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I've got a brand new, MS lightened clutch plate, and a brand new MS lightweight flywheel. When I mock up the parts, with the clutch disc between them, I end up with a fair gap between the drive straps and the 'horns' of the clutch plate.

From what I've read, the drive straps should be JUST touching, and if left uncorrected, this will lead to difficulty disengaging the clutch. The most obvious solution would be to shorten the spacers that were provided with the flywheel, but I've got a couple of questions:

-Is this typical of two new parts?
-Are the spacers intentionally left long, to be custom-fitted to the application?
-Is there any reason a hardened washer between the drive straps and plate 'horns' is not a valid solution?

Thanks

When you say you've trial fitted with the clutch plate, do you mean the friction / drive plate, I'm suspecting that you are referring to the backing plate as the clutch plate.

This is the Clutch plate

http://www.minispares.com/product/Class ... o%20search

I can't see from your pics if that's in there, but looking at the height of the Backing Plate posts, I'm guessing not.

The picture shows the stacked backing plate, friction plate, and flywheel. It's as if the spacers MS supplied with the flywheel are too tall, or the 'horns' on the backing plate are too short.

Maybe they've been listening and now you don't need to get the lugs machined down anymore.

Smiffy wrote:Maybe they've been listening and now you don't need to get the lugs machined down anymore.

Did that used to be common?

Have you supported the backplate off the bench to allow the clutch plate centre to drop through it?

What are the sockets doing in the photo?

The diaphragm should be flat when everything is clamped up. You need to take measurements to work out how much you should machine off the backplate lugs to achieve this, then machine the spacers to suit to keep the drive tangs level when clamped up. Well, that's how I do it, and it makes for a much lighter clutch action even with a grey diaphragm, and consequently much less force on the thrust washers. Theory is that the throw over pressure is minimized whilst the clamping pressure is maximized.

It's a old mod, iirc first time I saw this mentioned, was in Trickey's original mini tuning book years ago, so no it's not a new idea.

GraemeC wrote:Have you supported the backplate off the bench to allow the clutch plate centre to drop through it?

What are the sockets doing in the photo?

The sockets are supporting the backplate off the bench.

Smiffy wrote:It's a old mod, iirc first time I saw this mentioned, was in Trickey's original mini tuning book years ago, so no it's not a new idea.

What is an old mod?

Calm down Tony, not pretending its something new, I got it off Marcel Chichaks (?) website years ago. Anyway I did yours for you!!

R&R wrote:Calm down Tony, not pretending its something new, I got it off Marcel Chichaks (?) website years ago. Anyway I did yours for you!!

Thats the third one Paul, the one you did.

Benny wrote:
The sockets are supporting the backplate off the bench.

Ah, OK - the photograph is quite deceptive!

Had the same issue, but with an original plate (22G270). Just shortened the spacers and was good to go.
Make sure the diaphragm spring sits parallel to the flywheel.

http://i1212.photobucket.com/albums/cc444/rsn-mk1/MR-56-35/MR-56-35_0700_zps53298c5d.jpg

ricardo wrote:Had the same issue, but with an original plate (22G270). Just shortened the spacers and was good to go.

Thanks Ricardo,

The more I think about this, I'm beginning to think the extra "packing" is the better solution. Presumable, the spacers that MS provided were sized to make up the difference in thickness between a standard flywheel, and their lightweight unit.

If I were to shorten the spacers, I would be changing the relative position between the diaphragm and the flywheel, which would change the amount the diaphragm spring gets compressed. By adding my hardened washers, that relative position is maintained, allowing the diaphragm spring to behave normally.

Thoughts on that?

That's the whole point. I end up shortening all back plate lugs to get the diaphragm flat. You need to measure. Pop the diaphragm on, and take a new picture.

Vegard wrote:That's the whole point. I end up shortening all back plate lugs to get the diaphragm flat. You need to measure. Pop the diaphragm on, and take a new picture.

Ok, sorry, I misunderstood the comment about getting the diaphragm flat. Here is a pic of mine bolted up.....not very flat. I think I'm going to remove the hardened washers, and have my friend make up some new (shorter) spacers on his lathe.

The ones supplied by MS don't fit very tightly over the bolts anyway, so there is some chance for them to be slightly off-center, creating a tiny imbalance.

Benny wrote: Thanks Ricardo,

The more I think about this, I'm beginning to think the extra "packing" is the better solution. Presumable, the spacers that MS provided were sized to make up the difference in thickness between a standard flywheel, and their lightweight unit.

If I were to shorten the spacers, I would be changing the relative position between the diaphragm and the flywheel, which would change the amount the diaphragm spring gets compressed. By adding my hardened washers, that relative position is maintained, allowing the diaphragm spring to behave normally.

Thoughts on that?

Hi Benny,

I have to disagree on that. The main goal is to have the diaphragm parallel to the flywheel. Yours needs improvement. The 3 straps should be parallel too to avoid disengaging problems. So, remove the washers and get the diaphragm parallel (if needed, machine the horns) and then get the spacers sized correctly so the 3 strap groups sit parallel too.

I think the MS spacers are oversized so you can size them as needed. If they were short, they would be useless.

