Depending on the actual materials and the geometry of the valve train, if you do the math it looks as though the temperature difference could have made a few tenths of a thou difference, which - based on the actual clearance tolerance range - is possibly more than insignificant.
http://www.engineeringtoolbox.com/li...ents-d_95.html
It's a pity you didn't ask about the Engine Ice too
Douf