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MG Midget and Sprite Technical - Concentric Slave Cylinders. Preload or not preload

No wonder I got confused.

When I bought my T9 g/box conversion kit, I remember being told that I had a SAAB concentric slave cylinder (CSC). But when I googled it, mine didn't look like the Saab CSCs that came up. It looks like(is) the one in this picture. Then I saw mention of Burton, and found my CSC on their website, -- made by TITAN. But now I've found out that my CSC, is in fact a SAAB fitment CSC, made by Titan, but with an adapter base to fit a Ford T9 box. It runs the standard Saab roller bearing, which happens to be the same size required for a Ford Sierra clutch cover.

But there's more. As Rob is showing in his thread -- "More 5 speed woes... The Saga Continues" --, and others have shown previously, there are a lot of cheaper CSCs out there, than the one I have. And, they may well be better too, not just cheaper, because they have constant preload.

The Titan I have, DOESN'T preload the release bearing. It's SUPPOSED to be set up, so that when the clutch cover and plate are bolted to the flywheel, there is a circa 4/5mm gap from the bearing face to the clutch cover fingers, so that the bearing is free until the clutch pedal is pressed. However, that can cause wear on the fingers and bearing, each time the bearing 'lands' on the fingers, when the clutch pedal is pressed, because the bearing is initially stationary and has to come up to speed. And, as the clutch friction plate wears out(it gets thinner), the clutch cover fingers move ever closer to the bearing. Again, it's SUPPOSED to be set up, so that as the friction plate reaches it's max safe wear point(thinnest), the gap closes to 1mm. I.e. At max wear in the clutch plate, there should still be a gap between the bearing face, and the clutch cover fingers. IMPORTANT POINT THAT.

My bearing has started squealing. So my clutch friction plate must have worn. BUT, there's LOADS of friction material still on it, and it's far above the wear mark indicators. So, clearly the spacers I got in my kit, are too thick, because my bearing is now in constant contact with the clutch cover. Not with enough force enough to spin the bearing, but enough to wear the face of it. And now I've got the hassle of getting a thinner spacer, or getting mine skimmed.

I'd rather have a sprung preload.

AND, it gets worse. The Titan slave piston wears the bore of the CSC. So much so, that when the clutch is replaced, and is hence thicker, the piston moves the seals back further into the bore of the CSC again, and is likely to (possibly) cause the CSC to leak fluid past the seals. So a seal kit might not work, and a new CSC is needed. BURTON don't have any at the moment, but these people do.
http://www.sbdev.co.uk/Clutches/Clutch_Release_Mechanisms/Clutch_Release_Mechanisms.htm . However, their price for a TITAN CSC, is 126 quid plus vat. But at least they've used a hardened alloy in this newer version, to prevent future bore wear.

Rather than pay that kind of money, I think I may convert to another kind of -- cheaper -- CSC.

But this is interesting too.

"Clutch Slave Cylinders
Slave cylinders are divided into two primary categories: Concentric slave cylinder (CSC) and external slave cylinder.
Concentric Slave Cylinder
A CSC uses a large coil spring to maintain constant contact between the bearing face and diaphragm spring fingers. Therefore, no “lost travel” is required between the release bearing and diaphragm spring before the clutch pressure plate begins to disengage. However. In many instances, the CSC is equipped with a replaceable angular contact release bearing. Because the thrust face surface of this bearing maintains constant contact with the pressure plate diaphragm spring, the bearing may fail before the remainder of the CSC."

So, it's a trade off.

Either the bearing wears out due to being in constant contact with the clutch cover fingers, but never needs adjustment. OR, the bearing wears out more slowly, AND possibly the clutch cover fingers wear too, AND the gap spacing between the bearing and the clutch cover may need resetting from time to time, which is a pain, as it means getting to the inside of the g/box bellhousing.


Lawrence Slater

Preload can be achieved in two ways.

The first way is the way Ford and many others do it by making the piston easy to push back and providing a spring to keep the bearing in contact with the fingers.

