Now I haven't actually had a problem with one but it seems other people have... So what, exactly, IS the problem?
If it is one of just spinning on the shaft then lapping the wheel onto the shaft with grinding paste will probably fix it. Add to that installing a warmed-up flywheel onto a cooled crank shaft to give it some added 'bite' without having to rely on the nut pulling it harder into the taper.
Further to that using some Nord-lock washers would help if there is any indication of the nut backing off causing a loss of tension.
Machining some off the periphery (but not right where the crank sensor runs on the phonic wheel) is going to lower the polar moment of inertia and would help reduce the accelerative loads, especially at higher RPMs, so this would help reduce the torque demands on the 'lock' the taper provides.
The keyway is ONLY a locator and offers little or nothing to help with torque transmission capacity, so a bigger key would not help. Nor would two keys, or a pin etc.... If you don't believe this last statement test for yourself how much torque it takes to shear a key when the flywheel is not quite tight.... 3/5ths of sod-all is how much!
The taper, once tightened on correctly, takes up virtually all the torque loads.
If the mode of failure is one of the flywheel coming apart from itself, the Steel separating from the Aluminium, then this would not be helped by improving the 'lock' onto the crank. It would, however, be helped by lightening the periphery as mentioned above, as this is beyond the highly-stressed area within the flywheel and would lead to less stress being exerted on the composite parts' 'interface'.
If the failure appears to start at a stress raiser on the surface of the flywheel then some de-flashing and shot-peening would help significantly.
If the failure starts internally at the composite parts interface, and lightening and shot-peening is proven still not to be an adequate solution, then a complete new flywheel must be made.....
There is some room for a slightly larger diameter section for more support around the taper, in the middle of the stator if a little is machined from the ID of the alloy stator locator ring. This would make the flywheel less likely to stretch and lose tension on the taper, especially just at the key-groove where it is presently quite thin....
The phonic wheel is no problem at all to make, and different formats such as 36-1 or 60-2 would make it easy to use an alternative management system which would make 'live' dyno mapping more accessable than at present (emulating the 56 TSOP flash EPROM our MC1000s use is a nightmare and means 'scrapping' an ECU to comit it to 'development' duties ....)
The only thing that might prove less-easy would perhaps be the magnetic ring for the stator.... I have no idea how to go about doing that bit (yet). It seems there are manets placed N-S-N-S going around the inside but, beyond that I don't know....
So, COME ON, how do these things fail and does anyone have any busted ones for me to inspect? Or pictures even.....?
