These were the “conclusions” at the end of Marcels Article, all be it apx 20 years ago…..some fairly obvious and some debatable. All researched though and put out there with the best intentions.
CONCLUSIONS AND RECOMMENDATIONS
There are a few conclusions that can be drawn from this work:
1. Stay off the clutch except for gear changes. Sitting at traffic lights with the clutch disengaged for any length of time can lead to failure of the thrust washers and damage to the crankshaft. Revving the engine with the clutch disengaged is even worse.
2. Set up the clutch properly whenever any work is done on the engine and particularly if the friction faces have been resurfaced.
3. Use an appropriate spring for the application.
4. Ensure that the thrust washer clearances are at minimum size, ie 0.002". Use oversize thrust washers, available in +0.003" and +0.030", to get to minimum and have the crank thrust faces reground if necessary.
5. Use high quality engine oil (not synthetic) and change it often.
6. If the clutch engages lower and lower on the pedal stroke, renew all the clevis pins and repair wear on the master cylinder clevis and actuating arm ball end.
Optimising your clutch Flattening the diaphragm
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andy1071
- 998 Cooper
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Re: Optimising your clutch Flattening the diaphragm
Diaphragm clutches do not have a linear increase in clamping load, like coil springs
As the diaphragm goes through 'flat', the clamping load reduces, that's why the pedal pressure also reduces.. That's why you see the drop-off in pedal pressure.
-It's one of the advantages of using a diaphragm clutch compared to a coil-spring clutch: as you press the pedal down, the pedal-load reduces, so you have less fatigue while driving (less effort on your 'clutch leg').
When you press it 'far' through, the load goes up again -but, you are then over-stressing the diaphragm (so it can lose clamp-load, and/or break, like any spring...)
It's certainly a good idea to optimise the assembled clutch.. As standard, the clutch is designed to allow for tolerances, so a slight improvement can be made, but to get a significant improvement in clamp-load, you'll need a stronger spring...
As the diaphragm goes through 'flat', the clamping load reduces, that's why the pedal pressure also reduces.. That's why you see the drop-off in pedal pressure.
-It's one of the advantages of using a diaphragm clutch compared to a coil-spring clutch: as you press the pedal down, the pedal-load reduces, so you have less fatigue while driving (less effort on your 'clutch leg').
When you press it 'far' through, the load goes up again -but, you are then over-stressing the diaphragm (so it can lose clamp-load, and/or break, like any spring...)
It's certainly a good idea to optimise the assembled clutch.. As standard, the clutch is designed to allow for tolerances, so a slight improvement can be made, but to get a significant improvement in clamp-load, you'll need a stronger spring...