The second way is what's probably snookering me. The SAAB I know is very stiff to push back so ensuring the piston doesn't retract all the way when you release the clutch pedal. This ensures contact between release bearing and fingers. But if the clutch return pressure is less than the SAAB concentric was designed for, it could leave enough pressure on the fingers to cause the clutch to slip.

I'm pretty sure this is the situation I am in.

Rob
Rob aka MG Moneypit

The Saab CSCs all seem to have a bellows cover, at least on all the ones I've seen on the web. Does that bellows act as a spring, or enclose a 'hidden' spring, which gives definite preload, rather than just a stiff piston?
Lawrence Slater

I'm using the Ford Fiesta/ Mondeo / Granada CSC. It has a light preload. Inside the bellows (green) is a large diameter, but fairly weak spring as it is of quite thin wire. It presses the bearing face against the clutch fingers but not with sufficient pressure to start to deflect the fingers and operate the clutch. So no slippage is induced.

The benefit is no lost motion in operating the clutch. And I think that it is in fact beneficial both to the clutch fingers and the release bearing that it is in "constant mesh" as it were.

My thinking on this is that the bearing is well capable of running many thousands of miles of use with virtually no load on it.

This is far better I think than having a bearing which must accelerate very rapidly up to engine crank speeds and back down again to zero at every gear change. This must occur as the clutch is depressed so the bearing face is pressed hard in contact with the fingers causing this change of speed to take place, with presumably a lot of heat, friction and wear as a result. Compare this to the pre-loaded one which is already "up to speed" so there is no differential movement with the fingers as the clutch pressure is applied. Much better!
Guy W

I'd try to get some sort of pre-load if I were you. Had a citroen BX in the 90's and the clutch fingers went when we were on holiday in cornwall. Had to come home with it graunching every gearchange - not pleasant when you get the the Exeter traffic jams :-(
graeme jackson

Lawrence,

Beware of going too cheap. My ebay Burton 'style' item wasn't machined correctly where the hoses fastened in. The sealing surfaces weren't perpendicular to the tapped threads. I couldn't get them to seal. The box the CSC came in was marked with the Burton part number.

The replacement I got from Burton worked out of the box. As you described, I spaced it so that with the mechanism fully retracted there was 4-5mm clearance.
(MMC bellhousing-19mm spacer-Burton thrust bearing-AP 190mm clutch cover-MED flywheel)

I measured/calculated that with no friction plate at all I would have an interference of about 0.5mm. Therefore I should be able to run the plate right down to the rivets and still be ok with the thrust race clearance.

I've just run my new motor/gearbox for the first time (Woo Hoo) and it feels like the clutch is doing something; on axle stands.

Just have to bolt the wheels back on and, ... and...and

Mark
M Crossley

I think the earlier SAAB CSC's had covers but both the SAAB 9000's I have bought don't.

Rob
Rob aka MG Moneypit

So no spring then Rob. So no preload either.

Guy.
" -- better I think than having a bearing which must accelerate very rapidly up to engine crank speeds and back down again to zero at every gear change."

Exactly what I found and posted in Robs 5 speed woes.. thread. Because there is an "up to engine crank speeds", just like a planes tyres, there's a moment of squeal and wear when they land. I've found pic's of fingers almost worn through. So I agree, personally I'd rather have preload, and may swap to a different CSC.

However, my CSC(TITAN/Burton genuine item) has worked since 1990, and the bearing has just started squealing. But it seems that the TITAN CSC that I have, was primarily designed I think, for racing applications. This means far more frequent clutch changes, and hence it all gets looked at long before the fingers wear and snap.

My friction plate is barely worn. That suggests two possible causes to my squealing. Either the piston is sticking in the CSC. I cheked, it's not. Or the initial gap wasn't correct. I never cheked at the outset, I just fitted the spacers supplied. It's quite likely that the gap was too small to begin with.

So now I need to check the bore of the CSC. If worn, rather than kit it, and risk a leak, and rather than pay circa £150 for a replacement TITAN, I'd rather swap to the preloaded CSC that's a lot cheaper.

