Elan TTR chassis with T5 gearbox
lotuselan.net/forums/viewtop … ght=#80126
General 5 speed gearbox talk, 8 pages of posts
lotuselan.net/forums/viewtop … sc&start=0
Here’s some photos of my twincam with the Voigts T9 attached. The clutch actuator is working fine except for fluid weeping out of the hydraulics input, so engine and gearbox need to be split to tighten up the joints. I’ll be taking the engine completely out as I’ve a few other little jobs to do that’d be easier without the clutter. I think the concentric actuator is from a Mondeo, but not sure. It uses the clutch spring from the 4 speed box so you may have to replace the thrust bearing and clutch assembly also.
Allan Voigts may know whether this can be fitted to a standard box.
All the best.
Sean.
Ive got the Voight conversion with the MONDEO centrifugal slave which lasted 5000 miles without leaking. The replacement, supplied by Voight, lasted about 100 miles. My complaint to Voight brought forth the nugget that only one of the 3 clutch cover plates Lotus used is compatible. Thanks Alan. A new cover plate and still neither of the 2 Mondeo slaves fitted, but the shorter of the two needs a spacer. Oh yes Voight says, didnt you know? My request for a contribution to the labour costs involved met with no response. Why didnt he have the bell housing casting made with provision for an accessible exterior slave cylinder and a fork? Previously Id recommended this conversion but not now and I certainly wouldn`t recommend a centrifugal and inaccessible system.
Jim
I fitted a ford concentric slave cylinder (mine came from a Scorpio) along with a type 9 gerabox approx 10 years ago, I have never had any trouble, I used the standard 4 speed clutch cover and modiifed the front bearing carrier such that an alloy adaptor could bolt to it which then carried the slave cylinder.
The only problem I had was with the Sierra clutch disc having thicker linings than the original Lotus one, this required some shims to be placed between the clutch cover and the flywheel.
Jim and Sean,
could you care to detail mis-matches, causes of failure?
Also, how does Alan Voights’s conversion ensure concentricity of the bearing/actuator with the gearbox input shaft. Without concentricty, you will get sliding/rubbing between the clutch fingers and the bearing surface. I’m asuming that the bearing is in continuously contact with the clutch but essentially unloaded (apart from soft axial spring).
Regards
Gerry
Burton supply a range of concentric products to fit many of the variants mentioned. I’m sure a phone call will get you the correct fitment for a specific gearbox/bellhousing.
I agree with the many others here about accessability.
It was among many reasons why I chose to stay with my Elan gearbox & clutch operating system when I did put the Zetec engine in it.
A centrifugal slave sounds interesting though.
How do they work?
Take her for a spin & she’ll do anything for you? 
Cheers
John
John (DJ Pelly), I think the slave is concentric (ie annular and wrapped around the gearbox input shaft) rather than centrifugal.
Regards
Aah so it is fun then 
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.
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
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
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
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