Kind of a goofy question, but I have a book that shows clearances for Flathead tappets both warm and "cold". Got my Johnson wrenches Friday so I'm looking for time this weekend to sneak out to my garage and adjust lash. It's well below freezing right now and I work in an unheated garage - do I go further than the listed cold adjustment? Also, this is a new cam and lifters. About how long does it usually take before the valves have to be readjusted?