Lawrence Slater

"my bearing is now in constant contact with the clutch cover. Not with enough force enough to spin the bearing, but enough to wear the face of it."
Anyone else who, like me, doesn't think this is the case?
All the non-carbon release bearings I've seen are *very* free-running and the force to accelerate them from standstill is tiny, so tiny to be negligible.
David Smith

VERY interesting gentlemen! I'm sat here still waiting for my Burton kit to arrive (5 weeks so far and counting, but been promised it will arrive this week...).

After much deliberation and soul searching, I decided to go for the more expensive (and therefore better???) Burton CSC, mount, spacer (19mm an educated guess), thrust bearing and hyd hoses - total cost circa £250!

However, I'm now beginning to regret not going with my original plan to use a Ford Mondeo/Puma/Fiesta type unit at a fraction of the price which would have been pre-loaded against the fingers. I had ASSUMED that the Burton cylinder would also be pre-loaded.

Ah well, if I get the service Lawrence has enjoyed before it starts squealing then I guess I will ultimately be happy:)

Please keep posting and I'll let you know how I get on - when it finally arrives!!

Glynn
Glynn (1275RWA) Williams

Hi David.
I have two roller release bearings. One is brand new, and the other was in my Sprite. They are otherwise identical.

The NEW one spins 'less' freely than the worn one -- I assume because the sealed for life grease is in better viscous shape.

I'm holding the old release bearing in my right hand. My fingers are wedged in the centre(inner race), acting like a carrier.

Using my left forefinger, -- like you do on a wine glass to annoy people by making it squeal -- I'm rotating it round the outer part of the bearing.

Unless I press pretty firmly, the bearing doesn't rotate, my finger just runs around the face. If I do the same with the NEW bearing, I need even more pressure to make the outer race rotate.

Just did the same thing with my NEW ford sierra bearing, which is mounted on a carrier. Same thing. It needs a fair bit of pressure, to make it spin.
Lawrence Slater

My original Saab unit has the famous bellows and insidew iut there was a large spring that pushed the bearing against the clutch fingers

My present Ford unit seems to have a spring built in, but a the concertina bellows is fixed to the slave and the bearing back face I dont quite know whether there's a spring

The bearing runs against the clutch diaphragm fingers cont=stantly


Both types had freely running bearing faces ready for operation

One problem with the Saab unit I had was that the pressure bearing was a poor fit on the cylinder nose and fell off the nose of the unit when my 'incident' occurred

When the cap head retaining bolts vibrated loose enough to let the clutch break the bellows was destryoed

The spring remained intact though
bill l

here's one I've had kicking about for a while, unsure of the origin / seller. When I spin the bearing it takes no effort to get going and carrries on spinning for a few seconds afterwards. Do yours do this? There's no way this one would cause wear on the cover springs on engagement. (and before you ask there's not a single marking to be found on the bearing - I've looked!)

David Smith

"When I spin the bearing it takes no effort to get going and carrries on spinning for a few seconds afterwards. Do yours do this?"

Nope. All 3 of mine stop as instantly as I stop pushing them.

Is that the PM or the MMC job?
Lawrence Slater

Guess which one is the used one from my Sprite.

Lawrence Slater

Lawrence,

Have you a link to those gap details for the Titan release bearing to clutch or the cylinder assembly. To me due to the minimum gap change from initial set-up to worn state, 3mm - 4mm as you say, I wonder if the information is for a race clutch use and not an ordinary road clutch, the fact it mentions no contact also makes me wonder if that is the case.

I did a quick search for Titan and found a few companies doing car bits but none that seemed to do a release bearing, just others selling the Titan item, I did find one Titan item clutch set-up which was a multi plate race clutch that seemed to have information similar to what you're saying.
David Billington

Here's their address.

http://www.titan.uk.net/ui/content/content.aspx?ID=74

Nothing about the CSC though. But it is them, same logo.

http://www.burtonpower.com/parts-by-brand/brands-s-to-t/titan.html

Lawrence Slater

I do agree that clutch release bearings can be spun very freely with just finger pressure when not fitted. But my suspicion is that when the clutch is operated the bearings in the race are then under very considerable pressure and this must change the physics of that moment of contact with the clutch fingers doing 6000 rpm and the bearing at zero! Clearly it works, and works OK as generations of clutches from a whole host of car manufacturers use this method.