You're using the MS bolts too and there are 2 versions, short and long. Since your spacers are a bit tall, make sure you use the long ones for them (short version for the horns) and the thread is fully home.

For what it's worth...

The ONLY way to pull the diaphragm down so that the spring is "flat"
is to machine the horns off the back plate - the thickness of those
spacers has absolutely nothing to do with this.

To work out how much to machine off, try putting some dummy packing
between the friction disk and the backplate, say some "penny" washers.

Use as many as you can as this will spread the load and stop the lining
from getting damaged.

Clamp it all up again and see if the spring is flat, add or subtract thickness
here until you have found the right amount. Once you have this sorted,
measure the thickness of the packing/washers and have this amount
machined off the horns.

When you get the backplate back from the machine shop, do a trial
assembly. Screw the whole thing together to get the alignment, then undo
the bolts which go through the straps to the flywheel and slide out the spacers.

It is then simply a case of measuring the gap between the underside of the
strap and the flywheel and getting the spacers machined to the same thickness.

From the photo, I would suggest that as it is, this clutch would be very
weak and would start slipping in no time at all.

ianh1968 wrote:For what it's worth...

The ONLY way to pull the diaphragm down so that the spring is "flat"
is to machine the horns off the back plate - the thickness of those
spacers has absolutely nothing to do with this.

I would disagree with that. In the mock-up state, my straps are standing 'apart' from the clutch plate 'horns' by a distance of 0.170", which can be filled perfectly with the hardened washers shown in my second pic. By simply removing those washers from the 'horns', and having spacers made up that are 0.170" shorter, my straps would still be correct, and I would get an additional 0.170" compression on the diaphragm spring.

I agree that this might not put me EXACTLY where I need to be, but I disagree that the height of the spacers is not an issue here.

Please be assured that those spacers only affect the alignment of the straps,
they do not affect the actual mechanical workings of the diaphragm spring as
regards getting it "flat"...

If you get the spring flat, you are getting the maximum static clamping force
available from the diaphragm spring.

R&R Has summed it all up very nicely...

If your clutch feels "springy" it is because it is not set up correctly. If it just feels
progressive all the way down, you have done the job properly. Yes - A grey/gray
clutch can feel perfectly normal.

The straps are NOT the parts which provide the spring in the clutch, the diaphragm is.

The straps do bend a bit, but this is just to allow the the backplate to be pushed
back far enough to release the friction disk.

The actual "spring" itself is that 3/4" or so wide circular strip of metal which is
held in place on the pressing by 3 flimsy looking clips... The spring is sort of
concave shaped, rather like a giant belleville washer.

https://www.google.co.uk/search?q=belle ... 00&bih=764

DO NOT CONFUSE GETTING THE SPRING FLAT WITH GETTING THE STRAPS FLAT.

Both are separate issues and should be aimed for, but are mechanically
achieved by two different methods.

1) Getting the spring flat is adjusted by altering the horns.
2) Getting the straps flat is adjusted by altering the spacers.

... and in that order...

Try this:

Bolt your assembly together as it is now and have a look at the spring.
See how "not flat" it is? (i.e. Exactly as per the earlier photo...)

OK, now undo just the three bolts that go through the straps and spacers
then into the flywheel, and slide out the spacers. Nothing will happen apart
from the three pairs of drive straps will spring themselves back flat and there
will be an empty space between the strap and the outside of the flywheel.

Have another look at your diaphragm spring. It will be in exactly the same
place as it was before, and still "not flat" with NO spacer in. Getting a thicker
or thinner space made up will ONLY affect the angle of the straps compared to
the outside face of the flywheel.

If you put thicker spacers in, the drive straps will be bent further out from the
flywheel face, if you put thinner spacers in, the straps will be bent further
towards the flywheel.

Bend the straps in and out to give the same affect as using thicker or thinner
spacers. Nothing else will happen apart from the drive straps will bend...

To prove this point, as you tighten up the six bolts, have a look and you will
see that only the three that go into the backplate will cause the diaphragm
spring to compress. The other three will just bend the straps to the position
dictated by the thickness of the spacers.

The idea with these clutches is to get the diaphragm spring flat, then afterwards
adjust the spacers so that the pairs of drive straps are parallel to the outside face
of the flywheel, that is, they are neither sprung inwards nor sprung outwards.

My clutch is also made from MiniSpares parts and is probably almost identical
to the one being talked about here. When I originally did a trial assembly, my
spring looked about the same as the one in the photo.

I then undid it all and starting from the bottom I placed:

1) The backplate
2) Six "penny" washers, evenly spread round the backplate,
3) The friction disk,
4) The flywheel,
5) The straps,
6) The spring.

Clamping this lot all together effectively pulled the diaphragm down by the
thickness of my penny washers. By shear chance, the spring was now flat.

At this point, I was not even slightly interested in the thickness of the drive
strap spacers...

I then got the horns machined down by the same thickness as the penny
washers, which from memory was about 50thou.

Once done, I assembled the clutch without the penny washers and no spacers
and found that, as expected, the spring was now flat. Only at this point did I
measure up for the thickness of the drive strap spacers.

Would one of the experts here please confirm.