Jim,

I am unclear on one aspect of this "bending and/or lengthening" you guys have been discussing...

Doesn't the bi-metal expand, therby lengthening, albeit at different rates? Is that not what actually causes the "bending" as the two different metals expand, therby lengthen, at different amounts/rates for the same heat input?
(The following exerpt is from an elementary text on how a bimetal thermometer works...)

...A bimetallic strip is a piece of metal made by laminating two different types of metal together. The metals that make up the strip expand and contract when they are heated or cooled. Each type of metal has its own particular rate of expansion, and the two metals that make up the strip are chosen so that the rates of expansion and contraction are different...

This is not to say you or anyone here is wrong, or right... Just a matter of perspective, I guess. I would think there IS lengthening (expansion), and logically along the longitudinal axis, the amount of expansion would be greater than transverse. I agree the total amount of expansion will be minute for a small bi-metal strip such as employed on our clutches... I am sure the COE is published somewhere for different metals... I remember it from my early engineering classes...

The attached picture is from the MB manual for a 1988 560sl... Others, I'm sure, are gonna differ...

One other important thing to realize... When the clutch is disengaged, heat is going to be generated within the vcf due to friction in the fluid from the differenting operating speed of the components. This is why the vcf has "fins" on it... to radiate the heat generated. Of course, when the vcf clutch is engaged, all the internal parts of the vcf are moving at the same speed, thereby no extra heat generated.

Your thoughts...

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