But if a modern bearing can be designed to run continuously with little load for most of its operating life then it should be a better system with no "take up" losses in the system. I suspect that the advancement that allows Ford (and any others?) to use this arrangement is development of a long-life bearing that isn't immersed in oil. Possibly something not achieved in 1950?

Glynn, my concentric cost me £28 for a Ford slave and £5 for a billet of aluminium from which to turn a mounting block / spacer. Total cost £33 which compares rather well with your Burton price of £250. ;-)
Guy W

Guy,

Ford seem to have been using the constant contact system since at least the mk1 Escort and possibly earlier, it's just the Escort I am most familiar with in the Ford range. Those cars had cable operated clutches and the cable was tensioned lightly to maintain the release bearing in contact with the clutch diaphragm fingers. The cable outer was adjusted to have a small gap to its' stop but clutch wear would reduce this gap and failure to adjust could in extreme cases lead to sufficient tension in the cable to produce slip. So bearings that can run in constant contact in normal running are not a new development. IIRC the mk3 Escort and other Fords of the time introduced an automatic adjuster into the cable clutch so maintaining that gap was no longer a maintenance issue.

Regarding making such adapters and things for little money, I too can do this having spent many thousands of £ on machine tools and accessories but I do enjoy it. A few mates asked why I bothered as surely it would be cheaper to have a machinist do the work rather than buy the equipment but they failed to realise that often the part takes less time to make than to do the drawing a machinist would require and visiting a machinist takes time if you can find one, I have the machines in the workshop.
David Billington

I wish I had your kit and skills David. Part -- a big part I would argue -- is the sheer pleasure of making it yourself.

Without the kit and skills though, that doesn't stop me. lol.

As soon as my Ford Transit release arm turns up, I'm going to cut it down, weld a couple of apt sized rods on each end, put in my Sierra carrier and bearing, and stick it in the midget release fork.

I've decided to put a brand new bush in the Midget release arm, and make as sure as I can that the bearing sits centrally on the clutch cover thrust pad.

I agree too that 'some' clutch release bearing 'can' spin freely. But clearly not all. I have 3 that don't. All SKF. 2 NEW, and one part worn. The part worn will spin almost 1 revolution on it's own. The new ones stop as soon as I stop rotating them. I also looked at one more in a Europarts shop, and that was the same.
Lawrence Slater

Lawrence,

Do they spin freely when not fitted then not spin freely when fitted, if so maybe the mounting diameter for the bearing on the CSC is slightly too large and taking up the internal bearing clearance, doesn't take much.

Regarding your transit release arm, be careful, years ago I went to modify one, an Escort release arm at least, by cutting the cable end off to fit lugs for a CS push rod and my hacksaw just skated over the surface, turned out the enter surface of the release arm was harder than a hard thing. Likely Ford did a real good bit of engineering and made it out of some alloy steel that would easily harden providing the required longevity for the 3 pivot points and the rest was just hard as a result. I ended up using a cutting disk and brazing the lugs on and had no trouble with that but subsequently went back to cable. The heads up is that it is not a good idea to weld an unknown alloy as it could lead to a brittle result especially if using a low heat input method like MIG, with a process like TIG you can use certain alloy filler rods which are less prone to forming brittle welds or braze which is likely to be OK.
David Billington

Ah. That could be a problem then. I've only got a MIG. But I have a cunning plan if that's the case.

I'll cut some flats on the rod I'm going to use, and bolt the release arm to the rod.

It's really an experiment to test the principle. I intend to shove it in and run the engine for a week like it. If it survives and the clutch works ok, I'll pull the engine again and shove the Sussex carbon in, to see how that lasts. Then work up a decent roller carrier later -- maybe.

