C: Clutch Refreshing Vincent Twin Clutch seals and pieces

[oexing]

Am I wrong in thinking no matter, how hard you nip up that nut, whenever there is too much play within the splines of the carrier-gearshaft fit, you will never get the nut fixed for good : One side of the assembly stays put, but the other half will move with torque coming from the effectively non-existant ESA or from the gear shaft. Anyway, the torque going into this assembly must be exceeding the max chain load of 2 or 3 tons that break even that triplex chain ??? So I question being able to torque down the nut to fight these loads . You will only get wear in highly loaded shims that get eaten by micro motions due to play in the splines. So maybe one should be looking into fabricating hardened spacers that keep the carrier in its place without squeezing it with the nut. You can get hardened shims from axial needle bearings for adapting some sort of shim that will survive for a lot longer than thin soft shims. Or am I all wrong in my thinking? This trouble is very similar to the woes with the sprocket nut for the rear chain as recently discussed here.

Vic

 

[highbury731]

How tight should you do up C20?

 

[timetraveller]

I think that I am missing something here. All the nut is doing is locking the main shaft, the bearing centre, the spacer inside the oil seal and the shoe carrier together so that they rotate as one. Where does any chaffing motion come from? The tang on the spring just stops the nut rotating and becoming loose. It is some time since I worked on this part of a twin but either there is something vital I have forgotten (entirely possible) or some of the rest of you are chasing problems which do not exist. As for how tight I make the C20; well I do not use a torque spanner on it but a foot to a foot and a half long socket handle probably mean that I am applying somewhere about 30 ft lbs, but it could be more if I've been eating meat. The Instruction Sheets might have a figure but I do not have them available at the moment.

 

[BigEd]

.......... As for how tight I make the C20; well I do not use a torque spanner on it but a foot to a foot and a half long socket handle probably mean that I am applying somewhere about 30 ft lbs, but it could be more if I've been eating meat. The Instruction Sheets might have a figure but I do not have them available at the moment.

I have the Instruction Sheet No. 2D (December 1966) The Vincent Clutch Rapide and Black Shadow Models. In the Assembling Clutch section paragraph 4 makes no mention of the nut or tightening it and paragraph 5 only says, "Fit the locking spring with the turned-in tail snugly into the slots of the nut and shaft which are lined up previously."
I usually tighten to what I think is reasonable and then a little more until the tang just pushes into the next slot. Not very scientific but I've never had the nut come loose.

 

[Bill Thomas]

Maybe Loose, Was the wrong word I used, Have you never undone that nut, And thought, That was not as tight as I did it up last time ?.
As an old Sprinter, I do tend to Blast it off the line a lot, Trying to relive my Youth.
I think Greg said something about doing it up on a steel washer, Instead of different types of seal, To get the nut tight ?. Cheers Bill.

 

[Simon Dinsdale]

Same here Eddy. I tighten the nut tight by hand to reasonably tight with a socket wrench about foot long or slightly longer then look at the slots for the tang and continue to tighten to the next slot aligns and the tang just slides in. You cannot specify a torque as your aim is the "next slot alignment" and not a torque figure which may stop before then.
Never had a clutch nut come undone in nearly 30 years of ownership and always needed the same effort to undo the nut.

 

[craig]

Here is what I find in my clutch instruction sheets, page 9 and 10, but cropped to only step 3 of assembly.
Is there a torque spec for "very tightly"? 20ftlbs? 80ftlbs?


3) Remove all traces of oil or grease from the shoe linings and the drum. Apply a liberal coating of some non-setting gasket cement to the internal splines, and fit the carrier to the clutch shaft. Verify that the copper washer C18, or carrier seal C18/1 is correctly in its place in the recess in the outer face of the clutch carrier, this is most important. Verify that the thrust washer, C19, is in place on the clutch retaining nut. Smear a light coating of gasket cement in the thread of the nut, and screw it up very tightly. Check by turning the clutch shoe carrier backwards and forwards, by means of the projecting pins, that the carrier can move freely and that both sets of shoe linings can be brought hard into contact with the drum.

If this is correct, verify that one of the locking slots in the nut is in line with one of the slots in the shaft, if not, tighten the nut a little more, do not slacken it back. When tightening this nut, engage top gear, and put a bar through the rear wheel spokes and up underneath the rear fork tubes or else use a piece of steel to set as a sprag between the sprocket teeth and the gearbox casting, according to whether the rear chain is in place or has been detached.

 

[stumpy lord]

My approach is much more primitive. Put it into top gear. put a piece of wood through the spokes, near to where they enter the rim and brace it against the RFM. Tighten away.

ouwch

Here is what I find in my clutch instruction sheets, page 9 and 10, but cropped to only step 3 of assembly.
Is there a torque spec for "very tightly"? 20ftlbs? 80ftlbs?


3) Remove all traces of oil or grease from the shoe linings and the drum. Apply a liberal coating of some non-setting gasket cement to the internal splines, and fit the carrier to the clutch shaft. Verify that the copper washer C18, or carrier seal C18/1 is correctly in its place in the recess in the outer face of the clutch carrier, this is most important. Verify that the thrust washer, C19, is in place on the clutch retaining nut. Smear a light coating of gasket cement in the thread of the nut, and screw it up very tightly. Check by turning the clutch shoe carrier backwards and forwards, by means of the projecting pins, that the carrier can move freely and that both sets of shoe linings can be brought hard into contact with the drum.

If this is correct, verify that one of the locking slots in the nut is in line with one of the slots in the shaft, if not, tighten the nut a little more, do not slacken it back. When tightening this nut, engage top gear, and put a bar through the rear wheel spokes and up underneath the rear fork tubes or else use a piece of steel to set as a sprag between the sprocket teeth and the gearbox casting, according to whether the rear chain is in place or has been detached.

three white knuckles, as they used to say ,when I was a young sprog.
, in the R.A.F
sorry Norm but the spanner shown, is a better engineers way of holding the clutch for tightening the clutch nut than spraging, with all the risk of damage that goes with it . Just my view Norm

 

[timetraveller]

Hi Stumpy, I don't like to argue with a proper engineer but note that the Instruction Sheets recommend the same method that I use except that I use a piece of wood across the RFM and up against a spoke nipple whereas they recommend a piece of steel. So far I have never damaged anything doing this but each to his own.

 

[highbury731]

If like me you are building an engine from bits, and it isn't a bike (yet....) then you can't sprag the drive using wood in the rear wheel, or similar. Looks like I need The Charioteer's locking tool. Anyone got a discarded C21 inner clutch plate I can use?
Paul