4 or 6 spring clutch

[Swarfcut]

bergs, that driven plate may be from a 6 spring Plunger Clutch. Dimensions for this  part is 144mm OD, hole in the middle 92mm.

Early S/A 6 spring clutch driven plate OD is 153mm, hole in the middle  106mm  on the one I just measured.  Plate has 8 driving tabs.

OD's quoted do not include the drive tabs, the diameter is the size of the basic circle.

Swarfy.

[chaterlea25]

Hi Berger,
The friction plates are centered in the chainwheel not the inner drum
The plain plates locate on the inner drum
The weakness is that they are only supported by that small lip, so the spring pressure tends to bend them
Some other makers fitted a thick plate at the back to prevent/help with this
The later BSA / Tri with the thrust washer have no lip on the inner drum, the innermost plain plate sits against a friction plate sat at the rear of the chainwheel. This prevents the "flex"

John

[berger]

ok chaps think I have it I found an inner with the lip ground off and 2 triumph centres one for the thrust washer I think with large flange and scrapped the ground off middle ages ago because I thought someone had made a booboo. never mind , the only confusing bit is I put a friction plate in first which stops at the end of the slots in the chainwheel , It doesn't sit on the face that is riveted, then I put the inner drum in and a plain plate which mates with the friction one. I can't put the drum in and the first friction plate because it doesn't go over the lip on the drum. is this the way it is done with these clutches or am I barking up the wrong tree? I find it strange that the first friction plate doesn't sit flat on the chainwheel and the fact that this plate has to go in before the drum and the first plain plate onto the drum. I thought I had sussed it BUT . edit also why isn't the chainwheel made with friction material if a friction plate goes in first . very confusing to me

[ironhead]

ok chaps think I have it I found an inner with the lip ground off and 2 triumph centres one for the thrust washer I think with large flange and scrapped the ground off middle ages ago because I thought someone had made a booboo. never mind , the only confusing bit is I put a friction plate in first which stops at the end of the slots in the chainwheel , It doesn't sit on the face that is riveted, then I put the inner drum in and a plain plate which mates with the friction one. I can't put the drum in and the first friction plate because it doesn't go over the lip on the drum. is this the way it is done with these clutches or am I barking up the wrong tree? I find it strange that the first friction plate doesn't sit flat on the chainwheel and the fact that this plate has to go in before the drum and the first plain plate onto the drum. I thought I had sussed it BUT . edit also why isn't the chainwheel made with friction material if a friction plate goes in first . very confusing to me

G,day Bergs.
 Looks like you have a clutch basket case    The triumph centers won't fit the bsa mainshaft for a start
as they are a different taper. SRM I think make an adapter with the larger flange to accommodate a thrust washer. As Chater Lea says , the slots for the friction plates need to go deeper in the basket so the first plate can sit up hard against the back.  If you have a drum with no lip, all the plates should slide in, you won't have to fit the drum after any plates. Ya can't use a lipped drum with a friction plate up against the basket. If you are trying to make a std 4 spring setup using std parts with a lipped drum, the first plate in is a steel one.
.

[chaterlea25]

Hi Berger,
Go back to my earlier reply and read it again
Ironhead is correct
But you can opt to either remove the lip from the inner drum or bore /grind out the inner diameter of a friction plate so it fits easily over the lip
Triumph adaptors are easy to recognise, they do not have the section with the scroll at the back

John

[berger]

errr yes yes and hello ironhead  *wave*errr I showed a photo of an original adaptor compared to a pattern just like john has on a post ages ago so that isn't a problem I will be using the original one. Correct the two trimph centres are different tapers to the bsa and  have different size flanges, the large one for the thrust washer  set up I think  so they  will be put up for sale. john I shouldn't have scrapped the other drum I found with the ground off lip ok your idea of licking out a plate to clear the drum lip is a good one which I thought of this afternoon but  why have this lip on the inner drum anyway it just takes up space between chainwheel and itself. ironheads idea of plain plate first must  shorely reduce the number of plates leaving a gap between chainwheel and drum but also a good idea. SO if I put a plain plate first is this the 4 friction and 5 plain plate set up? and if I make the friction plate clear the lip and make it sit at the back of the chainwheel this must be the 5 and 6 plate set up. so if I put a plain in first up to the lip it seems to me a waste of space from the lip to the chainwheel. why don't they just have friction pads on the chainwheel and then start with the plain plate without a lip on the drum? you can't start with a plain if the lip isn't there or it will trash the chainwheel, these trump set ups are .  as columbo say's just one more thing ,does it need a thrust washer or a good thrashing ps john when the friction plate is in the wheel it doesn't sit flat against it so as the plain one can bend on the lip [ I have found one!] this could distort as well, what a set up! and they say its better than a 6 spring.