Then I can get back to the main event -- (which is getting my Sprite engines back together) -- which was so rudeoly interupted by the Midget clutch, and it turning too cold again for me to fancy being in the garage. :).

Bearings aren't mounted. They just don't spin freely. Now't wrong with them, just how they are.

Rob? You've got an SKF saab bearing too. Does yours spin freely?

Lawrence Slater

It only spins a couple of revolutions. Feels like lots of grease inside.

Rob
Rob aka MG Moneypit

Maybe it's the integral oil/grease seal as well, adding to the friction.
Lawrence Slater

I just rang Titan.

They're going to send me the set up instructions for the 'Burton' TITAN concentric slave.

I told him it took me a while to find out it was actually made by Titan, as most people just call it the Burton type. Oh dear he said. So I think that future issues may well get TITAN stamped on them somewhere. ;).

But anyway, he told me there should be a 7mm gap twixt bearing face and fingers. I never had that. No wonder my bearing squeals.
Lawrence Slater

Bill, I've been delving in the archive from 2013 and found pictures you posted of your Mondeo concentric setup. The release bearing face is flat and the fingers are also flat. How did this work out? because its recommended that with flat fingers the release bearing should have a round profile. And if you have a flat fronted bearing the fingers should be shaped not flat.

I had delivered today a Ford concentric from eBay

http://www.ebay.co.uk/itm/130799844342?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

which also has a flat face. I hadn't considered this when I bought the slave and was considering whether I needed to retain the bearing pad on the clutch, when I came across your thread in the archives. So was it all ok? Did the release bearing rotate on the inside or outside of the bearing?

Also noticed some input from JLH including images showing a Ford type concentric mounted on a nose piece for a Ford gearbox. I looked on JLH website hoping to find said nose piece but cannot find it.

So, anyone know if the nose piece is available from anyone for a Ford concentric?

Rob

Rob aka MG Moneypit

Rob , we use the Burton concentric which comes with the release bearing. We always use the rounded profile clutch cover. Had no problems at all over the last 8 years. Using the flat release bearing and flat fingers is asking for trouble. Caterham used to do this, but got away with it by saying that it was a performance cars will wear.
I'm currently off work sick so will not be able to help for a few weeks.
J L HEAP

Mine (Ford) is just as Bill's. Flat bearing face against fingers. No problems in almost 60,000 miles. And the Ford item doesn't require a "nose piece" It has its own inbuilt guide.
Guy W

Mine's the bearing JL talks about, and this is the curly finger type Sierra cover that I've been using for circa 15 years. Seems fine. -- Apart from the gap closing up and wearing the face of the bearing and fingers.

Lawrence Slater

JLH. It was this setup I saw (see Image)

Guy, when I say nose piece I mean a manufactured part that replaces the standard type 9 nose piece and to which the slave is bolted.
Did your clutch have flat fingers or shaped as lawrences' image?

Lawrence. Have you got a part number for that clutch?

Rob






Rob aka MG Moneypit

Rob, yes that was a Mondeo clutch release, with a bespoke spacer, worked very well on my racer, but was changed this year for a Burton unit. Nothing wrong with it, but as it had been in for 6 years I thought it prudent to change it. This was acting on an AP Racing paddle clutch.
J L HEAP

Rob my clutch is fine now

The pedal action is far better than the SAAB one gave me

Yes the bearing face is flat, but when I put a straight edge across it the face was actually angled toward the front by a few degrees (1 or 2º maybe)

This I take it, gives the fingers a different approach angle as they push into action

Maybe that is how Ford got round the often acknowledged curve/fingers problem
bill l

Bill, thanks for the info. I suppose as long as the fingers are not subject to much overthrow, i.e. only allowed to move enough to disengage the clutch, then the finger angle will be ok. I bet it's a close run thing though!!

JLH thanks for the info, hope you are feel better soon. Daytime TV is really awful!!!!

The only company I have found using the Mondeo CSC is RWD motorsport who have a setup for £145. I'll have to ask them if the do the nose piece/spacers on their own.

