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 Post subject: Another clutch puzzle
PostPosted: Fri Jul 03, 2009 9:12 am 
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848cc
848cc

Joined: Mon Mar 12, 2007 6:18 pm
Posts: 12
Location: Nelson NZ
Howdy folks, got the engine sorted, now the clutch...... Before I pulled it to bits the clutch was hard to push and disengaged close to the floor. It also slowed down the engine when the peddle was pushed. I discovered the clutch arm had been bent at the plunger end, so replaced it, didn't know about the diaphragm being flat at that stage and put it all back together, guess what, things got real bad. Engine stalled when clutch depressed. (groan, well can't write what really passed my lips)
Pulled it to bits again, thrust washers trashed, crankshaft thrust surfaces destroyed, 10 thou plus end float. Got that all fixed. So learned ones, what do you think would cause such a thing. I've been trawling through other threads looking for the answer, I did put the c washer back on the primary gear so that's not the problem. I came across a site somewhere that said don't take off the driving straps cos it will then be impossible to get the pressure plate concentric again with the flywheel, since the pressure plate is located by the driving straps. Nothing to do with my problem methinks, but is that true? This same site suggested ajax down the carb if the new rings don't bed in so it sounds a bit dodgy.
Couldn't be something really dumb like adjustment of the big nut at the bottom could it, did it by the book I thought. This is turning into a novel, thanks for any suggestions.


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PostPosted: Fri Jul 03, 2009 11:03 am 
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1275cc
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Joined: Mon Sep 19, 2005 4:57 pm
Posts: 3635
Location: Gulgong
I have found that the best way to adjust the clutch is to read the book and then give it to someone who doesn't understand what your trying to do and get them to read it also. Then ask them to explain how to adjust the clutch.

Somehow miraculously the clutch adjustment seems to make sense.

It does sound as though there is too much thrust on the crank shaft either by incorrect adjustment or too much hydraulic throw.

I presume you have the alignment of the pressure plate and the flywheel correct ???

Mike


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PostPosted: Fri Jul 03, 2009 12:07 pm 
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Joined: Fri Mar 19, 2004 6:19 pm
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Location: near Baulkham Hills, NSW
It could also be the clutch diaphragm is a heavy one and has not been set up properly so that the diaphragm is flat when assembled.
Check this setup procedure out when it's apart.
http://www.minimania.com/web/DisplayID/ ... ticleV.cfm

I find many clutches need the 3 backplate ears machined to get the height right, after the flywheel and backplate have been refaced a few times by everybody over the years.
Note that if the diaphragm is less than flat when assembled, the thrust on the crank increases as you push the clutch down.
It is designed to go past flat (ie slightly over centre) with clutch pedal pushed down, this reduces the thrust load.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Fri Jul 03, 2009 2:41 pm 
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848cc
848cc

Joined: Mon Mar 12, 2007 6:18 pm
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Location: Nelson NZ
Yes I think the diaphragm not being flat could be worth getting checked out, its a 1300 flywheel that"s had the big lump of metal turned off, wonder if some's been taken off somewhere else as well. That stuff about if the driving straps are removed the pressure plate gets reassembled off centre, do you think that's fair dinkum? Thanks, cheers.


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PostPosted: Fri Jul 03, 2009 3:58 pm 
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Location: near Baulkham Hills, NSW
Nope it's BS, provided the straps are in good condition with unworn, round holes, they are all the same (either an old SET or new ones), and the bolts are not grooved where the straps sit.

When Graham Russell balances a flywheel assembly he does the bare flywheel first, then he puts the straps and backplate on the flywheel and balances that, then bolts the diaphragm on. He checks all 3 positions it fits to get the least imbalance, and welds a spot on it if needed. Often it is OK without.

Finally he paintmarks all 3 components so you know how they go.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Fri Jul 03, 2009 4:37 pm 
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1098cc
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Joined: Sun Mar 29, 2009 10:46 pm
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Location: Outback Mini Man
Just tell me when you get it back together again that you havent got a damn clutch shudder, i still cant get rid of mine GRRRRRRR. :?

If your clutch isnt disengaging, which is why the motor would try to stall when you put your foot on the clutch, check the plunger, if its worn where the arm's ball goes into it, you will have issues.

The plunger shouldnt have any play around it, ie tilt sideways when the arm pushes it into towards the diaphram.

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Aussie Leyland, Aussie Factory, Aussie Mini S.


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PostPosted: Fri Jul 03, 2009 5:35 pm 
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848cc
848cc

Joined: Mon Mar 12, 2007 6:18 pm
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Location: Nelson NZ
Thanks for the feedback guys, know what to look for now. Didn't think that stuff with the pressure plate rang true. Might be a little while before I'm on the road again Drexxle, just spent the thick end of 3K on the engine, that's blown the budget. Maybe your shudder is an engine mount issue if the clutch has been set up correctly. Cheers.


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PostPosted: Fri Jul 03, 2009 5:52 pm 
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1098cc
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Joined: Sun Mar 29, 2009 10:46 pm
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Location: Outback Mini Man
Ive been going through this issue for some weeks now, replaced everything from master cylinder through to the clutch kit.

When i hit the pedal, its all good, BUT

When the arm pushes the plunger with the bearing into to meet the diaphram face, the bearing is meeting the face off centre, and its ALOT of centre, this is whats causing the shudder, which then spreads the oil seal and lets a little oil through. The oil isnt enough to cause the shudder im getting.

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Aussie Leyland, Aussie Factory, Aussie Mini S.


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