MadBill wrote:Wonder if maybe it depends on the percentage of the elastic limit to which the spring is being stressed? I can see a max-effort drag engine, maybe with 1"+ lift, having springs that would sag if parked for the off-season at max lift, but I think it's unlikely in an endurance or hot street engine which is not designed to run at the ragged edge of failure.
A shop I frequent builds engines of the former persuasion; I think I'll talk him into putting a big nut and bolt through such a spring (in good used condition), crushing it to 0.050" short of coil bind and parking it on the shelf, to be pulled out and load tested every three months for a year or more...
Checking a spring cold doesnt always tell the tale. Sometimes they fall off more when hot.
Backing off the valves is a good idea for more then springs as mentioned earlier in this thread. If you have an exhaust valve open with open headers its a short path to travel for moisture, most especially in a garage that is not heated and condensates from the temp going up and down.
People that want to spend all this time and money and thought on cylinder wall finish, but risk trashing it by not loosening rockers or pulling pushrods its just beyond me. Race gas doesnt leave a nice oily film to protect everything like pump gas does. It corrodes and oxidizes everything.