Rob
Rob aka MG Moneypit

The "wisdom" was round faced bearing against flat faced clutch and vice versa. But I think that really applies to those clutch covers that have a flat faced bearing ring attached to the fingers. In that case this should be removed unless the thrust has a rounded face. But most seem to be flat.

Otherwise, a flat faced bearing seems to be fine working directly on the fingers. The contact point with the fingers will move outwards as the clutch is depressed and the critical point is if the thrust bearing moves far enough forward for the fingers to pivot on the outside edge of the bearing. That is when wear of the fingers is most likely to occur. But if the bearing outer corner is chamfered/ rounded, then this will be fairly minimal.

On my Ford one there is just a slight rounding of the outer edge - not ideal but enough to avoid a sharp cutting edge, and it has worked OK bearing directly onto the fingers. Possibly it doesn't move far enough forward for the pivot point to transfer directly onto that outer edge.

Ah Rob, I see what you were getting at. The original standard ford nose piece acts as both a bearing guide tube and as the housing for the input shaft front oil seal. On mine I cut the actual nose section off - since the Ford concentric has this part built in - and retained the base section with its oil seal. Then my DIY alloy mounting block bolts in place to carry the ford concentric.

Guy W

Hi Rob.

It's a 190mm(7.5 inch) 23 spline kit. I thought you had a 6.5 flywheel. Mine was skimmed and drilled for the Sierra cover and 7.5 inch plate.

Ford OE Ref: 801206; 801206; 5010151; 5010151; 5011064; 5011064; 8012.

Borg and Beck clutch kit for a Sierra 1.6 '82-'87 is HK8941.
http://www.ebay.co.uk/itm/Ford-Sierra-1-6-Eng-1982-1985-Genuine-Borg-Beck-Clutch-Kit-190mm-x-23-Spl-/121600868959

What's actually supplied in HK8941 is a VALEO clutch. Part number for the kit is, -- from their catalogue 801206. You can get it direct from Euro car parts a bit cheaper, and from them on Ebay, free post. Here.
http://www.ebay.co.uk/itm/Valeo-3-Piece-Clutch-Kit-Inc-Bearing-190mm-Ford-Sierra-Cortina-80-Capri-MK3-/331380946796?pt=LH_DefaultDomain_3&fits=Car+Make%3AFordModel%3ASierra&hash=item4d27d7f76c

The original Borg and Beck cover number was 4LCKE07003A. So you could also use this cover which is identical. It's a bit cheaper -- but only has 19 or 20 splines in the plate supplied with the kit. So the plate is no good for a T9 g/box. But the cover is fine for the T9 g/box.
http://www.ebay.co.uk/itm/FORD-CAPRI-CORTINA-MK3-MK4-MK5-1-3-1-6-1970-1982-QUALITY-BORG-BECK-CLUTCH-KIT-/151201567590?pt=LH_DefaultDomain_3&hash=item233450d366

PS. Not just "wisdom" Guy. If you read all the clutch blurb from the makers, it's designed that way it seems.





Lawrence Slater

Rob. This is the Burton(TITAN) nose. It replaces the original nose/guide and oil seal on the T9. The Slave bolts to it -- via spacers if needed (they are for Spridgets) -- and incorporates a guide.

http://www.burtonpower.com/hydraulic-clutch-mount-apc5-5-speed-sierra-type-9-gearbox-apc6b.html



Lawrence Slater

" -- those clutch covers that have a flat faced bearing ring attached to the fingers. In that case this should be removed unless the thrust has a rounded face."

Don't forget that most clutches used to have the flat thrust plate ring, just like the standard A series Spridgets. They used a flat carbon bearing against it. This works without a problem because the two surfaces are always parallel to eachother.

Whereas, when you remove the thrust plate, the fingers become angled in relation to the release bearing, either initially, or when the fingers are pushed towards the engine by the release bearing. That's why one surface, either the relaease bearing or the fingers, needs to be rounded.

