C: Clutch Twin Clutch Drag

Bill Thomas

Well Known and Active Forum User
VOC Member
Peter, Might be better to send him a P.M.
Top right hand corner, Looks like an envelope,
Click on it and send him a " private message ".
Cheers Bill.
 

sharkey

Forum User
VOC Member
Bad terminology by me re C17 bush and C20 nut. I meant the diametrical fit between C20 o/d and C17 i/d.
C13 rotates easily but may be tilting due to excessive diametrical clearance?
I have installed a new C17 bush which is a beautiful fit on C20 especially against the 3 thou' diametrical slack of the old bush. The drag described in my original post has gone as it also has when stopping at lights etc.
Thanks to all who joined the discussion.
 

paw99

Well Known and Active Forum User
VOC Member
When operating the kickstart lever with engine stopped and the clutch pulled in there is no clutch drag but when operating the clutch having already applied pressure to the k/s lever there is some drag. C23 is not lifting absolutely square but has a minimum clearance of 25 rising to 40 thou' around the plates. All springs relatively new, are of equal length and free to move within their cups.
There is at least 25 thou' clearance between the clutch shoes and drum; plungers C11/1 are free and butting against the correct C14 pins but those pins have C16 sleeves besides the 3 in the normal C13 locations. The plunger springs are exerting reasonable pressure.
There is approx 10 thou' clearance at C19 shim.
I would appreciate thoughts on the cause of the drag and how it might be eliminated?
Hi sharkey ,
I now have that symptom.
Have you resolved it, and if so how.
If not, you may be interested in my journey to a current tentative diagnosis of clutch shaft runout.
Cheers, Peter
 

paw99

Well Known and Active Forum User
VOC Member
Just thinking how good it would be if we had NEW stuff,
My Gearbox mainshaft is slightly bent !, Too much Sprinting ?.
But it's OK.

Just thinking how good it would be if we had NEW stuff,
My Gearbox mainshaft is slightly bent !, Too much Sprinting ?.
But it's OK.
Hi Bill,
Thanks to all here for previous help.
My problem is as Sharky, I think caused by clutch pushrod pressure. I am interested in your bent mainshaft, as that is my current diagnosis. What runout do you have? I measured 6 thou on C20 ground surface, which I suspect is causing plate swash although I now have TTs excellent lifter. I also suspect this is causing shoes to wedge on and fail to centralise when clutch lifted. I hope to attach video where I put a bit of plate in place of C23 so can apply force while watching shoes. Only item left is plungers and springs.
I hope this works.
Cheers
Peter
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Morning Peter,
As long as you have 20 thou ish gap between the shoe linings and drum,
I think your trouble is not enough clearance on the bushes,
Maybe where they spin or end float ?.

I have never clocked the runout on my shaft, I can see it by eye,
So Don't want to know !,
I would like to rebuild the whole engine, But fear it would never get back together again,
So as long as it runs , Not too bad , I will leave well alone.
Cheers Bill.
 

greg brillus

Well Known and Active Forum User
VOC Member
If you back off the C20 nut a bit and the problem goes away, then as Bill suggests, the end float from the C 20 and the C 17 bush is not enough........It also pays to polish the running surface of the C20 nut so it can not grab in the C 17 bush at all.......When rebuilding these clutches, it is important to Not make all the tollerances too tight, as this will cause grab within the moving parts.......Good luck with it.
 
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