iv seen it spoken about (an awful lot!) on this forum - but i have no idea exactly what it "variates..."
I would love to know... even my "know it all" mechanic mate is a little confused... he seems to think it could be a number of things...
It changes the angle between the inlet cam driven cog and the cam itself, so that above a certain rpm the inlet cam timing is varied. It works on hydraulic pressure that is fed along the camshaft through a central drilling.
I'm a little confused now, what I understood from the official 156 service manual cd is that the variator actually varies the angle of the cam below 4000rpm to improve lowdown/midrange torque. The cam is already set up for high rpm performance