But on my diy roller release, I'm retaining the thrust plate on my 1275 clutch cover. As it happens, the Sierra roller release bearing that I'm going to use, does have a rounded outer profile, but I don't think it would matter if it was flat. And David Billington has confirmed that he's already done this on a Rocket box. So I'm hopeful. :).
Lawrence Slater

Hi Rob.
In your "5 speed saga and woes" thread you said ---
"With a standard 1275 clutch with the bearing pad the pressure is applied at the ends of the fingers. With a CSC you have to take off the pressure pad --- "

But why is this an imperative? And is it anyway?

Removing the pressure pad, moves the point of release bearing contact to the clutch cover further away from the CSC, and hence the release bearing. So you then add spacers to bring it closer again. I'd guess you'd still need to use spacers to get the right distance, but why can't a roller release just operate against an existing thrust pad on the clutch cover?

Maybe the reason they were removed in later clutch designs was for cost, and because they sometimes come loose and rattle, as you describe the spare you've found has done. So I guess running on the fingers is an improvement, and using a roller instead of a carbon release, negates the need for thrust pad to begin with.

But if you already have a thrust pad, and either a flat or rounded release bearing, CSC or retain the fork, why not leave the thrust pad in place? What problems can it cause?
Lawrence Slater

PS. "What problems can it cause?" Assuming it's centred properly. Answering my own question. ;).
Lawrence Slater

Lawrence, one thing you may need to watch out for is that the guide tube on the CSC clears the inside of the attached washer pad. Certainly with my ford arrangent this guide sits within the hole of the rotating clutch fingers. I think it would foul on any of the bearing washers that l have seen.
Guy W

Yes. Good point Guy. On the Midget, retaining the release fork as I am, that won't be an issue, because there isn't a guide tube.

But today, I've been working out the best way to get the side lugs onto my homemade bearing carrier. And I've come to the conclusion that if decent carbon release bearings really *can't* be obtained anymore, then it would be far better to fit a CSC to the standard A series Spridget. And as you say, that introduces a guide tube.

But does the guide tube extend beyond the face of the release bearing?

This is a kit you can get from Peter May for the ribcase g/box. The guide tube doesn't appear to protrude. Looks like a Titan CSC, with a ribcase adapter. I wonder how easy it would be to make a mount/adapter plate for the ribcase box, to take the same CSC you've used Guy? Looks fairly straightforward, and it would be a lot cheaper than the £215.00 from Peter May; -- +vat, as someone reminded me in another thread.

However, looking at the depth of that arrangement, to make room for it, I guess you'd have to remove the clutch cover thrust pad, even if the guide tube wasn't a problem.

Lawrence Slater

Lawrence, thanks for all the info about sierra clutches etc.
I've been out all day looking at a Sprite shell "darn souf" which I didn't like as soon as I saw it in the flesh.

RE the Burton nose piece. I emailed Burton and that nose piece can only be used with their CSC part number APC5. I asked about nose pieces for Mondeo CSC but they don't do them.

Guy, yes it's the "DIY alloy mounting block" block I'm after but I don't have the facilities to do it myself (DIM?).

Back to Lawrence. I needed to take the pad off because there wasn't enough room to leave it on when GB and Engine were bolted together. The hole in the pad was a lot smaller then the guide tube of the CSC. Without the pad the fingers create a hole that the CSC guide tube can fit through if necessary.

Bernie nearly fell foul of this when he installed his Burton CSC. He has a 1098 with a standard clutch. This clutch has a pad that has a hole through the centre a lot bigger than the 1275 pad. But, the Burton CSC guide tube actually touched the pad and he needed to have the pad machined a little.

The thing I was trying to get at with removing the pad was this. If you were able to retain the pad, the pad acts on the finger ends. If the CSC release bearing pushes the pad it is effectively pushing the finger ends.
Without the pad the CSC release bearing will contact the fingers part way down the finger. This alters the leverage. So with a pad the clutch would feel light and without a pad the clutch would feel heavier, even when using the same CSC setup. Also the throw would be different. With a pad you get a long throw to disengage the clutch, without a pad you find a shorter throw will disengage the clutch. If the CSC setup is the same in each case you run the risk of too much throw without a pad.

