No, it is a lock setscrew whose twofold purpose is to help secure the ring nut to the flywheel boss, and, at the same time, to lock into position the little plate that sets the limit for rearwards axial movement of the engine shaft. (The clutch shaft is the outer one that connects the clutch plate to the transmission.) Despite the fact that this was never documented by Ferrari, it is obviously the case. The small plate that the bottom of the setscrew contacts is positioned fixedly by its fit into the hole in the flywheel boss on one side and the pressure of the setscrew on the other. The plate does not move once it is locked in place by the setscrew at the bottom of it's hole so there is no "adjustment" You could leave the setscrew loose or even out, and then the plate will bounce around in the hole and thus allow the engine shaft to move further rearwards, but then the contact area of the splines through which torque is transmitted from the crankshaft to the shaft would decrease. Although, according to fatbillybob, even with the setscrew left out, (and the plate left out too?), the engine shaft does not move so far that it's splines actually lose engagement with the crank, this was clearly not intended.
I believe it has been proven in this thread that the engine shaft does NOT contact the spacer disc under any condition, and therefore the setscrew does not and can not have any effect on the rearward movement of the shaft.
>>the setscrew does not and can not have any effect on the rearward movement of the shaft I am not so sure of that. I think the confusion arises when people claim that the setscrew provides "adjustment". No adjustment is needed or desirable. However, once the flywheel is installed, something must halt the rearward movement of the shaft before the triple seals are exposed, as they are if the flywheel is off the car and the shaft is moved rearward to its internal limit. I believe that it is the "spacer" disc that is locked into position by the setscrew, but not having the engineering drawings or the parts in front of me, I can only surmise. If this is the case, certainly there is no constant force between the disc and the shaft. The disc merely provides a stop to random rearward movement, just as the snap ring does for forward movement. I call the movement "random" as there are no axial forces acting upon the shaft other than those as a result of acceleration and braking of the vehicle. I don't like the word "spacer" applied to the disc as that implies that the disc somehow provides "spacing". It does not, it merely provides a fixed floor enabling the setscrew to apply axial load to the ring nut's, (Well really it is a ring bolt, but I am not going to try to fix that misnomer.), threaded attachment to the flywheel, thereby helping to secure that attachment at a lower torque than would otherwise be required, and it also provides, I believe, a stop to the rearward movement of the shaft, but no spacing.
You are correct Jeff. The pictures I posted several pages back clearly show what the potential is of the shaft, the spacer, and the grub screw are. While there is no documentation from Ferrari as to the operational claims, many of us ,like you, who have worked on these systems have proved that it really does not matter since the real aim of all this is to transfer power and shift gears. What we, as a group, are doing is working and I individually have race proven it. I think we have many datapoints and feel confident that what we are doing is ok.
I know this is an old thread, but does anyone know what the dimensions are for that spacer (142989) ? Did not even know it was missing till I took my flywheel off to service it.