[ironhead]

errr yes yes and hello ironhead  *wave*errr I showed a photo of an original adaptor compared to a pattern just like john has on a post ages ago so that isn't a problem I will be using the original one. Correct the two trimph centres are different tapers to the bsa and  have different size flanges, the large one for the thrust washer  set up I think  so they  will be put up for sale. john I shouldn't have scrapped the other drum I found with the ground off lip ok your idea of licking out a plate to clear the drum lip is a good one which I thought of this afternoon but  why have this lip on the inner drum anyway it just takes up space between chainwheel and itself. ironheads idea of plain plate first must  shorely reduce the number of plates leaving a gap between chainwheel and drum but also a good idea. SO if I put a plain plate first is this the 4 friction and 5 plain plate set up? and if I make the friction plate clear the lip and make it sit at the back of the chainwheel this must be the 5 and 6 plate set up. so if I put a plain in first up to the lip it seems to me a waste of space from the lip to the chainwheel. why don't they just have friction pads on the chainwheel and then start with the plain plate without a lip on the drum? you can't start with a plain if the lip isn't there or it will trash the chainwheel, these trump set ups are .  as columbo say's just one more thing ,does it need a thrust washer or a good thrashing ps john when the friction plate is in the wheel it doesn't sit flat against it so as the plain one can bend on the lip [ I have found one!] this could distort as well, what a set up! and they say its better than a 6 spring.

G'day Berger. The std A10 4 spring clutches have 6 plain plates & 5 bonded. If you can only fit 5 plain & 4 bonded you probably have a pre-unit triumph center ( 500 if I remember right)
The friction plate against the chainwheel  came about on the unit Triumphs during the 60's & later A65's ( evolution?)  The weak point of the 4 spring type is as you mentioned, the 1st plain plate up against the drum lip.
( they probably should have had a double thickness one in this position)  All that being said a 4 spring in good condition is a simple & useful clutch. But when the horsepower went up in later years the extra plate helped.
Don't forget the T140 triumphs use basically the same clutch ( 1st friction plate against the chainwheel though)
& put out a lot more grunt than an A10. There are 7 plate conversions for these also.   

[duTch]

 

.....( they probably should have had a double thickness one in this position)  ........

 I think I did that with my Plunger six spring 'cause I  couldn't make the stock setup work

[JulianS]

The 7 plate conversion is too thick for the 4 spring chainwheel.

You can fit 6 bonded plates plus the extra plain plate to the A10 4 spring clutch but only if it has the full depth A10 parts.

The friction material appears different to the standard plates with bronze coloured particles in it.

I tried it 2 years ago.

Was it worth it?

Inconclusive. I wanted to fit a new chainwheel but the new bonded plates, although fitting the old chainwheel, were just a fraction too large outside diameter to fit freely in the new one.

[ironhead]

 G'day Dutch,
Somewhere in the old grey cells I seem to remember they had a thicker first plate originaly.

[ironhead]

The 7 plate conversion is too thick for the 4 spring chainwheel.

You can fit 6 bonded plates plus the extra plain plate to the A10 4 spring clutch but only if it has the full depth A10 parts.

The friction material appears different to the standard plates with bronze coloured particles in it.

I tried it 2 years ago.

Was it worth it?

Inconclusive. I wanted to fit a new chainwheel but the new bonded plates, although fitting the old chainwheel, were just a fraction too large outside diameter to fit freely in the new one.

Thanks Julian.  I was considering getting a 7 plate set to see if it would fit but now won't bother.
Looks like the old pattern parts gremlin strikes again.  New plates, new basket, no fit

[berger]

ironhead I recon your on it, I think the chainwheel part number 57-1549 is possibly a late trump one? and I think the drums and plates are from pre unit. well as its sunny at the workshop today I will shove it together putting the plates in both ways, friction fist and plain first and see what I find.  I think the mud is clearing

[berger]

I have been playing, it's good to play I got a friction plate and made it clear the lip on the inner drum by removing metal just about to the bonded bits, then to make it seat against the chainwheel I filed a bit out of the slots and put a radius in the corners, put plate in and checked that chain didn't interfere with it. it still didn't sit on the face of the drum so stuck it in lathering thing and turned about 8thou off the circumference on the drive tabs just down to the bonded bits then it sat nicely like a good little plate should do.  then in with rest of the plates and ended up with 5 and 5. then a problem with just the 5 plain plates  and the pressure plate on the spring cups were very nearly holding it off the last plate so I put the 6th plain on and jobs done. the only reason I have done this is I don't have one but maybe doing it this way it will prevent the first plain plate that goes up to the drum lip distorting when it hasn't got anything behind it, time will tell in the distant future and because I didn't grind the lip off I can always build it up as it should be built--- properly i think I need the pub and to stop messing with things . oh no this has been a total waste of time with the lip still on because it is only working from there onwards *bash*boing time for bed!! end of clutch story children

[Triton Thrasher]

If you file the lip off the centre, I think you can glue cork to the face of the drum, then fit a plain plate first.  I say “I think,” because I’ve only done it to a Triumph 3-spring clutch, which does not have the lip.

If your last plain plate is falling off the end of the centre when you free the clutch, you can bend three or four of the tabs in.

[berger]

Triton Thrasher built up as it was intended  to be with 5 friction and 6 plain there is no chance of a plate falling off, it is me being a pillock again thinking I could prevent a bent first plain plate that sits up to the lip. [this has been mentioned and I found one] . that idea has gone with the rest of those ideas I have had over the years. I will build it up as intended by the makers but I have some corks so now you have opened a can of worms for me. the two lonely corks are the ones left over from doing the 6 spring chainwheel that's on betsy beezer working well  bought from gaggs way before b*s***d john got all their stuff. they were the last 26 he had in an old tin. the others are some of the batch a kind mister gave me years ago that i did a spare 6 spring chainwheel with. so now it could be play time , although I think I would be better off going to the pub and leaving it as manufactured