Rob



Rob aka MG Moneypit

Lawrence, forgot to say that yes I do have a 6.5" clutch but maybe a conversion to 7.5" clutch would be part of a solution for my problems if I can't solve them with what I have.
Rob
Rob aka MG Moneypit

Hi Rob,

Yep your right. My Midget has a very light long throw clutch, -- thrust pad, when compared to my Sprite with the T9/Burton combination, -- curly fingers, which is short throw and definitely heavier - but not too heavy.

Re the thrust pad then. I guess that was the reason it was done away with. It interferes with a guide tube, which probably most modern g/boxes have.
Lawrence Slater

Finally got the TITAN -- SAAB(Burton) concentric slave setup details, in the form of the drawing pdf file.





Lawrence Slater

This extract makes it clearer I hope.

If anyone wants the pdf, send me an email and I'll send it to you.



Lawrence Slater

What SAAB csc is this? It doesn't look like the one I am using apart from the internals look similar.

Rob
Rob aka MG Moneypit

That looks like the later single port cylinders

There is a single pipe that feeds it and by some kind of black magic there's a bleed port fitted away from the unit up the pipe

I thought about fitting one to my car after my SAAB 900 unit packed in, got it cheap on ebay but there was no explanation of how to bleed it except "fit bleed valve assembly and pipe"

Not supplied but available for too much money second hand on the bay

Too much b=ggering about so I got the Ford one and I'm glad I did
bill l

That's the CSC in the 1st post of this thread. It's the one Burton sell. It's TITAN's version of the SAAB CSC.

Why the confusion?
Lawrence Slater

Bleed and Feed.

Lawrence Slater

Lawrence,

In your Titan information where is there any reference to a 4mm - 5mm gap between the release bearing and pressure plate fingers. All I can see from your posted information is dimensions for setting it up to account for wear in the driven plate so the CSC doesn't run out of backward travel as the clutch wears. Is there a spring in the Titan CSC to push it against the clutch fingers.
David Billington

Hi David,

No, no information on 4/5mm gap. I got that from Burton when I rang them, but they didn't have anything written down. Then I rang these people. http://www.sbdev.co.uk/Clutches/Clutch_Release_Mechanisms/Clutch_Release_Mechanisms.htm
They told me about making sure I had a 1mm with the clutch cover bolted on without the friction plate.

Then I rang Titan, and they sent me that pdf. That suggests 8mm min on a NEW clutch plate. 15mm Max, Non- preferrred, whatever that means.

No, no spring in the csc. The idea is that when the pedal is pressed, the gap -- 4/5 or 8mm, is taken up, and the fingers are pushed in. Then as the pedal is released, the fingers push the piston back in as far as the fingers go, and the piston retreats a tad more as the fluid pressure diminishes.

And that was how mine worked. But as I said in my 1st post, I didn't set mine up with a particular gap. I just used what I was given and bunged it in. Now though the running clearance isn't enough, and my bearing face and fingers are wearing. So I'm assuming that my spacers are too thick.
Lawrence Slater

Thanks Lawrence I didn't see beyond the hole in the top, good job I don't mess with such stuff much these days huh?

:)
bill l

Lawrence,
Just sent you an email...

Glynn
Glynn (1275RWA) Williams

On it's way Glynn.
Lawrence Slater

Thanks Lawrence :)
Glynn (1275RWA) Williams

FIVE WEEKS after placing my order, the Burton (Titan) CSC plus mount plus spacer plus bearing finally turned up this week :)

Hoping to test out this weekend whether my calculated guess at a 19mm spacer will provide the much-discussed 8mm min gap against my new pinto clutch assembly.....

Glynn

Glynn (1275RWA) Williams

Looks a tad neater than mine Glynn. :).
Lawrence Slater

My Burton kit on my 5 speed.
The addapterblock (28mm) wasmade to fit the clutch to a K-series.

Great kit!

Arie

This thread was discussed between 17/03/2015 and 28/03/2015

MG Midget and Sprite Technical index

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